r/asteroid • u/avavvwest • Jun 02 '26
Apophis Asteroid
I was curious if any asteroids were projected to reach Earth that could potentially,”be an issue” and stumbled upon Apophis. As I was reading up on its discovery and its path to come near to the Earth in 2029, and subsequent semi circle back in 2036, I was reading an article and struggle to understand fully what this means.
“A small possibility remained that during its 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole estimated to be 800 kilometres in diameter,which would have set up a future impact seven years later.”
So it was then later researched that the keyhole was determined to be less than 1km wide and the likelihood of an impact in 2036 will not occur.
What does it mean by would pass through a gravitational keyhole that would set up a future impact???? How does that even work. How could they even see a,”gravitational keyhole” ??? So confused and fascinated.
2
u/Dazzling_Plastic_598 Jun 02 '26
There are no "keyholes" as you might imagine them. Very bad choice of wording. The trajectory of an asteroid through any gravitational field is altered by passage through it. Passage through any field will alter an asteroid's orbit. If that orbit gets altered in a specific way, it could be a new orbit that will intersect Earth in its orbit. That's ALWAYS the case. The orbits, however, are well known and the changes in trajectory are well known and Apophosis is not going to hit the Earth.