Have you ever been happy to find out you made a mistake? We’re sure glad NASA’s calculations in 2004 were a little bit off... Back then, their calculations showed that a big asteroid named Apophis could impact Earth in 2029! Now that the corrections have been made, we can use this close-but-not-dangerously-close flyby to learn more about the asteroid and space.
Asteroid 99942 Apophis is named for the demon serpent who personified evil and chaos in ancient Egyptian mythology. It’s a near-Earth asteroid measuring more than 1000 feet (over 300 meters) in size that will pass harmlessly close to Earth on April 13, 2029.
After searching through some older astronomical images, scientists ruled out the possibility of a 2029 impact. It’s now predicted the asteroid will safely pass about 19,800 miles (31,900 kilometers) from our planet’s surface. While that’s a safe distance, it’s close enough that the asteroid will come between Earth and our Moon, which is about 238,855 miles (384,400 kilometers) away. It’s also within the distance that some spacecraft orbit Earth.
It’s rare for an asteroid of this size to pass so close to Earth, although smaller asteroids, in the range of 16 to 33 feet (5 to 10 meters) in size, have been observed passing by at similar distances.
“The Apophis close approach in 2029 will be an incredible opportunity for science,” said Marina Brozović, a radar scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who works on radar observations of near-Earth objects (NEOs). “We’ll observe the asteroid with both optical and radar telescopes. With radar observations, we might be able to see surface details that are only a few meters in size.”
During its 2029 flyby, Apophis will first become visible to the naked eye in the night sky over the southern hemisphere and will look like a speck of light moving from east to west over Australia. It will be mid-morning on the U.S. East Coast when Apophis is above Australia. Apophis will then cross above the Indian Ocean and continue west as it crosses the equator over Africa.
At its closest approach to Earth, just before 6 p.m. EDT, April 13, 2029, Apophis will be over the Atlantic Ocean. It will move so fast that it will cross the Atlantic in just an hour. By 7 p.m. EDT, the asteroid will have crossed over the U.S.
As it passes by Earth, it will get brighter and faster. At one point, it will appear to travel more than the width of the full Moon within a minute and it will grow as bright as the stars in the Little Dipper.