Infamous asteroid Apophis is “rediscovered”

Recently, scientists tested a warning system against dangerous asteroids. More than 100 scientists from 18 countries participated in the project, during which the sky was regularly scanned in search of potentially dangerous space bodies. As a result of the check, the system “rediscovered” the infamous asteroid 99942 Apophis.

Illustration of the asteroid 99942 Apophis. Source: CNET

The non-profit organization “B612 Foundation” supports research and technology for mapping and navigation of the Solar System. After re-scanning, Apophis again received the status of “potentially dangerous”.

Near-Earth asteroid in the artist’s image. Source: NASA/JPL-Caltech

Apophis has already caused a stir once when it was first discovered in 2004. At that time, the asteroid’s orbit was not well known. Therefore, a high risk of collision with the Earth in 2029 or 2036 was calculated. Now astronomers have been tasked with doing a re-analysis to prove the warning system’s ability to quickly identify and then assess the danger associated with any future asteroid.

Power of Apophis

During the tests, Apophis was first detected by the Catalina Sky Survey in Arizona, and then was recorded by the early warning system for asteroid collisions (ATLAS), which has observatories in Chile, Hawaii and South Africa. Perhaps the most important measurements were made by the NEOWISE spacecraft, which used its thermal vision to accurately measure the size and shape of Apophis. It identified it as “an elongated object with a diameter of 270 to 410 meters”.

A model of the surface of the asteroid Apophis. Source: UArizona/JPL/Arecibo

Based on NEOWISE measurements, scientists at NASA’s Ames Research Center in California have obtained a more accurate estimate of the energy that will be released if Apophis collides with Earth. They calculated that the impact would carry approximately 8.5 x 1019 joules of energy, which is equivalent to 20 million kilotons of TNT. The damage caused by Apophis will be devastating, but only on a regional scale; it is not massive enough to cause a global extinction of humanity. 

No collisions in the next 100 years

In 2020, the International Astronomical Union announced that the risk of Apophis colliding with the Earth is minimal. However, there was still not enough data to rule it out 100%.

“Despite the fact that we knew that Apophis would not collide with Earth in 2029, there were large uncertainties in the object’s orbit that theoretically allowed for a collision,” says Davide Farnocchia, a navigation engineer at NASA’s Jet Propulsion Laboratory.

Farnocchia led the effort to calculate the orbit of Apophis using the Goldstone Solar System Radar in California in 2021. This ground-based radar made it possible to obtain images of Apophis, and also measured its speed and distance, which made it possible to more accurately calculate the asteroid’s orbit. This information was enough to rule out a collision in 2029, or at least for the next 100 years.

Earlier, the OSIRIS-REx mission was sent to visit the most dangerous asteroid in the world.

According to Space

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