Should we panic about interstellar comet 3I/ATLAS? – DW – 07/04/2025
Beyond the fact that this is the third known interstellar object to have entered our solar system, "we don't know very much," said Larry Denneau, co-principle investigator at ATLAS, a telescope in Chile that spotted 3I/ATLAS on July 1, 2025.
It's not exactly reassuring when scientists say "we don't know," but at least it's honest.
Astronomers do know that 3I/ATLAS is a comet that's about 670 million kilometers (416 million miles) away from the sun. Based on current projections, it poses no danger to planet Earth.
"Scientists are still determining the velocity and trajectory to a degree that will allow accurate predictions for the future," wrote Richard Moissl, who heads the European Space Agency's Planetary Defense office, in an email to DW.
The closest it will get to our planet is about 240 million kilometers away, when it will fly by in October. That is more than 1.5 times the distance between us and the sun, and about 624 times the distance between the Earth and our moon. It is also thought to be about 20 kilometers (12.4 miles) wide and traveling at about 60 kilometers per second (an impressive 134,000 miles per hour).
But this is all relatively basic data — the very data that allowed astronomers at the Asteroid Terrestrial-impact Last Alert System in Chile to spot it. When they saw the object on an unusual trajectory, they immediately began to track and measure it.
Then, other astronomers based at telescopes in Hawaii and Australia, began monitoring the object's flight progress and confirmed it as an interstellar comet.
"We are seeing an onset of [normal] cometary activity," wrote Moissl.
Comet 3I/ATLAS flew through the heliosphere to enter our solar system. The heliosphere is a barrier that protects us from interstellar winds and radiation.
The heliosphere is, however, an imperfect barrier — some interstellar radiation gets through, and it clearly doesn't stop icy intergalactic wanderers like 3I/ATLAS.
Interstellar objects in our solar system are thought to be quite rare though. The first known interstellar object was 1I/'Oumuamua, detected in 2017, and 2I/Borisov, detected in 2019.
"This is only the third interstellar [object] ever to be detected, hence a precise forecast of the expected frequency is not possible at this point," wrote Moissl.
But telescopes have got more technologically advanced and scientists do now scan the night sky continuously. So we may begin to see more of them.
"The Legacy Survey in Space and Time at the Vera Rubins telescope in Chile goes online this year. It is more efficient than existing surveys and expected to detect several new Interstellar objects over the next 10 years," said Moissl's colleague at ESA, Michael Kueppers.
Kueppers is a Comet Interceptor Project scientist. Comet Interceptor is a spacecraft that will rest in a "parking orbit" and intercept distant comets and asteroids if they come too close to Earth. It's scheduled to launch in 2029.
The short (and obvious) answer is that comets, like 3I/ATLAS, 1I/'Oumuamua and 2I/Borisov, come from other planetary systems.
To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
Much like comets and asteroids within our solar system, interstellar objects are considered to be untouched specimens from elsewhere in our galaxy, the Milky Way, if not fragments from the very beginnings of the universe.
Moissl said this new object "came roughly from the direction of the Galactic Center region," which, as the name suggests, is towards the center of the Milky Way. But astronomers do not know its precise origin or "home star."
Based on its brightness, 3I/ATLAS appears to be bigger than the other two stray comets — 1I/'Oumuamua and 2I/Borisov — which are thought to have entered our solar system from a different region of the Milky Way.
Astronomers will want to continue monitoring 3I/ATLAS to assess its composition and behavior. ESA said that as an active comet, it may heat up as it gets closer to Earth, and "sublimate" — that's when frozen gases on a comet turn into vapor, creating a glowing coma and trail of dust and ice particles.
You should be able to see it from Earth with a telescope by September — but "you'll need a big telescope to see it," wrote Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics in an email to DW.
When it's closest to Earth it will be hidden by the sun but then reappear by early December.
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DW
a day ago
- DW
Should we panic about interstellar comet 3I/ATLAS? – DW – 07/04/2025
Sometimes "the universe comes to us," writes the European Space Agency. For the third time since 2017, an interstellar object will enter our solar system. What is it and are we prepared? Beyond the fact that this is the third known interstellar object to have entered our solar system, "we don't know very much," said Larry Denneau, co-principle investigator at ATLAS, a telescope in Chile that spotted 3I/ATLAS on July 1, 2025. It's not exactly reassuring when scientists say "we don't know," but at least it's honest. Astronomers do know that 3I/ATLAS is a comet that's about 670 million kilometers (416 million miles) away from the sun. Based on current projections, it poses no danger to planet Earth. "Scientists are still determining the velocity and trajectory to a degree that will allow accurate predictions for the future," wrote Richard Moissl, who heads the European Space Agency's Planetary Defense office, in an email to DW. The closest it will get to our planet is about 240 million kilometers away, when it will fly by in October. That is more than 1.5 times the distance between us and the sun, and about 624 times the distance between the Earth and our moon. It is also thought to be about 20 kilometers (12.4 miles) wide and traveling at about 60 kilometers per second (an impressive 134,000 miles per hour). But this is all relatively basic data — the very data that allowed astronomers at the Asteroid Terrestrial-impact Last Alert System in Chile to spot it. When they saw the object on an unusual trajectory, they immediately began to track and measure it. Then, other astronomers based at telescopes in Hawaii and Australia, began monitoring the object's flight progress and confirmed it as an interstellar comet. "We are seeing an onset of [normal] cometary activity," wrote Moissl. Comet 3I/ATLAS flew through the heliosphere to enter our solar system. The heliosphere is a barrier that protects us from interstellar winds and radiation. The heliosphere is, however, an imperfect barrier — some interstellar radiation gets through, and it clearly doesn't stop icy intergalactic wanderers like 3I/ATLAS. Interstellar objects in our solar system are thought to be quite rare though. The first known interstellar object was 1I/'Oumuamua, detected in 2017, and 2I/Borisov, detected in 2019. "This is only the third interstellar [object] ever to be detected, hence a precise forecast of the expected frequency is not possible at this point," wrote Moissl. But telescopes have got more technologically advanced and scientists do now scan the night sky continuously. So we may begin to see more of them. "The Legacy Survey in Space and Time at the Vera Rubins telescope in Chile goes online this year. It is more efficient than existing surveys and expected to detect several new Interstellar objects over the next 10 years," said Moissl's colleague at ESA, Michael Kueppers. Kueppers is a Comet Interceptor Project scientist. Comet Interceptor is a spacecraft that will rest in a "parking orbit" and intercept distant comets and asteroids if they come too close to Earth. It's scheduled to launch in 2029. The short (and obvious) answer is that comets, like 3I/ATLAS, 1I/'Oumuamua and 2I/Borisov, come from other planetary systems. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Much like comets and asteroids within our solar system, interstellar objects are considered to be untouched specimens from elsewhere in our galaxy, the Milky Way, if not fragments from the very beginnings of the universe. Moissl said this new object "came roughly from the direction of the Galactic Center region," which, as the name suggests, is towards the center of the Milky Way. But astronomers do not know its precise origin or "home star." Based on its brightness, 3I/ATLAS appears to be bigger than the other two stray comets — 1I/'Oumuamua and 2I/Borisov — which are thought to have entered our solar system from a different region of the Milky Way. Astronomers will want to continue monitoring 3I/ATLAS to assess its composition and behavior. ESA said that as an active comet, it may heat up as it gets closer to Earth, and "sublimate" — that's when frozen gases on a comet turn into vapor, creating a glowing coma and trail of dust and ice particles. You should be able to see it from Earth with a telescope by September — but "you'll need a big telescope to see it," wrote Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics in an email to DW. When it's closest to Earth it will be hidden by the sun but then reappear by early December.
DW
2 days ago
- DW
Why the panic about interstellar comet 3I/ATLAS? – DW – 07/04/2025
Sometimes, "the universe comes to us," writes the European Space Agency — the third time now since 2017. What is it and are we prepared? Beyond the fact that this is the third known interstellar object to have entered our solar system, "we don't know very much," said Larry Denneau, co-principle investigator at ATLAS, a telescope in Chile that spotted 3I/ATLAS on July 1, 2025. It's not exactly reassuring when scientists say "we don't know," but at least it's honest. Astronomers do know that 3I/ATLAS is a comet that's about 670 million kilometers (416 million miles) away from the sun. Based on current projections, it poses no danger to planet Earth. "Scientists are still determining the velocity and trajectory to a degree that will allow accurate predictions for the future," wrote Richard Moissl, who heads the European Space Agency's Planetary Defense office, in an email to DW. The closest it will get to our planet is about 240 million km away, when it will fly by in October. That is more than 1.5 times the distance between us and the sun, and about 624 times the distance between the Earth and our moon. It is also thought to be about 20 km (12.4 miles) wide and traveling at about 60 km per second (an impressive 134,000 miles per hour). But this is all relatively basic data — the very data that allowed astronomers at the Asteroid Terrestrial-impact Last Alert System in Chile to spot it. When they saw the object on an unusual trajectory, they immediately began to track and measure it. Then, other astronomers based at telescopes in Hawaii and Australia, began monitoring the object's flight progress and confirm it as an interstellar comet. "We are seeing an onset of [normal] cometary activity," wrote Moissl. Comet 3I/ATLAS flew through the heliosphere to enter our solar system. The heliosphere is a barrier that protects us from interstellar winds and radiation. The heliosphere is, however, an imperfect barrier — some interstellar radiation gets through, and it clearly doesn't stop icy intergalactic wanderers, like 3I/ATLAS. Interstellar objects in our solar system are thought to be quite rare, though. The first known interstellar object was 1I/'Oumuamua, detected in 2017, and 2I/Borisov, detected in 2019. "This is only the third interstellar [object] ever to be detected, hence a precise forecast of the expected frequency is not possible at this point," wrote Moissl. But telescopes have got more technologically advanced and scientists do now scan the night sky continuously. So, we may begin to see more of them. "The Legacy Survey in Space and Time at the Vera Rubins telescope in Chile goes online this year. It is more efficient than existing surveys and expected to detect several new Interstellar Objects over the next 10 years," said Moissl's colleague at ESA, Michael Kueppers. Kueppers is a Comet Interceptor Project Scientist. Comet Interceptor is a spacecraft that will rest in a "parking orbit" and intercept distant comets and asteroids if they come too close to planet Earth. It's scheduled to launch in 2029. The short (and obvious) answer is that comets, like 3I/ATLAS, 1I/'Oumuamua and 2I/Borisov, come from other planetary systems. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Much like comets and asteroids within our solar system, interstellar objects are considered to be untouched specimens from elsewhere in our galaxy, the Milky Way — if not fragments from the very beginnings of the universe. Moissl said this new object "came roughly from the direction of the Galactic Center region," which, as the name suggests, is towards the center of the Milky Way. But astronomers do not know its precise origin or "home star". Based on its brightness, 3I/ATLAS appears to be bigger than the other two stray comets — 1I/'Oumuamua and 2I/Borisov — which are thought to have entered our solar system from a different region of the Milky Way. Astronomers will want to continue monitoring 3I/ATLAS to assess its composition and behavior. ESA said that as an active comet, it may heat up as it gets closer to Earth, and "sublimate" — that's when frozen gases on a comet turn into vapor, creating a glowing coma and trail of dust and ice particles. You should be able to see it from Earth with a telescope by September. When it's closest to Earth, it will be hidden by the sun, but then reappear by early December.
Int'l Business Times
3 days ago
- Int'l Business Times
Possible Interstellar Object Spotted Zooming Through Solar System
An object that appears to be from beyond our Solar System has been spotted hurtling towards the Sun, which if confirmed would be the third visitor from the stars ever detected, the European Space Agency said Wednesday. The object, which is currently being referred to as A11pl3Z, poses no threat to Earth, the ESA's planetary defence head Richard Moissl told AFP. "It will fly deep through the Solar System, passing just inside the orbit of Mars," but will not hit our neighbouring planet, he said. Excited astronomers are still refining their calculations, but the object appears to be zooming more than 60 kilometres (37 miles) a second. This would mean it is not bound by the Sun's orbit, unlike comets and asteroids, which all originate from within the Solar System. Its trajectory also "means it's not orbiting our star, but coming from interstellar space and flying off to there again," Moissl said. "We are not 100 percent certain at the moment, but anything else would be a surprise," he added. Official confirmation is expected to come from the International Astronomical Union's Minor Planet Center, which has recorded more than 100 observations of the object so far. The NASA-funded ATLAS survey in Hawaii first discovered the object on Tuesday, US astronomer David Rankin wrote on the social media platform Bluesky. Professional and amateur astronomers across the world then searched through past telescope data, tracing its trajectory back to at least June 14. The object is currently estimated to be roughly 10-20 kilometres wide, Moissl said. But the object could be smaller if it is made out of ice, which reflects more light. "It will get brighter and closer to the Sun until late October and then still be observable (by telescope) until next year," Moissl said. It would be the third time humanity has detected something coming from the stars. The first, 'Oumuamua, was discovered in 2017. It was so strange that at least one prominent scientist became convinced it was an alien vessel -- though this has since been dismissed by further research. Our second interstellar visitor, 2I/Borisov, was spotted in 2019. Mark Norris, an astronomer at the UK's University of Central Lancashire, told AFP that the new object appears to be "moving considerably faster than the other two extra-solar objects that we previously discovered." The object is currently roughly around the distance from Jupiter away from Earth, Norris said. He lamented that he would not be able to observe the object on his telescope on Wednesday night, because it is currently only visible in the Southern Hemisphere. Norris pointed to modelling estimating that there could be as many 10,000 interstellar objects drifting through the Solar System at any given time, though most would be smaller than the newly discovered object. If true, this suggests that the newly online Vera C. Rubin Observatory in Chile could soon be finding these dim interstellar visitors every month, Norris said. Moissl said it is not feasible to send a mission into space to intercept the new object. Still, these visitors offer scientists a rare chance to study something outside of our Solar System. For example, if we detected precursors of life such as amino acids on such an object, it would give us "a lot more confidence that the conditions for life exist in other star systems," Norris said. An artist's impression of 'Oumuamua, the first known visitor from the stars to our Solar System AFP
