The Apophis asteroid grabbed public attention ever since it was discovered in 2004. It’s big enough to destroy a city and it’s headed our way. Lately, some social media seem to have discovered this menace for the first time and have given it scary publicity. So let’s look at the actual facts.
On Friday the 13th of April, 2029, just four years from now, Apophis will make a record-setting close approach to Earth. It’ll come nearer than any celestial body in recorded history, without hitting us. We’ll actually see it visibly move across the sky, without even needing a telescope. It will pass just 22,000 miles overhead, the height of TV satellites.
Then our gravity will change the asteroid’s orbit. After we’ve circled the sun six times, we meet Apophis again in 2036. And THAT was the worrisome encounter. Once again the two of us meet on a Friday the 13th of April.
At first, the collision odds were pinned at 2.7 percent. Then, better data dropped it to one chance in 45,000, which still worried some people, probably the same group that buys lottery tickets. But radar measurements in 2021 let NASA scientists again recalculate the asteroid’s path, now showing it to have no chance of hitting us for at least the next century.
This business of first detecting a seemingly dangerous space object but then later deciding it’s no threat, is a familiar pattern. NASA finds and tracks asteroids and comets passing close to Earth to determine if any could be potentially hazardous. If one looks like it might hit us in the future, it gets headlines. Then, invariably, the odds always get longer for a simple, fascinating reason. Earth and any asteroid are like two zooming bullets, where one path is well-known but the other only approximate. As more information arrives, there is just one specific way the second bullet’s path can precisely shift to create a collision. But there’s a million ways we can miss by an even wider margin.
So, as usual, we’re safe. Even if Apophis ultimately proves a deadly menace in the coming centuries.
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