An asteroid the size of three football fields will pass near Earth in three years, giving scientists a rare chance to study a colossal space rock from close range.
Named Apophis — after the ancient Egyptian deity known as the “god of chaos” — the asteroid is expected to zoom past the planet on April 13, 2029, according to NASA. It will come within about 20,000 miles of Earth’s surface, which is closer than many orbiting satellites, the agency said. The highest satellites typically orbit around 22,000 miles above the equator.
Scientists consider Apophis to be “a potentially hazardous asteroid,” but NASA has reassured the public that it will safely clear Earth during its 2029 passage. After years of monitoring, scientists say they’re confident that there’s no risk of Earth impact for at least 100 years.
“There is no danger to Earth, to anyone or anything living on it, or to astronauts or satellites in space,” the agency said. “But the event is an amazing and totally unprecedented opportunity to learn much more about Apophis and similar near-Earth asteroids.”
NASA 
People on the ground in the Eastern Hemisphere will be able to observe the asteroid with their own eyes, weather permitting, according to NASA.
It’s extremely uncommon for an asteroid as large as Apophis to pass as close to Earth. NASA estimates such events happen once every few thousand years on average. If that estimate is correct, then the asteroid’s 2029 flyby will be the first of its kind in history to be closely observed with modern technology.
Although Apophis won’t endanger people on the ground when it passes by, Earth’s gravitational pull during the close encounter could potentially “stretch” and “squeeze” the asteroid, possibly triggering small landslides or other similar movements on its surface, NASA said.
How the asteroid responds will help scientists better understand Apophis and its composition. NASA scientists believe it’s made from leftover cosmic materials from the early solar system that were never part of any planets or moons.
Its mean diameter — a standardized measurement of the distance from one side of the rock to the other — is 1,115 feet, roughly the size of three football fields. The distance between the asteroid’s two farthest points is quite a bit longer, at 1,480 feet or more, NASA said. Its shape is not known, but observations suggest it could look something like a peanut.
Apophis was first discovered on June 19, 2004, by astronomers Roy Tucker, David Tholen and Fabrizio Bernardi at Kitt Peak National Observatory in Arizona. Another group of astronomers caught sight of the asteroid again, later that same year, at an observatory in Australia.
