Asteroid 99942 Apophis has been a serious reminder for the past 17 years that there are plenty of space rocks out there ready to hit the Earth and wipe out a significant portion of our planet. Although there are still dangerous Near-Earth Objects (NEOs) out there, we can now tell with certainty that asteroid Apophis is not one of them. For the next century, at least.
Planetary scientists around the world were able to better estimate the possibility of a collision between Earth and Apophis in 2068 thanks to observations made at the beginning of March when the asteroid swung by Earth. NASA and the European Space Agency (ESA) have now confidently taken the space rock off the Risk List.
Apophis is about 340 meters (1,100 feet) long, and astronomers knew when it was discovered that it would pass close to Earth many times this century, with the most alarming dates being 2029, 2036, and 2068.
On April 13, 2029, it will pass Earth at a distance of less than 35,000 kilometers (21,750 miles). Our planet’s gravity would have a major impact on its orbit. The expected changes in its trajectory made it possible that it would impact Earth in 2068. Although the chances were low, it was very important to be prepared, refine the measurement, and work out its trajectory.
“A 2068 impact is not in the realm of possibility anymore, and our calculations don’t show any impact risk for at least the next 100 years,” Davide Farnocchia of NASA’s Center for Near-Earth Object Studies (CNEOS), which is managed by NASA’s Jet Propulsion Laboratory, said in a statement.
“With the support of recent optical observations and additional radar observations, the uncertainty in Apophis’s orbit has collapsed from hundreds of kilometers to just a handful of kilometers when projected to 2029. This greatly improved knowledge of its position in 2029 provides more certainty of its future motion, so we can now remove Apophis from the risk list.”
Apophis’ radio and optical observations provided us with more knowledge about this dangerous object. It flew 16.9 million kilometers (10.5 million miles) from us on March 6, a very safe distance for risk and a very near distance for data collection. Radar images with a resolution of 38.75 meters (127 feet) per pixel were obtained by researchers. We’ll get a better view in 2029 where the asteroid will be actually visible to the naked eye.
When it comes to Apophis, we can now all breathe a sigh of relief, but there is still a lot of work to be done in locating all of the potentially dangerous objects that orbit near our planet and could one day collide with it.
“The discovery of Apophis, and early work done to track and understand its orbit, occurred when today’s Planetary Defence activities were still in their infancy,” Juan Luis Cano from ESA’s Near-Earth Object Coordination Centre explained in a statement.
“That this happened at such an early period in the discipline served as strong motivation to improve our capabilities to accurately predict the motion of these interesting and potentially dangerous objects. With today’s removal of Apophis from the Risk List, we are closing a very enlightening chapter in the history of Planetary Defence.”