Artist’s impression of asteroid (99942) Apophis.
Friday the 13th might be considered an unlucky day, but on Friday, April 13, 2029 at 5:45 a.m. EDT (11:45 a.m. CEST), the opposite will be proven when a “dinosaur killer”-sized asteroid makes a safe pass by Earth.
Everyone will be watching. At about 1,230 feet (375 meters) in diameter, asteroid Apophis is larger than 90% of space rocks.
It will fly by just 19,635 miles (31,600 kilometers) from Earth’s surface, the closest approach to an asteroid of this size that humanity has ever experienced. It will pass between Earth’s geostationary satellites and the Atlantic Ocean, a mere tenth of the distance between Earth and the Moon.
Apophis will be visible to the naked eye. When it crosses the Atlantic, several billion people in Europe, Africa and Asia can see it for several hours in the night sky, if the sky is clear.
It was discovered exactly 20 years ago this week, and here’s everything you need to know about asteroid Apophis:
‘Demon Of Chaos’
Asteroid 99942 Apophis was discovered on June 19, 2004 by astronomers at Kitt Peak National Observatory, who revealed that this solid S-type asteroid orbits the Sun every 324 days and approaches Earth roughly every ten years. It made headlines after a paper was published that predicted it could hit Earth in 2029, 2036 or 2068. It was therefore named after Apophis, the Egyptian demon of chaos and destruction.
Although there was only a 2.7% chance of a direct hit by Apophis, the devastation caused by it hitting Earth (the crater it would leave would be far more enormous than the asteroid impact that killed the dinosaurs) led astronomers to try to understand its orbit. in more detail. In 2021, radar observations by the Goldstone Deep Space Communications Complex in California and the Green Bank Observatory in West Virginia in March 2021 refined its orbit. It has been reported that Apophis will not hit Earth in 2029, 2036 or 2068.
On Friday, April 13, 2029, the asteroid Apophis will approach Earth. Earth’s gravity will … [+]
A future threat?
However, the trajectory of an asteroid can only be calculated far into the future. Although it will approach Earth at a greater distance in 2044, astronomers can only rule out an impact for the next 100 years.
The calculations are difficult because a close flyby — like the one in 2029 — will change Apophis’ path so that it could hit Earth in a future orbit. However, astronomers have reduced the uncertainty in Apophis’ orbit from hundreds to just a few miles.
Apophis’ close flyby in 2029 is a rare opportunity to visit, so NASA already has a spacecraft in hot pursuit. This close flyby is considered the perfect opportunity to learn more about planetary defenses and how an asteroid reacts to a flyby so close to a body with such enormous gravity. Apophis is predicted to be compressed enough to cause asteroid shocks and landslides.
These images represent radar observations of asteroid 99942 Apophis on March 8, 9, and 10, 2021. … [+]
Mission to Apophis
It will be closely monitored by NASA’s OSIRIS-Apophis Explorer (OSIRIS-APEX) spacecraft. It is the identical spacecraft that visited Asteroid Bennu in 2020. Then called OSIRIS-REx, NASA’s first mission to return asteroid samples returned a packet of samples to Utah in September 2023 before redirecting to Apophis in a mission extension that cost NASA $200 million. OSIRIS-APEX will orbit Apophis for 18 months when it flies past Earth in 2029.
The European Space Agency is also considering launching an Apophis mission in 2027, the Rapid Apophis Mission for SEcurity and Safety (RAMSES).
For now, what scientists will learn from sending a spacecraft to study Apophis in 2029 will be about how the early solar system relic responds to gravity. The findings could be crucial for future Earthlings hundreds of years from now, when the massive asteroid will pose a greater threat.
I wish you clear skies and wide eyes.
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