Antarctic meteorites are sinking in melting ice

The EarthSky team created this 1-minute video summary for you.

• Some 60% of meteorites – or rocks from space – are found in Antarctica. These meteorites offer key insights about how life on Earth arose and other fundamental questions.
• But Antarctica is warming, and its ice is melting. Approximately 5,000 meteorites are now being lost annually – five times the collection rate – leading to a potential loss of 3/4 of all Antarctic meteorites by 2100.
• Scientists who study Antarctic meteorites are calling for urgent international efforts to recover as many meteorites as possible before they vanish under the ice.

Please help EarthSky keep going! Our annual crowd-funder is going on now. PLEASE DONATE today to continue enjoying updates on your cosmos and world.

Antarctic meteorites are sinking through melting ice

Meteorites – or rocks from space that strike Earth’s surface – have provided a wealth of information about other bodies in our solar system. And, to date, about 60% of all meteorites ever found on Earth have been collected from the surface of the Antarctic ice sheet. The dark rocks on the white ice sheet are easy to find. And the cold, dry environment helps keep them relatively pristine, said scientists from the Switzerland and Belgium, this month.

But, along with the rest of Earth’s globe, Antarctica is warming. And these scientists said that meteorites are dropping through melting ice. They said on April 8, 2024, that for every 1/10 of a degree of warming, approximately 9,000 meteorites sink under the ice. By 2050, about a quarter of the estimated 300,000 to 800,000 meteorites in Antarctica will be lost.

That’s around 5,000 meteorites lost in Antarctica a year, or about five times the collection rate of Antarctic meteorites.

Scientists care about this because studies of meteorites collected in Antarctica have led to insights into how life arose on Earth, and how our moon was formed. The loss of Antarctic meteorites is a blow to the pursuit of knowledge. Scientists estimate that, by the year 2100, 3/4 of all Antarctic meteorites could be lost.

The recent study of their loss came from an international team of researchers who used artificial intelligence, satellite data and climate modeling to reach their conclusions. The team published their findings in the peer-reviewed journal Nature Climate Change on April 8, 2024.

Extreme heat on blue ice in Antarctica is causing meteorites to sink beneath the surface. Image via José Jorquera (Antarctica.cl)/ University of Santiago, Chile/ ETH Zurich.

A scientist takes measurements of a meteorite sinking into the ice in Antarctica. Most meteorite samples collected from Antarctica are lying on top of the ice. But warming temperatures brings melting ice, and Antarctic meteorites are sinking, becoming lost to the science of our time. Image via Katherine Joy/ University of Manchester/ The Lost Meteorites of Antarctica project/ ETH Zurich.

Lost to melting ice

Researchers who visit Antarctica look for meteorites in areas they call meteorite stranding zones. These are regions where the flow of the ice sheet leaves a concentration of meteorites. And most meteorites have a charred crust from their fiery entry through our atmosphere, so their dark color makes them easy to spot on the white ice sheet.

So the dark color of the meteorites helps scientists locate them on the ice. But the dark color is also part of the problem. Dark colors heat up more quickly. Sunlight warms the meteorites, as it’s warming the ice the meteorites are resting upon. And thus the meteorites sink into the ice more quickly than lighter-colored objects would.

And, once the meteorites are below the ice sheet, scientists lose the ability to detect them, even at shallow depths.

Veronica Tollenaar of the Université Libre de Bruxelles said:

Even when temperatures of the ice are well below zero, the dark meteorites warm up so much in the sun that they can melt the ice directly beneath the meteorite. Through this process, the warm meteorite creates a local depression in the ice and over time fully disappears under the surface.

Climate change threatens Antarctic meteorites ??

Precious meteorites are rapidly disappearing from the ice sheet surface due to global warming. Thus, an unparalleled wealth of information on our Solar System. https://t.co/MtF4rM3ChG#Antactic #Meteorites

— ETH Zurich (@ETH_en) April 9, 2024

Save the meteorites!

Scientists who study Antarctic meteorites are calling for a major international effort to collect as many as possible before they are lost. Harry Zekollari of Vrije Universiteit Brussel in Belgium said:

We need to accelerate and intensify efforts to recover Antarctic meteorites. The loss of Antarctic meteorites is much like the loss of data that scientists glean from ice cores collected from vanishing glaciers. Once they disappear, so do some of the secrets of the universe.

Scientists are also hoping to increase the efficiency of their meteorite recovery missions. To do this, they’ll need to identify unexplored meteorite stranding zones.

The next step, they said, is to map the areas of blue ice, where most meteorite recoveries are made.

Thousands of meteorites could sink more quickly into Antarctic ice as a result of warming temperatures, accelerating the inaccessibility of many of these samples of extraterrestrial material, suggests a study published in @NatureClimate. https://t.co/mxANIjEudz pic.twitter.com/LON0GXSiPu

— Nature Portfolio (@NaturePortfolio) April 8, 2024

Bottom line: Warming temperatures are causing Antarctic meteorites to sink through melting ice. These samples of our solar system are keys to understanding earthly life. Scientists are calling for a major effort to collect as many as possible before they are gone.

Source: Antarctic meteorites threatened by climate warming

Via ETH Zurich

Read more: World’s largest iceberg headed toward warm waters

The post Antarctic meteorites are sinking in melting ice first appeared on EarthSky.

from EarthSky https://ift.tt/CNLvFGT

The EarthSky team created this 1-minute video summary for you.

• Some 60% of meteorites – or rocks from space – are found in Antarctica. These meteorites offer key insights about how life on Earth arose and other fundamental questions.
• But Antarctica is warming, and its ice is melting. Approximately 5,000 meteorites are now being lost annually – five times the collection rate – leading to a potential loss of 3/4 of all Antarctic meteorites by 2100.
• Scientists who study Antarctic meteorites are calling for urgent international efforts to recover as many meteorites as possible before they vanish under the ice.

Please help EarthSky keep going! Our annual crowd-funder is going on now. PLEASE DONATE today to continue enjoying updates on your cosmos and world.

Antarctic meteorites are sinking through melting ice

Meteorites – or rocks from space that strike Earth’s surface – have provided a wealth of information about other bodies in our solar system. And, to date, about 60% of all meteorites ever found on Earth have been collected from the surface of the Antarctic ice sheet. The dark rocks on the white ice sheet are easy to find. And the cold, dry environment helps keep them relatively pristine, said scientists from the Switzerland and Belgium, this month.

But, along with the rest of Earth’s globe, Antarctica is warming. And these scientists said that meteorites are dropping through melting ice. They said on April 8, 2024, that for every 1/10 of a degree of warming, approximately 9,000 meteorites sink under the ice. By 2050, about a quarter of the estimated 300,000 to 800,000 meteorites in Antarctica will be lost.

That’s around 5,000 meteorites lost in Antarctica a year, or about five times the collection rate of Antarctic meteorites.

Scientists care about this because studies of meteorites collected in Antarctica have led to insights into how life arose on Earth, and how our moon was formed. The loss of Antarctic meteorites is a blow to the pursuit of knowledge. Scientists estimate that, by the year 2100, 3/4 of all Antarctic meteorites could be lost.

The recent study of their loss came from an international team of researchers who used artificial intelligence, satellite data and climate modeling to reach their conclusions. The team published their findings in the peer-reviewed journal Nature Climate Change on April 8, 2024.

Extreme heat on blue ice in Antarctica is causing meteorites to sink beneath the surface. Image via José Jorquera (Antarctica.cl)/ University of Santiago, Chile/ ETH Zurich.

A scientist takes measurements of a meteorite sinking into the ice in Antarctica. Most meteorite samples collected from Antarctica are lying on top of the ice. But warming temperatures brings melting ice, and Antarctic meteorites are sinking, becoming lost to the science of our time. Image via Katherine Joy/ University of Manchester/ The Lost Meteorites of Antarctica project/ ETH Zurich.

Lost to melting ice

Researchers who visit Antarctica look for meteorites in areas they call meteorite stranding zones. These are regions where the flow of the ice sheet leaves a concentration of meteorites. And most meteorites have a charred crust from their fiery entry through our atmosphere, so their dark color makes them easy to spot on the white ice sheet.

So the dark color of the meteorites helps scientists locate them on the ice. But the dark color is also part of the problem. Dark colors heat up more quickly. Sunlight warms the meteorites, as it’s warming the ice the meteorites are resting upon. And thus the meteorites sink into the ice more quickly than lighter-colored objects would.

And, once the meteorites are below the ice sheet, scientists lose the ability to detect them, even at shallow depths.

Veronica Tollenaar of the Université Libre de Bruxelles said:

Even when temperatures of the ice are well below zero, the dark meteorites warm up so much in the sun that they can melt the ice directly beneath the meteorite. Through this process, the warm meteorite creates a local depression in the ice and over time fully disappears under the surface.

Climate change threatens Antarctic meteorites ??

Precious meteorites are rapidly disappearing from the ice sheet surface due to global warming. Thus, an unparalleled wealth of information on our Solar System. https://t.co/MtF4rM3ChG#Antactic #Meteorites

— ETH Zurich (@ETH_en) April 9, 2024

Save the meteorites!

Scientists who study Antarctic meteorites are calling for a major international effort to collect as many as possible before they are lost. Harry Zekollari of Vrije Universiteit Brussel in Belgium said:

We need to accelerate and intensify efforts to recover Antarctic meteorites. The loss of Antarctic meteorites is much like the loss of data that scientists glean from ice cores collected from vanishing glaciers. Once they disappear, so do some of the secrets of the universe.

Scientists are also hoping to increase the efficiency of their meteorite recovery missions. To do this, they’ll need to identify unexplored meteorite stranding zones.

The next step, they said, is to map the areas of blue ice, where most meteorite recoveries are made.

Thousands of meteorites could sink more quickly into Antarctic ice as a result of warming temperatures, accelerating the inaccessibility of many of these samples of extraterrestrial material, suggests a study published in @NatureClimate. https://t.co/mxANIjEudz pic.twitter.com/LON0GXSiPu

— Nature Portfolio (@NaturePortfolio) April 8, 2024

Bottom line: Warming temperatures are causing Antarctic meteorites to sink through melting ice. These samples of our solar system are keys to understanding earthly life. Scientists are calling for a major effort to collect as many as possible before they are gone.

Source: Antarctic meteorites threatened by climate warming

Via ETH Zurich

Read more: World’s largest iceberg headed toward warm waters

The post Antarctic meteorites are sinking in melting ice first appeared on EarthSky.

from EarthSky https://ift.tt/CNLvFGT

How Pluto got its heart

EarthSky’s Deborah Byrd created this 1-minute video summary for you. How Pluto got its heart!

• New insights on the origin of Pluto’s heart-shaped feature came from scientists using numerical simulations.
• They said a cataclysmic collision created the western lobe of Pluto’s heart, called Sputnik Planitia. The impacting body was over 400 miles in diameter. It altered Pluto’s inner structure.
• These scientists now doubt Pluto has a subsurface ocean. Their simulations suggest the heart’s formation and position on Pluto can explained by a local mass excess from the impact, rather than ocean dynamics.

NASA’s New Horizons spacecraft stunned the world when it captured this bright heart-shaped feature on the dwarf planet Pluto in 2015. Now scientists think they know how Pluto got its heart. Image via NASA/ Johns Hopkins University APL/ Southwest Research Institute/ University of Arizona.

How Pluto got its heart

Scientists said yesterday they have new insights about how the dwarf planet Pluto got its giant heart-shaped feature. NASA’s New Horizons spacecraft first spied Pluto’s heart when it swept past the little world in 2015. Scientists named the heart-shaped feature Tombaugh Regio for Clyde Tombaugh, who discovered Pluto in 1930. But the heart on Pluto has puzzled scientists with its unique shape, geological composition and elevation. Now scientists have used numerical simulations to investigate the origins of the western lobe of Pluto’s heart, which they call Sputnik Planitia. They said a cataclysmic event created Pluto’s heart, a collision with a planetary body a little over 400 miles (650 km) in diameter.

Meanwhile, Sputnik Planitia itself covers an area of approximately 750 by 1,250 miles (1,200 by 2,000 km), equivalent to about 1/4 of Europe or the United States.

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

These scientists – from the University of Bern in Switzerland and the University of Arizona in Tucson – published their findings in the peer-reviewed journal Nature Astronomy. They said their work suggests that the inner structure of Pluto is different from what was previously assumed.

And they said that, contrary to earlier assertions, there’s no reason to believe that Pluto – like so many small worlds in the outer solar system – has a subsurface ocean.

More than just heart-shaped

Pluto’s heart is a fantastic feature, and not just because it’s heart-shaped. It’s also covered in a brighter material than the rest of Pluto’s surface.

Plus, Sputnik Planitia – in the western lobe of the heart – is roughly 2.5 miles (4 km) lower in elevation than other parts of Pluto. Harry Ballantyne of University of Bern in Switzerland is lead author of the study. He commented:

The vast majority of Pluto’s surface consists of methane ice and its derivatives covering a water-ice crust. But the Planitia is predominantly filled with nitrogen ice, which most likely accumulated quickly after the impact due to the lower altitude.

Meanwhile, these scientists said, the eastern part of the heart is also covered by a similar but much-thinner layer of nitrogen ice. Scientists don’t entirely understand its origin. But they did suggest the origin of the heart’s western and eastern lobes are likely related.

Dead-on, or oblique?

The scientists’ statement said:

The elongated shape of Sputnik Planitia and its location at the equator strongly suggest that the impact was not a direct head-on collision but rather an oblique one. That’s according to Martin Jutzi of the University of Bern, who initiated the study.

Like several others around the world, the team used Smoothed Particle Hydrodynamics simulation software to digitally re-create the impacts. In their simulations, they varied both the composition of Pluto and its impactor, as well as the velocity and angle of the impactor.

The scientists said the simulations confirmed their suspicions about the oblique angle of impact. And, they said, it determined the composition of the impactor. Ballantyne explained:

Pluto’s core is so cold that the rocks remained very hard and did not melt despite the heat of the impact. And, thanks to the angle of impact and the low velocity, the core of the impactor did not sink into Pluto’s core. Instead, it remained intact as a splat on it.

The scientists said this core strength of Pluto – and the relatively low velocity of the impactor – were key to these simulations. They said lower core strength for Pluto would result in a symmetrical surface feature, not the heart shape observed by NASA’s New Horizons probe during its flyby of Pluto in 2015. Another study co-author, Erik Asphaug of the Lunar and Planetary Laboratory, has explored the idea of planetary “splats” to explain, for instance, features on the far side of Earth’s moon. He said:

We think of planetary collisions as incredibly intense events where you can ignore the details except for things like energy, momentum and density. But, in the distant solar system, the velocities of the impactors are much slower than closer to the sun. And solid ice, like that on Pluto’s surface, is strong. So you have to be much more precise in your calculations.

That’s where the fun starts.

Artist’s concept of the huge, slow impact on Pluto that might have led to the formation of the western lobe of the heart-shaped structure on its surface. Via Thibaut Roger/ University of Bern/ University of Arizona.

What about Pluto’s subsurface ocean?

Not long ago, scientists thought Earth was the only place in our solar system with an ocean. Now we suspect several icy moons in the outer solar system are also water worlds. These alien oceans are different from Earth’s oceans: they’re not on the surfaces of the moons, but below the moons’ surface crusts of ice. Beginning in 2020, scientists began talking about evidence for another such ocean, this time not on an outer planet moon, but on the outer dwarf planet Pluto.

The evidence was based on what the scientists called “ripples” on Pluto’s surface.

The current study contradicts the idea of an ocean for Pluto. The scientists in Arizona and Switzerland say their simulation suggests a giant impact likely occurred early in Pluto’s history. Their statement explained:

But there was a problem. A giant depression like Sputnik Planitia is expected to slowly drift toward the pole of the dwarf planet over time due to the laws of physics, since it is less massive than its surroundings. Yet it has remained near the equator. The previous theorized explanation invoked a subsurface liquid water ocean, similar to several other planetary bodies in the outer solar system. According to this hypothesis, Pluto’s icy crust would be thinner in the Sputnik Planitia region, causing the ocean to bulge upward. And since liquid water is denser than ice, it would have caused a mass surplus that induces migration toward the equator.

The new study offers an alternative perspective, according to the authors.

Their simulations suggest that – as the impactor’s core material splatted onto Pluto’s core – it created a local mass excess. This excess can explain the migration of mass toward Pluto’s equator, without the need to call upon a subsurface ocean. Or, the team said:

… at most a very thin one.

Bottom line: The New Horizons spacecraft stunned the world in 2015, when it saw a heart-shaped feature on Pluto. New computer simulations suggest an impact created Pluto’s heart.

Source: Sputnik Planitia as an impactor remnant indicative of an ancient rocky mascon in an oceanless Pluto

Via University of Arizona

The post How Pluto got its heart first appeared on EarthSky.

from EarthSky https://ift.tt/pM0vTkh

EarthSky’s Deborah Byrd created this 1-minute video summary for you. How Pluto got its heart!

• New insights on the origin of Pluto’s heart-shaped feature came from scientists using numerical simulations.
• They said a cataclysmic collision created the western lobe of Pluto’s heart, called Sputnik Planitia. The impacting body was over 400 miles in diameter. It altered Pluto’s inner structure.
• These scientists now doubt Pluto has a subsurface ocean. Their simulations suggest the heart’s formation and position on Pluto can explained by a local mass excess from the impact, rather than ocean dynamics.

NASA’s New Horizons spacecraft stunned the world when it captured this bright heart-shaped feature on the dwarf planet Pluto in 2015. Now scientists think they know how Pluto got its heart. Image via NASA/ Johns Hopkins University APL/ Southwest Research Institute/ University of Arizona.

How Pluto got its heart

Scientists said yesterday they have new insights about how the dwarf planet Pluto got its giant heart-shaped feature. NASA’s New Horizons spacecraft first spied Pluto’s heart when it swept past the little world in 2015. Scientists named the heart-shaped feature Tombaugh Regio for Clyde Tombaugh, who discovered Pluto in 1930. But the heart on Pluto has puzzled scientists with its unique shape, geological composition and elevation. Now scientists have used numerical simulations to investigate the origins of the western lobe of Pluto’s heart, which they call Sputnik Planitia. They said a cataclysmic event created Pluto’s heart, a collision with a planetary body a little over 400 miles (650 km) in diameter.

Meanwhile, Sputnik Planitia itself covers an area of approximately 750 by 1,250 miles (1,200 by 2,000 km), equivalent to about 1/4 of Europe or the United States.

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

These scientists – from the University of Bern in Switzerland and the University of Arizona in Tucson – published their findings in the peer-reviewed journal Nature Astronomy. They said their work suggests that the inner structure of Pluto is different from what was previously assumed.

And they said that, contrary to earlier assertions, there’s no reason to believe that Pluto – like so many small worlds in the outer solar system – has a subsurface ocean.

More than just heart-shaped

Pluto’s heart is a fantastic feature, and not just because it’s heart-shaped. It’s also covered in a brighter material than the rest of Pluto’s surface.

Plus, Sputnik Planitia – in the western lobe of the heart – is roughly 2.5 miles (4 km) lower in elevation than other parts of Pluto. Harry Ballantyne of University of Bern in Switzerland is lead author of the study. He commented:

The vast majority of Pluto’s surface consists of methane ice and its derivatives covering a water-ice crust. But the Planitia is predominantly filled with nitrogen ice, which most likely accumulated quickly after the impact due to the lower altitude.

Meanwhile, these scientists said, the eastern part of the heart is also covered by a similar but much-thinner layer of nitrogen ice. Scientists don’t entirely understand its origin. But they did suggest the origin of the heart’s western and eastern lobes are likely related.

Dead-on, or oblique?

The scientists’ statement said:

The elongated shape of Sputnik Planitia and its location at the equator strongly suggest that the impact was not a direct head-on collision but rather an oblique one. That’s according to Martin Jutzi of the University of Bern, who initiated the study.

Like several others around the world, the team used Smoothed Particle Hydrodynamics simulation software to digitally re-create the impacts. In their simulations, they varied both the composition of Pluto and its impactor, as well as the velocity and angle of the impactor.

The scientists said the simulations confirmed their suspicions about the oblique angle of impact. And, they said, it determined the composition of the impactor. Ballantyne explained:

Pluto’s core is so cold that the rocks remained very hard and did not melt despite the heat of the impact. And, thanks to the angle of impact and the low velocity, the core of the impactor did not sink into Pluto’s core. Instead, it remained intact as a splat on it.

The scientists said this core strength of Pluto – and the relatively low velocity of the impactor – were key to these simulations. They said lower core strength for Pluto would result in a symmetrical surface feature, not the heart shape observed by NASA’s New Horizons probe during its flyby of Pluto in 2015. Another study co-author, Erik Asphaug of the Lunar and Planetary Laboratory, has explored the idea of planetary “splats” to explain, for instance, features on the far side of Earth’s moon. He said:

We think of planetary collisions as incredibly intense events where you can ignore the details except for things like energy, momentum and density. But, in the distant solar system, the velocities of the impactors are much slower than closer to the sun. And solid ice, like that on Pluto’s surface, is strong. So you have to be much more precise in your calculations.

That’s where the fun starts.

Artist’s concept of the huge, slow impact on Pluto that might have led to the formation of the western lobe of the heart-shaped structure on its surface. Via Thibaut Roger/ University of Bern/ University of Arizona.

What about Pluto’s subsurface ocean?

Not long ago, scientists thought Earth was the only place in our solar system with an ocean. Now we suspect several icy moons in the outer solar system are also water worlds. These alien oceans are different from Earth’s oceans: they’re not on the surfaces of the moons, but below the moons’ surface crusts of ice. Beginning in 2020, scientists began talking about evidence for another such ocean, this time not on an outer planet moon, but on the outer dwarf planet Pluto.

The evidence was based on what the scientists called “ripples” on Pluto’s surface.

The current study contradicts the idea of an ocean for Pluto. The scientists in Arizona and Switzerland say their simulation suggests a giant impact likely occurred early in Pluto’s history. Their statement explained:

But there was a problem. A giant depression like Sputnik Planitia is expected to slowly drift toward the pole of the dwarf planet over time due to the laws of physics, since it is less massive than its surroundings. Yet it has remained near the equator. The previous theorized explanation invoked a subsurface liquid water ocean, similar to several other planetary bodies in the outer solar system. According to this hypothesis, Pluto’s icy crust would be thinner in the Sputnik Planitia region, causing the ocean to bulge upward. And since liquid water is denser than ice, it would have caused a mass surplus that induces migration toward the equator.

The new study offers an alternative perspective, according to the authors.

Their simulations suggest that – as the impactor’s core material splatted onto Pluto’s core – it created a local mass excess. This excess can explain the migration of mass toward Pluto’s equator, without the need to call upon a subsurface ocean. Or, the team said:

… at most a very thin one.

Bottom line: The New Horizons spacecraft stunned the world in 2015, when it saw a heart-shaped feature on Pluto. New computer simulations suggest an impact created Pluto’s heart.

Source: Sputnik Planitia as an impactor remnant indicative of an ancient rocky mascon in an oceanless Pluto

Via University of Arizona

The post How Pluto got its heart first appeared on EarthSky.

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Meet Sextans, the constellation of the sextant

Sextans the Sextant is a faint constellation south of the bright star Regulus and above Alphard in the constellation Hydra.

The constellation Sextans the Sextant represents an astronomer’s device once used to measure the positions of the stars. Johannes Hevelius named this constellation in the 1600s. Hevelius created new constellations when he carved out dark patches of sky located between more prominent constellations. He made Sextans out of the somewhat empty space between Leo the Lion and Hydra the Water Snake.

Help! EarthSky needs your support to continue. Our yearly crowd-funding campaign is going on now. Donate here.

Location and stars

Sextans the Sextant is notable for what it lacks. From the Northern Hemisphere in April, Sextans is in the deep and dark empty patch of sky beneath Leo the Lion. You’ll want to head to a dark-sky site to check out this area of sky during Northern Hemisphere’s spring. The constellation’s border begins just 6 degrees below the bright star Regulus in Leo.

The brightest star in all of Sextans, although not very bright, is a dim 4.48-magnitude light known as Alpha Sextantis. It lies about 287 light-years from Earth. Gamma Sextantis and Beta Sextantis are two 5th-magnitude stars that complete the simple V-shape of Sextans the Sextant.

Deep-sky observing targets in Sextans

Clusters and nebulae are scarce in Sextans, although many galaxies reside there. However, only one of these galaxies is brighter than 10th magnitude. That galaxy is NGC 3115. NGC 3115, aka the Spindle Galaxy, lies in the western portion of the constellation, not far from Hydra. The Spindle Galaxy is magnitude 9.9 and lies about 32 million light-years away.

It’s a lenticular galaxy that’s a few times larger than our home galaxy, the Milky Way. Lenticular galaxies have characteristics of both a spiral galaxy and an elliptical galaxy. Often we see these galaxies edge-on, making it hard to determine if they are truly ellipticals or spirals.

William Herschel discovered the Spindle Galaxy on February 22, 1787. In 1992, researchers at the University of Hawaii and University of Michigan announced that they had found a supermassive black hole at the center of this galaxy. At about 2 billion times the mass of the sun, it is one of the largest black holes known. The black hole was easy to find due to its large size compared to the rest of the galaxy. The ages of the stars show the Spindle Galaxy to be an older galaxy, and its black hole is no longer growing and consuming neighboring stars.

NGC 3115 should not be confused with NGC 5866, which is also known as the Spindle Galaxy but lies in the constellation Draco the Dragon.

NGC 3115, the Spindle Galaxy in Sextans, is a lenticular galaxy with a supermassive black hole at its center. Image via NASA. X-ray: NASA/ CXC/ University of Alabama/ K. Wong et al. Optical: ESO/ VLT.

Other notable galaxies in Sextans

Read about other unique galaxies in Sextans, including a large galaxy proto-supercluster and a bright galaxy in the early universe with first generation stars.

Bottom line: Sextans the Sextant is in a dim patch of sky that lies between Leo and Hydra and is home to some interesting galaxies.

The post Meet Sextans, the constellation of the sextant first appeared on EarthSky.

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Sextans the Sextant is a faint constellation south of the bright star Regulus and above Alphard in the constellation Hydra.

The constellation Sextans the Sextant represents an astronomer’s device once used to measure the positions of the stars. Johannes Hevelius named this constellation in the 1600s. Hevelius created new constellations when he carved out dark patches of sky located between more prominent constellations. He made Sextans out of the somewhat empty space between Leo the Lion and Hydra the Water Snake.

Help! EarthSky needs your support to continue. Our yearly crowd-funding campaign is going on now. Donate here.

Location and stars

Sextans the Sextant is notable for what it lacks. From the Northern Hemisphere in April, Sextans is in the deep and dark empty patch of sky beneath Leo the Lion. You’ll want to head to a dark-sky site to check out this area of sky during Northern Hemisphere’s spring. The constellation’s border begins just 6 degrees below the bright star Regulus in Leo.

The brightest star in all of Sextans, although not very bright, is a dim 4.48-magnitude light known as Alpha Sextantis. It lies about 287 light-years from Earth. Gamma Sextantis and Beta Sextantis are two 5th-magnitude stars that complete the simple V-shape of Sextans the Sextant.

Deep-sky observing targets in Sextans

Clusters and nebulae are scarce in Sextans, although many galaxies reside there. However, only one of these galaxies is brighter than 10th magnitude. That galaxy is NGC 3115. NGC 3115, aka the Spindle Galaxy, lies in the western portion of the constellation, not far from Hydra. The Spindle Galaxy is magnitude 9.9 and lies about 32 million light-years away.

It’s a lenticular galaxy that’s a few times larger than our home galaxy, the Milky Way. Lenticular galaxies have characteristics of both a spiral galaxy and an elliptical galaxy. Often we see these galaxies edge-on, making it hard to determine if they are truly ellipticals or spirals.

William Herschel discovered the Spindle Galaxy on February 22, 1787. In 1992, researchers at the University of Hawaii and University of Michigan announced that they had found a supermassive black hole at the center of this galaxy. At about 2 billion times the mass of the sun, it is one of the largest black holes known. The black hole was easy to find due to its large size compared to the rest of the galaxy. The ages of the stars show the Spindle Galaxy to be an older galaxy, and its black hole is no longer growing and consuming neighboring stars.

NGC 3115 should not be confused with NGC 5866, which is also known as the Spindle Galaxy but lies in the constellation Draco the Dragon.

NGC 3115, the Spindle Galaxy in Sextans, is a lenticular galaxy with a supermassive black hole at its center. Image via NASA. X-ray: NASA/ CXC/ University of Alabama/ K. Wong et al. Optical: ESO/ VLT.

Other notable galaxies in Sextans

Read about other unique galaxies in Sextans, including a large galaxy proto-supercluster and a bright galaxy in the early universe with first generation stars.

Bottom line: Sextans the Sextant is in a dim patch of sky that lies between Leo and Hydra and is home to some interesting galaxies.

The post Meet Sextans, the constellation of the sextant first appeared on EarthSky.

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Webb telescope peers into young planetary systems

New features detected by Webb are superimposed in orange on HL Tauri and its protoplanetary disk, located 357 light-years from Earth. The image reveals material in the envelope immediately surrounding the young star, apart from the larger disk. There is also an opening formed by material flowing out of the system. HL Tauri was one of the targets imaged by NASA’s Webb Space Telescope in its search for baby planets in young planetary systems. Image via Camryn Mullin et al./ The Astronomical Journal/ University of Arizona (CC BY 4.0).

• The James Webb Space Telescope has now acquired images of three planet-forming disks. These are disks of gas and dust around young stars, where new planets might be forming.
• Webb didn’t see any baby planets in the disks. But, astronomers said, the planets might orbit too closely to their stars to be seen, even by Webb. Or they might be too faint.
• One astronomer said a particular disk – around the star HL Tau – “blew his mind.” He said he saw features of the disk resembling streams, clearly showing material flowing from the young star into the planet-forming disk.

Searching for baby planets in young planetary systems

Our own solar system – our sun and its family of planets – formed from a massive disk of gas and dust around the newborn sun. Likewise, astronomers have now seen and photographed many young planet-forming disks – called protoplanetary disks – over the years.

Recently, the James Webb Space Telescope obtained its first images and observations of three young protoplanetary disks. Researchers at the University of Arizona led the new observations. They said that Webb didn’t detect any actual forming planets, but that is likely because the disks are still too young or the fledgling planets are too faint to be seen, even with Webb.

The research team, led by Jarron Leisenring at the University of Arizona’s Steward Observatory, published three peer-reviewed papers in The Astrophysical Journal on March 27, 2024. You can read them here, here and here.

Two additional papers are also being written, but are not yet published.

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.

3 protoplanetary systems

The 3rd paper details some of the most interesting findings that Webb made. Specifically, the paper focuses on a protoplanetary disk around the young star HL Tauri, or HL Tau, 457 light-years away. Like most protoplanetary disks in young planetary systems, this one has multiple rings of material in the disk.

Scientists first saw those rings using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Atacama Desert, Chile. And the gaps between the rings are where new planets might be developing.

Additionally, Webb observed the protoplanetary disk systems SAO 206462 and MWC 758, as discussed in the other two papers.

Planets or no planets?

So, do any of these protoplanetary disks have baby planets? In order to examine them in the most detail possible, the researchers combined the new Webb images with previous ones from the Hubble Space Telescope and ALMA. This enabled the astronomers to see new details of the interactions between the disks and the envelopes of gas and dust that surround the young stars.

The observations, ultimately, did not reveal the presence of any planets. But the researchers said there may be a couple of reasons for that.

Kevin Wagner, also at the University of Arizona’s Stewart Observatory, is a co-author on the HL Tau paper and lead author on the MWC 758 paper. He said:

The lack of planets detected in HL Tau, and really in all three systems, tells us that the planets causing the gaps and spiral arms either are too close to their host stars or too faint to be seen with JWST. If the latter is true, it tells us that they’re of relatively low mass, low temperature, enshrouded in dust or some combination of the three, as is likely the case in MWC 758.

View larger. | Artist’s concept of a young star still surrounded by a protoplanetary disk of gas and dust in which planets are forming. Image via ESO/ L. Calçada.

Comparison with other young planetary systems containing planets

Leisenring added:

While there is a ton of evidence for ongoing planet formation, HL Tau is too young with too much intervening dust to see the planets directly. We have already begun looking at other young systems with known planets to help form a more complete picture.

New views of proto-stellar envelopes

Even though Webb didn’t see any planets, it did make other important findings. For example, it obtained unprecedented views of the proto-stellar envelope. This envelope is a collapsing cloud of gas and dust – separate from the larger planet-forming protoplanetary disk – directly shrouding the young star. The gas and dust are just beginning to coalesce together in the envelope.

This was particularly evident in the images of HL Tauri, Wagner said:

When I saw the JWST images of HL Tau, they just blew my mind. I was expecting to see the disk or the rings, or maybe some planets in the rings, but instead, what we see are these features of the proto-stellar envelope resembling streams, clearly showing material flowing into the protoplanetary disk.

Leisenring also commented on the streams, saying:

We see a very complex and dynamic system with ‘streamers’ feeding material from the outer envelope into the inner regions of the disk, where we expect planets to be forming.

Bottom line: NASA’s Webb space telescope looked for baby planets in the protoplanetary disks of three young planetary systems. It didn’t find any so far. Scientists explain why.

Sources:

JWST/NIRCam Imaging of Young Stellar Objects. I. Constraints on Planets Exterior to the Spiral Disk Around MWC 758

JWST/NIRCam Imaging of Young Stellar Objects. II. Deep Constraints on Giant Planets and a Planet Candidate Outside of the Spiral Disk Around SAO 206462

JWST/NIRCam Imaging of Young Stellar Objects. III. Detailed Imaging of the Nebular Environment around the HL Tau Disk

Via University of Arizona

Read more: 1st planet-forming disk found in another galaxy

Read more: Astonishing image of planet-forming disk from ALMA

The post Webb telescope peers into young planetary systems first appeared on EarthSky.

from EarthSky https://ift.tt/EvjXm5o

New features detected by Webb are superimposed in orange on HL Tauri and its protoplanetary disk, located 357 light-years from Earth. The image reveals material in the envelope immediately surrounding the young star, apart from the larger disk. There is also an opening formed by material flowing out of the system. HL Tauri was one of the targets imaged by NASA’s Webb Space Telescope in its search for baby planets in young planetary systems. Image via Camryn Mullin et al./ The Astronomical Journal/ University of Arizona (CC BY 4.0).

• The James Webb Space Telescope has now acquired images of three planet-forming disks. These are disks of gas and dust around young stars, where new planets might be forming.
• Webb didn’t see any baby planets in the disks. But, astronomers said, the planets might orbit too closely to their stars to be seen, even by Webb. Or they might be too faint.
• One astronomer said a particular disk – around the star HL Tau – “blew his mind.” He said he saw features of the disk resembling streams, clearly showing material flowing from the young star into the planet-forming disk.

Searching for baby planets in young planetary systems

Our own solar system – our sun and its family of planets – formed from a massive disk of gas and dust around the newborn sun. Likewise, astronomers have now seen and photographed many young planet-forming disks – called protoplanetary disks – over the years.

Recently, the James Webb Space Telescope obtained its first images and observations of three young protoplanetary disks. Researchers at the University of Arizona led the new observations. They said that Webb didn’t detect any actual forming planets, but that is likely because the disks are still too young or the fledgling planets are too faint to be seen, even with Webb.

The research team, led by Jarron Leisenring at the University of Arizona’s Steward Observatory, published three peer-reviewed papers in The Astrophysical Journal on March 27, 2024. You can read them here, here and here.

Two additional papers are also being written, but are not yet published.

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.

3 protoplanetary systems

The 3rd paper details some of the most interesting findings that Webb made. Specifically, the paper focuses on a protoplanetary disk around the young star HL Tauri, or HL Tau, 457 light-years away. Like most protoplanetary disks in young planetary systems, this one has multiple rings of material in the disk.

Scientists first saw those rings using the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in the Atacama Desert, Chile. And the gaps between the rings are where new planets might be developing.

Additionally, Webb observed the protoplanetary disk systems SAO 206462 and MWC 758, as discussed in the other two papers.

Planets or no planets?

So, do any of these protoplanetary disks have baby planets? In order to examine them in the most detail possible, the researchers combined the new Webb images with previous ones from the Hubble Space Telescope and ALMA. This enabled the astronomers to see new details of the interactions between the disks and the envelopes of gas and dust that surround the young stars.

The observations, ultimately, did not reveal the presence of any planets. But the researchers said there may be a couple of reasons for that.

Kevin Wagner, also at the University of Arizona’s Stewart Observatory, is a co-author on the HL Tau paper and lead author on the MWC 758 paper. He said:

The lack of planets detected in HL Tau, and really in all three systems, tells us that the planets causing the gaps and spiral arms either are too close to their host stars or too faint to be seen with JWST. If the latter is true, it tells us that they’re of relatively low mass, low temperature, enshrouded in dust or some combination of the three, as is likely the case in MWC 758.

View larger. | Artist’s concept of a young star still surrounded by a protoplanetary disk of gas and dust in which planets are forming. Image via ESO/ L. Calçada.

Comparison with other young planetary systems containing planets

Leisenring added:

While there is a ton of evidence for ongoing planet formation, HL Tau is too young with too much intervening dust to see the planets directly. We have already begun looking at other young systems with known planets to help form a more complete picture.

New views of proto-stellar envelopes

Even though Webb didn’t see any planets, it did make other important findings. For example, it obtained unprecedented views of the proto-stellar envelope. This envelope is a collapsing cloud of gas and dust – separate from the larger planet-forming protoplanetary disk – directly shrouding the young star. The gas and dust are just beginning to coalesce together in the envelope.

This was particularly evident in the images of HL Tauri, Wagner said:

When I saw the JWST images of HL Tau, they just blew my mind. I was expecting to see the disk or the rings, or maybe some planets in the rings, but instead, what we see are these features of the proto-stellar envelope resembling streams, clearly showing material flowing into the protoplanetary disk.

Leisenring also commented on the streams, saying:

We see a very complex and dynamic system with ‘streamers’ feeding material from the outer envelope into the inner regions of the disk, where we expect planets to be forming.

Bottom line: NASA’s Webb space telescope looked for baby planets in the protoplanetary disks of three young planetary systems. It didn’t find any so far. Scientists explain why.

Sources:

JWST/NIRCam Imaging of Young Stellar Objects. I. Constraints on Planets Exterior to the Spiral Disk Around MWC 758

JWST/NIRCam Imaging of Young Stellar Objects. II. Deep Constraints on Giant Planets and a Planet Candidate Outside of the Spiral Disk Around SAO 206462

JWST/NIRCam Imaging of Young Stellar Objects. III. Detailed Imaging of the Nebular Environment around the HL Tau Disk

Via University of Arizona

Read more: 1st planet-forming disk found in another galaxy

Read more: Astonishing image of planet-forming disk from ALMA

The post Webb telescope peers into young planetary systems first appeared on EarthSky.

from EarthSky https://ift.tt/EvjXm5o

Media we love: The Big Ones, a book review

Seismologist Lucy Jones is the author of The Big Ones: How Natural Disasters Have Shaped Us (And What We Can Do About Them). Image via Penguin Random House.

Kelly Kizer Whitt recommends The Big Ones: How Natural Disasters Have Shaped Us (And What We Can Do About Them), a book by world-known earthquake scientist Lucy Jones. What many of us think of as disasters – earthquakes, floods, tsunamis, hurricanes, and volcanoes – are natural events. The resulting disaster isn’t inevitable. Jones discusses some of the “big ones” that changed our world and how we can work to prevent the disaster.

The Big Ones

Lucy Jones was a seismologist for the U.S. Geological Survey for more than three decades. As a native of Los Angeles, she’s done a lot to work with the local government to make the city safer. Since a seismic network was installed in Southern California in the 1990s, the region has never gone more than 12 hours without an earthquake. The majority of these earthquakes are small and not even felt by locals. They are not “Big Ones”. But the Big One, Jones says, is coming.

Jones explains how the faults in Southern California work, and that the San Andreas fault has been worn so smooth that when the next earthquake hits there, there’s nothing to keep it from growing to a magnitude 7 or 8. It’s been 330 years since the last earthquake on this particular part of the San Andreas fault, about twice the average time between its previous quakes. So, Jones says:

Someday, maybe tomorrow, maybe in a decade, probably in the lifetimes of many people reading this book, some point on the fault will lose its frictional grip and start to move. Once it does, the weak fault, with all that stored energy, will have no way of holding it back.

She expects the resulting earthquake could reach up to a magnitude 8.2.

Join us in our mission to educate and inspire people about the universe. Your donation can make a difference in astronomy and contribute to our growth and sustainability.

Natural hazards versus disasters

Natural hazards are inevitable; the disaster is not.

This is a common refrain in emergency management circles. We can’t stop earthquakes, wildfires and hurricanes from happening. But those won’t necessarily create a disaster. Disasters happen to communities that are vulnerable. Preparedness, resilience, and a swift response can prevent the destruction and suffering that creates the disaster.

California’s worst natural disaster in its history was not an earthquake. Nor was it a wildfire. It was a flood in the winter of 1861-62. A 300-mile-long (480 km) flood in the Central Valley covered farmland up to 30 feet (9 m) deep. Central Valley simply became The Lake.

This brings up a hurdle to compelling people to plan for future hazards. Our memories are short, and if it did not happen to us personally, we are more likely to discount it and may not even know about it. And, Jones says, hidden dangers provoke more fear than ones we’re familiar with. Earthquakes trigger more fear than the rain that brings a flood.

Big Ones around the world

Jones also ventures far from her native California in this book. You’ll learn about earthquakes in Portugal and China. She recounts the tsunamis of the Indian Ocean in 2004 and Japan in 2011, along with some women in Japan who found ways to help the many victims. You’ll learn more about the volcanic eruption in Pompeii and about one in Iceland in the 1700s that became the deadliest natural disaster in human history. The Laki volcanic eruption lasted for eight months and led to devastation around the globe, killing millions.

Jones sums up her book with some tips for all of us. Some of the advice she has includes:

Don’t assume government has you covered.
Work with your community.
Remember that disasters are more than the moment at which they happen.
Educate yourself.

And one way to begin to educate yourself is to read this book.

Bottom line: The Big Ones by Lucy Jones looks at some of the most destructive natural events in history, how they changed our world and how we can prepare for and recover from them.

Read more reviews in Media we love

The post Media we love: The Big Ones, a book review first appeared on EarthSky.

from EarthSky https://ift.tt/Jrw4niK

Seismologist Lucy Jones is the author of The Big Ones: How Natural Disasters Have Shaped Us (And What We Can Do About Them). Image via Penguin Random House.

Kelly Kizer Whitt recommends The Big Ones: How Natural Disasters Have Shaped Us (And What We Can Do About Them), a book by world-known earthquake scientist Lucy Jones. What many of us think of as disasters – earthquakes, floods, tsunamis, hurricanes, and volcanoes – are natural events. The resulting disaster isn’t inevitable. Jones discusses some of the “big ones” that changed our world and how we can work to prevent the disaster.

The Big Ones

Lucy Jones was a seismologist for the U.S. Geological Survey for more than three decades. As a native of Los Angeles, she’s done a lot to work with the local government to make the city safer. Since a seismic network was installed in Southern California in the 1990s, the region has never gone more than 12 hours without an earthquake. The majority of these earthquakes are small and not even felt by locals. They are not “Big Ones”. But the Big One, Jones says, is coming.

Jones explains how the faults in Southern California work, and that the San Andreas fault has been worn so smooth that when the next earthquake hits there, there’s nothing to keep it from growing to a magnitude 7 or 8. It’s been 330 years since the last earthquake on this particular part of the San Andreas fault, about twice the average time between its previous quakes. So, Jones says:

Someday, maybe tomorrow, maybe in a decade, probably in the lifetimes of many people reading this book, some point on the fault will lose its frictional grip and start to move. Once it does, the weak fault, with all that stored energy, will have no way of holding it back.

She expects the resulting earthquake could reach up to a magnitude 8.2.

Join us in our mission to educate and inspire people about the universe. Your donation can make a difference in astronomy and contribute to our growth and sustainability.

Natural hazards versus disasters

Natural hazards are inevitable; the disaster is not.

This is a common refrain in emergency management circles. We can’t stop earthquakes, wildfires and hurricanes from happening. But those won’t necessarily create a disaster. Disasters happen to communities that are vulnerable. Preparedness, resilience, and a swift response can prevent the destruction and suffering that creates the disaster.

California’s worst natural disaster in its history was not an earthquake. Nor was it a wildfire. It was a flood in the winter of 1861-62. A 300-mile-long (480 km) flood in the Central Valley covered farmland up to 30 feet (9 m) deep. Central Valley simply became The Lake.

This brings up a hurdle to compelling people to plan for future hazards. Our memories are short, and if it did not happen to us personally, we are more likely to discount it and may not even know about it. And, Jones says, hidden dangers provoke more fear than ones we’re familiar with. Earthquakes trigger more fear than the rain that brings a flood.

Big Ones around the world

Jones also ventures far from her native California in this book. You’ll learn about earthquakes in Portugal and China. She recounts the tsunamis of the Indian Ocean in 2004 and Japan in 2011, along with some women in Japan who found ways to help the many victims. You’ll learn more about the volcanic eruption in Pompeii and about one in Iceland in the 1700s that became the deadliest natural disaster in human history. The Laki volcanic eruption lasted for eight months and led to devastation around the globe, killing millions.

Jones sums up her book with some tips for all of us. Some of the advice she has includes:

Don’t assume government has you covered.
Work with your community.
Remember that disasters are more than the moment at which they happen.
Educate yourself.

And one way to begin to educate yourself is to read this book.

Bottom line: The Big Ones by Lucy Jones looks at some of the most destructive natural events in history, how they changed our world and how we can prepare for and recover from them.

Read more reviews in Media we love

The post Media we love: The Big Ones, a book review first appeared on EarthSky.

from EarthSky https://ift.tt/Jrw4niK

New Horizons finds evidence for 2nd Kuiper Belt

Only 5 earthly spacecraft are headed out of solar system, into interstellar space. These are the Pioneers 10 and 11, Voaygers 1 and 2, and New Horizons. This image shows their approximate trajectories. Image (not to scale!) via NASA/ Johns Hopkins APL/ SwRI.

• The New Horizons spacecraft, launched in 2006, achieved historic flybys of Pluto in 2015 and Arrokoth in 2019, making it the fastest spacecraft ever sent from Earth.
• Chief scientist Alan Stern here provides an update, highlighting unexpected discoveries of dust impacts, an extended Kuiper Belt or even a second one, and outlines plans for future exploration.
• Its long-term mission goals include reaching the heliosphere’s termination shock and venturing into interstellar space, using its modern instrumentation to complement the findings of NASA’s Voyager spacecraft.

New Horizons visited Pluto in 2015

Remember how exciting it was when the New Horizons spacecraft encountered Pluto? This craft – the fastest one ever sent outward from Earth – launched on January 19, 2006, passed the moon’s orbit in just 9 hours, and then spent 10 years crossing the 3-billion-mile distance to Pluto. It swept past Pluto in 2015, passing within about 7,750 miles (12,500 km) of the little world and discovering, among many other things, a large, young, heart-shaped region of ice on Pluto plus mountains made of water ice. In 2019, New Horizons swept past Arrokoth, which thereby became the farthest and most primitive object in our solar system ever to be visited by a spacecraft. On April 4, 2024, New Horizons chief scientist Alan Stern provided an update of the mission’s findings, as it continues to move outward. He said New Horizons has found evidence for a 2nd Kuiper Belt.He also said the New Horizons team is still hopeful that groundbased searches will reveal new Kuiper Belt Objects that the spacecraft might be able to explore. He reported:

The spacecraft continues to collect round-the-clock data on our sun’s cocoon in the galaxy, called the heliosphere, and transmit that data, as well as the final data from our flyby of Kuiper Belt object Arrokoth, back to Earth … The first of those was the publication of exciting new results from our onboard dust counter instrument, which you can find online. It shows that over the past few years, the instrument detected an unexpectedly high number of dust impacts.

Why is that so exciting? Because it indicates more dust at greater distances from the sun than expected, which in turn could be evidence of an extended Kuiper Belt, or even a second Kuiper Belt, lying ahead.

Join us in our mission to educate and inspire people about the universe. Your donation can make a difference in astronomy and contribute to our growth and sustainability.

The inner edge of the Kuiper Belt begins at the orbit of Neptune, at about 30 astronomical units (AU) from the sun (1 AU = 1 Earth-sun distance). The outer edge continues outward to nearly 1,000 AU, with some bodies on orbits that go even further beyond. The Kuiper Belt is much like the asteroid belt between Mars and Jupiter, but much more massive. Besides Pluto, it contains bits of rock and ice, comets and larger objects such as Eris, Makemake and Haumea. Image via Space Center Houston.

More Kuiper Belt Objects ahead?

So New Horizons is finding more dust than it expected in the far outer reaches of our solar system. And Alan Stern explained that there are other possibilities for the high dust-impact rate in this part of the solar system.

But, he said, the New Horizons team is also using groundbased telescopes to search along the spacecraft’s outbound trajectory for additional Kuiper Belt Objects. If any lie near the spacecraft’s path, perhaps it will be possible to study them. And he said those searches have led to:

… a surprising number of very distant KBOs ahead of us. That leads to a similar conclusion that the Kuiper Belt could be more extended, or even that there could be a 2nd Kuiper Belt, still farther ahead. These new groundbased results have been submitted for scientific peer review but aren’t yet published. However, a summary of them is posted here and here.

Together, these results have ignited renewed interest in the possibility of finding a distant KBO that New Horizons could fly past in the late 2020s or even 2030s. Toward that end, our team has proposed a multiyear KBO flyby target search to NASA.

If approved by NASA, that effort would initially continue the deep, groundbased KBO searches with the Japanese Subaru Telescope we’ve been using, but with more search time and a deeper search enabled by a new, high-throughput filter that the New Horizons project provided to Subaru.

Beginning in 2025 …

Then, beginning in 2025, we plan to propose to use the even more capable Vera Rubin Observatory (VRO), which is jointly funded by the National Science Foundation and the U.S. Department of Energy, for this search. VRO is a new observatory scheduled to come online in late 2024, and can search even more deeply than Subaru can.

Later, once NASA’s Roman Space Telescope is launched in 2027 or 2028, we would propose to employ this still even more capable observatory, also with custom machine-learning software and supercomputers to crunch those data.

Our calculations indicate that, given the evidence for an extended Kuiper Belt and very distant KBOs, that this triad of searches might just find New Horizons a second flyby KBO. But the calculations also show that even such a search is a longshot, looking for proverbial needles in the cosmic haystack, and might come up dry.

In 2019 New Horizons made the first spacecraft reconnaissance of any Kuiper Belt object (KBO), exploring this small and ancient world called Arrokoth, just 21 miles (33 km) long. Image via NASA/ Johns Hopkins APL/ SwRI.

Nonetheless, he said …

We know that the odds of finding a new flyby target are much more remote without this newly envisioned set of searches. We also know that the scientific payoff of another KBO close flyby for planetary science in general are immense. And the New Horizons team is eager to search. We are willing to try everything humanly possible to get to another KBO flyby. If we do succeed, we’ll have hit the jackpot, and will have the ability to once again be firing our engines to intercept a KBO for close up study, just as we did to achieve the 2019 flyby of KBO Arrokoth — the first KBO ever examined by any spacecraft!

Also just ahead for New Horizons is our continuing studies of the Sun’s outer heliosphere, observing KBOs we pass in the distance, and making other scientific measurements that only a spacecraft in the distant Kuiper Belt can make.

New Horizons is in excellent health, and has sufficient fuel and power to continue to explore into the 2040s, at least. By the late 2020s or 2030s, the spacecraft should fly through the heliosphere’s so-called termination shock, which is the precursor to the heliopause and our entry into interstellar space! NASA’s venerable Voyager spacecraft have already studied the termination shock, the heliopause and interstellar space, but New Horizons has more modern sensors aboard, to greatly supplement what the Voyagers could do.

How can New Horizons keep exploring?

Stern concluded:

To make all this possible, as our spacecraft’s nuclear battery produces less and less power each year, we plan to uplink new software. That software package is called autonomy and fault protection, and the team is already designing and coding it. After extensive testing, we expect to transmit it to New Horizons using NASA’s Deep Space Network of communications antennas. You can learn more about the Deep Space Network.
I’m excited about all of these plans for New Horizons. I’m also excited for us to continue to making scientific discoveries in data we’ve already acquired and the data we’ll collect in 2024. Nearly two-dozen scientific papers with such results, ranging from Kuiper Belt and KBO studies, to heliospheric science, and more, were published in 2023, and a similar number is planned for this year.

Ways to follow New Horizons news and commentary

NASA’s New Horizons website

New Horizons mission website

NASA New Horizons on X

New Horizons on Facebook

New Horizons eNews signup

This depiction of the Sun’s heliosphere includes the termination shock that New Horizons will cross in the years ahead, the first of several heliospheric boundaries as our spacecraft approaches interstellar space. Image via NASA/I BEX/ Adler Planetarium/ Johns Hopkins APL.

Bottom line: News from the Pluto spacecraft New Horizons. It is still alive and still speeding outward. It has recently found evidence for a 2nd Kuiper Belt. The team is hopeful new spacecraft targets will be found.

Via Alan Stern, New Horizons

The post New Horizons finds evidence for 2nd Kuiper Belt first appeared on EarthSky.

from EarthSky https://ift.tt/AF7DYH0

Only 5 earthly spacecraft are headed out of solar system, into interstellar space. These are the Pioneers 10 and 11, Voaygers 1 and 2, and New Horizons. This image shows their approximate trajectories. Image (not to scale!) via NASA/ Johns Hopkins APL/ SwRI.

• The New Horizons spacecraft, launched in 2006, achieved historic flybys of Pluto in 2015 and Arrokoth in 2019, making it the fastest spacecraft ever sent from Earth.
• Chief scientist Alan Stern here provides an update, highlighting unexpected discoveries of dust impacts, an extended Kuiper Belt or even a second one, and outlines plans for future exploration.
• Its long-term mission goals include reaching the heliosphere’s termination shock and venturing into interstellar space, using its modern instrumentation to complement the findings of NASA’s Voyager spacecraft.

New Horizons visited Pluto in 2015

Remember how exciting it was when the New Horizons spacecraft encountered Pluto? This craft – the fastest one ever sent outward from Earth – launched on January 19, 2006, passed the moon’s orbit in just 9 hours, and then spent 10 years crossing the 3-billion-mile distance to Pluto. It swept past Pluto in 2015, passing within about 7,750 miles (12,500 km) of the little world and discovering, among many other things, a large, young, heart-shaped region of ice on Pluto plus mountains made of water ice. In 2019, New Horizons swept past Arrokoth, which thereby became the farthest and most primitive object in our solar system ever to be visited by a spacecraft. On April 4, 2024, New Horizons chief scientist Alan Stern provided an update of the mission’s findings, as it continues to move outward. He said New Horizons has found evidence for a 2nd Kuiper Belt.He also said the New Horizons team is still hopeful that groundbased searches will reveal new Kuiper Belt Objects that the spacecraft might be able to explore. He reported:

The spacecraft continues to collect round-the-clock data on our sun’s cocoon in the galaxy, called the heliosphere, and transmit that data, as well as the final data from our flyby of Kuiper Belt object Arrokoth, back to Earth … The first of those was the publication of exciting new results from our onboard dust counter instrument, which you can find online. It shows that over the past few years, the instrument detected an unexpectedly high number of dust impacts.

Why is that so exciting? Because it indicates more dust at greater distances from the sun than expected, which in turn could be evidence of an extended Kuiper Belt, or even a second Kuiper Belt, lying ahead.

Join us in our mission to educate and inspire people about the universe. Your donation can make a difference in astronomy and contribute to our growth and sustainability.

The inner edge of the Kuiper Belt begins at the orbit of Neptune, at about 30 astronomical units (AU) from the sun (1 AU = 1 Earth-sun distance). The outer edge continues outward to nearly 1,000 AU, with some bodies on orbits that go even further beyond. The Kuiper Belt is much like the asteroid belt between Mars and Jupiter, but much more massive. Besides Pluto, it contains bits of rock and ice, comets and larger objects such as Eris, Makemake and Haumea. Image via Space Center Houston.

More Kuiper Belt Objects ahead?

So New Horizons is finding more dust than it expected in the far outer reaches of our solar system. And Alan Stern explained that there are other possibilities for the high dust-impact rate in this part of the solar system.

But, he said, the New Horizons team is also using groundbased telescopes to search along the spacecraft’s outbound trajectory for additional Kuiper Belt Objects. If any lie near the spacecraft’s path, perhaps it will be possible to study them. And he said those searches have led to:

… a surprising number of very distant KBOs ahead of us. That leads to a similar conclusion that the Kuiper Belt could be more extended, or even that there could be a 2nd Kuiper Belt, still farther ahead. These new groundbased results have been submitted for scientific peer review but aren’t yet published. However, a summary of them is posted here and here.

Together, these results have ignited renewed interest in the possibility of finding a distant KBO that New Horizons could fly past in the late 2020s or even 2030s. Toward that end, our team has proposed a multiyear KBO flyby target search to NASA.

If approved by NASA, that effort would initially continue the deep, groundbased KBO searches with the Japanese Subaru Telescope we’ve been using, but with more search time and a deeper search enabled by a new, high-throughput filter that the New Horizons project provided to Subaru.

Beginning in 2025 …

Then, beginning in 2025, we plan to propose to use the even more capable Vera Rubin Observatory (VRO), which is jointly funded by the National Science Foundation and the U.S. Department of Energy, for this search. VRO is a new observatory scheduled to come online in late 2024, and can search even more deeply than Subaru can.

Later, once NASA’s Roman Space Telescope is launched in 2027 or 2028, we would propose to employ this still even more capable observatory, also with custom machine-learning software and supercomputers to crunch those data.

Our calculations indicate that, given the evidence for an extended Kuiper Belt and very distant KBOs, that this triad of searches might just find New Horizons a second flyby KBO. But the calculations also show that even such a search is a longshot, looking for proverbial needles in the cosmic haystack, and might come up dry.

In 2019 New Horizons made the first spacecraft reconnaissance of any Kuiper Belt object (KBO), exploring this small and ancient world called Arrokoth, just 21 miles (33 km) long. Image via NASA/ Johns Hopkins APL/ SwRI.

Nonetheless, he said …

We know that the odds of finding a new flyby target are much more remote without this newly envisioned set of searches. We also know that the scientific payoff of another KBO close flyby for planetary science in general are immense. And the New Horizons team is eager to search. We are willing to try everything humanly possible to get to another KBO flyby. If we do succeed, we’ll have hit the jackpot, and will have the ability to once again be firing our engines to intercept a KBO for close up study, just as we did to achieve the 2019 flyby of KBO Arrokoth — the first KBO ever examined by any spacecraft!

Also just ahead for New Horizons is our continuing studies of the Sun’s outer heliosphere, observing KBOs we pass in the distance, and making other scientific measurements that only a spacecraft in the distant Kuiper Belt can make.

New Horizons is in excellent health, and has sufficient fuel and power to continue to explore into the 2040s, at least. By the late 2020s or 2030s, the spacecraft should fly through the heliosphere’s so-called termination shock, which is the precursor to the heliopause and our entry into interstellar space! NASA’s venerable Voyager spacecraft have already studied the termination shock, the heliopause and interstellar space, but New Horizons has more modern sensors aboard, to greatly supplement what the Voyagers could do.

How can New Horizons keep exploring?

Stern concluded:

To make all this possible, as our spacecraft’s nuclear battery produces less and less power each year, we plan to uplink new software. That software package is called autonomy and fault protection, and the team is already designing and coding it. After extensive testing, we expect to transmit it to New Horizons using NASA’s Deep Space Network of communications antennas. You can learn more about the Deep Space Network.
I’m excited about all of these plans for New Horizons. I’m also excited for us to continue to making scientific discoveries in data we’ve already acquired and the data we’ll collect in 2024. Nearly two-dozen scientific papers with such results, ranging from Kuiper Belt and KBO studies, to heliospheric science, and more, were published in 2023, and a similar number is planned for this year.

Ways to follow New Horizons news and commentary

NASA’s New Horizons website

New Horizons mission website

NASA New Horizons on X

New Horizons on Facebook

New Horizons eNews signup

This depiction of the Sun’s heliosphere includes the termination shock that New Horizons will cross in the years ahead, the first of several heliospheric boundaries as our spacecraft approaches interstellar space. Image via NASA/I BEX/ Adler Planetarium/ Johns Hopkins APL.

Bottom line: News from the Pluto spacecraft New Horizons. It is still alive and still speeding outward. It has recently found evidence for a 2nd Kuiper Belt. The team is hopeful new spacecraft targets will be found.

Via Alan Stern, New Horizons

The post New Horizons finds evidence for 2nd Kuiper Belt first appeared on EarthSky.

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Is Titan’s subsurface ocean habitable?

View larger. | Titan is well-known for its lakes and seas of liquid methane and ethane. This image from Cassini in 2017 shows light glinting off the lakes. But Titan is also thought to have an ocean of liquid water deep underground. Is Titan’s subsurface ocean habitable? Image via NASA/ JPL-Caltech/ University of Arizona/ University of Idaho.

Saturn’s large moon Titan teems with liquid. We’ve long known about its liquid methane and ethane lakes and seas. More recent evidence suggests a subsurface ocean of liquid water. Could Titan’s underground ocean be habitable? Earlier this year, a new study suggested it likely isn’t. The study said there probably isn’t enough organic material transferring from Titan’s surface to the ocean below to sustain life.

Astrobiologist Catherine Neish and her colleagues at Western University in Ontario, Canada published their peer-reviewed findings in the journal Astrobiology on February 2, 2024.

What does habitability mean to astronomers?

Is Titan’s subsurface ocean habitable?

NASA’s Cassini spacecraft found evidence that Titan has a deep ocean beneath its outer icy crust. This is similar to other moons such as Europa, Enceladus, Ganymede and others. But is it habitable, by earthly standards? Even with water, life still requires a source of heat, organic material and chemical nutrients. And all life on Earth uses water as a solvent to develop in. Neish said:

Life as we know it here on Earth needs water as a solvent, so planets and moons with lots of water are of interest when looking for extraterrestrial life.

Cometary impacts

We don’t yet know the exact conditions in Titan’s subsurface ocean. In the new study, however, Neish and her colleagues wanted to test how much organic material can make it from Titan’s surface down into the ocean. Organics, of course, including amino acids, are essential building blocks of life on Earth. The researchers used impact cratering data to determine how much organic material might be in Titan’s ocean. Those organics originated from the impacts on the surface.

Titan is blanketed in organics, with its hydrocarbon dunes, lakes and seas. Even its atmosphere is filled with a thick hydrocarbon. But does any of that organic material makes it down into the ocean? Impacts from comets – which can also have their own organics – can temporarily melt the icy surface. The meltwater could then sink through the ice.

The researchers estimated how many comets have impacted Titan throughout its history. Knowing this, the team could then estimate how much water has flowed from the surface down through the ice, possibly all the way to the ocean.

Not enough organics for life in Titan’s subsurface ocean

As it turned out, the results suggest that there wouldn’t be enough organics getting into the ocean to make life feasible. There would only be about 16,000 pounds (7,500 kg) per year of glycine, the simplest amino acid. That’s about the same mass as a single African male elephant. Amino acids are essential as they are the building blocks of proteins. Neish said:

One elephant per year of glycine into an ocean 12 times the volume of Earth’s oceans is not sufficient to sustain life. In the past, people often assumed that water equals life, but they neglected the fact that life needs other elements, in particular, carbon.

This work shows that it is very hard to transfer the carbon on Titan’s surface to its subsurface ocean. Basically, it’s hard to have both the water and carbon needed for life in the same place.

The paper stated:

Unless biologically available compounds can be sourced from Titan’s interior, or be delivered from the surface by other mechanisms, our calculations suggest that even the most organic-rich ocean world in the solar system may not be able to support a large biosphere.

Still much to learn about Titan’s subsurface ocean

It would be disappointing if the ocean isn’t well-suited for life. But Titan is still a fascinating world, with plenty of prebiotic chemistry occurring on its surface and in its atmosphere. As Neish noted:

Even if the subsurface ocean isn’t habitable, we can learn a lot about prebiotic chemistry on Titan, and Earth, by studying the reactions on Titan’s surface. We’d really like to know if interesting reactions are occurring there, especially where the organic molecules mix with liquid water generated in impacts.

NASA’s upcoming Dragonfly mission to Titan will be able to sample in spots where meltwater from impacts has mixed with the ice. Dragonfly is currently scheduled to launch in 2026 and arrive in 2034. Neish continued:

If all the melt produced by impacts sinks into the ice crust, we wouldn’t have samples near the surface where water and organics have mixed. These are regions where Dragonfly could search for the products of those prebiotic reactions, teaching us about how life may arise on different planets. The results from this study are even more pessimistic than I realized with regards to the habitability of Titan’s surface ocean, but it also means that more interesting prebiotic environments exist near Titan’s surface, where we can sample them with the instruments on Dragonfly.

View larger. | Titan has a global subsurface ocean of water, represented here by the dark blue layer. Image via NASA.

Pessimism about other ocean moons

The study puts forth a pessimistic view of life on the other ocean moons in the solar system as well. As Neish explained:

Unfortunately, we will now need to be a little less optimistic when searching for extraterrestrial lifeforms within our own solar system. The scientific community has been very excited about finding life in the icy worlds of the outer solar system, and this finding suggests that it may be less likely than we previously assumed.

The study argues that other ocean moons such as Europa and Enceladus have less organics and carbon on their surfaces to begin with. Therefore, they might have even less organics in their oceans.

Other moon’s oceans may still be habitable

However, other studies have pointed to those two oceans, Enceladus in particular, as being promisingly habitable. In the case of Enceladus, the Cassini spacecraft detected a variety of organic molecules in the water vapor plumes, which originate from the ocean below. There is also evidence for hydrothermal vents on the ocean floor, which would provide heat and nutrients. Enceladus’ ocean even contains phosphorus, another key building block of life.

Last September, researchers said that carbon dioxide ice deposits on Europa’s surface likely originated from its internal ocean. So at least in one way, the scenario is opposite that of Titan. The organic carbon rises to the surface through cracks, instead of sinking down through the ice. This shows that organics can indeed be present in such underground oceans, without having to get there from the surface. The organics in Enceladus’ plumes also suggest this.

Bottom line: Saturn’s largest moon Titan has an underground ocean of water. But is Titan’s subsurface ocean habitable? A new study casts doubt.

Source: Organic Input to Titan’s Subsurface Ocean Through Impact Cratering

Via Western University

Read more: Titan’s magic islands appear and disappear in liquid seas

Read more: Did Europa’s carbon dioxide come from its ocean?

The post Is Titan’s subsurface ocean habitable? first appeared on EarthSky.

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View larger. | Titan is well-known for its lakes and seas of liquid methane and ethane. This image from Cassini in 2017 shows light glinting off the lakes. But Titan is also thought to have an ocean of liquid water deep underground. Is Titan’s subsurface ocean habitable? Image via NASA/ JPL-Caltech/ University of Arizona/ University of Idaho.

Saturn’s large moon Titan teems with liquid. We’ve long known about its liquid methane and ethane lakes and seas. More recent evidence suggests a subsurface ocean of liquid water. Could Titan’s underground ocean be habitable? Earlier this year, a new study suggested it likely isn’t. The study said there probably isn’t enough organic material transferring from Titan’s surface to the ocean below to sustain life.

Astrobiologist Catherine Neish and her colleagues at Western University in Ontario, Canada published their peer-reviewed findings in the journal Astrobiology on February 2, 2024.

What does habitability mean to astronomers?

Is Titan’s subsurface ocean habitable?

NASA’s Cassini spacecraft found evidence that Titan has a deep ocean beneath its outer icy crust. This is similar to other moons such as Europa, Enceladus, Ganymede and others. But is it habitable, by earthly standards? Even with water, life still requires a source of heat, organic material and chemical nutrients. And all life on Earth uses water as a solvent to develop in. Neish said:

Life as we know it here on Earth needs water as a solvent, so planets and moons with lots of water are of interest when looking for extraterrestrial life.

Cometary impacts

We don’t yet know the exact conditions in Titan’s subsurface ocean. In the new study, however, Neish and her colleagues wanted to test how much organic material can make it from Titan’s surface down into the ocean. Organics, of course, including amino acids, are essential building blocks of life on Earth. The researchers used impact cratering data to determine how much organic material might be in Titan’s ocean. Those organics originated from the impacts on the surface.

Titan is blanketed in organics, with its hydrocarbon dunes, lakes and seas. Even its atmosphere is filled with a thick hydrocarbon. But does any of that organic material makes it down into the ocean? Impacts from comets – which can also have their own organics – can temporarily melt the icy surface. The meltwater could then sink through the ice.

The researchers estimated how many comets have impacted Titan throughout its history. Knowing this, the team could then estimate how much water has flowed from the surface down through the ice, possibly all the way to the ocean.

Not enough organics for life in Titan’s subsurface ocean

As it turned out, the results suggest that there wouldn’t be enough organics getting into the ocean to make life feasible. There would only be about 16,000 pounds (7,500 kg) per year of glycine, the simplest amino acid. That’s about the same mass as a single African male elephant. Amino acids are essential as they are the building blocks of proteins. Neish said:

One elephant per year of glycine into an ocean 12 times the volume of Earth’s oceans is not sufficient to sustain life. In the past, people often assumed that water equals life, but they neglected the fact that life needs other elements, in particular, carbon.

This work shows that it is very hard to transfer the carbon on Titan’s surface to its subsurface ocean. Basically, it’s hard to have both the water and carbon needed for life in the same place.

The paper stated:

Unless biologically available compounds can be sourced from Titan’s interior, or be delivered from the surface by other mechanisms, our calculations suggest that even the most organic-rich ocean world in the solar system may not be able to support a large biosphere.

Still much to learn about Titan’s subsurface ocean

It would be disappointing if the ocean isn’t well-suited for life. But Titan is still a fascinating world, with plenty of prebiotic chemistry occurring on its surface and in its atmosphere. As Neish noted:

Even if the subsurface ocean isn’t habitable, we can learn a lot about prebiotic chemistry on Titan, and Earth, by studying the reactions on Titan’s surface. We’d really like to know if interesting reactions are occurring there, especially where the organic molecules mix with liquid water generated in impacts.

NASA’s upcoming Dragonfly mission to Titan will be able to sample in spots where meltwater from impacts has mixed with the ice. Dragonfly is currently scheduled to launch in 2026 and arrive in 2034. Neish continued:

If all the melt produced by impacts sinks into the ice crust, we wouldn’t have samples near the surface where water and organics have mixed. These are regions where Dragonfly could search for the products of those prebiotic reactions, teaching us about how life may arise on different planets. The results from this study are even more pessimistic than I realized with regards to the habitability of Titan’s surface ocean, but it also means that more interesting prebiotic environments exist near Titan’s surface, where we can sample them with the instruments on Dragonfly.

View larger. | Titan has a global subsurface ocean of water, represented here by the dark blue layer. Image via NASA.

Pessimism about other ocean moons

The study puts forth a pessimistic view of life on the other ocean moons in the solar system as well. As Neish explained:

Unfortunately, we will now need to be a little less optimistic when searching for extraterrestrial lifeforms within our own solar system. The scientific community has been very excited about finding life in the icy worlds of the outer solar system, and this finding suggests that it may be less likely than we previously assumed.

The study argues that other ocean moons such as Europa and Enceladus have less organics and carbon on their surfaces to begin with. Therefore, they might have even less organics in their oceans.

Other moon’s oceans may still be habitable

However, other studies have pointed to those two oceans, Enceladus in particular, as being promisingly habitable. In the case of Enceladus, the Cassini spacecraft detected a variety of organic molecules in the water vapor plumes, which originate from the ocean below. There is also evidence for hydrothermal vents on the ocean floor, which would provide heat and nutrients. Enceladus’ ocean even contains phosphorus, another key building block of life.

Last September, researchers said that carbon dioxide ice deposits on Europa’s surface likely originated from its internal ocean. So at least in one way, the scenario is opposite that of Titan. The organic carbon rises to the surface through cracks, instead of sinking down through the ice. This shows that organics can indeed be present in such underground oceans, without having to get there from the surface. The organics in Enceladus’ plumes also suggest this.

Bottom line: Saturn’s largest moon Titan has an underground ocean of water. But is Titan’s subsurface ocean habitable? A new study casts doubt.

Source: Organic Input to Titan’s Subsurface Ocean Through Impact Cratering

Via Western University

Read more: Titan’s magic islands appear and disappear in liquid seas

Read more: Did Europa’s carbon dioxide come from its ocean?

The post Is Titan’s subsurface ocean habitable? first appeared on EarthSky.

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