An asteroid the size of a football stadium will pass between the Earth and the moon on Saturday morning, marking the second of two astronomical close encounters in three days.
Near miss in this case is a relative term: Asteroid 2024 MK on Saturday came within 180,000 miles of Earth, while asteroid 2011 UL21 flew within 4 million miles on Thursday.
But Saturday’s passage of 2024 MK, which scientists discovered just two weeks ago, coincides with a grim reminder of the threat from space.
Sunday marks Asteroid Day, the anniversary of a rock from space exploding over a Russian town in 1908. Astronomers have warned that such dangers are ever-lurking as Earth hurtles through space.
Here’s what you need to know about asteroids, risks from space, and Saturday’s flyby.
What are asteroids?
Asteroids are space rocks that orbit the Sun, like planets, occasionally crossing their orbits.
And like planets, asteroids formed from the condensed clouds of dust and gas that formed our solar system over 4.6 billion years ago. This means they’re time capsules of a long time ago, before the Earth or Sun were formed.
Scientists have identified about 1.3 million asteroids orbiting in the vast space between Mars and Jupiter. Asteroids tend to be small, both individually and collectively, and the combined mass of all asteroids in the solar system is thought to be less than the Moon.
Over time, asteroid impacts may have also played a crucial role in the development of life on Earth.
In other asteroid news from the past week, scientists on Wednesday The results were announced A probe is due to land on the asteroid Bennu in 2023 and bring back samples that suggest it may be teeming with water.
These findings suggest that asteroid impacts could have a positive side: “Such asteroids could have played an important role in bringing water and the building blocks of life to Earth,” said co-author Nick Timms of Curtin University.
What would happen if it hit Earth now?
Asteroids don’t need to be very big to do damage: For example, one 62-foot-diameter asteroid that exploded about 20 miles above Siberia in 2013 released 30 times more energy than the atomic bomb that hit Hiroshima.
Most of the impact energy was absorbed by the atmosphere, but the explosion created shock waves that blew out windows and More than 1,000 people injured.
Sunday’s Asteroid Day marks the anniversary of an even larger impact over Siberia, the Tunguska event of 1908.
The Russian newspaper Siberia reported on the incident, saying that peasants who looked up saw “a strangely bright (invisible) pale-white object which moved downward for ten minutes.”
According to the article, the body was cylindrical, like a “pipe,” and when it hit the thick air above the forest it began to “smudge” and exploded, emitting black smoke.
“A loud noise (not thunder) was heard, as if a large stone had fallen or a cannon had been fired. All the buildings shook. At the same time the cloud began to emit indistinct shapes of flames. All the villagers panicked and took to the streets, the women cried, thinking it was the end of the world.”
If the 500- to 800-foot-diameter 2024MK were to collide with Earth on Saturday rather than pass by it, it wouldn’t be the end of the world — at least, not completely. Such a collision would “correspond to impact energies of hundreds of megatons to close to gigatons,” says Peter Brown of Western University in Canada. He told the Canadian Broadcasting Service.
This is a huge potential impact: the explosion would be 10 to 20 times larger than most hydrogen bombs ever tested. In the 50 megaton range.
“If this were to hit the East Coast of the United States it would have a devastating effect on most of the East Coast, but not on a scale that would have a global impact,” Brown said.
The impact of a potential collision with asteroid 2011 UL21, which passed Earth on Thursday, would be far more devastating. Although the asteroid is too far out in space to collide with Earth, it is very large — roughly the size of Mount Everest.
The asteroid, 1.5 miles in diameter, was about a quarter the size of the one that struck Earth 65 million years ago, wiping out all walking dinosaurs and most life on Earth.
How high is the risk of collision?
Studies have shown that it’s extremely unlikely. NASA estimates that a civilization-ending event (like an asteroid the size of Thursday hitting Earth) would happen in: Every few million years.
And such an impact from an asteroid larger than half a mile in diameter would be nearly impossible for a very long time. According to the survey results It was published in the Astronomical Journal last year.
“This is good news,” study leader Oscar Fuentes Muñoz of the University of Colorado Boulder told MIT Technology Review. “As far as we know, there will be no impacts for the next 1,000 years.”
NASA’s catalog of large, dangerous objects like the 2011 UL21 is now 95 percent complete, Technology Review reports.
But even smaller asteroids “have the potential to cause significant damage”, as the 1908 and 2013 explosions suggested, Áine O’Brien of the University of Glasgow warned Technology Review.
A map of an asteroid the size of which will pass between Earth and the moon on Saturday and could destroy cities if it hits Earth is only 40 percent complete, the magazine reported. According to Big Think.
How do scientists detect and track asteroids?
They continually scan the sky, looking for relatively small, fast-moving objects. 2024 MK detected It’s one of many investigations looking for risk.
Alan Fitzsimmons of Queen’s University in Northern Ireland told CBC that these surveys will provide early warning that could help prevent asteroid impacts.
“This is the only natural disaster we can stop. You can’t stop a tsunami, you can’t stop an earthquake, you can’t stop a volcano,” he said. “At least in theory, an asteroid impact can actually be stopped or prevented.”
In 2022, NASA’s Double Asteroid Reorientation Test (DART) mission will smash a satellite the weight of a small car into Dimorphos, a rock roughly the same size as 2024 MK, slightly altering the asteroid’s orbit and successfully deflecting it off its path.
The DART mission, which required NASA to carry out a precision collision seven million miles away, showed that “NASA is prepared for anything the space throws at us,” NASA Administrator Bill Nelson said. He said in a briefing at that time.
But there’s an old adage in science that says there’s no difference between theory and practice, but there is a difference in practice: Accomplishing a feat like the DART mission to stop an asteroid from hitting Earth “is certainly possible, but it would be a difficult and expensive task,” says Canadian astronomer Alistair Gunn. The University of Manchester For the British Broadcasting Corporation.
“The key will be to deflect the asteroid from a collision course with Earth and not shatter it into equally dangerous pieces,” Gunn added.
He also noted that a grace period of at least five years is needed to make that happen, which is why early warning is “critically important.”
The need for early warning is one of the reasons the passage of 2024 MK is so disturbing – scientists discovered it just this month.
Earlier this week, NASA announced that there were still “significant gaps” in its plan to deflect the asteroid, USA Today reported.
“We’re leveraging the capabilities that we have to eliminate that hazard, understand what’s out there and know if anything poses a threat,” said Kelly Fast, NASA’s acting planetary defense administrator. He told the media.
Will Americans be able to see Saturday’s asteroid?
Yes, if you are in the right area, well prepared and with a bit of luck it is possible.
Americans in the southwestern United States or Hawaii, far from light pollution and willing to get up before dawn, may have a chance to see 2024 MK as a rapidly moving dot when it makes its closest approach to Earth around 9:46 a.m. Eastern Time.
That will be 90 minutes before dawn in Hawaii and about an hour after dawn on the West Coast, but the asteroid will be vaguely visible before it passes by.
For everyone outside these regions, the Virtual Telescope Project Live Streaming the Aisle.
Queen’s University’s Fitzsimmons told CBC that even if you’re in the right area, observing the transit could be difficult. Stargazers will need a telescope and be prepared to spot faint, fast-moving objects. “You have to know exactly where to look,” he said. “It’s moving really fast.”
