Possible hycean world found by Webb telescope

View larger. | This is an artist’s concept of a hycean world. These exoplanets are thought to have deep hydrogen atmospheres and global water oceans on their surfaces. Image via Pablo Carlos Budassi/ Wikimedia Commons (CC BY SA 4.0).

Meet TOI-270 d, a possible hycean world

• Recent research suggests that exoplanet TOI-270 d is likely a hycean planet – a world with a global ocean beneath a thick hydrogen atmosphere – located 70 light-years from Earth.
• But another research team thinks the planet is too hot to be considered hycean. Temperatures on its sunlit side might be as high as 7,200 degrees Fahrenheit (4,000 degrees Celsius).
• Both research groups also identified the presence of carbon disulfide, a compound potentially linked to biological activity on Earth, but also produced through alternative processes in hydrogen-rich atmospheres.

Hycean worlds are planets with global oceans beneath a thick hydrogen atmosphere. Scientists say they may be common in our galaxy. Researchers at the University of Cambridge in the U.K. said that the exoplanet TOI-270 d is likely a hycean planet. Their study is based on data from NASA’s James Webb Space Telescope. The Guardian newspaper first reported the tantalizing discovery on March 8, 2024. Another international research team, led by the University of Montreal in Canada, however, isn’t convinced yet that TOI-270 d really is an ocean world, saying it is likely too hot.

The U.K. researchers published their peer-reviewed paper in the journal Astronomy & Astrophysics on March 7, 2024. The Canadian and international research team submitted their paper to arXiv on March 5, 2024.

Is this sub-Neptune a hot ocean planet?

TOI-270 d is about twice the diameter of Earth and is 70 light-years away. Astronomers classify it as a sub-Neptune.

Nikku Madhusudhan at the University of Cambridge co-led the analysis of data about TOI-270 d. He explained that the ocean, if actually there, is likely quite hot:

The ocean could be upwards of 212 degrees Fahrenheit (100 degrees Celsius) or more. At high atmospheric pressure, an ocean this hot could still be liquid, but it’s not clear if it would be habitable.

The data from Webb shows that the atmosphere of the planet contains water vapor, methane and carbon dioxide. That is consistent with an atmosphere that is predominantly hydrogen, with a global water ocean beneath it. There is also a lack of ammonia, which also supports the hycean ocean world scenario. That’s because chemistry says it should occur naturally in a hydrogen atmosphere. But it would be depleted if there was an ocean because ammonia is highly soluble in water. Madhusudhan said:

One interpretation is that this is a so-called “hycean” world, with a water ocean under a hydrogen-rich atmosphere.

Please help EarthSky continue its mission to bring you night sky information and science news! Will you join our annual crowd-funding campaign with a donation today?

Too hot for an ocean?

The results are tantalizing, but not conclusive yet. With this in mind, another research team, led by Björn Benneke at the University of Montreal in Quebec, Canada, said that the planet would probably be hot for liquid water. They found the same gases in the atmosphere as the other team, but calculate the atmosphere could be much hotter, as much as 7,200 degrees Fahrenheit (4,000 degrees Celsius).

Benneke told The Guardian:

The temperature in our view is too warm for water to be liquid.

He and his team also think that there is too much water vapor in the atmosphere. They suggest that this wouldn’t leave enough water to form an ocean. Instead, the water might be in a supercritical state, called a supercritical fluid (SFC). A supercritical fluid is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. This makes it more difficult to distinguish between a liquid and gas. Benneke said that:

… It’s almost like a thick, hot fluid.

In this scenario, instead of being a hycean ocean world, the planet would have a rocky surface with no ocean. The atmosphere would be dense with hydrogen and water vapor.

An ocean world unlike Earth

If TOI-270 d does have an ocean, conditions wouldn’t be exactly like those on Earth. This is because the planet is tidally locked to its star. Much as one side of the moon always faces Earth, one side of TOI-270 d always faces its star. This means that one side is always in sunlight while the other is in perpetual night. As a result, temperatures on the sunlight side are always hotter. As Madhusudhan said in The Guardian:

The ocean would be extremely hot on the day side. The night side could potentially host habitable conditions.

Also, the hydrogen atmosphere would have crushing pressure, tens or hundreds of times that of Earth’s atmosphere. Reminiscent of Venus, but even more so. The ocean itself would also be different to those on Earth, perhaps up to hundreds of times deeper than Earth’s oceans. The seabed, instead of rock, would likely be high-pressure ice, also known as Ice VI. Even deeper down, a rocky core.

View larger. | Artist’s illustration of the James Webb Space Telescope. Webb discovered the potential new ocean exoplanet. Image via NASA.

Carbon disulfide

Along with the other atmospheric gases, both research teams also discovered something else: carbon disulfide. On Earth, it can be related to biological activity. But as the researchers point out, other processes can produce it as well, especially in hydrogen atmospheres. So it’s interesting, but not proof of life. As Madhusudhan explained:

We can’t tie [carbon disulfide] to biological activity. In a hydrogen-rich atmosphere, it is relatively easy to make it. But if we’re able to measure the unique molecule it’s promising that we should be able to measure habitable planets in the future.

We need to be extremely careful about how we communicate findings on this kind of object. It’s easy for the public to jump on to the idea that we’re finding life already.

The finding is similar to that of K2-18 b, another sub-Neptune with a deep hydrogen atmosphere. Last year, scientists announced a tentative detection of dimethyl sulfide (DMS) in its atmosphere.

On Earth, the molecule is only known to be produced by life, or in a laboratory. But the detection was weak, and scientists are still debating whether it actually exists on K2-18 b or not.

Bottom line: NASA’s Webb Space Telescope has discovered a possible hycean world, with a deep hydrogen atmosphere and a global water ocean. Or is this world too hot?

Source: Possible hycean conditions in the sub-Neptune TOI-270 d

Source: JWST Reveals CH4, CO2, and H2O in a Metal-rich Miscible Atmosphere on a Two-Earth-Radius Exoplanet

Via The Guardian

Read more: Hycean planets might be habitable ocean worlds

Read more: Is this nearby exoplanet a water world? Or a mini-Neptune?

The post Possible hycean world found by Webb telescope first appeared on EarthSky.

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View larger. | This is an artist’s concept of a hycean world. These exoplanets are thought to have deep hydrogen atmospheres and global water oceans on their surfaces. Image via Pablo Carlos Budassi/ Wikimedia Commons (CC BY SA 4.0).

Meet TOI-270 d, a possible hycean world

• Recent research suggests that exoplanet TOI-270 d is likely a hycean planet – a world with a global ocean beneath a thick hydrogen atmosphere – located 70 light-years from Earth.
• But another research team thinks the planet is too hot to be considered hycean. Temperatures on its sunlit side might be as high as 7,200 degrees Fahrenheit (4,000 degrees Celsius).
• Both research groups also identified the presence of carbon disulfide, a compound potentially linked to biological activity on Earth, but also produced through alternative processes in hydrogen-rich atmospheres.

Hycean worlds are planets with global oceans beneath a thick hydrogen atmosphere. Scientists say they may be common in our galaxy. Researchers at the University of Cambridge in the U.K. said that the exoplanet TOI-270 d is likely a hycean planet. Their study is based on data from NASA’s James Webb Space Telescope. The Guardian newspaper first reported the tantalizing discovery on March 8, 2024. Another international research team, led by the University of Montreal in Canada, however, isn’t convinced yet that TOI-270 d really is an ocean world, saying it is likely too hot.

The U.K. researchers published their peer-reviewed paper in the journal Astronomy & Astrophysics on March 7, 2024. The Canadian and international research team submitted their paper to arXiv on March 5, 2024.

Is this sub-Neptune a hot ocean planet?

TOI-270 d is about twice the diameter of Earth and is 70 light-years away. Astronomers classify it as a sub-Neptune.

Nikku Madhusudhan at the University of Cambridge co-led the analysis of data about TOI-270 d. He explained that the ocean, if actually there, is likely quite hot:

The ocean could be upwards of 212 degrees Fahrenheit (100 degrees Celsius) or more. At high atmospheric pressure, an ocean this hot could still be liquid, but it’s not clear if it would be habitable.

The data from Webb shows that the atmosphere of the planet contains water vapor, methane and carbon dioxide. That is consistent with an atmosphere that is predominantly hydrogen, with a global water ocean beneath it. There is also a lack of ammonia, which also supports the hycean ocean world scenario. That’s because chemistry says it should occur naturally in a hydrogen atmosphere. But it would be depleted if there was an ocean because ammonia is highly soluble in water. Madhusudhan said:

One interpretation is that this is a so-called “hycean” world, with a water ocean under a hydrogen-rich atmosphere.

Please help EarthSky continue its mission to bring you night sky information and science news! Will you join our annual crowd-funding campaign with a donation today?

Too hot for an ocean?

The results are tantalizing, but not conclusive yet. With this in mind, another research team, led by Björn Benneke at the University of Montreal in Quebec, Canada, said that the planet would probably be hot for liquid water. They found the same gases in the atmosphere as the other team, but calculate the atmosphere could be much hotter, as much as 7,200 degrees Fahrenheit (4,000 degrees Celsius).

Benneke told The Guardian:

The temperature in our view is too warm for water to be liquid.

He and his team also think that there is too much water vapor in the atmosphere. They suggest that this wouldn’t leave enough water to form an ocean. Instead, the water might be in a supercritical state, called a supercritical fluid (SFC). A supercritical fluid is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. This makes it more difficult to distinguish between a liquid and gas. Benneke said that:

… It’s almost like a thick, hot fluid.

In this scenario, instead of being a hycean ocean world, the planet would have a rocky surface with no ocean. The atmosphere would be dense with hydrogen and water vapor.

An ocean world unlike Earth

If TOI-270 d does have an ocean, conditions wouldn’t be exactly like those on Earth. This is because the planet is tidally locked to its star. Much as one side of the moon always faces Earth, one side of TOI-270 d always faces its star. This means that one side is always in sunlight while the other is in perpetual night. As a result, temperatures on the sunlight side are always hotter. As Madhusudhan said in The Guardian:

The ocean would be extremely hot on the day side. The night side could potentially host habitable conditions.

Also, the hydrogen atmosphere would have crushing pressure, tens or hundreds of times that of Earth’s atmosphere. Reminiscent of Venus, but even more so. The ocean itself would also be different to those on Earth, perhaps up to hundreds of times deeper than Earth’s oceans. The seabed, instead of rock, would likely be high-pressure ice, also known as Ice VI. Even deeper down, a rocky core.

View larger. | Artist’s illustration of the James Webb Space Telescope. Webb discovered the potential new ocean exoplanet. Image via NASA.

Carbon disulfide

Along with the other atmospheric gases, both research teams also discovered something else: carbon disulfide. On Earth, it can be related to biological activity. But as the researchers point out, other processes can produce it as well, especially in hydrogen atmospheres. So it’s interesting, but not proof of life. As Madhusudhan explained:

We can’t tie [carbon disulfide] to biological activity. In a hydrogen-rich atmosphere, it is relatively easy to make it. But if we’re able to measure the unique molecule it’s promising that we should be able to measure habitable planets in the future.

We need to be extremely careful about how we communicate findings on this kind of object. It’s easy for the public to jump on to the idea that we’re finding life already.

The finding is similar to that of K2-18 b, another sub-Neptune with a deep hydrogen atmosphere. Last year, scientists announced a tentative detection of dimethyl sulfide (DMS) in its atmosphere.

On Earth, the molecule is only known to be produced by life, or in a laboratory. But the detection was weak, and scientists are still debating whether it actually exists on K2-18 b or not.

Bottom line: NASA’s Webb Space Telescope has discovered a possible hycean world, with a deep hydrogen atmosphere and a global water ocean. Or is this world too hot?

Source: Possible hycean conditions in the sub-Neptune TOI-270 d

Source: JWST Reveals CH4, CO2, and H2O in a Metal-rich Miscible Atmosphere on a Two-Earth-Radius Exoplanet

Via The Guardian

Read more: Hycean planets might be habitable ocean worlds

Read more: Is this nearby exoplanet a water world? Or a mini-Neptune?

The post Possible hycean world found by Webb telescope first appeared on EarthSky.

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Jupiter’s stormy weather on display in new Hubble images

View larger. | NASA’s Hubble Space Telescope captured these views (opposite hemispheres) of Jupiter’s stormy weather. Image via NASA/ ESA/ STScI/ Amy Simon (NASA-GSFC).

• New images of Jupiter from the Hubble Space Telescope the whole of the gas giant as it rotates. These images provide insights into Jupiter’s stormy weather patterns.
• Jupiter’s weather is intense, due the fact that its atmosphere is tens of thousands of miles deep with no solid surface beneath. The thick jovian atmosphere hosts big and little storms, including cyclones and anticyclones, some larger than Earth.
• The new images show Jupiter’s famous Great Red Spot, plus what scientists call Red Spot Jr., a smaller anticyclone that brushes past the Great Red Spot about every two years.

Hubble watches Jupiter’s stormy weather

Jupiter – biggest planet in our solar system – is a dynamic world! Its deep atmosphere is constantly churning with cyclones, wind shear and other violent storms. The Great Red Spot is the largest and most well-known of Jupiter’s storms. And Jupiter is also famous for its distinct red-and-tan cloud bands, which you can see even in small telescopes. On March 14, 2024, NASA released new images of the gas giant planet, taken by the Hubble Space Telescope. Hubble has been busy tracking Jupiter’s stormy weather. The new images, taken on January 5-6, 2024, show both hemispheres of this mighty world, as it spins on its axis once about every 10 hours.

Hubble took the images as part of the Outer Planet Atmospheres Legacy program (OPAL). In OPAL, Hubble monitors all the giant planets – Jupiter, Saturn, Uranus and Neptune – and their weather systems every year. Scientists call it Hubble’s Grand Tour of the Outer Solar System. Unlike the smaller rocky planets (with the exception of Venus), these gas and ice giants are completely blanketed by deep, turbulent atmospheres. Ferocious winds churn up the clouds and hazes. Hence, weather patterns are always changing, and scientists want to keep track of the changes.

On Jupiter in particular, storms of various sizes – some much larger than Earth – churn in the atmosphere. These include both cyclones and anticyclones, rotating in opposite directions to each other. This shows that there are high-pressure and low-pressure weather systems that sometimes interact with each other.

Help spread the wonders of astronomy! Please donate now to EarthSky.org and ensure that people around the world can learn about the night sky and our universe.

The new images in detail

Indeed, there is much to see in the new images. In the left image above, you can easily see Jupiter’s Great Red Spot, even though it has been gradually shrinking in size. To its lower right is Red Spot Jr., a much smaller anticyclone. It formed when two other storms merged together in 1998 and 2000. Its color has varied over the years as well. It was distinctly red in 2006, then became paler. Now, in 2024, it looks redder again.

The Great Red Spot and Red Spot Jr. don’t collide, but they do pass each other about every two years.

Bouncing and repelling storms

And there’s more! The right image, above, shows the opposite hemisphere of Jupiter as it rotated into view. Another cyclone and anticyclone appear close together, both deeply red in color. The cyclone features an upwelling of clouds on the edges. Other clouds are descending in the middle of the cyclone. This causes a clearing in the otherwise obscuring atmospheric haze. Scientists say these storms should bounce past and repel each other, because they’re rotating in opposite directions. OPAL project lead Amy Simon at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said:

The many large storms and small white clouds are a hallmark of a lot of activity going on in Jupiter’s atmosphere right now.

View larger. | 12-panel sequence of images from Hubble showing Jupiter from January 5-6, 2024. Image via NASA/ ESA/ Joseph DePasquale (STScI).

This video shows a full rotation of Jupiter for OPAL 2024. Hubble snapshots of the planet, taken January 5-6, 2024, have been photo-mapped onto a sphere, and the model is then rotated in animation. Video via NASA/ ESA/ Amy Simon (NASA-GSFC)/ Joseph DePasquale (STScI).

In addition, you can see Jupiter’s volcanic moon Io to the left of the planet in the right image. In fact, Io is the most volcanically active known body in the solar system, even more than Earth.

Deep, turbulent atmosphere

Jupiter’s atmosphere is tens of thousands of miles deep, with no solid surface below. And, along with the other storms, there are also clouds of ammonia ice crystals. By comparison, they are only about 30 miles (48 km) thick. These clouds also give Jupiter its banded appearance. In the bands, air is flowing up to almost 350 miles per hour (560 km/h) in different directions and at various latitudes.

Last January, the ESPRESSO planet-hunter also turned its gaze to Jupiter, capturing some stunning views. ESPRESSO is the spectrograph on the Very Large Telescope (VLT) in Chile, designed primarily to look for exoplanets.

And, speaking of Jupiter, have you seen these photos of the moon and Jupiter together? EarthSky readers took these images on March 13 and 14, 2024.

Bottom line: NASA’s Hubble Space Telescope has sent back new images of Jupiter’s stormy weather. Hubble monitors the atmospheres of all the giant planets every year.

Via Hubblesite/NASA

Read more: The ESPRESSO planet-hunter looks at Jupiter

Read more: Jupiter’s moon Io as you’ve never seen it

The post Jupiter’s stormy weather on display in new Hubble images first appeared on EarthSky.

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View larger. | NASA’s Hubble Space Telescope captured these views (opposite hemispheres) of Jupiter’s stormy weather. Image via NASA/ ESA/ STScI/ Amy Simon (NASA-GSFC).

• New images of Jupiter from the Hubble Space Telescope the whole of the gas giant as it rotates. These images provide insights into Jupiter’s stormy weather patterns.
• Jupiter’s weather is intense, due the fact that its atmosphere is tens of thousands of miles deep with no solid surface beneath. The thick jovian atmosphere hosts big and little storms, including cyclones and anticyclones, some larger than Earth.
• The new images show Jupiter’s famous Great Red Spot, plus what scientists call Red Spot Jr., a smaller anticyclone that brushes past the Great Red Spot about every two years.

Hubble watches Jupiter’s stormy weather

Jupiter – biggest planet in our solar system – is a dynamic world! Its deep atmosphere is constantly churning with cyclones, wind shear and other violent storms. The Great Red Spot is the largest and most well-known of Jupiter’s storms. And Jupiter is also famous for its distinct red-and-tan cloud bands, which you can see even in small telescopes. On March 14, 2024, NASA released new images of the gas giant planet, taken by the Hubble Space Telescope. Hubble has been busy tracking Jupiter’s stormy weather. The new images, taken on January 5-6, 2024, show both hemispheres of this mighty world, as it spins on its axis once about every 10 hours.

Hubble took the images as part of the Outer Planet Atmospheres Legacy program (OPAL). In OPAL, Hubble monitors all the giant planets – Jupiter, Saturn, Uranus and Neptune – and their weather systems every year. Scientists call it Hubble’s Grand Tour of the Outer Solar System. Unlike the smaller rocky planets (with the exception of Venus), these gas and ice giants are completely blanketed by deep, turbulent atmospheres. Ferocious winds churn up the clouds and hazes. Hence, weather patterns are always changing, and scientists want to keep track of the changes.

On Jupiter in particular, storms of various sizes – some much larger than Earth – churn in the atmosphere. These include both cyclones and anticyclones, rotating in opposite directions to each other. This shows that there are high-pressure and low-pressure weather systems that sometimes interact with each other.

Help spread the wonders of astronomy! Please donate now to EarthSky.org and ensure that people around the world can learn about the night sky and our universe.

The new images in detail

Indeed, there is much to see in the new images. In the left image above, you can easily see Jupiter’s Great Red Spot, even though it has been gradually shrinking in size. To its lower right is Red Spot Jr., a much smaller anticyclone. It formed when two other storms merged together in 1998 and 2000. Its color has varied over the years as well. It was distinctly red in 2006, then became paler. Now, in 2024, it looks redder again.

The Great Red Spot and Red Spot Jr. don’t collide, but they do pass each other about every two years.

Bouncing and repelling storms

And there’s more! The right image, above, shows the opposite hemisphere of Jupiter as it rotated into view. Another cyclone and anticyclone appear close together, both deeply red in color. The cyclone features an upwelling of clouds on the edges. Other clouds are descending in the middle of the cyclone. This causes a clearing in the otherwise obscuring atmospheric haze. Scientists say these storms should bounce past and repel each other, because they’re rotating in opposite directions. OPAL project lead Amy Simon at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said:

The many large storms and small white clouds are a hallmark of a lot of activity going on in Jupiter’s atmosphere right now.

View larger. | 12-panel sequence of images from Hubble showing Jupiter from January 5-6, 2024. Image via NASA/ ESA/ Joseph DePasquale (STScI).

This video shows a full rotation of Jupiter for OPAL 2024. Hubble snapshots of the planet, taken January 5-6, 2024, have been photo-mapped onto a sphere, and the model is then rotated in animation. Video via NASA/ ESA/ Amy Simon (NASA-GSFC)/ Joseph DePasquale (STScI).

In addition, you can see Jupiter’s volcanic moon Io to the left of the planet in the right image. In fact, Io is the most volcanically active known body in the solar system, even more than Earth.

Deep, turbulent atmosphere

Jupiter’s atmosphere is tens of thousands of miles deep, with no solid surface below. And, along with the other storms, there are also clouds of ammonia ice crystals. By comparison, they are only about 30 miles (48 km) thick. These clouds also give Jupiter its banded appearance. In the bands, air is flowing up to almost 350 miles per hour (560 km/h) in different directions and at various latitudes.

Last January, the ESPRESSO planet-hunter also turned its gaze to Jupiter, capturing some stunning views. ESPRESSO is the spectrograph on the Very Large Telescope (VLT) in Chile, designed primarily to look for exoplanets.

And, speaking of Jupiter, have you seen these photos of the moon and Jupiter together? EarthSky readers took these images on March 13 and 14, 2024.

Bottom line: NASA’s Hubble Space Telescope has sent back new images of Jupiter’s stormy weather. Hubble monitors the atmospheres of all the giant planets every year.

Via Hubblesite/NASA

Read more: The ESPRESSO planet-hunter looks at Jupiter

Read more: Jupiter’s moon Io as you’ve never seen it

The post Jupiter’s stormy weather on display in new Hubble images first appeared on EarthSky.

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Equinox sun rises due east and sets due west

The equinox is on March 19-20, 2024. At the equinoxes, the ecliptic and the celestial equator intersect. See the intersection point on this imaginary great circle, representing the dome of Earth’s sky? The celestial equator is directly above Earth’s equator. The ecliptic is the sun’s apparent path across our sky. And the celestial equator intersects your horizon at points due east and due west. That’s why – at every equinox, no matter where you are on the globe – the sun, on the celestial equator, rises due east and sets due west. Read more about the equinox sun below. Image via NASA.

The March equinox happens at 3:06 UTC on March 20, 2024 (10:06 p.m. CDT on March 19.)

The equinox sun rises due east and sets due west

It’s not true that day and night are precisely equal on the day of an equinox. But here’s an equinox fact that is true. The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Join us in making sure everyone has access to the wonders of astronomy. Donate now!

Our seasons result from the Earth’s rotational axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

Now think about what is an equinox. It’s an event that happens on the imaginary dome of Earth’s sky. And it marks that special moment when the sun crosses the celestial equator going from one hemisphere to the other. Of course, it also represents a point in Earth’s orbit.

The celestial equator

The celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern hemispheres. Additionally, the celestial equator wraps the sky directly above Earth’s equator. Following the September equinox, the sun crosses the celestial equator to enter the sky’s Southern Hemisphere.

All these components are imaginary, yet what happens at every equinox is very real. In fact, it’s as real as the sun’s passage across the sky each day and as real as the change of seasons.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

The history of the seasons

Our ancestors may not have understood the equinoxes and solstices as events that occur during Earth’s yearly orbit around the sun. But if they were observant – and some were very observant indeed – they surely marked the day of the equinox as being midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.

Now we can say with reasonably high accuracy that the sun rises due east and sets due west on the day of the equinox. And this is the same for everyone around the globe.

If you are seeking more precision for the sunrise/sunset direction in your part of the world, check out the altitude/azimuth for the sun via timeanddate.com.

EarthSky’s Raúl Cortés caught the March equinox sun at sunrise in 2021. Thanks, Raúl! See more of Raúl’s photos here.

Bottom line: The 2024 March equinox occurs on March 20 at 3:06 UTC (10:06 p.m. CDT on March 19). At the equinox, the sun rises and sets due east and due west.

March equinox 2024: Everything you need to know

Hamal: Ancient equinox star

The post Equinox sun rises due east and sets due west first appeared on EarthSky.

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The equinox is on March 19-20, 2024. At the equinoxes, the ecliptic and the celestial equator intersect. See the intersection point on this imaginary great circle, representing the dome of Earth’s sky? The celestial equator is directly above Earth’s equator. The ecliptic is the sun’s apparent path across our sky. And the celestial equator intersects your horizon at points due east and due west. That’s why – at every equinox, no matter where you are on the globe – the sun, on the celestial equator, rises due east and sets due west. Read more about the equinox sun below. Image via NASA.

The March equinox happens at 3:06 UTC on March 20, 2024 (10:06 p.m. CDT on March 19.)

The equinox sun rises due east and sets due west

It’s not true that day and night are precisely equal on the day of an equinox. But here’s an equinox fact that is true. The sun rises due east and sets due west at the equinox. It might seem counterintuitive. But it’s true no matter where you live on Earth (except at the North and South Poles). Here’s how to visualize it.

To understand the nearly due-east and due-west rising and setting of an equinox sun, you have to think of the reality of Earth in space. First think about why the sun’s path across our sky shifts from season to season. That’s because our world is tilted on its axis with respect to its orbit around the sun.

Join us in making sure everyone has access to the wonders of astronomy. Donate now!

Our seasons result from the Earth’s rotational axis tilting 23.5 degrees out of the perpendicular to the ecliptic, or Earth’s orbital plane. Image via National Weather Service/ weather.gov.

Now think about what is an equinox. It’s an event that happens on the imaginary dome of Earth’s sky. And it marks that special moment when the sun crosses the celestial equator going from one hemisphere to the other. Of course, it also represents a point in Earth’s orbit.

The celestial equator

The celestial equator is a great circle dividing the imaginary celestial sphere into its northern and southern hemispheres. Additionally, the celestial equator wraps the sky directly above Earth’s equator. Following the September equinox, the sun crosses the celestial equator to enter the sky’s Southern Hemisphere.

All these components are imaginary, yet what happens at every equinox is very real. In fact, it’s as real as the sun’s passage across the sky each day and as real as the change of seasons.

It’s the same all over the globe

So no matter where you are on Earth (except for the North and South Poles), you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator, the imaginary great circle above the true equator of Earth.

And that’s why the sun rises close to due east and sets close to due west, for all of us, at the equinox. The equinox sun is on the celestial equator. Which means, no matter where you are on Earth, the celestial equator intersects your horizon at due east and due west.

This fact makes the day of an equinox a good day for finding east and west from your yard or favorite site for watching the sky. Just go outside around sunset or sunrise and notice the location of the sun on the horizon with respect to familiar landmarks.

If you do this, you’ll be able to use those landmarks to find those cardinal directions in the weeks and months ahead. Plus, you’ll know those directions long after Earth has moved on in its orbit around the sun.

The history of the seasons

Our ancestors may not have understood the equinoxes and solstices as events that occur during Earth’s yearly orbit around the sun. But if they were observant – and some were very observant indeed – they surely marked the day of the equinox as being midway between the sun’s lowest path across the sky in winter and highest path across the sky in summer.

Now we can say with reasonably high accuracy that the sun rises due east and sets due west on the day of the equinox. And this is the same for everyone around the globe.

If you are seeking more precision for the sunrise/sunset direction in your part of the world, check out the altitude/azimuth for the sun via timeanddate.com.

EarthSky’s Raúl Cortés caught the March equinox sun at sunrise in 2021. Thanks, Raúl! See more of Raúl’s photos here.

Bottom line: The 2024 March equinox occurs on March 20 at 3:06 UTC (10:06 p.m. CDT on March 19). At the equinox, the sun rises and sets due east and due west.

March equinox 2024: Everything you need to know

Hamal: Ancient equinox star

The post Equinox sun rises due east and sets due west first appeared on EarthSky.

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March equinox 2024: All you need to know

Happy March equinox, y’all!

What is it? The March equinox – aka the vernal equinox – marks the sun’s crossing above Earth’s equator, moving from south to north. Earth’s tilt on its axis is what causes this northward shift of the sun’s path across our sky at this time of year. Earth’s tilt is now bringing spring and summer to the Northern Hemisphere. At the same time, the March equinox marks the beginning of autumn – and a shift toward winter – in the Southern Hemisphere.
When is it? The sun will cross the celestial equator – a line directly above Earth’s equator – at 3:06 UTC on March 20, 2024 (10:06 p.m. CDT on March 19).

No matter where you are on Earth, the equinox brings us a number of seasonal effects, noticeable to nature lovers around the globe.

Join us in making sure everyone has access to the wonders of astronomy. Donate now!

Equal day and night on the equinox?

At the equinox, Earth’s two hemispheres are receiving the sun’s rays equally. Night and day are often said to be equal in length. In fact, the word equinox comes from the Latin aequus (equal) and nox (night). For our ancestors, whose timekeeping was less precise than ours, day and night likely did seem equal. But today we know it’s not exactly so.

Read more: Are day and night equal at the equinox?

Fastest sunsets at the equinoxes

The fastest sunsets and sunrises of the year happen at the equinoxes. We’re talking here about the length of time it takes for the whole sun to sink below the horizon.

Read more: Fastest sunsets happen near equinoxes

View at EarthSky Community Photos. | Iaroslav Kourzenkov of Halifax, Nova Scotia, Canada, captured this image of the sunset on the equinox on March 20, 2023. Thank you, Iaroslav!

Sun rises due east and sets due west?

Here’s another equinox phenomenon. You might hear that the sun rises due east and sets due west at the equinox. Is that true? Yes it is. In fact, it’s the case no matter where you live on Earth, with the exception of the North and South Poles. At the equinoxes, the sun appears overhead at noon as seen from Earth’s equator, as the illustration below shows. This illustration shows the sun’s location on the celestial equator, every hour, on the day of the equinox.

No matter where you are on Earth – except at the Earth’s North and South Poles – you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator: the imaginary line above the true equator of the Earth.

The sun is on the celestial equator, and the celestial equator intersects all of our horizons at points due east and due west. Voila! The sun rises due east and sets due west.

Read more: Sun rises due east and sets due west

The day arc of the sun, every hour, at the equinox, as seen on the (imaginary) celestial sphere surrounding Earth. At the equinox, the sun is directly above Earth’s equator. Image via Tau’olunga/ Wikimedia Commons (CC BY-SA 2.5).

More March equinox effects

And there are also plenty more effects in play around the time of the March equinox that all of us can notice. In the Northern Hemisphere, the March equinox brings earlier sunrises, later sunsets and sprouting plants.

Meanwhile, you’ll find the opposite season – later sunrises, earlier sunsets, chillier winds, dry and falling leaves – south of the equator.

The equinoxes and solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. You can think of an equinox as happening on the imaginary dome of our sky, or as an event that happens in Earth’s orbit around the sun.

The Earth-centered view

If you think of it from an Earth-centered perspective, you can think of the celestial equator as a great circle dividing Earth’s sky into its Northern and Southern Hemispheres. The celestial equator is an imaginary line wrapping the sky directly above Earth’s equator. At the equinox, the sun crosses the celestial equator to enter the sky’s Northern Hemisphere.

This illustration shows the day arc of the equinox sun, as seen from Earth’s equator. Also showing are twilight suns (in red) down to -18 degrees altitude. Note that the sun is at its highest point at noon. And see that the tree’s shadow at noon is cast straight down. That is – as seen from the equator on the day of an equinox – a tree stands in the center of its own shadow. Image via Tau’olunga/ Wikimedia Commons (CC BY-SA 2.5).

The Earth-in-space view

If you think of it from an Earth-in-space perspective, you have to think of Earth in orbit around the sun. And we all know Earth doesn’t orbit upright but is instead tilted on its axis by 23 1/2 degrees. So Earth’s Northern and Southern Hemispheres trade places in receiving the sun’s light and warmth most directly. We have an equinox twice a year – spring and fall – when the tilt of the Earth’s axis and Earth’s orbit around the sun combine in such a way that the axis is inclined neither away from nor toward the sun.

Here are satellite views of Earth on the solstices and equinoxes, via NASA Earth Observatory.

Things change fast around the equinoxes

Since Earth never stops moving around the sun, the position of the sunrise and sunset – and the days of approximately equal sunlight and night – will change quickly.

The video below was the Astronomy Picture of the Day for March 19, 2014. APOD explained:

At an equinox, the Earth’s terminator – the dividing line between day and night – becomes vertical and connects the North and South Poles. The time-lapse video [below] demonstrates this by displaying an entire year on planet Earth in 12 seconds. From geosynchronous orbit, the Meteosat satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical.

As the Earth revolved around the sun, the terminator was seen to tilt in a way that provides less daily sunlight to the Northern Hemisphere, causing winter in the north. As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in the Southern Hemisphere and summer in the north. The captured year ends again with the September equinox, concluding another of billions of trips the Earth has taken – and will take – around the sun.

The equinox is an event that takes place in Earth’s orbit around the sun. Image via National Weather Service/ weather.gov.

Where are signs of the March equinox in nature?

Everywhere! Forget about the weather for a moment, and think only about daylight. In terms of daylight, the knowledge that spring is here – and summer is coming – permeates all of nature on the northern half of Earth’s globe.

Notice the arc of the sun across the sky each day. You’ll find that it’s shifting toward the north. Responding to the change in daylight, birds and butterflies are migrating back northward, too, along with the path of the sun.

The longer days do bring with them warmer weather. People are leaving their winter coats at home. Trees are budding, and plants are beginning a new cycle of growth. In many places, spring flowers are beginning to bloom.

Meanwhile, in the Southern Hemisphere, the days are getting shorter and nights longer. A chill is in the air. Fall is here, and winter is coming!

Bottom line: The 2024 March equinox falls March 20 at 3:06 UTC. So many parts of the world will see the equinox arrive on March 19. What is an equinox? How do we experience it on Earth? All you need to know, here.

The post March equinox 2024: All you need to know first appeared on EarthSky.

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Happy March equinox, y’all!

What is it? The March equinox – aka the vernal equinox – marks the sun’s crossing above Earth’s equator, moving from south to north. Earth’s tilt on its axis is what causes this northward shift of the sun’s path across our sky at this time of year. Earth’s tilt is now bringing spring and summer to the Northern Hemisphere. At the same time, the March equinox marks the beginning of autumn – and a shift toward winter – in the Southern Hemisphere.
When is it? The sun will cross the celestial equator – a line directly above Earth’s equator – at 3:06 UTC on March 20, 2024 (10:06 p.m. CDT on March 19).

No matter where you are on Earth, the equinox brings us a number of seasonal effects, noticeable to nature lovers around the globe.

Join us in making sure everyone has access to the wonders of astronomy. Donate now!

Equal day and night on the equinox?

At the equinox, Earth’s two hemispheres are receiving the sun’s rays equally. Night and day are often said to be equal in length. In fact, the word equinox comes from the Latin aequus (equal) and nox (night). For our ancestors, whose timekeeping was less precise than ours, day and night likely did seem equal. But today we know it’s not exactly so.

Read more: Are day and night equal at the equinox?

Fastest sunsets at the equinoxes

The fastest sunsets and sunrises of the year happen at the equinoxes. We’re talking here about the length of time it takes for the whole sun to sink below the horizon.

Read more: Fastest sunsets happen near equinoxes

View at EarthSky Community Photos. | Iaroslav Kourzenkov of Halifax, Nova Scotia, Canada, captured this image of the sunset on the equinox on March 20, 2023. Thank you, Iaroslav!

Sun rises due east and sets due west?

Here’s another equinox phenomenon. You might hear that the sun rises due east and sets due west at the equinox. Is that true? Yes it is. In fact, it’s the case no matter where you live on Earth, with the exception of the North and South Poles. At the equinoxes, the sun appears overhead at noon as seen from Earth’s equator, as the illustration below shows. This illustration shows the sun’s location on the celestial equator, every hour, on the day of the equinox.

No matter where you are on Earth – except at the Earth’s North and South Poles – you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator: the imaginary line above the true equator of the Earth.

The sun is on the celestial equator, and the celestial equator intersects all of our horizons at points due east and due west. Voila! The sun rises due east and sets due west.

Read more: Sun rises due east and sets due west

The day arc of the sun, every hour, at the equinox, as seen on the (imaginary) celestial sphere surrounding Earth. At the equinox, the sun is directly above Earth’s equator. Image via Tau’olunga/ Wikimedia Commons (CC BY-SA 2.5).

More March equinox effects

And there are also plenty more effects in play around the time of the March equinox that all of us can notice. In the Northern Hemisphere, the March equinox brings earlier sunrises, later sunsets and sprouting plants.

Meanwhile, you’ll find the opposite season – later sunrises, earlier sunsets, chillier winds, dry and falling leaves – south of the equator.

The equinoxes and solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. You can think of an equinox as happening on the imaginary dome of our sky, or as an event that happens in Earth’s orbit around the sun.

The Earth-centered view

If you think of it from an Earth-centered perspective, you can think of the celestial equator as a great circle dividing Earth’s sky into its Northern and Southern Hemispheres. The celestial equator is an imaginary line wrapping the sky directly above Earth’s equator. At the equinox, the sun crosses the celestial equator to enter the sky’s Northern Hemisphere.

This illustration shows the day arc of the equinox sun, as seen from Earth’s equator. Also showing are twilight suns (in red) down to -18 degrees altitude. Note that the sun is at its highest point at noon. And see that the tree’s shadow at noon is cast straight down. That is – as seen from the equator on the day of an equinox – a tree stands in the center of its own shadow. Image via Tau’olunga/ Wikimedia Commons (CC BY-SA 2.5).

The Earth-in-space view

If you think of it from an Earth-in-space perspective, you have to think of Earth in orbit around the sun. And we all know Earth doesn’t orbit upright but is instead tilted on its axis by 23 1/2 degrees. So Earth’s Northern and Southern Hemispheres trade places in receiving the sun’s light and warmth most directly. We have an equinox twice a year – spring and fall – when the tilt of the Earth’s axis and Earth’s orbit around the sun combine in such a way that the axis is inclined neither away from nor toward the sun.

Here are satellite views of Earth on the solstices and equinoxes, via NASA Earth Observatory.

Things change fast around the equinoxes

Since Earth never stops moving around the sun, the position of the sunrise and sunset – and the days of approximately equal sunlight and night – will change quickly.

The video below was the Astronomy Picture of the Day for March 19, 2014. APOD explained:

At an equinox, the Earth’s terminator – the dividing line between day and night – becomes vertical and connects the North and South Poles. The time-lapse video [below] demonstrates this by displaying an entire year on planet Earth in 12 seconds. From geosynchronous orbit, the Meteosat satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical.

As the Earth revolved around the sun, the terminator was seen to tilt in a way that provides less daily sunlight to the Northern Hemisphere, causing winter in the north. As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in the Southern Hemisphere and summer in the north. The captured year ends again with the September equinox, concluding another of billions of trips the Earth has taken – and will take – around the sun.

The equinox is an event that takes place in Earth’s orbit around the sun. Image via National Weather Service/ weather.gov.

Where are signs of the March equinox in nature?

Everywhere! Forget about the weather for a moment, and think only about daylight. In terms of daylight, the knowledge that spring is here – and summer is coming – permeates all of nature on the northern half of Earth’s globe.

Notice the arc of the sun across the sky each day. You’ll find that it’s shifting toward the north. Responding to the change in daylight, birds and butterflies are migrating back northward, too, along with the path of the sun.

The longer days do bring with them warmer weather. People are leaving their winter coats at home. Trees are budding, and plants are beginning a new cycle of growth. In many places, spring flowers are beginning to bloom.

Meanwhile, in the Southern Hemisphere, the days are getting shorter and nights longer. A chill is in the air. Fall is here, and winter is coming!

Bottom line: The 2024 March equinox falls March 20 at 3:06 UTC. So many parts of the world will see the equinox arrive on March 19. What is an equinox? How do we experience it on Earth? All you need to know, here.

The post March equinox 2024: All you need to know first appeared on EarthSky.

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SpaceX Starship 3rd test flight launch ‘end of week’

Watch Starship's third flight test https://t.co/1u46r769Vp

— SpaceX (@SpaceX) March 5, 2024

Click the image above to watch the SpaceX Starship 3rd test flight livestream when it is announced.

Update: Elon Musk posted on X March 12 that the 3rd test flight would occur at the end of this week, pending weather. No word yet on licensing and regulatory approval.

Flight 3 end of week, pending weather https://t.co/DLGD6Vj7SB

— Elon Musk (@elonmusk) March 12, 2024

SpaceX Starship 3rd test flight scheduled

SpaceX announced on March 5, 2024, it has a date for the third test flight of their mighty Starship, pending regulatory approval. The company posted a message on X/Twitter with the new launch date of March 14, and the livestream starting at 6:30 a.m. CDT. Starship launches from SpaceX’s Starbase in Boca Chica, Texas. If you want to watch the SpaceX launch livestream, click on the image above.

In addition, SpaceX said that they’ve made improvements after the first two launches, including flying a new trajectory:

… with Starship targeted to splashdown in the Indian Ocean. This new flight path enables us to attempt new techniques like in-space engine burns while maximizing public safety.

Estimated Starship IFT-3 planned trajectory pic.twitter.com/2Ubrp2B9yH

— Jonathan McDowell (@planet4589) March 7, 2024

Stay tuned for updates!

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

Starship’s 2nd test flight

On Saturday, November 18, 2023, Starship made its second test launch a bit after 7 a.m. CT. After a brief delay, the powerful rocketship lifted off slowly and majestically from SpaceX’s Starbase in Boca Chica, Texas.

Liftoff of Starship! pic.twitter.com/qXnGXXZP5k

— SpaceX (@SpaceX) November 18, 2023

Unfortunately, neither stage of the test vehicle survived the flight. Following a successful stage separation about 165 seconds into the mission, the main stage flipped itself around for its planned touchdown in the Gulf of Mexico. Then, it exploded. The RUD – rapid unscheduled disassembly – came about 30 seconds after stage separation.

Stage separation! pic.twitter.com/PipaCW1PDT

— SpaceX (@SpaceX) November 18, 2023

Starship’s 2nd stage continued its journey despite the booster’s explosion. Mission control, however, lost contact with the vehicle soon after. Go here to see Starship’s fiery reentry near Puerto Rico.

A replay of the epic launch is available on the SpaceX official Twitter account.

Watch Starship’s second integrated flight test ? https://t.co/bJFjLCiTbK https://t.co/cahoRQ72lm

— SpaceX (@SpaceX) November 18, 2023

The greatest rocket ever flown

In case you haven’t heard, Starship is the world’s tallest and most powerful rocket. The initial launch came in April 2023 and ended in a dramatic mid-air explosion. Among other problems, the launch also obliterated the concrete launch pad beneath the mighty rocket and blew out some windows.

Afterwards, the Federal Aviation Administration (FAA) had questions. And SpaceX could not launch Starship without further FAA approval. The nod from the FAA – which was much awaited by both space fans and SpaceX – arrived just three days before the hoped-for launch.

The SpaceX Starship 25 (S25) was hoisted aloft in the chopsticks lifting mechanism at Starbase in Boca Chica, Texas, on September 5, 2023. In October, SpaceX performed tests and rehearsals on the launchpad as they awaited final approval from the Federal Aviation Administration (FAA) to try launching again. Image from SpaceX, via X. Used with permission.

What went wrong with SpaceX Starship the 1st time?

SpaceX gave a rundown of how its first attempt to get Starship to orbit went wrong. Indeed, from the moment the engines ignited, there were problems that continued until the vehicle finally exploded about 39 km (24 miles) over the Gulf of Mexico.

The company provided a brief timeline of the flight and how they’re going to prevent a repeat of its mishaps:

During ascent, the vehicle sustained fires from leaking propellant in the aft end of the Super Heavy booster, which eventually severed connection with the vehicle’s primary flight computer. This led to a loss of communications to the majority of booster engines and, ultimately, control of the vehicle. SpaceX has since implemented leak mitigations and improved testing on both engine and booster hardware. As an additional corrective action, SpaceX has significantly expanded Super Heavy’s preexisting fire suppression system in order to mitigate against future engine bay fires.

Additionally, it also addressed the disintegration of a massive reinforced concrete slab under the launchpad during liftoff.

SpaceX also made significant upgrades to the orbital launch mount and pad system in order to prevent a recurrence of the pad foundation failure observed during the first flight test. These upgrades include significant reinforcements to the pad foundation and the addition of a flame deflector, which SpaceX has successfully tested multiple times.

Bottom line: The SpaceX Starship – the world’s most powerful rocket – is ready for its 3rd test flight. Elon Musk said on March 12 it would be at the ‘end of week’.

The post SpaceX Starship 3rd test flight launch ‘end of week’ first appeared on EarthSky.

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Watch Starship's third flight test https://t.co/1u46r769Vp

— SpaceX (@SpaceX) March 5, 2024

Click the image above to watch the SpaceX Starship 3rd test flight livestream when it is announced.

Update: Elon Musk posted on X March 12 that the 3rd test flight would occur at the end of this week, pending weather. No word yet on licensing and regulatory approval.

Flight 3 end of week, pending weather https://t.co/DLGD6Vj7SB

— Elon Musk (@elonmusk) March 12, 2024

SpaceX Starship 3rd test flight scheduled

SpaceX announced on March 5, 2024, it has a date for the third test flight of their mighty Starship, pending regulatory approval. The company posted a message on X/Twitter with the new launch date of March 14, and the livestream starting at 6:30 a.m. CDT. Starship launches from SpaceX’s Starbase in Boca Chica, Texas. If you want to watch the SpaceX launch livestream, click on the image above.

In addition, SpaceX said that they’ve made improvements after the first two launches, including flying a new trajectory:

… with Starship targeted to splashdown in the Indian Ocean. This new flight path enables us to attempt new techniques like in-space engine burns while maximizing public safety.

Estimated Starship IFT-3 planned trajectory pic.twitter.com/2Ubrp2B9yH

— Jonathan McDowell (@planet4589) March 7, 2024

Stay tuned for updates!

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

Starship’s 2nd test flight

On Saturday, November 18, 2023, Starship made its second test launch a bit after 7 a.m. CT. After a brief delay, the powerful rocketship lifted off slowly and majestically from SpaceX’s Starbase in Boca Chica, Texas.

Liftoff of Starship! pic.twitter.com/qXnGXXZP5k

— SpaceX (@SpaceX) November 18, 2023

Unfortunately, neither stage of the test vehicle survived the flight. Following a successful stage separation about 165 seconds into the mission, the main stage flipped itself around for its planned touchdown in the Gulf of Mexico. Then, it exploded. The RUD – rapid unscheduled disassembly – came about 30 seconds after stage separation.

Stage separation! pic.twitter.com/PipaCW1PDT

— SpaceX (@SpaceX) November 18, 2023

Starship’s 2nd stage continued its journey despite the booster’s explosion. Mission control, however, lost contact with the vehicle soon after. Go here to see Starship’s fiery reentry near Puerto Rico.

A replay of the epic launch is available on the SpaceX official Twitter account.

Watch Starship’s second integrated flight test ? https://t.co/bJFjLCiTbK https://t.co/cahoRQ72lm

— SpaceX (@SpaceX) November 18, 2023

The greatest rocket ever flown

In case you haven’t heard, Starship is the world’s tallest and most powerful rocket. The initial launch came in April 2023 and ended in a dramatic mid-air explosion. Among other problems, the launch also obliterated the concrete launch pad beneath the mighty rocket and blew out some windows.

Afterwards, the Federal Aviation Administration (FAA) had questions. And SpaceX could not launch Starship without further FAA approval. The nod from the FAA – which was much awaited by both space fans and SpaceX – arrived just three days before the hoped-for launch.

The SpaceX Starship 25 (S25) was hoisted aloft in the chopsticks lifting mechanism at Starbase in Boca Chica, Texas, on September 5, 2023. In October, SpaceX performed tests and rehearsals on the launchpad as they awaited final approval from the Federal Aviation Administration (FAA) to try launching again. Image from SpaceX, via X. Used with permission.

What went wrong with SpaceX Starship the 1st time?

SpaceX gave a rundown of how its first attempt to get Starship to orbit went wrong. Indeed, from the moment the engines ignited, there were problems that continued until the vehicle finally exploded about 39 km (24 miles) over the Gulf of Mexico.

The company provided a brief timeline of the flight and how they’re going to prevent a repeat of its mishaps:

During ascent, the vehicle sustained fires from leaking propellant in the aft end of the Super Heavy booster, which eventually severed connection with the vehicle’s primary flight computer. This led to a loss of communications to the majority of booster engines and, ultimately, control of the vehicle. SpaceX has since implemented leak mitigations and improved testing on both engine and booster hardware. As an additional corrective action, SpaceX has significantly expanded Super Heavy’s preexisting fire suppression system in order to mitigate against future engine bay fires.

Additionally, it also addressed the disintegration of a massive reinforced concrete slab under the launchpad during liftoff.

SpaceX also made significant upgrades to the orbital launch mount and pad system in order to prevent a recurrence of the pad foundation failure observed during the first flight test. These upgrades include significant reinforcements to the pad foundation and the addition of a flame deflector, which SpaceX has successfully tested multiple times.

Bottom line: The SpaceX Starship – the world’s most powerful rocket – is ready for its 3rd test flight. Elon Musk said on March 12 it would be at the ‘end of week’.

The post SpaceX Starship 3rd test flight launch ‘end of week’ first appeared on EarthSky.

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Uncontrolled space junk hit Earth over the Pacific on Friday

In 2021, ground controllers for the space station jettisoned this equipment pallet. The space junk has been orbiting Earth for the last few years. It most likely made its reentry on March 8, 2024, over the Pacific. Some fragments should have survived to hit the ocean. Image via NASA/ Jonathan McDowell on X/Twitter.

Update: According to Jonathan McDowell of the Harvard–Smithsonian Center for Astrophysics, who was tracking the pallet’s reentry, the space junk should have hit somewhere over the Pacific Ocean on March 8, 2024.

EP-9 has probably reentered by now, most likely over the Pacific Ocean

— Jonathan McDowell (@planet4589) March 8, 2024

That location would not be surprising. If you want a good visual of just how much of Earth’s territory is consumed by the Pacific Ocean, rotate this view of the 3D interactive globe until it fills the side of Earth you’re viewing. Although this was an uncontrolled reentry, controlled reentries usually aim for the Pacific Ocean, specifically an area called the spacecraft cemetery. Also called Point Nemo, Wikipedia calls it:

… the oceanic pole of inaccessibility, the location farthest from any land.

Discarded pallet was from 2020

In 2020, a Japanese supply ship arrived at the International Space Station. It brought along an equipment pallet to help astronauts replace old nickel-hydrogen batteries with new lithium-ion batteries. Then, in 2021, ground control jettisoned the SUV-sized pallet, and it began its long journey back to Earth. The pallet had been orbiting Earth for the past few years but reentered Earth’s atmosphere on March 8, 2024. The space junk was large enough that not all of it burned up in our atmosphere. According to Jonathan McDowell of the Harvard–Smithsonian Center for Astrophysics, around 1/2 a ton of fragments would have hit Earth’s surface.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

Reentry of the EP-9 battery pallet jettisoned from ISS in 2021 is currently predicted (by Space Force) between 1230 UTC Mar 8 and 0830 UTC Mar 9. It will not totally burn up on reentry – about half a tonne of fragments will likely hit the Earth's surface.

— Jonathan McDowell (@planet4589) March 7, 2024

The problem of space junk

Last November, spacewalking astronauts lost a tool bag that floated off into space. The tool bag should reenter Earth’s atmosphere between March and July. However, the tool bag is much smaller and should completely burn up in our atmosphere. Some people were even able to spot it from space and took video of it.

Still, increasing space junk is a real problem in near-Earth orbit. According to Chris Impey of the University of Arizona, no one’s in charge of cleaning it up. More than 37,000 pieces of debris larger than a softball are currently orbiting Earth.

But this problem is not new. As early as 1978, NASA scientist Donald Kessler was pondering what would happen as more satellites took up residence in orbit around Earth. Now known as the Kessler syndrome, the scenario imagines the density of objects in low-Earth orbit becoming high enough that it creates a cascade of collisions, with each collision generating space debris that increases the likelihood of further collisions.

And the garbage is not just in orbit. In fact, there are 100 bags of human waste on the moon. When the Artemis mission finally reaches the moon, that number will grow.

This NASA illustration shows the extent of orbital debris currently tracked. In fact, more than 37,000 pieces of debris larger than a softball are currently in orbit. With more countries and private companies entering space, space junk is increasing. Image via NASA.

Bottom line: Space junk jettisoned from the International Space Station in 2021 hit Earth on March 8, 2024. The space junk likely reentered over the Pacific Ocean.

The post Uncontrolled space junk hit Earth over the Pacific on Friday first appeared on EarthSky.

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In 2021, ground controllers for the space station jettisoned this equipment pallet. The space junk has been orbiting Earth for the last few years. It most likely made its reentry on March 8, 2024, over the Pacific. Some fragments should have survived to hit the ocean. Image via NASA/ Jonathan McDowell on X/Twitter.

Update: According to Jonathan McDowell of the Harvard–Smithsonian Center for Astrophysics, who was tracking the pallet’s reentry, the space junk should have hit somewhere over the Pacific Ocean on March 8, 2024.

EP-9 has probably reentered by now, most likely over the Pacific Ocean

— Jonathan McDowell (@planet4589) March 8, 2024

That location would not be surprising. If you want a good visual of just how much of Earth’s territory is consumed by the Pacific Ocean, rotate this view of the 3D interactive globe until it fills the side of Earth you’re viewing. Although this was an uncontrolled reentry, controlled reentries usually aim for the Pacific Ocean, specifically an area called the spacecraft cemetery. Also called Point Nemo, Wikipedia calls it:

… the oceanic pole of inaccessibility, the location farthest from any land.

Discarded pallet was from 2020

In 2020, a Japanese supply ship arrived at the International Space Station. It brought along an equipment pallet to help astronauts replace old nickel-hydrogen batteries with new lithium-ion batteries. Then, in 2021, ground control jettisoned the SUV-sized pallet, and it began its long journey back to Earth. The pallet had been orbiting Earth for the past few years but reentered Earth’s atmosphere on March 8, 2024. The space junk was large enough that not all of it burned up in our atmosphere. According to Jonathan McDowell of the Harvard–Smithsonian Center for Astrophysics, around 1/2 a ton of fragments would have hit Earth’s surface.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

Reentry of the EP-9 battery pallet jettisoned from ISS in 2021 is currently predicted (by Space Force) between 1230 UTC Mar 8 and 0830 UTC Mar 9. It will not totally burn up on reentry – about half a tonne of fragments will likely hit the Earth's surface.

— Jonathan McDowell (@planet4589) March 7, 2024

The problem of space junk

Last November, spacewalking astronauts lost a tool bag that floated off into space. The tool bag should reenter Earth’s atmosphere between March and July. However, the tool bag is much smaller and should completely burn up in our atmosphere. Some people were even able to spot it from space and took video of it.

Still, increasing space junk is a real problem in near-Earth orbit. According to Chris Impey of the University of Arizona, no one’s in charge of cleaning it up. More than 37,000 pieces of debris larger than a softball are currently orbiting Earth.

But this problem is not new. As early as 1978, NASA scientist Donald Kessler was pondering what would happen as more satellites took up residence in orbit around Earth. Now known as the Kessler syndrome, the scenario imagines the density of objects in low-Earth orbit becoming high enough that it creates a cascade of collisions, with each collision generating space debris that increases the likelihood of further collisions.

And the garbage is not just in orbit. In fact, there are 100 bags of human waste on the moon. When the Artemis mission finally reaches the moon, that number will grow.

This NASA illustration shows the extent of orbital debris currently tracked. In fact, more than 37,000 pieces of debris larger than a softball are currently in orbit. With more countries and private companies entering space, space junk is increasing. Image via NASA.

Bottom line: Space junk jettisoned from the International Space Station in 2021 hit Earth on March 8, 2024. The space junk likely reentered over the Pacific Ocean.

The post Uncontrolled space junk hit Earth over the Pacific on Friday first appeared on EarthSky.

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List of SpaceX Starlink launches for March 2024

SpaceX’s Starlink Group 6-39 launched from Florida on February 25, 2024. Image via SpaceX.

Upcoming Starlink launches in March 2024

Starlink Group 6-40: March 1, 2024, 10:00 a.m. – 2:31 p.m. EST (15:00 – 19:31 UTC)
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-41: March 3, 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-42: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 8-4: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 8-3: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 8-2: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 7-16: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 8-5: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-43: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-44: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-45: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

You can watch a recorded livestream of the Starlink launches on SpaceX’s X account.

Watch this space for updates!

After launch, look for a train of lights

Following every Starlink launch, the internet buzzes with people asking:

What’s that long line of lights in the sky that looks like a train?

What you’re seeing is the Starlink satellites moving into a higher orbit. You can check to see if they will pass over your area using the Find Starlink website.

Growing numbers amid controversy

According to Wikipedia, as of January 2024, Starlink consists of over 5,275 mass-produced small satellites in low Earth orbit that communicate with designated ground transceivers. They provide internet access to more than 2 million subscribers.

Love ’em or hate ’em, these Starlink satellites are part of SpaceX’s vision for a global internet communication satellite constellation. They deliver high-speed internet service worldwide, mainly to locations where ground-based internet is unreliable, unavailable, or expensive. The private company is well-known for launching batches back-to-back, several times a month, regularly lofting 60 satellites at a time. And SpaceX plans to build up to perhaps as many as 30,000 eventually.

Most thought it was exciting to see the first few Starlink satellites traveling together in the night sky. But then more were launched, and then more. And astronomers began to worry.

Because Starlinks are bright, astronomers say they’re photobombing astronomical images. Therefore, they have the potential to interfere with the professional astronomical observations that have brought us our modern-day view of the cosmos. And although SpaceX has tried to address the issue, they remain far from what astronomers say is acceptable.

Bottom line: SpaceX currently has one Starlink launch planned for the month of March 2024.

Read more from EarthSky: Starlink satellites can look like a plume or train of light

Via Space Launch Schedule

The post List of SpaceX Starlink launches for March 2024 first appeared on EarthSky.

from EarthSky https://ift.tt/hBF2NkX

SpaceX’s Starlink Group 6-39 launched from Florida on February 25, 2024. Image via SpaceX.

Upcoming Starlink launches in March 2024

Starlink Group 6-40: March 1, 2024, 10:00 a.m. – 2:31 p.m. EST (15:00 – 19:31 UTC)
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-41: March 3, 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-42: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 8-4: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 8-3: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 8-2: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 7-16: March 2024, TBD
Falcon 9 Block 5 | Vandenberg Space Force Station, California | DATE/TIME MAY CHANGE

Starlink Group 8-5: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-43: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-44: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

Starlink Group 6-45: March 2024, TBD
Falcon 9 Block 5 | Cape Canaveral Space Force Station, Florida | DATE/TIME MAY CHANGE

You can watch a recorded livestream of the Starlink launches on SpaceX’s X account.

Watch this space for updates!

After launch, look for a train of lights

Following every Starlink launch, the internet buzzes with people asking:

What’s that long line of lights in the sky that looks like a train?

What you’re seeing is the Starlink satellites moving into a higher orbit. You can check to see if they will pass over your area using the Find Starlink website.

Growing numbers amid controversy

According to Wikipedia, as of January 2024, Starlink consists of over 5,275 mass-produced small satellites in low Earth orbit that communicate with designated ground transceivers. They provide internet access to more than 2 million subscribers.

Love ’em or hate ’em, these Starlink satellites are part of SpaceX’s vision for a global internet communication satellite constellation. They deliver high-speed internet service worldwide, mainly to locations where ground-based internet is unreliable, unavailable, or expensive. The private company is well-known for launching batches back-to-back, several times a month, regularly lofting 60 satellites at a time. And SpaceX plans to build up to perhaps as many as 30,000 eventually.

Most thought it was exciting to see the first few Starlink satellites traveling together in the night sky. But then more were launched, and then more. And astronomers began to worry.

Because Starlinks are bright, astronomers say they’re photobombing astronomical images. Therefore, they have the potential to interfere with the professional astronomical observations that have brought us our modern-day view of the cosmos. And although SpaceX has tried to address the issue, they remain far from what astronomers say is acceptable.

Bottom line: SpaceX currently has one Starlink launch planned for the month of March 2024.

Read more from EarthSky: Starlink satellites can look like a plume or train of light

Via Space Launch Schedule

The post List of SpaceX Starlink launches for March 2024 first appeared on EarthSky.

from EarthSky https://ift.tt/hBF2NkX

Charlotte the Stingray is pregnant without a male

This is a screenshot from a video that Team ECCO shared on TikTok on February 21, 2024. Here we see Charlotte the stingray and her plump belly as she glides by the window in the aquarium tank. Watch the full video here. Image via Team ECCO.

Charlotte the stingray is pregnant!

Charlotte the stingray is a social media sensation. She lives at the Aquarium & Shark Lab run by Team ECCO in Hendersonville, North Carolina. On February 11, 2024, Team ECCO shared an ultrasound on TikTok showing that Charlotte is pregnant. But, as the announcement said:

Thing is, we have no male ray in the tank! One possibility is that the babies have gone through the process called parthenogenesis where the cell inside of the egg splits on its own and creates an exact clone of the mother. Another possibility is that she was impregnated by one of our two male white spotted bamboo sharks that we introduced to the tank in July 2023. We won’t know for sure until DNA testing is done on Charlotte’s pups.

Since then, millions have been checking in every day to find out if Charlotte had her babies. As of February 29, 2024, she’s still pregnant!

What is parthenogenesis?

Charlotte is between 12 and 14 years old. She’s been in a tank with young male sharks named Moe and Larry since July 2023, but the staff thought the sharks were too young to father children. So that would leave parthenogenesis as the likely cause of Charlotte’s pregnancy.

Parthenogenesis is a type of asexual reproduction. It happens when an embryo develops from an unfertilized egg. Charlotte would be the first-known round stingray to reproduce by parthenogenesis. Other rays and sharks have had babies through this asexual method of reproduction, though.

Here’s the latest video of Charlotte, from February 28:

@_teamecco_ Charlotte update 2-28-24. Thank you all for continuing to be patient while we all await for Charlotte to give birth! Please visit the link in our bio to support Charlotte and her nursery! ???? #teamecco #aquarium #stingray ? Show Me How – Men I Trust

Bottom line: Charlotte the stingray is pregnant in a North Carolina aquarium. The stingray has not had a male ray in her tank.

Read more: Fish can do math, researchers say

The post Charlotte the Stingray is pregnant without a male first appeared on EarthSky.

from EarthSky https://ift.tt/nBIUJPC

This is a screenshot from a video that Team ECCO shared on TikTok on February 21, 2024. Here we see Charlotte the stingray and her plump belly as she glides by the window in the aquarium tank. Watch the full video here. Image via Team ECCO.

Charlotte the stingray is pregnant!

Charlotte the stingray is a social media sensation. She lives at the Aquarium & Shark Lab run by Team ECCO in Hendersonville, North Carolina. On February 11, 2024, Team ECCO shared an ultrasound on TikTok showing that Charlotte is pregnant. But, as the announcement said:

Thing is, we have no male ray in the tank! One possibility is that the babies have gone through the process called parthenogenesis where the cell inside of the egg splits on its own and creates an exact clone of the mother. Another possibility is that she was impregnated by one of our two male white spotted bamboo sharks that we introduced to the tank in July 2023. We won’t know for sure until DNA testing is done on Charlotte’s pups.

Since then, millions have been checking in every day to find out if Charlotte had her babies. As of February 29, 2024, she’s still pregnant!

What is parthenogenesis?

Charlotte is between 12 and 14 years old. She’s been in a tank with young male sharks named Moe and Larry since July 2023, but the staff thought the sharks were too young to father children. So that would leave parthenogenesis as the likely cause of Charlotte’s pregnancy.

Parthenogenesis is a type of asexual reproduction. It happens when an embryo develops from an unfertilized egg. Charlotte would be the first-known round stingray to reproduce by parthenogenesis. Other rays and sharks have had babies through this asexual method of reproduction, though.

Here’s the latest video of Charlotte, from February 28:

@_teamecco_ Charlotte update 2-28-24. Thank you all for continuing to be patient while we all await for Charlotte to give birth! Please visit the link in our bio to support Charlotte and her nursery! ???? #teamecco #aquarium #stingray ? Show Me How – Men I Trust

Bottom line: Charlotte the stingray is pregnant in a North Carolina aquarium. The stingray has not had a male ray in her tank.

Read more: Fish can do math, researchers say

The post Charlotte the Stingray is pregnant without a male first appeared on EarthSky.

from EarthSky https://ift.tt/nBIUJPC

Star clouds in the Milky Way are doing the wave

• A huge structure of star clouds – containing stellar nurseries – in our sun’s backyard are doin’ the wave! That is, they’re oscillating in such a way as to create a wavelike appearance.
• These star clouds run along the Local Arm of our Milky Way galaxy. Astronomers found them making a wavelike shape in 2020. More recently, they discovered that this string of star clouds is not only shaped like a wave, it’s also doing the wave.
• The structure oscillates due to gravity from the Milky Way. Now astronomers are wondering if this happens all over our galaxy and others.

The Harvard-Smithsonian Center for Astrophysics published this original article on February 20, 2024. Edits by EarthSky.

Star clouds in the Milky Way are doing the wave

A few years ago, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) uncovered one of our Milky Way galaxy’s greatest secrets: an enormous, wave-shaped chain of gaseous clouds in our sun’s backyard. The structure is giving birth to clusters of stars along the spiral arm of the galaxy we call home.

Astronomers named this astonishing new structure the Radcliffe Wave, after the Harvard Radcliffe Institute, where they discovered it. On February 20, 2024, researchers said they’ve now discovered the Radcliffe Wave not only looks like a wave, but also moves like one.

In other words, the whole structure oscillating through space, much like “the wave” moving through a stadium full of fans.

The researchers published their discovery in the peer-reviewed journal Nature on February 20, 2024. Lead author Ralf Konietzka of Harvard said:

By using the motion of baby stars born in the gaseous clouds along the Radcliffe Wave. We can trace the motion of their natal gas to show that the Radcliffe Wave is actually waving.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

The discovery of the wave structure

In 2018, University of Vienna professor João Alves was a fellow at Harvard Radcliffe Institute and worked with Catherine Zucker and Alyssa Goodman (both currently at CfA). They mapped out the 3D positions of the stellar nurseries in the sun’s galactic neighborhood. They combined brand-new data from the European Space Agency’s Gaia mission with the data-intensive “3D Dust Mapping” technique. And they noticed a pattern emerging, leading to the discovery of the Radcliffe Wave in 2020.

The star clouds are in our backyard

The wave of star clouds is in our own neighborhood. Zucker said:

It’s the largest coherent structure we know of, and it’s really, really close to us. It’s been there the whole time. We just didn’t know about it, because we couldn’t build these high-resolution models of the distribution of gaseous clouds near the sun, in 3D.

The 2020 3D dust map clearly showed the Radcliffe Wave existed, but no measurements available then were good enough to see if the wave was moving. But in 2022, using a newer release of Gaia data, Alves’ group assigned 3D motions to the young star clusters in the Radcliffe Wave. With the clusters’ positions and motions in hand, Konietzka’s team then determined that the entire Radcliffe Wave is indeed waving.

The star clusters along the Radcliffe Wave move up and down, like people in a sports stadium doing “the wave,” creating a pattern that travels through our galactic backyard. Konietzka said:

Similar to how fans in a stadium are being pulled back to their seats by the Earth’s gravity, the Radcliffe Wave oscillates due to the gravity of the Milky Way.

Understanding the behavior of this 9,000-light-year-long, gargantuan structure in our galactic backyard, just 500 light-years away from the sun at its closest point, allows researchers to now turn their attention to even more challenging questions.

Why is the wave happening?

No one yet knows what caused the Radcliffe Wave or why it moves the way it does. Zucker said:

Now we can go and test all these different theories for why the wave formed in the first place.

Konietzka added:

Those theories range from explosions of massive stars, called supernovae, to out-of-galaxy disturbances, like a dwarf satellite galaxy colliding with our Milky Way.

A look at the nearby star clouds that make up the Radcliffe Wave. This oscillating structure moves through the backyard of our sun (yellow dot). Blue dots are clusters of baby stars. The white line is a theoretical model by Ralf Konietzka and collaborators that explains its current shape and motion. The magenta and green lines show how it will move in the future. Background is a model of the Milky Way. Image via CfA/ Harvard and Smithsonian/ Ralf Konietzka/ Alyssa Goodman/ WorldWide Telescope.

Is dark matter involved?

The Nature article also includes a calculation on how much dark matter might be contributing to the gravity responsible for the Wave’s motion. Konietzka said:

It turns out that no significant dark matter is needed to explain the motion we observe. The gravity of ordinary matter alone is enough to drive the waving of the Wave.

More questions

In addition, the discovery of the oscillation raises new questions about the preponderance of these waves both across the Milky Way and other galaxies. Since the Radcliffe Wave appears to form the backbone of the nearest spiral arm in the Milky Way, the waving of the Wave could imply that spiral arms of galaxies oscillate in general, making galaxies even more dynamic than previously thought. Goodman said:

The question is, what caused the displacement giving rise to the waving we see? And does it happen all over the galaxy? In all galaxies? Does it happen occasionally? Does it happen all the time?

Bottom line: Star clouds peppered with stellar nurseries form a huge, wave-like structure in the Local Arm of our galaxy. Now astronomers have discovered that the structure is in motion, doing the wave.

Source: The Radcliffe Wave is Oscillating

Via Center for Astrophysics | Harvard & Smithsonian

The post Star clouds in the Milky Way are doing the wave first appeared on EarthSky.

from EarthSky https://ift.tt/LfH7y34

• A huge structure of star clouds – containing stellar nurseries – in our sun’s backyard are doin’ the wave! That is, they’re oscillating in such a way as to create a wavelike appearance.
• These star clouds run along the Local Arm of our Milky Way galaxy. Astronomers found them making a wavelike shape in 2020. More recently, they discovered that this string of star clouds is not only shaped like a wave, it’s also doing the wave.
• The structure oscillates due to gravity from the Milky Way. Now astronomers are wondering if this happens all over our galaxy and others.

The Harvard-Smithsonian Center for Astrophysics published this original article on February 20, 2024. Edits by EarthSky.

Star clouds in the Milky Way are doing the wave

A few years ago, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) uncovered one of our Milky Way galaxy’s greatest secrets: an enormous, wave-shaped chain of gaseous clouds in our sun’s backyard. The structure is giving birth to clusters of stars along the spiral arm of the galaxy we call home.

Astronomers named this astonishing new structure the Radcliffe Wave, after the Harvard Radcliffe Institute, where they discovered it. On February 20, 2024, researchers said they’ve now discovered the Radcliffe Wave not only looks like a wave, but also moves like one.

In other words, the whole structure oscillating through space, much like “the wave” moving through a stadium full of fans.

The researchers published their discovery in the peer-reviewed journal Nature on February 20, 2024. Lead author Ralf Konietzka of Harvard said:

By using the motion of baby stars born in the gaseous clouds along the Radcliffe Wave. We can trace the motion of their natal gas to show that the Radcliffe Wave is actually waving.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

The discovery of the wave structure

In 2018, University of Vienna professor João Alves was a fellow at Harvard Radcliffe Institute and worked with Catherine Zucker and Alyssa Goodman (both currently at CfA). They mapped out the 3D positions of the stellar nurseries in the sun’s galactic neighborhood. They combined brand-new data from the European Space Agency’s Gaia mission with the data-intensive “3D Dust Mapping” technique. And they noticed a pattern emerging, leading to the discovery of the Radcliffe Wave in 2020.

The star clouds are in our backyard

The wave of star clouds is in our own neighborhood. Zucker said:

It’s the largest coherent structure we know of, and it’s really, really close to us. It’s been there the whole time. We just didn’t know about it, because we couldn’t build these high-resolution models of the distribution of gaseous clouds near the sun, in 3D.

The 2020 3D dust map clearly showed the Radcliffe Wave existed, but no measurements available then were good enough to see if the wave was moving. But in 2022, using a newer release of Gaia data, Alves’ group assigned 3D motions to the young star clusters in the Radcliffe Wave. With the clusters’ positions and motions in hand, Konietzka’s team then determined that the entire Radcliffe Wave is indeed waving.

The star clusters along the Radcliffe Wave move up and down, like people in a sports stadium doing “the wave,” creating a pattern that travels through our galactic backyard. Konietzka said:

Similar to how fans in a stadium are being pulled back to their seats by the Earth’s gravity, the Radcliffe Wave oscillates due to the gravity of the Milky Way.

Understanding the behavior of this 9,000-light-year-long, gargantuan structure in our galactic backyard, just 500 light-years away from the sun at its closest point, allows researchers to now turn their attention to even more challenging questions.

Why is the wave happening?

No one yet knows what caused the Radcliffe Wave or why it moves the way it does. Zucker said:

Now we can go and test all these different theories for why the wave formed in the first place.

Konietzka added:

Those theories range from explosions of massive stars, called supernovae, to out-of-galaxy disturbances, like a dwarf satellite galaxy colliding with our Milky Way.

A look at the nearby star clouds that make up the Radcliffe Wave. This oscillating structure moves through the backyard of our sun (yellow dot). Blue dots are clusters of baby stars. The white line is a theoretical model by Ralf Konietzka and collaborators that explains its current shape and motion. The magenta and green lines show how it will move in the future. Background is a model of the Milky Way. Image via CfA/ Harvard and Smithsonian/ Ralf Konietzka/ Alyssa Goodman/ WorldWide Telescope.

Is dark matter involved?

The Nature article also includes a calculation on how much dark matter might be contributing to the gravity responsible for the Wave’s motion. Konietzka said:

It turns out that no significant dark matter is needed to explain the motion we observe. The gravity of ordinary matter alone is enough to drive the waving of the Wave.

More questions

In addition, the discovery of the oscillation raises new questions about the preponderance of these waves both across the Milky Way and other galaxies. Since the Radcliffe Wave appears to form the backbone of the nearest spiral arm in the Milky Way, the waving of the Wave could imply that spiral arms of galaxies oscillate in general, making galaxies even more dynamic than previously thought. Goodman said:

The question is, what caused the displacement giving rise to the waving we see? And does it happen all over the galaxy? In all galaxies? Does it happen occasionally? Does it happen all the time?

Bottom line: Star clouds peppered with stellar nurseries form a huge, wave-like structure in the Local Arm of our galaxy. Now astronomers have discovered that the structure is in motion, doing the wave.

Source: The Radcliffe Wave is Oscillating

Via Center for Astrophysics | Harvard & Smithsonian

The post Star clouds in the Milky Way are doing the wave first appeared on EarthSky.

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Zodiacal light best in dark skies around the March equinox

Marcy Curran created this zodiacal light video for you. We hope you enjoy it!

View at EarthSky Community Photos. | Christoph Stopka in Westcliffe, Colorado, took this gorgeous image of the zodiacal light on March 1, 2022, over the high peaks of the Sangre de Cristo mountain range, part of the Colorado Rockies. It looks like a pyramid of light on the horizon, and appears when all traces of twilight have left the evening sky. Thank you, Cristoph! Read more about this photo.

Zodiacal light around March equinox

The zodiacal light is a cone of eerie light in the sky just after evening twilight ends, or before twilight begins at dawn. If you’re in the Northern Hemisphere, you’ve got the best chance of seeing it in the west after nightfall during the weeks around the equinox on March 20. You can watch for the zodiacal light starting around February 26 until around March 12, 2024. The new moon falls on March 10, 2024. So mid March 2024 will feature lovely scenes of a young crescent moon placed in the midst of the zodiacal light. What’s more, bright Jupiter and Mercury will be in the west after sunset then, too, so they’ll be visible with the zodiacal light. Then, the days around March 27 through April 10, 2024, are good to watch for the zodiacal light.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

View at EarthSky Community Photos. | Michael Flynn captured this image on February 19, 2023, near Pine Mountain Club, California. He wrote: “The zodiacal light over the Pacific … at the top of the image is the Pleiades star cluster; at the bottom of the image are the planets Jupiter and Venus setting into the light pollution and marine layer.” Thank you, Michael!

Around late February, through March, and into early May, the zodiacal light looks like a hazy pyramid of light extending up from your western horizon after evening twilight ends.

Some call it the false dusk.

And northerners’ best chance to see this light in the east before dawn will come around the September equinox. Then it’ll go by the name false dawn.

Once you spot them, you’ll know what it is

Maybe you’ve seen the zodiacal light in the sky and not realized it. Maybe you glimpsed it while driving on a highway or country road at this time of year. Suppose you’re driving toward the west in springtime around 90 minutes after sunset. You notice what you think is the lingering evening twilight, or the light of a nearby town, over the horizon. Instead, you might be seeing the zodiacal light.

Note for Southern Hemisphere: Around late February through March, and into early May – for you – the zodiacal light looks like a hazy pyramid of light extending up from your eastern horizon before morning twilight begins.

If you see it, let us know! If you capture a shot of the zodiacal light, you can submit it here at EarthSky Community Photos.

What is this eerie light?

People used to think zodiacal light originated somehow from phenomena in Earth’s upper atmosphere. But today we understand it as sunlight reflecting off dust grains that circle the sun in the inner solar system. These grains were once thought to be left over from the process that created our Earth and the other planets of our solar system 4.5 billion years ago. In recent years, though, there’s been discussion about their possible origin in dust storms on the planet Mars. Read more: Do Mars dust storms cause the zodiacal light?

Whatever their origin, these dust grains in space spread out from the sun in the same flat disk of space inhabited by Mercury, Venus, Earth and Mars. This flat space around the sun – the plane of our solar system – translates on our sky to a narrow pathway called the ecliptic. This is the same pathway traveled by the sun and moon as they journey across our sky.

Ancient civilizations called the pathway of the sun and moon the zodiac or pathway of animals, in honor of the constellations seen beyond it. Hence the name zodiacal light.

The grains of dust are thought to range from about millimeter-sized to micron-sized, densest around the immediate vicinity of the sun and extending outward beyond the orbit of Mars. Sunlight shines on these dust grains to create the light we see.

Springtime? Autumn? What’s best?

The answer to that varies. For both hemispheres, springtime is the best time to see the zodiacal light in the evening. Autumn is the best time to see it before dawn. Look for the zodiacal light in the east around the time of the autumn equinox. Look for it in the west after sunset around the time of the spring equinox.

But, of course, spring and autumn fall in different months for Earth’s Northern and Southern Hemispheres. So if you’re in the Northern Hemisphere look for the zodiacal light before dawn from about late August through early November. In those same months, if you’re in the Southern Hemisphere, look for the light in the evening.

Likewise, if you’re in the Northern Hemisphere, look for the evening zodiacal light from late February through early May. During those months, from the Southern Hemisphere, look for the light in the morning.

How to see the light

The zodiacal light can be extremely bright and easy to see from latitudes like those in the southern U.S.

Meanwhile, skywatchers in the northern U.S. or Canada sometimes say, wistfully, that they’ve never seen it.

You’ll need a dark sky location to see the zodiacal light, someplace where city lights aren’t obscuring the natural lights in the sky. The zodiacal light is even milkier in appearance than the summer Milky Way. It’s most visible after dusk in spring because, as seen from the Northern Hemisphere, the ecliptic – or path of the sun and moon – stands nearly straight up in spring with respect to the western horizon after dusk. Likewise, the zodiacal light is easiest to see before dawn in autumn, because then the ecliptic is most perpendicular to the eastern horizon in the morning.

In spring, the zodiacal light can be seen for up to an hour after dusk ends. Or, in autumn, it can be seen for up to an hour before dawn. Unlike true dusk, though, there’s no rosy color to the zodiacal light. The reddish skies at dawn and dusk are caused by Earth’s atmosphere, while the zodiacal light originates far outside our atmosphere.

The darker your sky, the better your chances of seeing it. Your best bet is to pick a night when the moon is out of the sky, although it’s definitely possible, and very lovely, to see a slim crescent moon in the midst of this strange milky pyramid of light. In the springtime, the best time to look for the zodiacal light – and avoid moonlight – is a few days after the full moon through a few days after a new moon.

Zodiacal light photos from our community

View at EarthSky Community Photos. | Jeff Andrew captured this image in Summit County, Colorado, on March 13, 2023, and wrote: “A nice display of zodiacal light that appears to emanate from the setting planet Venus, but in reality is a glow of diffuse sunlight scattered by interplanetary dust. The light extends towards and past the Pleiades open star cluster and the Taurus constellation ending near the planet Mars. Also visible in this image is the Orion constellation, the Andromeda Galaxy, the Perseus constellation, the Double Star Cluster in Perseus, and the Aries constellation. In the foreground is the snow-covered Gore Mountain Range of central Colorado.” Thank you, Jeff!

View at EarthSky Community Photos. | Michael Flynn in Pine Mountain Club, California, took this image on September 26, 2022. Thank you, Michael!

View at EarthSky Community Photos. | Caroline Haldeman captured this image from Flagstaff, Arizona, on January 11, 2021. On the left you see the hazy pyramid of the zodiacal light. On the right is the starry band of the Milky Way. The image is part of a video she made, which you can see here. Thanks, Caroline!

Bottom line: If you’re in the Northern Hemisphere, you can see the zodiacal light from late February to early May as a hazy pyramid of light extending up from the western horizon, beginning about an hour after sunset. Southern Hemisphere? Look east before dawn.

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The post Zodiacal light best in dark skies around the March equinox first appeared on EarthSky.

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Marcy Curran created this zodiacal light video for you. We hope you enjoy it!

View at EarthSky Community Photos. | Christoph Stopka in Westcliffe, Colorado, took this gorgeous image of the zodiacal light on March 1, 2022, over the high peaks of the Sangre de Cristo mountain range, part of the Colorado Rockies. It looks like a pyramid of light on the horizon, and appears when all traces of twilight have left the evening sky. Thank you, Cristoph! Read more about this photo.

Zodiacal light around March equinox

The zodiacal light is a cone of eerie light in the sky just after evening twilight ends, or before twilight begins at dawn. If you’re in the Northern Hemisphere, you’ve got the best chance of seeing it in the west after nightfall during the weeks around the equinox on March 20. You can watch for the zodiacal light starting around February 26 until around March 12, 2024. The new moon falls on March 10, 2024. So mid March 2024 will feature lovely scenes of a young crescent moon placed in the midst of the zodiacal light. What’s more, bright Jupiter and Mercury will be in the west after sunset then, too, so they’ll be visible with the zodiacal light. Then, the days around March 27 through April 10, 2024, are good to watch for the zodiacal light.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here.

View at EarthSky Community Photos. | Michael Flynn captured this image on February 19, 2023, near Pine Mountain Club, California. He wrote: “The zodiacal light over the Pacific … at the top of the image is the Pleiades star cluster; at the bottom of the image are the planets Jupiter and Venus setting into the light pollution and marine layer.” Thank you, Michael!

Around late February, through March, and into early May, the zodiacal light looks like a hazy pyramid of light extending up from your western horizon after evening twilight ends.

Some call it the false dusk.

And northerners’ best chance to see this light in the east before dawn will come around the September equinox. Then it’ll go by the name false dawn.

Once you spot them, you’ll know what it is

Maybe you’ve seen the zodiacal light in the sky and not realized it. Maybe you glimpsed it while driving on a highway or country road at this time of year. Suppose you’re driving toward the west in springtime around 90 minutes after sunset. You notice what you think is the lingering evening twilight, or the light of a nearby town, over the horizon. Instead, you might be seeing the zodiacal light.

Note for Southern Hemisphere: Around late February through March, and into early May – for you – the zodiacal light looks like a hazy pyramid of light extending up from your eastern horizon before morning twilight begins.

If you see it, let us know! If you capture a shot of the zodiacal light, you can submit it here at EarthSky Community Photos.

What is this eerie light?

People used to think zodiacal light originated somehow from phenomena in Earth’s upper atmosphere. But today we understand it as sunlight reflecting off dust grains that circle the sun in the inner solar system. These grains were once thought to be left over from the process that created our Earth and the other planets of our solar system 4.5 billion years ago. In recent years, though, there’s been discussion about their possible origin in dust storms on the planet Mars. Read more: Do Mars dust storms cause the zodiacal light?

Whatever their origin, these dust grains in space spread out from the sun in the same flat disk of space inhabited by Mercury, Venus, Earth and Mars. This flat space around the sun – the plane of our solar system – translates on our sky to a narrow pathway called the ecliptic. This is the same pathway traveled by the sun and moon as they journey across our sky.

Ancient civilizations called the pathway of the sun and moon the zodiac or pathway of animals, in honor of the constellations seen beyond it. Hence the name zodiacal light.

The grains of dust are thought to range from about millimeter-sized to micron-sized, densest around the immediate vicinity of the sun and extending outward beyond the orbit of Mars. Sunlight shines on these dust grains to create the light we see.

Springtime? Autumn? What’s best?

The answer to that varies. For both hemispheres, springtime is the best time to see the zodiacal light in the evening. Autumn is the best time to see it before dawn. Look for the zodiacal light in the east around the time of the autumn equinox. Look for it in the west after sunset around the time of the spring equinox.

But, of course, spring and autumn fall in different months for Earth’s Northern and Southern Hemispheres. So if you’re in the Northern Hemisphere look for the zodiacal light before dawn from about late August through early November. In those same months, if you’re in the Southern Hemisphere, look for the light in the evening.

Likewise, if you’re in the Northern Hemisphere, look for the evening zodiacal light from late February through early May. During those months, from the Southern Hemisphere, look for the light in the morning.

How to see the light

The zodiacal light can be extremely bright and easy to see from latitudes like those in the southern U.S.

Meanwhile, skywatchers in the northern U.S. or Canada sometimes say, wistfully, that they’ve never seen it.

You’ll need a dark sky location to see the zodiacal light, someplace where city lights aren’t obscuring the natural lights in the sky. The zodiacal light is even milkier in appearance than the summer Milky Way. It’s most visible after dusk in spring because, as seen from the Northern Hemisphere, the ecliptic – or path of the sun and moon – stands nearly straight up in spring with respect to the western horizon after dusk. Likewise, the zodiacal light is easiest to see before dawn in autumn, because then the ecliptic is most perpendicular to the eastern horizon in the morning.

In spring, the zodiacal light can be seen for up to an hour after dusk ends. Or, in autumn, it can be seen for up to an hour before dawn. Unlike true dusk, though, there’s no rosy color to the zodiacal light. The reddish skies at dawn and dusk are caused by Earth’s atmosphere, while the zodiacal light originates far outside our atmosphere.

The darker your sky, the better your chances of seeing it. Your best bet is to pick a night when the moon is out of the sky, although it’s definitely possible, and very lovely, to see a slim crescent moon in the midst of this strange milky pyramid of light. In the springtime, the best time to look for the zodiacal light – and avoid moonlight – is a few days after the full moon through a few days after a new moon.

Zodiacal light photos from our community

View at EarthSky Community Photos. | Jeff Andrew captured this image in Summit County, Colorado, on March 13, 2023, and wrote: “A nice display of zodiacal light that appears to emanate from the setting planet Venus, but in reality is a glow of diffuse sunlight scattered by interplanetary dust. The light extends towards and past the Pleiades open star cluster and the Taurus constellation ending near the planet Mars. Also visible in this image is the Orion constellation, the Andromeda Galaxy, the Perseus constellation, the Double Star Cluster in Perseus, and the Aries constellation. In the foreground is the snow-covered Gore Mountain Range of central Colorado.” Thank you, Jeff!

View at EarthSky Community Photos. | Michael Flynn in Pine Mountain Club, California, took this image on September 26, 2022. Thank you, Michael!

View at EarthSky Community Photos. | Caroline Haldeman captured this image from Flagstaff, Arizona, on January 11, 2021. On the left you see the hazy pyramid of the zodiacal light. On the right is the starry band of the Milky Way. The image is part of a video she made, which you can see here. Thanks, Caroline!

Bottom line: If you’re in the Northern Hemisphere, you can see the zodiacal light from late February to early May as a hazy pyramid of light extending up from the western horizon, beginning about an hour after sunset. Southern Hemisphere? Look east before dawn.

Enjoying EarthSky? Sign up for our free daily newsletter today!

The post Zodiacal light best in dark skies around the March equinox first appeared on EarthSky.

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