Will ‘Apophis’ Hit Earth In 2029? We’ll Know In 2027, Scientist Says

06 Nov 2024 by Jamie Carter · Forbes

Apophis, the most famous ‘potentially hazardous’ asteroid, will make a close approach to Earth in ... [+] 2029 — but could it strike?getty

A “city killer” asteroid the size of the Empire State Building is still a potential threat to Earth in 2029, according to new simulations.

Asteroid 99942, which is about 1,200 feet/370 meters wide — larger than 90% of asteroids — orbits the sun every 324 days and comes close to Earth roughly every decade.

It was given the nickname “Apophis” — the Egyptian god of chaos — when it was first discovered in 2004 because it appeared to perhaps be on a collision course with Earth in 2029, 2036 or 2068. Astronomers gave a 2.7% chance of a direct hit. In 2021, NASA ruled that out after calculations refined its orbit, but new research at least partly revives the original concern.

Asteroid Apophis: New Trajectory?

Astronomers still don’t think Apophis will collide with Earth on its current trajectory. On April 13, 2029, they now predicted it will come within 19,400 miles (31,200 kilometers) of Earth. It will be the the closest approach of an asteroid of this size that humankind has ever experienced and within the orbits of Earth’s geostationary satellites.

However, simulations suggest that there is a small chance that its trajectory could be altered if another asteroid nudged it. That could have potentially devastating consequences for Earth.

Asteroid Apophis: Small Chance Of Striking Earth

A paper published in the Planetary Science Journal claims that Apophis could collide with a small asteroid like the ones that frequently and unpredictably strike Earth, which could alter its trajectory. “The odds of a small unseen asteroid colliding with Apophis in such a way as to create a dangerous outcome are exceptionally small,” said lead author Paul Wiegert at the University of Western Ontario in the paper.

“This new paper computes the odds of Apophis being significantly deflected by such an impact to be less than 1 in a million and only 1 in a billion that the deflection will be dangerous to Earth,” he said in an online article about his paper. “The overall odds of a small asteroid deflecting Apophis onto a dangerous path is extremely small.”

Asteroid Apophis: Hard To See

There is another problem. “Apophis is in the daytime sky and unobservable from mid-2021 to 2027,” Paul Wiegert, meaning any change in its trajectory will go unseen until just two years before April 12, 2029. However, he adds that a single observation during 2027 would be necessary to determine whether the asteroid threatened “an impending Earth impact.”

“The deflection of Apophis by a small asteroid onto a collision course with Earth in 2029 — in addition to being extremely unlikely — will most likely be quickly eliminated as a possibility by simple telescopic observations when Apophis returns to visibility in 2027,” said Wiegert.

Asteroid Apophis: Space Missions

The exceptionally close-pass of Asteroid Apophis is a great chance to do science. To that end, NASA has repurposed its OSIRIS-REx mission — its first asteroid sample-return mission that returned samples from Asteroid Bennu in September 2023 — and sent it to study the threatening asteroid.

Now called OSIRIS-Apophis Explorer (OSIRIS-APEX), it will orbit Apophis for 18 months, though will only reach it just after it passes Earth in 2029. Already there will be a European Space Agency mission called RAMSES.

Wishing you clear skies and wide eyes.