Stream the party on our YouTube channel or via the player above.
Starship watch party Sunday morning … Join us!
SpaceX’s Starship will make its fifth test flight at 7 a.m. CT (12:00 UTC) on Sunday, October 13. We’ll be live watching the world’s most powerful rocket take to the sky! Join the party with EarthSky’s Dave Adalian and, who knows, maybe some surprise guests!
The launch window will open as early as 7:00 a.m. CT. As is the case with all developmental testing, the schedule is dynamic and likely to change, so be sure to stay tuned to our X account for updates.
SpaceX’s Starship will launch on its 5th test flight at 7 a.m. CT (12:00 UTC) this Sunday, October 13. Join EarthSky’s Dave Adalian for a live launch party. Watch via the player at the top of this page or on EarthSky’s YouTube page. See you then!
Stream the party on our YouTube channel or via the player above.
Starship watch party Sunday morning … Join us!
SpaceX’s Starship will make its fifth test flight at 7 a.m. CT (12:00 UTC) on Sunday, October 13. We’ll be live watching the world’s most powerful rocket take to the sky! Join the party with EarthSky’s Dave Adalian and, who knows, maybe some surprise guests!
The launch window will open as early as 7:00 a.m. CT. As is the case with all developmental testing, the schedule is dynamic and likely to change, so be sure to stay tuned to our X account for updates.
SpaceX’s Starship will launch on its 5th test flight at 7 a.m. CT (12:00 UTC) this Sunday, October 13. Join EarthSky’s Dave Adalian for a live launch party. Watch via the player at the top of this page or on EarthSky’s YouTube page. See you then!
View at EarthSky Community Photos. | Joel Weatherly captured the October 10 auroral display from Edmonton, Alberta, Canada. He wrote: “Today’s coronal mass ejection impact was potent, sparking severe geomagnetic storms and filling our skies with auroras. The pinks and reds were astonishingly vibrant to the eye. This photo is looking due east.” Beautiful shot, Joel!
Did you see the northern and southern lights?
People around the globe saw an incredible outbreak of auroras on the night of October 10 to 11, 2024. There were sightings as far south as Turkey, Mexico, Florida and the Bahamas! With geomagnetic storm levels reaching G4 (severe) for extended periods, Earth’s magnetic field went through a night of disturbance to rival the May 2024 superstorm. And the auroral displays really delivered. Here’s a collection of just some of the photos that poured into our EarthSky Community Photos page. Thank you if you submitted a photo to us!
The geomagnetic storm that brought the auroras was caused by a strong coronal mass ejection – a blob of solar material and magnetic fields – that was launched straight at Earth by an X1.8 solar flare early on October 9. It impacted Earth’s magnetic field just after midday on October 10, and geomagnetic disturbance rocketed to G4 (severe) not long after. And the aurora images started to roll in as soon as the skies darkened.
Auroras everywhere!
View at EarthSky Community Photos. | Tim Rubbert captured the auroral display from Whitefish, Montana. Tim wrote: “Looking east. The aurora borealis surrounded me in all directions and directly above.” Thank you, Tim!View at EarthSky Community Photos. | Sheryl R Garrison saw the aurora in Southern Alberta, Canada. Sheryl wrote: “It was almost impossible to choose just one photo tonight. But it was sure fun to start photographing early for a change! Amazingly beautiful show.” Agreed, Sheryl! Thank you.View at EarthSky Community Photos. | Elmarie van Rooyen in Smoky Lake, Alberta, Canada, captured last night’s aurora from below. What a great view! Thank you, Elmarie.
More amazing auroras
View at EarthSky Community Photos. | Kent Carlson had a great view of the aurora from Rocky Mountain National Park in Colorado. He wrote: “Thank you X flares! At least an hour of nice auroras, many visible to the eye. Curtains of reds and pinks lit up the sky over a diffuse base of green.” Thank you X flares indeed! And thank you, Kent.View at EarthSky Community Photos. | Arash Sefidgaran captured the aurora from Mitcham Common, London. Arash wrote: “After a powerful X1.8 solar flare was unleashed directly toward Earth on October 8, this breathtaking geomagnetic storm was perfectly predicted for the night of October 10-11, which was visible to the unaided eye even in heavily light-polluted skies! And how lucky can one be? Living in London with all its cloudy nights, yet on this night, the sky remained clear throughout!” Very lucky indeed, Arash! Thanks for sharing your photo.View at EarthSky Community Photos. | Graham Galloway imaged the October 10 aurora from Grande Prairie, Alberta, Canada. Thanks, Graham!
More aurora images
View at EarthSky Community Photos. | Martin Curran captured this image of the aurora in Cheyenne, Wyoming, on October 11, 2024. He named his photo “fire clouds”. Thank you, Martin!View at EarthSky Community Photos. | Cecille Kennedy of Depoe Bay, Oregon, captured this image on October 10, 2024, and wrote: “On the night of the northern lights, looking west, the purple pink hues of the sky and the moon’s light on the sea from the setting moon hidden behind the leaves on the left of the image make for a surreal scene.” Thank you, Cecille!View at EarthSky Community Photos. | Todd Weiler captured this image in Wisconsin. Todd wrote: “One of many red-tinted auroras that came through after midnight October 11, 2024. Looking west from Harrington State Park.” Thank you, Todd!
But wait, there’s more …
View at EarthSky Community Photos. | Diane Rains of Hudson, Wisconsin, captured this image on October 11, 2024. Diane wrote: “We had a light but blanketing cloud cover in Hudson during most of last night’s mega G4 aurora. There were a few moments of intense color, but I found the many pastel watercolor patterns to be lovely in their own right!” Thank you, Diane!View at EarthSky Community Photos. | Glenn Hughson captured this image in Lawrence, Kansas, on October 10, 2024. Glenn wrote: “I went to Clinton Lake to try and capture photos of the aurora borealis and was not disappointed! It was even clearly visible to the unaided eye for a good while! It is extremely rare to see the northern lights in this part of Kansas, but this is the brightest that I have ever seen them around here.” Thank you, Glenn!View at EarthSky Community Photos. | Lisa Durick of Grand Forks, North Dakota, captured this image on October 11, 2024. Lisa wrote: “Big Dipper floating above an aurora storm.” Thank you, Lisa!
Bottom line: People around the globe saw an incredible outbreak of auroras on the evening of October 10 to 11, 2024. Check out some of our favorite images from the EarthSky community.
View at EarthSky Community Photos. | Joel Weatherly captured the October 10 auroral display from Edmonton, Alberta, Canada. He wrote: “Today’s coronal mass ejection impact was potent, sparking severe geomagnetic storms and filling our skies with auroras. The pinks and reds were astonishingly vibrant to the eye. This photo is looking due east.” Beautiful shot, Joel!
Did you see the northern and southern lights?
People around the globe saw an incredible outbreak of auroras on the night of October 10 to 11, 2024. There were sightings as far south as Turkey, Mexico, Florida and the Bahamas! With geomagnetic storm levels reaching G4 (severe) for extended periods, Earth’s magnetic field went through a night of disturbance to rival the May 2024 superstorm. And the auroral displays really delivered. Here’s a collection of just some of the photos that poured into our EarthSky Community Photos page. Thank you if you submitted a photo to us!
The geomagnetic storm that brought the auroras was caused by a strong coronal mass ejection – a blob of solar material and magnetic fields – that was launched straight at Earth by an X1.8 solar flare early on October 9. It impacted Earth’s magnetic field just after midday on October 10, and geomagnetic disturbance rocketed to G4 (severe) not long after. And the aurora images started to roll in as soon as the skies darkened.
Auroras everywhere!
View at EarthSky Community Photos. | Tim Rubbert captured the auroral display from Whitefish, Montana. Tim wrote: “Looking east. The aurora borealis surrounded me in all directions and directly above.” Thank you, Tim!View at EarthSky Community Photos. | Sheryl R Garrison saw the aurora in Southern Alberta, Canada. Sheryl wrote: “It was almost impossible to choose just one photo tonight. But it was sure fun to start photographing early for a change! Amazingly beautiful show.” Agreed, Sheryl! Thank you.View at EarthSky Community Photos. | Elmarie van Rooyen in Smoky Lake, Alberta, Canada, captured last night’s aurora from below. What a great view! Thank you, Elmarie.
More amazing auroras
View at EarthSky Community Photos. | Kent Carlson had a great view of the aurora from Rocky Mountain National Park in Colorado. He wrote: “Thank you X flares! At least an hour of nice auroras, many visible to the eye. Curtains of reds and pinks lit up the sky over a diffuse base of green.” Thank you X flares indeed! And thank you, Kent.View at EarthSky Community Photos. | Arash Sefidgaran captured the aurora from Mitcham Common, London. Arash wrote: “After a powerful X1.8 solar flare was unleashed directly toward Earth on October 8, this breathtaking geomagnetic storm was perfectly predicted for the night of October 10-11, which was visible to the unaided eye even in heavily light-polluted skies! And how lucky can one be? Living in London with all its cloudy nights, yet on this night, the sky remained clear throughout!” Very lucky indeed, Arash! Thanks for sharing your photo.View at EarthSky Community Photos. | Graham Galloway imaged the October 10 aurora from Grande Prairie, Alberta, Canada. Thanks, Graham!
More aurora images
View at EarthSky Community Photos. | Martin Curran captured this image of the aurora in Cheyenne, Wyoming, on October 11, 2024. He named his photo “fire clouds”. Thank you, Martin!View at EarthSky Community Photos. | Cecille Kennedy of Depoe Bay, Oregon, captured this image on October 10, 2024, and wrote: “On the night of the northern lights, looking west, the purple pink hues of the sky and the moon’s light on the sea from the setting moon hidden behind the leaves on the left of the image make for a surreal scene.” Thank you, Cecille!View at EarthSky Community Photos. | Todd Weiler captured this image in Wisconsin. Todd wrote: “One of many red-tinted auroras that came through after midnight October 11, 2024. Looking west from Harrington State Park.” Thank you, Todd!
But wait, there’s more …
View at EarthSky Community Photos. | Diane Rains of Hudson, Wisconsin, captured this image on October 11, 2024. Diane wrote: “We had a light but blanketing cloud cover in Hudson during most of last night’s mega G4 aurora. There were a few moments of intense color, but I found the many pastel watercolor patterns to be lovely in their own right!” Thank you, Diane!View at EarthSky Community Photos. | Glenn Hughson captured this image in Lawrence, Kansas, on October 10, 2024. Glenn wrote: “I went to Clinton Lake to try and capture photos of the aurora borealis and was not disappointed! It was even clearly visible to the unaided eye for a good while! It is extremely rare to see the northern lights in this part of Kansas, but this is the brightest that I have ever seen them around here.” Thank you, Glenn!View at EarthSky Community Photos. | Lisa Durick of Grand Forks, North Dakota, captured this image on October 11, 2024. Lisa wrote: “Big Dipper floating above an aurora storm.” Thank you, Lisa!
Bottom line: People around the globe saw an incredible outbreak of auroras on the evening of October 10 to 11, 2024. Check out some of our favorite images from the EarthSky community.
October 12, 1915. On this date, the Scottish-born astronomer Robert Innes, at the Union Observatory in Johannesburg, South Africa, announced the discovery of what we now know as the nearest star to our sun. That star is Proxima Centauri, one of three known stars in the Alpha Centauri system, with the other two stars being Alpha Centauri A and B. He announced his discovery in a paper dated October 12, 1915, titled A Faint Star of Large Proper Motion.
Formerly, before this announcement, astronomers believed that Alpha Centauri was the closest star to our solar system.
However, Proxima – a relatively small red dwarf star – is closer at a distance of about 4.24 light-years. Conversely, Alpha Centauri lies 4.36 light-years away.
Another 2-dimensional chart showing the distance to the Alpha Centauri system – including Proxima Centauri – in light-years. Image via ESO. Used with permission.
The 100-year-anniversary celebration
By the way, SAASTA – the South African Agency for Science and Technology Advancement – celebrated Proxima’s centenary in 2015. And at its website, SAASTA explained:
Although Innes had thoroughly observed Alpha Centauri, with his vast experience and passion for observing double stars he suspected that Alpha Centauri might have a companion. Innes compared photographic plates taken five years apart and observed that a certain faint star had moved. He found that this movement was about the same as that of Alpha Centauri.
After further investigation, he concluded that it was closer to the sun than Alpha. In 1917 he proposed the new star should be called Proxima Centauri, proxima being the Latin word for ‘nearest.’
Proxima Centauri has 3 known exoplanets
Today, Proxima remains the closest star to Earth, but it is too dim to see without optical aid. Also, Proxima Centauri has three confirmed planets, known as Proxima Centauri b, c and d. So these three exoplanets are the nearest planets outside our solar system. Interestingly, Proxima b orbits inside the star’s habitable zone.
View larger. | The 2 bright stars here are Alpha and Beta Centauri. The red circle below shows the location of Proxima Centauri. It is much dimmer than its companions. Therefore, it is more difficulte to see from Earth. But, at just over one parsec away, it is the closest star to our sun. Also, sitting in the southern constellation Centaurus the Centaur, it is most likely gravitationally bound to the bright star on the right: Alpha Centauri. Image via Skatebiker/ Wikimedia Commons/ CC Share Alike 3.0.
Bottom line: October 12, 1915, was the date of the publication of a paper announcing that the little star Proxima Centauri – in the Alpha Centauri system – is the nearest star to our sun.
October 12, 1915. On this date, the Scottish-born astronomer Robert Innes, at the Union Observatory in Johannesburg, South Africa, announced the discovery of what we now know as the nearest star to our sun. That star is Proxima Centauri, one of three known stars in the Alpha Centauri system, with the other two stars being Alpha Centauri A and B. He announced his discovery in a paper dated October 12, 1915, titled A Faint Star of Large Proper Motion.
Formerly, before this announcement, astronomers believed that Alpha Centauri was the closest star to our solar system.
However, Proxima – a relatively small red dwarf star – is closer at a distance of about 4.24 light-years. Conversely, Alpha Centauri lies 4.36 light-years away.
Another 2-dimensional chart showing the distance to the Alpha Centauri system – including Proxima Centauri – in light-years. Image via ESO. Used with permission.
The 100-year-anniversary celebration
By the way, SAASTA – the South African Agency for Science and Technology Advancement – celebrated Proxima’s centenary in 2015. And at its website, SAASTA explained:
Although Innes had thoroughly observed Alpha Centauri, with his vast experience and passion for observing double stars he suspected that Alpha Centauri might have a companion. Innes compared photographic plates taken five years apart and observed that a certain faint star had moved. He found that this movement was about the same as that of Alpha Centauri.
After further investigation, he concluded that it was closer to the sun than Alpha. In 1917 he proposed the new star should be called Proxima Centauri, proxima being the Latin word for ‘nearest.’
Proxima Centauri has 3 known exoplanets
Today, Proxima remains the closest star to Earth, but it is too dim to see without optical aid. Also, Proxima Centauri has three confirmed planets, known as Proxima Centauri b, c and d. So these three exoplanets are the nearest planets outside our solar system. Interestingly, Proxima b orbits inside the star’s habitable zone.
View larger. | The 2 bright stars here are Alpha and Beta Centauri. The red circle below shows the location of Proxima Centauri. It is much dimmer than its companions. Therefore, it is more difficulte to see from Earth. But, at just over one parsec away, it is the closest star to our sun. Also, sitting in the southern constellation Centaurus the Centaur, it is most likely gravitationally bound to the bright star on the right: Alpha Centauri. Image via Skatebiker/ Wikimedia Commons/ CC Share Alike 3.0.
Bottom line: October 12, 1915, was the date of the publication of a paper announcing that the little star Proxima Centauri – in the Alpha Centauri system – is the nearest star to our sun.
EarthSky’s roving nature reporter, Kelly Kizer Whitt, spent October 3 to 5, 2024, at Minnesota’s North Shore, where the arrowhead of Minnesota meets Lake Superior. She hiked around and took in some of the area’s most popular sights, while the fall colors were at their peak. Watch a video that captures the best of this autumn explosion.
Why do leaves change color in the fall?
Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. Indeed, the vivid yellows and oranges of fall leaves are there, but hidden. However, in the fall, trees break down the green pigments and nutrients stored in their leaves. Then, the nutrients move into the tree’s roots for reuse in the spring. So, it’s then that the trees take on their autumn hues.
As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, a former professor of chemistry and biochemistry at DePauw University who studies plant pigments. For example, some tree leaves turn mostly brown, indicating that all pigments are gone.
View at EarthSky Community Photos. | Sharon Kizer, who is mother to EarthSky’s Kelly Kizer Whitt, took this image of fiery maples and rain clouds on October 9, 2022, in Madison, Wisconsin. It illustrates some of the vivid reds of autumn as leaves change color. Thank you, Sharon!
What brings out the reds in leaves?
Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:
The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves, especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.
View at EarthSky Community Photos. | Our friend Abhijit Patil captured this image via drone from northeastern Vermont on September 29, 2019. He wrote: “The brilliance is back for the season!” Thank you, Abhijit! Read more to learn why leaves change color every fall.
Sometimes there is a mixture of colors when leaves change
Furthermore, in some cases, about half of a tree’s leaves are red/orange and the other half green. Dudle says that results from micro-environmental factors, such as only half the tree is exposed to sunlight or cold.
Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.
When leaves turn color they may be protecting the tree
The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?
Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:
It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.
Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:
In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.
Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.
Country scene with golden fall leaves at Vedauwoo, Wyoming. Image via Marcy Curran.
Bottom line: Biologists discuss why leaves turn color in the fall.
EarthSky’s roving nature reporter, Kelly Kizer Whitt, spent October 3 to 5, 2024, at Minnesota’s North Shore, where the arrowhead of Minnesota meets Lake Superior. She hiked around and took in some of the area’s most popular sights, while the fall colors were at their peak. Watch a video that captures the best of this autumn explosion.
Why do leaves change color in the fall?
Throughout the spring and summer, the deep green color of chlorophyll, which helps plants absorb life-giving sunlight, hides any other colors present in the leaves of trees. Indeed, the vivid yellows and oranges of fall leaves are there, but hidden. However, in the fall, trees break down the green pigments and nutrients stored in their leaves. Then, the nutrients move into the tree’s roots for reuse in the spring. So, it’s then that the trees take on their autumn hues.
As leaves lose their chlorophyll, other pigments become visible to the human eye, according to Bryan A. Hanson, a former professor of chemistry and biochemistry at DePauw University who studies plant pigments. For example, some tree leaves turn mostly brown, indicating that all pigments are gone.
View at EarthSky Community Photos. | Sharon Kizer, who is mother to EarthSky’s Kelly Kizer Whitt, took this image of fiery maples and rain clouds on October 9, 2022, in Madison, Wisconsin. It illustrates some of the vivid reds of autumn as leaves change color. Thank you, Sharon!
What brings out the reds in leaves?
Burgundy and red colors are a different story. Dana A. Dudle is a DePauw professor of biology who researches red pigment in plant flowers, stems and leaves. Dudle said:
The red color is actively made in leaves by bright light and cold. The crisp, cold nights in the fall combine with bright, sunny days to spur production of red in leaves, especially in sugar maple and red maple trees. Burgundy leaves often result from a combination of red pigment and chlorophyll. Autumn seasons with a lot of sunny days and cold nights will have the brightest colors.
View at EarthSky Community Photos. | Our friend Abhijit Patil captured this image via drone from northeastern Vermont on September 29, 2019. He wrote: “The brilliance is back for the season!” Thank you, Abhijit! Read more to learn why leaves change color every fall.
Sometimes there is a mixture of colors when leaves change
Furthermore, in some cases, about half of a tree’s leaves are red/orange and the other half green. Dudle says that results from micro-environmental factors, such as only half the tree is exposed to sunlight or cold.
Hardwoods in the Midwest and on the East Coast are famous for good color selections. Some of the more reliably colorful trees, Hanson notes, are liquidambar trees (also called sweetgum) that turn a variety of colors on the same tree, and sometimes the same leaf. Ash tree leaves often turn a deep burgundy color. Ginkgo trees, although not native to North America, will feature an intense yellow, almost golden, color.
When leaves turn color they may be protecting the tree
The colors are doing something for the plant, or they wouldn’t be there, said Hansen. But what is the colors’ purpose?
Scientists think that with some trees, pigments serve as a kind of sunscreen to filter out sunlight. Hanson said:
It’s an underappreciated fact that plants cannot take an infinite amount of sun. Some leaves, if they get too much sun, will get something equivalent of a sunburn. They get stressed out and die.
Another theory is that the color of a plant’s leaves is often related to the ability to warn away pests or attract insect pollinators. Hanson said:
In some cases, a plant and insect might have co-evolved. One of the more intriguing scientific theories is that the beautiful leaf colors we see today are indicative of a relationship between a plant and insects that developed millions of years ago. However, as the Earth’s climate changed over the years, the insects might have gone extinct, but the plant was able to survive for whatever reason.
Because plants evolve very slowly, we still see the colors. So leaf color is a fossil memory, something that existed for a reason millions of years ago but that serves no purpose now.
Country scene with golden fall leaves at Vedauwoo, Wyoming. Image via Marcy Curran.
Bottom line: Biologists discuss why leaves turn color in the fall.
Here’s Comet Encke – whose orbit lasts only 3.3 years – riding along its pebbly trail of debris around our sun. Every October, Earth passes through Encke’s wake, resulting in the well-known Taurid meteor shower. And about every 7 years we see Taurid fireballs, or especially bright meteors. But just how large is the icy debris in Encke’s wake? Astronomers have speculated whether this comet might be the source of a doomsday asteroid swarm. Now they say that’s less likely. Image via NASA/ JPL-Caltech/ Univ. of Minnesota.
Every year, Earth plows through icy debris left behind by Comet Encke. These small particles strike Earth and light the sky in an annual meteor shower known as the Taurids.
Astronomers feared there were larger chunks – perhaps kilometer-sized rocks – in the comet’s orbit, which might also plow into Earth with destructive force.
But a new study suggests there are fewer large asteroids than once expected, perhaps just nine to 14. They also think Comet Encke itself is about 10 times smaller than they once believed.
Astronomers have good news about potentially hazardous asteroids lurking near our planet: there aren’t as many as we thought.
A team of researchers led by the University of Maryland used the Zwicky Transient Facility (ZTF) telescope to survey large expanses of sky. They investigated a stream of space debris known to drift near Earth called the Taurid swarm. The Taurids are likely remnants of a large comet called Encke. They appear from Earth as highly visible meteor showers in October and November. This region has long intrigued astronomers due to its potential for harboring hidden, dangerous asteroids. But researchers could not confirm or disprove the existence of such hazards … until now.
The group announced its findings at the American Astronomical Society’s Division for Planetary Sciences annual meeting on October 8, 2024.
Quanzhi Ye, who supervised the project and is an assistant research scientist in UMD’s Department of Astronomy, said:
We took advantage of a rare opportunity when this swarm of asteroids passed closer to Earth, allowing us to more efficiently search for objects that could pose a threat to our planet. Our findings suggest that the risk of being hit by a large asteroid in the Taurid swarm is much lower than we believed, which is great news for planetary defense.
Large asteroids in the Taurid swarm?
Prior to this study, researchers speculated the Taurid swarm contained a considerable number of large, kilometer-class space rocks. These rocks would’ve been left behind by a large object possibly up to 100 kilometers (62 miles) wide. Large objects can cause regional damage if they were to impact Earth. For example, the Chelyabinsk asteroid that hit Russia in 2013 injured more than 1,600 people. Even larger objects can cause extinction-level events, such as the asteroid that killed the dinosaurs over 66 million years ago.
Ye explained:
Fortunately, we found that it’s likely there may only be a handful of asteroids – perhaps only nine to 14 of them – that fit this large size class in the swarm. Judging from our findings, the parent object that originally created the swarm was probably closer to 10 kilometers in diameter rather than a massive 100-kilometer object. While we still need to be vigilant about asteroid impacts, we can probably sleep better knowing these results.
Important clues to planetary evolution
According to Ye, the Taurid swarm holds important clues about planetary evolution, especially due to its connection to Comet Encke. Encke has the one of the shortest orbital periods (the time it takes to complete one rotation around the sun) of known comets at just 3.3 years. It’s also unusually large and dusty for a short-period comet (orbiting the sun in 200 years or less). Considering all available evidence, scientists believe Encke experienced significant fragmentation in the past. And it may continue to fall apart similarly in the future.
Ye said:
Studying the Taurid swarm helps us understand how small celestial bodies like comets and asteroids form and break apart over time. Our research has implications not just for asteroid detection and planetary defense, but also for our broader understanding of solar system objects.
While the study’s results are reassuring, the team believes that they also underscore the need for ongoing vigilance and improved detection capabilities. Using advanced facilities such as the ZTF telescope, which can efficiently conduct vast sky surveys and track potentially hazardous near-Earth objects, the researchers plan to conduct follow-up observations in the coming years when the Taurid asteroid swarm passes close to Earth again. Ye said:
We have opportunities in 2025 and 2026 to further refine our results. As a result, we’re excited to continue this important work.
Bottom line: Astronomers studying the debris that causes the Taurid meteor shower said it’s unlikely there’s a doomsday asteroid swarm with many large asteroids hidden in the debris.
Here’s Comet Encke – whose orbit lasts only 3.3 years – riding along its pebbly trail of debris around our sun. Every October, Earth passes through Encke’s wake, resulting in the well-known Taurid meteor shower. And about every 7 years we see Taurid fireballs, or especially bright meteors. But just how large is the icy debris in Encke’s wake? Astronomers have speculated whether this comet might be the source of a doomsday asteroid swarm. Now they say that’s less likely. Image via NASA/ JPL-Caltech/ Univ. of Minnesota.
Every year, Earth plows through icy debris left behind by Comet Encke. These small particles strike Earth and light the sky in an annual meteor shower known as the Taurids.
Astronomers feared there were larger chunks – perhaps kilometer-sized rocks – in the comet’s orbit, which might also plow into Earth with destructive force.
But a new study suggests there are fewer large asteroids than once expected, perhaps just nine to 14. They also think Comet Encke itself is about 10 times smaller than they once believed.
Astronomers have good news about potentially hazardous asteroids lurking near our planet: there aren’t as many as we thought.
A team of researchers led by the University of Maryland used the Zwicky Transient Facility (ZTF) telescope to survey large expanses of sky. They investigated a stream of space debris known to drift near Earth called the Taurid swarm. The Taurids are likely remnants of a large comet called Encke. They appear from Earth as highly visible meteor showers in October and November. This region has long intrigued astronomers due to its potential for harboring hidden, dangerous asteroids. But researchers could not confirm or disprove the existence of such hazards … until now.
The group announced its findings at the American Astronomical Society’s Division for Planetary Sciences annual meeting on October 8, 2024.
Quanzhi Ye, who supervised the project and is an assistant research scientist in UMD’s Department of Astronomy, said:
We took advantage of a rare opportunity when this swarm of asteroids passed closer to Earth, allowing us to more efficiently search for objects that could pose a threat to our planet. Our findings suggest that the risk of being hit by a large asteroid in the Taurid swarm is much lower than we believed, which is great news for planetary defense.
Large asteroids in the Taurid swarm?
Prior to this study, researchers speculated the Taurid swarm contained a considerable number of large, kilometer-class space rocks. These rocks would’ve been left behind by a large object possibly up to 100 kilometers (62 miles) wide. Large objects can cause regional damage if they were to impact Earth. For example, the Chelyabinsk asteroid that hit Russia in 2013 injured more than 1,600 people. Even larger objects can cause extinction-level events, such as the asteroid that killed the dinosaurs over 66 million years ago.
Ye explained:
Fortunately, we found that it’s likely there may only be a handful of asteroids – perhaps only nine to 14 of them – that fit this large size class in the swarm. Judging from our findings, the parent object that originally created the swarm was probably closer to 10 kilometers in diameter rather than a massive 100-kilometer object. While we still need to be vigilant about asteroid impacts, we can probably sleep better knowing these results.
Important clues to planetary evolution
According to Ye, the Taurid swarm holds important clues about planetary evolution, especially due to its connection to Comet Encke. Encke has the one of the shortest orbital periods (the time it takes to complete one rotation around the sun) of known comets at just 3.3 years. It’s also unusually large and dusty for a short-period comet (orbiting the sun in 200 years or less). Considering all available evidence, scientists believe Encke experienced significant fragmentation in the past. And it may continue to fall apart similarly in the future.
Ye said:
Studying the Taurid swarm helps us understand how small celestial bodies like comets and asteroids form and break apart over time. Our research has implications not just for asteroid detection and planetary defense, but also for our broader understanding of solar system objects.
While the study’s results are reassuring, the team believes that they also underscore the need for ongoing vigilance and improved detection capabilities. Using advanced facilities such as the ZTF telescope, which can efficiently conduct vast sky surveys and track potentially hazardous near-Earth objects, the researchers plan to conduct follow-up observations in the coming years when the Taurid asteroid swarm passes close to Earth again. Ye said:
We have opportunities in 2025 and 2026 to further refine our results. As a result, we’re excited to continue this important work.
Bottom line: Astronomers studying the debris that causes the Taurid meteor shower said it’s unlikely there’s a doomsday asteroid swarm with many large asteroids hidden in the debris.
Europa Clipper is NASA’s mission to explore one of Jupiter’s four large Galilean satellites. Europa has an icy outer crust that covers an ocean world. It holds twice as much water as Earth. So, Scientists want to know more about the habitability of this large moon.
To get Europa Clipper from Earth to Jupiter in about 5 1/2 years, the trajectory has to take advantage of flybys in the solar system. Therefore, the mission must launch between October 10 and Nov 5, 2024, due to planetary alignments. The first date, October 10, became a no-go after Hurricane Milton appeared on the scene, threatening Florida. Here’s a list of the next launch opportunities for the mission.
If the launch goes as planned, Europa Clipper will arrive at Jupiter in April 2030.
Europa Clipper is NASA’s largest planetary exploration spacecraft yet. When the solar sails unfold, they’ll be 100 feet (30 meters) tall. At launch, the spacecraft will weigh as much as an African elephant.
What will the mission do?
Europa Clipper carries nine instruments. Some of the instruments will look down at the moon and record what it observes. While others will sample the environment the spacecraft passes through. The space around Europa is bathed with intense radiation from Jupiter. But this region may also have plumes of water erupting from under the moon’s icy crust.
To protect the spacecraft, Europa Clipper will be orbiting Jupiter and not the moon itself. The spacecraft will only dip into Europa’s environment during close flybys. The spacecraft will make 49 flybys, one every two to three weeks of its mission. Europa Clipper will get as close as 16 miles (25 km) from the moon’s surface.
The mission’s three main science objectives are to understand the nature of the ice shell and the ocean beneath it, along with the moon’s composition and geology. The mission’s detailed exploration of Europa will help scientists better understand the astrobiological potential for habitable worlds beyond our planet.
View larger. | Artist’s concept of Europa Clipper sweeping past Europa, one of the large, fascinating moons of giant Jupiter. Image via NASA/ JPL-Caltech.
Could Europa be habitable?
Could life exist in the oceans of Europa under the layers of ice? That’s what scientists want to know. Plus, how is there liquid water under ice in such a cold place? James O’Donoghue of the University of Reading wrote for The Conversation:
The water in Europa’s ocean is kept liquid due to frictional heating. This heating occurs because Europa becomes stretched and then relaxed as it interacts with Jupiter’s gravity on its orbital path around the giant planet. For Europa’s ocean to be habitable, a steady supply of ingredients is needed to allow some form of chemosynthesis to take place.
If these ingredients exist, they could come from hydrothermal vents on Europa’s rocky seafloor, like those on Earth, or from material seeping down through the icy crust, the ‘sea ceiling’ if you like. We do not yet know if these mechanisms are plausible, so we need more data from many different angles.
There is growing evidence that plumes of material are escaping from Europa’s surface into space. If this material is from the ocean, measuring its composition would give us insights into the habitability of that ocean.
Artist’s concept (not to scale) showing a cutaway of Europa’s interior. At top is the outer icy shell with plumes, then an ocean of liquid water and finally a rocky interior with possible hydrothermal vents on the seafloor. Image via NASA/ JPL-Caltech.
Bottom line: Europa Clipper is NASA’s mission to explore the icy, ocean moon of Jupiter. Scientists want to know if life could exist in Europa’s ocean.
Europa Clipper is NASA’s mission to explore one of Jupiter’s four large Galilean satellites. Europa has an icy outer crust that covers an ocean world. It holds twice as much water as Earth. So, Scientists want to know more about the habitability of this large moon.
To get Europa Clipper from Earth to Jupiter in about 5 1/2 years, the trajectory has to take advantage of flybys in the solar system. Therefore, the mission must launch between October 10 and Nov 5, 2024, due to planetary alignments. The first date, October 10, became a no-go after Hurricane Milton appeared on the scene, threatening Florida. Here’s a list of the next launch opportunities for the mission.
If the launch goes as planned, Europa Clipper will arrive at Jupiter in April 2030.
Europa Clipper is NASA’s largest planetary exploration spacecraft yet. When the solar sails unfold, they’ll be 100 feet (30 meters) tall. At launch, the spacecraft will weigh as much as an African elephant.
What will the mission do?
Europa Clipper carries nine instruments. Some of the instruments will look down at the moon and record what it observes. While others will sample the environment the spacecraft passes through. The space around Europa is bathed with intense radiation from Jupiter. But this region may also have plumes of water erupting from under the moon’s icy crust.
To protect the spacecraft, Europa Clipper will be orbiting Jupiter and not the moon itself. The spacecraft will only dip into Europa’s environment during close flybys. The spacecraft will make 49 flybys, one every two to three weeks of its mission. Europa Clipper will get as close as 16 miles (25 km) from the moon’s surface.
The mission’s three main science objectives are to understand the nature of the ice shell and the ocean beneath it, along with the moon’s composition and geology. The mission’s detailed exploration of Europa will help scientists better understand the astrobiological potential for habitable worlds beyond our planet.
View larger. | Artist’s concept of Europa Clipper sweeping past Europa, one of the large, fascinating moons of giant Jupiter. Image via NASA/ JPL-Caltech.
Could Europa be habitable?
Could life exist in the oceans of Europa under the layers of ice? That’s what scientists want to know. Plus, how is there liquid water under ice in such a cold place? James O’Donoghue of the University of Reading wrote for The Conversation:
The water in Europa’s ocean is kept liquid due to frictional heating. This heating occurs because Europa becomes stretched and then relaxed as it interacts with Jupiter’s gravity on its orbital path around the giant planet. For Europa’s ocean to be habitable, a steady supply of ingredients is needed to allow some form of chemosynthesis to take place.
If these ingredients exist, they could come from hydrothermal vents on Europa’s rocky seafloor, like those on Earth, or from material seeping down through the icy crust, the ‘sea ceiling’ if you like. We do not yet know if these mechanisms are plausible, so we need more data from many different angles.
There is growing evidence that plumes of material are escaping from Europa’s surface into space. If this material is from the ocean, measuring its composition would give us insights into the habitability of that ocean.
Artist’s concept (not to scale) showing a cutaway of Europa’s interior. At top is the outer icy shell with plumes, then an ocean of liquid water and finally a rocky interior with possible hydrothermal vents on the seafloor. Image via NASA/ JPL-Caltech.
Bottom line: Europa Clipper is NASA’s mission to explore the icy, ocean moon of Jupiter. Scientists want to know if life could exist in Europa’s ocean.
The star Alpheratz is the brightest star in the famous star pattern known as the Great Square of Pegasus. Alpheratz connects Pegasus to the constellation Andromeda. And people often find the Andromeda Galaxy by star-hopping from Alpheratz – to Mirach and Mu Andromedae – to the galaxy. Chart via EarthSky.
The Great Square of Pegasus
There’s a large, easily recognizable pattern of four medium-bright stars – up in the sky on October and November evenings – that stargazers call the Great Square of Pegasus. However, one of these stars doesn’t formally belong to the constellation Pegasus. It’s Alpheratz, the brightest star in the constellation Andromeda. In fact, many people use this star to locate the Andromeda Galaxy in the night sky. While it appears as a single star to the unaided eye, Alpheratz is actually a tight double star system.
When can you see the star Alpheratz?
This star reaches its midnight culmination – its highest point in the sky at midnight – on October 9. So, it’s generally considered an autumn star for Northern Hemisphere observers. Yet you can see it in the summertime when it rises late at night. And by late winter, Alpheratz is setting with the sun.
At magnitude 2.06, Alpheratz isn’t as bright as the sky’s brightest stars. But you can spot it easily, except in very light-polluted areas.
Use Alpheratz to find the Andromeda Galaxy
The Andromeda galaxy, also known as M31, is the nearest large spiral galaxy to Earth. It’s the most distant thing we can see with the unaided eye, though you’ll need a dark sky to see it. Autumn is a good time to look.
People often find the Andromeda Galaxy by star-hopping from Alpheratz to two other stars in the constellation Andromeda, Mirach and Mu Andromedae. After you find those two stars, you can draw a line between them, and extend that line to find the galaxy, as shown in the chart below.
Alpheratz, at a relatively nearby distance of 97 light-years, is actually two stars orbiting about a common center of gravity every 97 days. We know it’s a binary stellar system because Alpheratz’s light spectrum shows two distinct sets of spectroscopic lines.
The larger of the pair is almost four times the sun’s mass, close to three times its size, and 200 times the sun’s total brightness. Its surface temperature is high, almost 14,000 Kelvin (approximately 27,400 Fahrenheit or 13,700 Celsius), more than twice that of our sun (that has a surface temperature of less than half that at 5,778 Kelvin). The spectral class of this star is B8p. The B8 represents a star that is much hotter and more massive than our sun. The “p” indicates that this is a “peculiar” star. It is peculiar in the sense that its spectrum reveals an unexpected amount of manganese and mercury.
The smaller companion is almost twice the sun’s mass and over 1 1/2 times its size. Its surface temperature is also hotter than the sun’s, at 8,500 Kelvin (14,840 F or 8,227 C), with a total brightness 10 times that of the sun.
Together, these two hot stars appear blue in the sky.
History and mythology
The most interesting part of this star’s history, from our modern perspective, is its assignment to the constellation Andromeda in the 1930s by the International Astronomical Union (IAU). Before that, Alpheratz was often referred to as Delta Pegasi, indicating that it was the fourth-brightest star in Pegasus. But some classical star charts showed it as part of Andromeda. So, it was considered part of the constellation Pegasus, or part of the constellation Andromeda, or, by some people, part of both constellations. Today, Alpheratz is officially Alpha Andromedae, the brightest star in Andromeda.
Early Arabian stargazers certainly saw Alpheratz as part of Pegasus, not Andromeda. We know this because the name Alpheratz derives from an Arabic phrase meaning the horse’s navel. This is an obvious reference to Pegasus the Flying Horse. Also, according to Richard Hinckley Allen, in his classic book “Star Names, Their Lore and Meaning,” Alpheratz was also called Sirrah, a derivation of another Arabic name, Surrat al Faras or the horse’s navel.
View at EarthSky Community Photos. | Jan Curtis in Cheyenne, Wyoming, used a telephoto lens to capture this view of Messier 31, the Andromeda galaxy, on September 25, 2024. Jan wrote: “With the Fujifilm X-T5, the sensor resolution is 45 MB. As a result, deep-sky images can be chopped without loss of resolution. M31 is well placed this time of year for all night viewing. Taken from Cheyenne, WY, under clear Bortle 5.5 skies.” Thank you, Jan!
Bottom line: Alpheratz appears to our eyes as a single star but it is actually a close binary star system. Many stargazers use it to locate the Andromeda Galaxy.
The star Alpheratz is the brightest star in the famous star pattern known as the Great Square of Pegasus. Alpheratz connects Pegasus to the constellation Andromeda. And people often find the Andromeda Galaxy by star-hopping from Alpheratz – to Mirach and Mu Andromedae – to the galaxy. Chart via EarthSky.
The Great Square of Pegasus
There’s a large, easily recognizable pattern of four medium-bright stars – up in the sky on October and November evenings – that stargazers call the Great Square of Pegasus. However, one of these stars doesn’t formally belong to the constellation Pegasus. It’s Alpheratz, the brightest star in the constellation Andromeda. In fact, many people use this star to locate the Andromeda Galaxy in the night sky. While it appears as a single star to the unaided eye, Alpheratz is actually a tight double star system.
When can you see the star Alpheratz?
This star reaches its midnight culmination – its highest point in the sky at midnight – on October 9. So, it’s generally considered an autumn star for Northern Hemisphere observers. Yet you can see it in the summertime when it rises late at night. And by late winter, Alpheratz is setting with the sun.
At magnitude 2.06, Alpheratz isn’t as bright as the sky’s brightest stars. But you can spot it easily, except in very light-polluted areas.
Use Alpheratz to find the Andromeda Galaxy
The Andromeda galaxy, also known as M31, is the nearest large spiral galaxy to Earth. It’s the most distant thing we can see with the unaided eye, though you’ll need a dark sky to see it. Autumn is a good time to look.
People often find the Andromeda Galaxy by star-hopping from Alpheratz to two other stars in the constellation Andromeda, Mirach and Mu Andromedae. After you find those two stars, you can draw a line between them, and extend that line to find the galaxy, as shown in the chart below.
Alpheratz, at a relatively nearby distance of 97 light-years, is actually two stars orbiting about a common center of gravity every 97 days. We know it’s a binary stellar system because Alpheratz’s light spectrum shows two distinct sets of spectroscopic lines.
The larger of the pair is almost four times the sun’s mass, close to three times its size, and 200 times the sun’s total brightness. Its surface temperature is high, almost 14,000 Kelvin (approximately 27,400 Fahrenheit or 13,700 Celsius), more than twice that of our sun (that has a surface temperature of less than half that at 5,778 Kelvin). The spectral class of this star is B8p. The B8 represents a star that is much hotter and more massive than our sun. The “p” indicates that this is a “peculiar” star. It is peculiar in the sense that its spectrum reveals an unexpected amount of manganese and mercury.
The smaller companion is almost twice the sun’s mass and over 1 1/2 times its size. Its surface temperature is also hotter than the sun’s, at 8,500 Kelvin (14,840 F or 8,227 C), with a total brightness 10 times that of the sun.
Together, these two hot stars appear blue in the sky.
History and mythology
The most interesting part of this star’s history, from our modern perspective, is its assignment to the constellation Andromeda in the 1930s by the International Astronomical Union (IAU). Before that, Alpheratz was often referred to as Delta Pegasi, indicating that it was the fourth-brightest star in Pegasus. But some classical star charts showed it as part of Andromeda. So, it was considered part of the constellation Pegasus, or part of the constellation Andromeda, or, by some people, part of both constellations. Today, Alpheratz is officially Alpha Andromedae, the brightest star in Andromeda.
Early Arabian stargazers certainly saw Alpheratz as part of Pegasus, not Andromeda. We know this because the name Alpheratz derives from an Arabic phrase meaning the horse’s navel. This is an obvious reference to Pegasus the Flying Horse. Also, according to Richard Hinckley Allen, in his classic book “Star Names, Their Lore and Meaning,” Alpheratz was also called Sirrah, a derivation of another Arabic name, Surrat al Faras or the horse’s navel.
View at EarthSky Community Photos. | Jan Curtis in Cheyenne, Wyoming, used a telephoto lens to capture this view of Messier 31, the Andromeda galaxy, on September 25, 2024. Jan wrote: “With the Fujifilm X-T5, the sensor resolution is 45 MB. As a result, deep-sky images can be chopped without loss of resolution. M31 is well placed this time of year for all night viewing. Taken from Cheyenne, WY, under clear Bortle 5.5 skies.” Thank you, Jan!
Bottom line: Alpheratz appears to our eyes as a single star but it is actually a close binary star system. Many stargazers use it to locate the Andromeda Galaxy.
