The article was contributed to Space.com's expert voices: op-ed and insights.
If you've been on the internet recently, you've probably seen news of a "planet killer" asteroid named 2022 AP7
Scott Sheppard at the Carnegie Institution for Science said that AP7 has no chance of hitting the Earth currently. A trio of large asteroids obscured by the sun's glare were observed by his international team of colleagues.
AP7 crosses Earth's path when it is on the other side of the sun. It will cross much closer by in the future, but it will be centuries into the future.
We don't know enough about the future of AP7 to make an accurate prediction. We think there could be other killers out there. How many are you talking about? What are the steps being taken to find them?
There are many ways to stop an asteroid.
The largest potentially hazardous asteroid has a diameter between 1.1 and 2.3 km. Mass extinction events can be triggered by an asteroid with a diameter more than 1 km.
An asteroid that has a diameter greater than 1 km is considered potentially dangerous. Any threat is centuries away. It can now be tracked thanks to the fact that it has been detected. The best outcome is this one.
About 85% of potentially hazardous asteroids have been discovered and there are less than 1000 of them. Some 50 asteroids will be hunted down by Sheppard and colleagues.
How big is a space rock?
All known objects in the solar system are tracked by NASA. Every now and again, an object will surprise us.
We had a close call with an asteroid in the year 2021. It was only a few thousand kilometers away from the earth. This is very close. It was only two meters across and there was no risk.
It's not uncommon for objects of this size to impact Earth. Most of the object burns up in the air and creates a spectacular light show.
An asteroid with a 100 meter diameter passed by Earth in the year 2019. The announcement was made just hours before it flew past. It was of a much bigger concern than it was.
The importance of speeding up the search for near- Earth objects is underscored by these near misses.
Observational blind spots and the fact we can't observe all parts of the sky all the time are the reasons why we haven't found every object that could pass near Earth.
After the sun had set, Sheppard and colleagues used a telescope to locate AP7. They had to do this because they were looking for asteroids. Venus is on the side of the sun that is not visible to the naked eye.
It's hard to make observations near the sun. The weak light reflected off small asteroids is presented as a blind spot by the glare of the sun. The sun's glare doesn't block the view just before and after sunset.
There are only about 25 asteroids that have been determined to be in Earth's path. Some of the missing asteroids may be contributed to by more discoveries.
Humans can change the trajectory of asteroids. There is a 160-meter diameter moonlet called Dimorphos.
Dimorphos's 12-hour orbital period was altered by more than 30 minutes as a result of the collision. If we find a hazardous asteroid, it is possible for humans to move it.
We would have to locate it in advance. A bigger collision is required with plenty of lead time because of the larger asteroids.
NASA wants to use a telescope in space to look for hazardous objects. The Near-Earth Object (NEO) Surveyor will be able to survey the solar system in a way that is very efficient.
Earth's atmosphere causes the glare we see when we observe from Earth. There is no atmosphere in space.
New objects will be revealed and we will be able to better understand threats.
The key is to find as many objects as possible, categorise them, track the risks, and plan a redirecting mission as soon as possible. It's an amazing feat of science and engineering that all of these elements of planetary defence are now a reality. We have never had these capabilities before.
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