Latest news with #Binzel
Yahoo
03-03-2025
- Science
- Yahoo
Why do the odds of asteroids hitting Earth keep fluctuating?
Recently the asteroid 2024 YR4, which is expected to pass Earth in 2032, was calculated to have a 1 in 83 chance of striking our planet. Then a week passed and suddenly there was a new headline: Asteroid 2024 YR4 was now believed to have only a 1 in 43 chance of striking our planet — the highest odds ever recorded for a space rock to hit our planet. Later the space rock fluctuated again, this time to a figuratively and literally astronomical 1 in 59,000 chance for impact. In short, asteroid 2024 YR4 went from breaking records for known threatening asteroids to being a near-zero threat. At some point in the near future, this risk may be out of date. The rock is 130 – 300 feet across (40 – 90 meters), meaning if such a collision were to occur, it would at the very least cause an airburst, shattering windows and infrastructure if it took place near a large city. The impact would be much less damaging if it occurred over the ocean, as asteroid 2024 YR4 is not large enough even at the outer range of projections to trigger a tsunami. Even so, most humans want absolute zero certainty rather than near-zero likelihood in their disaster forecasts. Reality does not instill the same confidence one sees in sci-fi depictions of scenarios in which near-Earth objects like asteroids and comets approach our planet. In 'Deep Impact' and 'Armageddon,' astronauts know for sure that our planet is in danger, how much time they have to solve the problem and how to use nuclear weapons to blow up those dangerous near-Earth objects before they wipe out all life as we know it. Yet according to Richard P. Binzel, a professor of astronomy and planetary science at the Massachusetts Institute of Technology who invented the Torino Impact Hazard Scale for measuring these space rocks, we should not think in terms of conclusive eventualities and solutions on this issue. Binzel literally created the system scientists and ordinary people alike utilize to assess the threats posed by near-Earth objects on a scale of 0 (no threat) to 10 (will definitely hit Earth and destroy all life.) Because the sky is so vast and our knowledge of it is so limited that the scale is not capable of doing anything more than operating within probabilities. This way the Torino scale allows our species to honestly know what we are dealing with, on a mathematical level, as we become aware of the increasing number of variables pertaining to a given asteroid or comet. We will need any information we can get. Should our species in our lifetimes ever be so unlucky as to actually face a potentially apocalyptic near-Earth object, Binzel noted that the elegant solutions depicted in cinema are far, far from what we would really have at our disposal. This interview has been edited for clarity and length. How did you develop the Torino Scale? Once upon a time, if you go back to the beginning, it would be Eugene Shoemaker, who was studying craters. He was going to be an Apollo astronaut but got washed out [Shoemarker developed Addison's disease, an endocrine disorder], so he studied craters. He's the geologist that determined that the meteor crater in Arizona was a crater by finding minerals underneath the bottom of the crater which could only have been formed by a high-heat, high-intensity shockwave, which is an impact crater. And so Shoemaker began wanting to know what was making craters on the Earth, on the Moon. He transformed himself from a geologist to an astronomer and began searching for these objects in the 1970s. I actually worked as a summer intern for Shoemaker in 1980. I began focusing on, or at least being aware of, working in the field of near-Earth objects as far back as 1980. As we were discovering these objects and surveys that Shoemaker was doing, and then others came along, we would get to the point where we would discover an object that had a non-zero probability of striking the earth. Could be one in 20,000, one in 60,000, just a number that was really small, but not zero. And so astronomers were perplexed: What do we do with these? Do we keep these objects secret until we get enough data and can make it go away, and then we don't have to upset anyone?The problem with that is twofold. One is, the data, the observations are always public, and so anyone who couldn't read the listing of asteroid observations could do these kinds of orbit solutions themselves and declare it to the public. Secondly, the sky is free and open to everyone, so it doesn't seem right to ever not tell you to be public about what you find in the sky. As we were getting to the point of finding objects that could pose a threat to Earth, or at least for which we could not rule out some small chance of striking Earth on a distant date, we had no set way of communicating. It would be a little bit of a tower of Babel, with different astronomers saying different things. Not that the numbers were different, but they would express themselves in different ways, and that could be very confusing to the public. This was the motivation for finding a common communication system, a common scale that we could put into context any newly discovered object. And so this now goes back to 1995 when a guy named John L. Remo brought together a conference at the United Nations for people to discuss the discovery and calculation of orbits of asteroids coming near the Earth. And that's where I presented the first concept of a common language or common scale. I called it a hazard index. That first presentation in 1995, it was a zero-to-five scale, and it generated a lot of discussion, but not a lot of enthusiasm. So I carried the proposal forward, took a lot of input from my colleagues, from science journalists, in terms of what could we do that would make a communication system better. From that I revised the proposal to a 10 point scale, added some broad characterizations for the different categories of what merits attention by astronomers, what would be an actual threat, and then what would classify as a certain collision. That's the lower limit of categorizing objects on the Torino Scale. So a small object that's discovered that's going to disintegrate in the atmosphere, or maybe land a few pieces on the ground, is zero on the Torino Scale, even if we're certain it's going to hit. So where's the bottom limit? And then at what probability does something become interesting? For example, on average in any given year, an object the size of 2024 YR4 has perhaps a one-in-a-thousand chance of striking the Earth or taking us by surprise. That's the level at which it would become a one on the Torino Scale: If we discover an object and it has a probability higher than just sort of the average background of being taken by surprise in any given year. Anything under four [on the scale], I wouldn't worry about. What do you think of the various scientific theories about how we could deflect or otherwise protect ourselves from near-Earth objects? Which ones do you think are viable and which do you think are more fanciful? The most important thing about near-Earth objects is to find them early. The earlier you have, or the more years or more decades you have to find an object, the more options you have such as a deflection, which is easiest to do. The more years you have, the tinier the nudge you need to make sure the objects will miss the Earth. At the moment, that's the capability we have, or the capability we've tested is a deflection technique, to nudge an asteroid slightly off course. That's why these new surveys are actually important because the sooner we start completing the inventory of what's out there, the more time we'll have, in case there's some object out there with our name on it. Do you believe that, aside from the near-Earth objects that have made the news, there are other bodies out there we should be concerned about? There are thousands and thousands of objects like 2024 YR4 and smaller that are out there. We simply need to do a thorough job of cataloging them as the first step towards making sure that we are never taken by surprise, by any sizable object.
CNN
25-02-2025
- Science
- CNN
Asteroid 2024 YR4's chances of colliding with Earth drop near zero
Asteroid 2024 YR4, deemed the riskiest asteroid on record last week, now has nearly a zero percent chance of impacting Earth in 2032, according to NASA and the European Space Agency. NASA estimates that the space rock has a 0.0017% chance of hitting Earth in December 2032, while the ESA has a similar risk assessment of 0.002%. That's a 1 in 59,000 possibility of impact, meaning there is a 99.9983% chance that the asteroid will safely zip by Earth in seven years, according to NASA. The agency also shared that the new data suggested that the asteroid had a 1.7% chance of hitting the moon, but those slight odds of impact do not pose a risk to Earth. 'When first discovered, asteroid 2024 YR4 had a very small, but notable chance of impacting our planet in 2032,' the agency shared on Monday. 'As observations of the asteroid continued to be submitted to the Minor Planet Center, experts at NASA Jet Propulsion Laboratory's Center for Near-Earth Object Studies were able to calculate more precise models of the asteroid's trajectory and now have found there is no significant potential for this asteroid to impact our planet for the next century. The latest observations have further reduced the uncertainty of its future trajectory, and the range of possible locations the asteroid could be on Dec. 22, 2032, has moved farther away from the Earth.' Over the weekend, the asteroid also dropped to a ranking of 0 out of 10 on the Torino Impact Hazard Scale, a tool for categorizing potential collisions of space objects with Earth. The ranking indicates 'the likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.' Asteroid 2024 YR4, detected by telescopes on December 27, 2024, is estimated to be 131 to 295 feet (40 to 90 meters) wide, comparable to a large building, and could cause local devastation if it were to collide with our planet. The quick de-escalation of the asteroid's risk assessment is thanks to 'unsung, meticulous work by astronomers' who conducted a steady stream of follow-up observations of the space rock using telescopes across the globe, said Richard Binzel, inventor of the Torino Scale. Binzel is a professor of planetary sciences, joint professor of aerospace engineering and MacVicar Faculty Fellow at the Massachusetts Institute of Technology. 'I'm pleasantly surprised that we could reduce the probability numbers so quickly,' Binzel said. 'It would not have done anyone any good to have this probability hang around for a long time because it was going to go to zero. The reason I say it was going to go to zero is at the end of the day, the probability is either zero and it misses you, or it's one and it hits you. Any number in between is just the space of your uncertainty. We didn't want us to have to sit in that time and space of uncertainty for months and months.' From record-breaking to nonthreatening Early last week, 2024 YR4 briefly broke a record once reached by the asteroid Apophis after it was first spotted in 2004. At its peak threat level, 2024 YR4 reached a 3 on the Torino Scale and had an estimated 3.1% chance of hitting Earth in 2032, according to NASA. The ESA's observations reached a peak of a 2.8% risk. The narrow difference was due to the two agencies' use of different tools for determining the asteroid's orbit and modeling its potential impact. But both percentages rose above the 2.7% chance of collision once associated with Apophis, making 2024 YR4 the most significant space rock to be spotted within the past two decades. However, as with Apophis, astronomers expected the risk for 2024 YR4 to spike and then fall to zero as they obtained more observational data to reduce uncertainties about the asteroid's path. Measuring 1,148 feet (350 meters) in diameter, Apophis was previously considered one of the most hazardous asteroids, with a chance of hitting our planet and reaching a 4 out of 10 on the Torino Scale. The rating meant that the asteroid merited astronomers' attention and tracking. Apophis reached a 4 because it was a larger object capable of regional damage, while 2024 YR4 garnered a 3 because it would cause local damage, Binzel said. But like 2024 YR4, Apophis also quickly dropped from a 4 to a 0 on the Torino Scale after astronomers spotted archival observations of the asteroid that more precisely clarified its orbit. While Apophis is still set to make a close flyby of Earth in 2029 that will be studied by multiple spacecraft, it poses no risk to Earth within this century. The biggest obstacle astronomers face when trying to determine the risk posed by newly discovered asteroids is calculating the unknowns. In the case of 2024 YR4, that includes the space rock's size as well as its orbit. Observations taken during the dark skies necessary for ground-based telescopes to track faint, small asteroids after February's full moon, which shone brightly in the night sky on February 12, helped astronomers quickly decrease the risk assessment for 2024 YR4. Key telescopes have included the Canada-France-Hawaii Telescope, the Subaru Telescope and Haleakala-Faulkes Telescope North, all located in the Hawaiian Islands, as well as New Mexico's Magdalena Ridge Observatory, the Gemini South Observatory in the Chilean Andes, Arizona's Lowell Discovery Telescope and the Nordic Optical Telescope in the Canary Islands. 'The atmosphere above Maunakea tends to be very stable, and it enables telescopes to produce very sharp images, sharper than most other observatory locations,' said David Tholen, an astronomer at the University of Hawaii's Institute for Astronomy, in a statement. The likelihood of 2024 YR4's impact has dropped just in time. Astronomers were concerned because the space rock's trajectory, carrying it away from Earth in a straight line, meant the asteroid would be out of reach of ground-based telescopes in April and wouldn't reappear until June 2028. However, astronomers plan to remain vigilant in observing the space rock to ensure that 2024 YR4 poses no risk, and the James Webb Space Telescope is expected to observe the asteroid in early March to pin down more details about its orbit and exact size.
Yahoo
24-02-2025
- Science
- Yahoo
The riskiest asteroid on record now has near-zero chance of hitting Earth
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Asteroid 2024 YR4, deemed the riskiest asteroid on record last week, now has nearly a zero percent chance of impacting Earth in 2032, according to NASA and the European Space Agency. NASA estimates that the space rock has a 0.0017% chance of hitting Earth in December 2032, while the ESA has a similar risk assessment of 0.002%. That's a 1 in 59,000 possibility of impact, meaning there is a 99.9983% chance that the asteroid will safely zip by Earth in seven years, according to NASA. The agency also shared that the new data suggested that the asteroid had a 1.7% chance of hitting the moon, but those slight odds of impact do not pose a risk to Earth. 'When first discovered, asteroid 2024 YR4 had a very small, but notable chance of impacting our planet in 2032,' the agency shared on Monday. 'As observations of the asteroid continued to be submitted to the Minor Planet Center, experts at NASA Jet Propulsion Laboratory's Center for Near-Earth Object Studies were able to calculate more precise models of the asteroid's trajectory and now have found there is no significant potential for this asteroid to impact our planet for the next century. The latest observations have further reduced the uncertainty of its future trajectory, and the range of possible locations the asteroid could be on Dec. 22, 2032, has moved farther away from the Earth.' Over the weekend, the asteroid also dropped to a ranking of 0 out of 10 on the Torino Impact Hazard Scale, a tool for categorizing potential collisions of space objects with Earth. The ranking indicates 'the likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.' Asteroid 2024 YR4, detected by telescopes on December 27, 2024, is estimated to be 131 to 295 feet (40 to 90 meters) wide, comparable to a large building, and could cause local devastation if it were to collide with our planet. The quick de-escalation of the asteroid's risk assessment is thanks to 'unsung, meticulous work by astronomers' who conducted a steady stream of follow-up observations of the space rock using telescopes across the globe, said Richard Binzel, inventor of the Torino Scale. Binzel is a professor of planetary sciences, joint professor of aerospace engineering and MacVicar Faculty Fellow at the Massachusetts Institute of Technology. 'I'm pleasantly surprised that we could reduce the probability numbers so quickly,' Binzel said. 'It would not have done anyone any good to have this probability hang around for a long time because it was going to go to zero. The reason I say it was going to go to zero is at the end of the day, the probability is either zero and it misses you, or it's one and it hits you. Any number in between is just the space of your uncertainty. We didn't want us to have to sit in that time and space of uncertainty for months and months.' Early last week, 2024 YR4 briefly broke a record once reached by the asteroid Apophis after it was first spotted in 2004. At its peak threat level, 2024 YR4 reached a 3 on the Torino Scale and had an estimated 3.1% chance of hitting Earth in 2032, according to NASA. The ESA's observations reached a peak of a 2.8% risk. The narrow difference was due to the two agencies' use of different tools for determining the asteroid's orbit and modeling its potential impact. But both percentages rose above the 2.7% chance of collision once associated with Apophis, making 2024 YR4 the most significant space rock to be spotted within the past two decades. However, as with Apophis, astronomers expected the risk for 2024 YR4 to spike and then fall to zero as they obtained more observational data to reduce uncertainties about the asteroid's path. Measuring 1,148 feet (350 meters) in diameter, Apophis was previously considered one of the most hazardous asteroids, with a chance of hitting our planet and reaching a 4 out of 10 on the Torino Scale. The rating meant that the asteroid merited astronomers' attention and tracking. Apophis reached a 4 because it was a larger object capable of regional damage, while 2024 YR4 garnered a 3 because it would cause local damage, Binzel said. But like 2024 YR4, Apophis also quickly dropped from a 4 to a 0 on the Torino Scale after astronomers spotted archival observations of the asteroid that more precisely clarified its orbit. While Apophis is still set to make a close flyby of Earth in 2029 that will be studied by multiple spacecraft, it poses no risk to Earth within this century. The biggest obstacle astronomers face when trying to determine the risk posed by newly discovered asteroids is calculating the unknowns. In the case of 2024 YR4, that includes the space rock's size as well as its orbit. Observations taken during the dark skies necessary for ground-based telescopes to track faint, small asteroids after February's full moon, which shone brightly in the night sky on February 12, helped astronomers quickly decrease the risk assessment for 2024 YR4. Key telescopes have included the Canada-France-Hawaii Telescope, the Subaru Telescope and Haleakala-Faulkes Telescope North, all located in the Hawaiian Islands, as well as New Mexico's Magdalena Ridge Observatory, the Gemini South Observatory in the Chilean Andes, Arizona's Lowell Discovery Telescope and the Nordic Optical Telescope in the Canary Islands. 'The atmosphere above Maunakea tends to be very stable, and it enables telescopes to produce very sharp images, sharper than most other observatory locations,' said David Tholen, an astronomer at the University of Hawaii's Institute for Astronomy, in a statement. The likelihood of 2024 YR4's impact has dropped just in time. Astronomers were concerned because the space rock's trajectory, carrying it away from Earth in a straight line, meant the asteroid would be out of reach of ground-based telescopes in April and wouldn't reappear until June 2028. However, astronomers plan to remain vigilant in observing the space rock to ensure that 2024 YR4 poses no risk, and the James Webb Space Telescope is expected to observe the asteroid in early March to pin down more details about its orbit and exact size.
Yahoo
24-02-2025
- Science
- Yahoo
Asteroid 2024 YR4's chances of colliding with Earth drop near zero
Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Asteroid 2024 YR4, deemed the riskiest asteroid on record last week, now has nearly a zero percent chance of impacting Earth in 2032, according to NASA and the European Space Agency. NASA estimates that the space rock has a 0.0017% chance of hitting Earth in December 2032, while the ESA has a similar risk assessment of 0.002%. That's a 1 in 59,000 possibility of impact, meaning there is a 99.9983% chance that the asteroid will safely zip by Earth in seven years, according to NASA. The agency also shared that the new data suggested that the asteroid had a 1.7% chance of hitting the moon, but those slight odds of impact do not pose a risk to Earth. 'When first discovered, asteroid 2024 YR4 had a very small, but notable chance of impacting our planet in 2032,' the agency shared on Monday. 'As observations of the asteroid continued to be submitted to the Minor Planet Center, experts at NASA Jet Propulsion Laboratory's Center for Near-Earth Object Studies were able to calculate more precise models of the asteroid's trajectory and now have found there is no significant potential for this asteroid to impact our planet for the next century. The latest observations have further reduced the uncertainty of its future trajectory, and the range of possible locations the asteroid could be on Dec. 22, 2032, has moved farther away from the Earth.' Over the weekend, the asteroid also dropped to a ranking of 0 out of 10 on the Torino Impact Hazard Scale, a tool for categorizing potential collisions of space objects with Earth. The ranking indicates 'the likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.' Asteroid 2024 YR4, detected by telescopes on December 27, 2024, is estimated to be 131 to 295 feet (40 to 90 meters) wide, comparable to a large building, and could cause local devastation if it were to collide with our planet. The quick de-escalation of the asteroid's risk assessment is thanks to 'unsung, meticulous work by astronomers' who conducted a steady stream of follow-up observations of the space rock using telescopes across the globe, said Richard Binzel, inventor of the Torino Scale. Binzel is a professor of planetary sciences, joint professor of aerospace engineering and MacVicar Faculty Fellow at the Massachusetts Institute of Technology. 'I'm pleasantly surprised that we could reduce the probability numbers so quickly,' Binzel said. 'It would not have done anyone any good to have this probability hang around for a long time because it was going to go to zero. The reason I say it was going to go to zero is at the end of the day, the probability is either zero and it misses you, or it's one and it hits you. Any number in between is just the space of your uncertainty. We didn't want us to have to sit in that time and space of uncertainty for months and months.' Early last week, 2024 YR4 briefly broke a record once reached by the asteroid Apophis after it was first spotted in 2004. At its peak threat level, 2024 YR4 reached a 3 on the Torino Scale and had an estimated 3.1% chance of hitting Earth in 2032, according to NASA. The ESA's observations reached a peak of a 2.8% risk. The narrow difference was due to the two agencies' use of different tools for determining the asteroid's orbit and modeling its potential impact. But both percentages rose above the 2.7% chance of collision once associated with Apophis, making 2024 YR4 the most significant space rock to be spotted within the past two decades. However, as with Apophis, astronomers expected the risk for 2024 YR4 to spike and then fall to zero as they obtained more observational data to reduce uncertainties about the asteroid's path. Measuring 1,148 feet (350 meters) in diameter, Apophis was previously considered one of the most hazardous asteroids, with a chance of hitting our planet and reaching a 4 out of 10 on the Torino Scale. The rating meant that the asteroid merited astronomers' attention and tracking. Apophis reached a 4 because it was a larger object capable of regional damage, while 2024 YR4 garnered a 3 because it would cause local damage, Binzel said. But like 2024 YR4, Apophis also quickly dropped from a 4 to a 0 on the Torino Scale after astronomers spotted archival observations of the asteroid that more precisely clarified its orbit. While Apophis is still set to make a close flyby of Earth in 2029 that will be studied by multiple spacecraft, it poses no risk to Earth within this century. The biggest obstacle astronomers face when trying to determine the risk posed by newly discovered asteroids is calculating the unknowns. In the case of 2024 YR4, that includes the space rock's size as well as its orbit. Observations taken during the dark skies necessary for ground-based telescopes to track faint, small asteroids after February's full moon, which shone brightly in the night sky on February 12, helped astronomers quickly decrease the risk assessment for 2024 YR4. Key telescopes have included the Canada-France-Hawaii Telescope, the Subaru Telescope and Haleakala-Faulkes Telescope North, all located in the Hawaiian Islands, as well as New Mexico's Magdalena Ridge Observatory, the Gemini South Observatory in the Chilean Andes, Arizona's Lowell Discovery Telescope and the Nordic Optical Telescope in the Canary Islands. 'The atmosphere above Maunakea tends to be very stable, and it enables telescopes to produce very sharp images, sharper than most other observatory locations,' said David Tholen, an astronomer at the University of Hawaii's Institute for Astronomy, in a statement. The likelihood of 2024 YR4's impact has dropped just in time. Astronomers were concerned because the space rock's trajectory, carrying it away from Earth in a straight line, meant the asteroid would be out of reach of ground-based telescopes in April and wouldn't reappear until June 2028. However, astronomers plan to remain vigilant in observing the space rock to ensure that 2024 YR4 poses no risk, and the James Webb Space Telescope is expected to observe the asteroid in early March to pin down more details about its orbit and exact size.
CNN
24-02-2025
- Science
- CNN
Asteroid 2024 YR4's chances of colliding with Earth drop near zero
Asteroid 2024 YR4, deemed the riskiest asteroid on record last week, now has nearly a zero percent chance of impacting Earth in 2032, according to NASA and the European Space Agency. NASA estimates that the space rock has a 0.0017% chance of hitting Earth in December 2032, while the ESA has a similar risk assessment of 0.002%. That's a 1 in 59,000 possibility of impact, meaning there is a 99.9983% chance that the asteroid will safely zip by Earth in seven years, according to NASA. The agency also shared that the new data suggested that the asteroid had a 1.7% chance of hitting the moon, but those slight odds of impact do not pose a risk to Earth. 'When first discovered, asteroid 2024 YR4 had a very small, but notable chance of impacting our planet in 2032,' the agency shared on Monday. 'As observations of the asteroid continued to be submitted to the Minor Planet Center, experts at NASA Jet Propulsion Laboratory's Center for Near-Earth Object Studies were able to calculate more precise models of the asteroid's trajectory and now have found there is no significant potential for this asteroid to impact our planet for the next century. The latest observations have further reduced the uncertainty of its future trajectory, and the range of possible locations the asteroid could be on Dec. 22, 2032, has moved farther away from the Earth.' Over the weekend, the asteroid also dropped to a ranking of 0 out of 10 on the Torino Impact Hazard Scale, a tool for categorizing potential collisions of space objects with Earth. The ranking indicates 'the likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.' Asteroid 2024 YR4, detected by telescopes on December 27, 2024, is estimated to be 131 to 295 feet (40 to 90 meters) wide, comparable to a large building, and could cause local devastation if it were to collide with our planet. The quick de-escalation of the asteroid's risk assessment is thanks to 'unsung, meticulous work by astronomers' who conducted a steady stream of follow-up observations of the space rock using telescopes across the globe, said Richard Binzel, inventor of the Torino Scale. Binzel is a professor of planetary sciences, joint professor of aerospace engineering and MacVicar Faculty Fellow at the Massachusetts Institute of Technology. 'I'm pleasantly surprised that we could reduce the probability numbers so quickly,' Binzel said. 'It would not have done anyone any good to have this probability hang around for a long time because it was going to go to zero. The reason I say it was going to go to zero is at the end of the day, the probability is either zero and it misses you, or it's one and it hits you. Any number in between is just the space of your uncertainty. We didn't want us to have to sit in that time and space of uncertainty for months and months.' From record-breaking to nonthreatening Early last week, 2024 YR4 briefly broke a record once reached by the asteroid Apophis after it was first spotted in 2004. At its peak threat level, 2024 YR4 reached a 3 on the Torino Scale and had an estimated 3.1% chance of hitting Earth in 2032, according to NASA. The ESA's observations reached a peak of a 2.8% risk. The narrow difference was due to the two agencies' use of different tools for determining the asteroid's orbit and modeling its potential impact. But both percentages rose above the 2.7% chance of collision once associated with Apophis, making 2024 YR4 the most significant space rock to be spotted within the past two decades. However, as with Apophis, astronomers expected the risk for 2024 YR4 to spike and then fall to zero as they obtained more observational data to reduce uncertainties about the asteroid's path. Measuring 1,148 feet (350 meters) in diameter, Apophis was previously considered one of the most hazardous asteroids, with a chance of hitting our planet and reaching a 4 out of 10 on the Torino Scale. The rating meant that the asteroid merited astronomers' attention and tracking. Apophis reached a 4 because it was a larger object capable of regional damage, while 2024 YR4 garnered a 3 because it would cause local damage, Binzel said. But like 2024 YR4, Apophis also quickly dropped from a 4 to a 0 on the Torino Scale after astronomers spotted archival observations of the asteroid that more precisely clarified its orbit. While Apophis is still set to make a close flyby of Earth in 2029 that will be studied by multiple spacecraft, it poses no risk to Earth within this century. The biggest obstacle astronomers face when trying to determine the risk posed by newly discovered asteroids is calculating the unknowns. In the case of 2024 YR4, that includes the space rock's size as well as its orbit. Observations taken during the dark skies necessary for ground-based telescopes to track faint, small asteroids after February's full moon, which shone brightly in the night sky on February 12, helped astronomers quickly decrease the risk assessment for 2024 YR4. Key telescopes have included the Canada-France-Hawaii Telescope, the Subaru Telescope and Haleakala-Faulkes Telescope North, all located in the Hawaiian Islands, as well as New Mexico's Magdalena Ridge Observatory, the Gemini South Observatory in the Chilean Andes, Arizona's Lowell Discovery Telescope and the Nordic Optical Telescope in the Canary Islands. 'The atmosphere above Maunakea tends to be very stable, and it enables telescopes to produce very sharp images, sharper than most other observatory locations,' said David Tholen, an astronomer at the University of Hawaii's Institute for Astronomy, in a statement. The likelihood of 2024 YR4's impact has dropped just in time. Astronomers were concerned because the space rock's trajectory, carrying it away from Earth in a straight line, meant the asteroid would be out of reach of ground-based telescopes in April and wouldn't reappear until June 2028. However, astronomers plan to remain vigilant in observing the space rock to ensure that 2024 YR4 poses no risk, and the James Webb Space Telescope is expected to observe the asteroid in early March to pin down more details about its orbit and exact size.
