Topline
Ahead of Asteroid Day on Sunday, an asteroid larger than 99% of all known near-Earth asteroids and a second asteroid that will come closer than the moon, will pass Earth this week, and scientists are keeping an eye on them because of their size and how close they’re coming, though any threat level is low.
Key Facts
A 7,200-foot asteroid is expected to pass by Earth Thursday, coming within 4.1 million miles of the planet—about 17 times further than the moon—according to NASA Jet Propulsion Laboratory.
The large asteroid, called (415029) 2011 UL21, orbits the sun about every three years, though the next time it comes close won’t happen until 2052, when it will come within around 26 million miles of Earth.
A second asteroid, 2024 MK, passes on Saturday and should make an even closer approach at 180,198 miles, and although it’s not expected to come anywhere near Earth it would cause “considerable damage” if it did, according to the ESA.
2024 MK will be making its first close approach just 11 days after it was discovered last Sunday, and it’s estimated to be between 393 feet and 853 feet.
NASA labels objects larger than 150 meters that come within 4.6 million miles of Earth “potentially hazardous objects,” so scientists monitor their potential danger even though they don’t expect the asteroids to pose a threat.
When Will The Asteroids Pass Earth?
(415029) 2011 UL21 is expected to pass the Earth around 4:16 p.m. EDT on Thursday. Asteroid 2024 MK is expected to pass by on Saturday around 9:46 a.m. EDT.
How Can I See The Asteroids?
Because of the distance, (415029) 2011 UL21 may not be visible to the naked eye. However, NASA offers a virtual asteroid tracker to watch where in the solar system asteroids are in real time, and the Virtual Telescope Project will livestream the event. 2024 MK may be visible with a small telescope and dark, clear skies, according to the ESA.
Key Background
This year’s Asteroid Day is Sunday. The United Nations-endorsed event commemorates the anniversary of the largest-observed asteroid strike in history. On June 30, 1908, an asteroid around 160 feet wide traveling 62,000 miles per hour exploded in the skies above Tunguska in Russia. The asteroid’s impact caused massive wildfires, trees to blow over and houses and buildings were destroyed. People close to the explosion reported being thrown into the air and knocked unconscious, though just a few deaths were reported in the sparsely populated area. Asteroid Day is used to raise awareness about the dangers of asteroid impacts.
Tangent
(415029) 2011 UL21 and 2024 MK won’t be the only asteroids flying by Earth this week. Three smaller, airplane-size asteroids are expected to pass Earth. 2022 MM1 will pass by Earth at around 8:16 p.m. EDT Thursday, 2010 XN will pass by at 11:13 p.m. EDT Thursday and 2022 HD1 will make its approach at 12:10 a.m. EDT on Saturday.
