Astronomers observing asteroids can predict their orbits around the Sun and therefore predict when the observed asteroid will make its closest approach to Earth.
One asteroid, in particular, will be making a close approach with Earth in the future, and when it was first discovered back in 2004, astronomers briefly believed that it might pose a risk to Earth. However, in 2021 researchers ruled out any possibility for asteroid 99942 Apophis being a danger to Earth, but it will pass close to our planet, and that's a good thing.
A new study from Brazilian astronomers details an opportunity for researchers to learn more about the surface of the asteroid when it makes it closest approach. The researchers write that asteroid 99942 Apophis is estimated to be around 1115 feet wide, and after performing a simulation with the acquired data, the researchers discovered the asteroid's shape isn't circular and is irregular.
A model of the Apophis asteroid. Image credits: Astronomical Institute of the Charles University
Additionally, the gravity from Earth and the Sun is putting pressure on the asteroid, and due to its irregular shape, some parts of the asteroid are being battered more than others. A good way to think of this is imagining strong winds hitting your face, and as the air passes over your skin, it causes a contour from the pressure.
The asteroid will make its closest approach to Earth in 2029, where researchers hope to use observational instruments to learn more about its surface.