Why do NASA and other space agencies give asteroids names like Apophis if they don't want us to freak out about them colliding with Earth? It sounds apocalyptic.
The ancient Egyptian god of Chaos was named Apophis. He was an evil serpent that was the enemy of light and truth. People were understandably anxious when they were told that an asteroid named Apophis was due for a close encounter with Earth in 2029. The previous dominant inhabitants were evicted by an asteroid.
We have been following Apophis since it was discovered in 2004. There was a chance that Apophis would change its trajectory. It was feared that it could hit Earth. We know that we are safe for at least 100 years. We might have our planetary defence system operational by that time.
In 2029, Apophis is going to approach things in a way that is not frightening. The event is a chance to study the rock and see how it responds to being on Earth.
The paper outlines what the encounter might be like. The paper deals with the effects of the 2029 Earth's encounter on the surface. The Monthly Notices of the Royal Astronomical Society accepted it. The first author is Giulia Valvano.
Apophis has been studied. It has a diameter of over a thousand feet. It is an S-type asteroid, so it has a different composition than a carbonaceous one. A number of asteroids are S-types. S-type asteroids like Apophis are rare further out in the Solar System.
Thermal observations show that Apophis is a rubble-pile asteroid, similar to Itokawa. The asteroid has a tumbling retrograde rotator. If you know where to look, Apophis will be visible during its 2029 approach.
Scientists have constructed models of Apophis' motion, shape, density, composition, and surface characteristics. The asteroid will come close to Earth in 2029. It is an opportunity to test and refine the models when Apophis flies by.
The trajectory of Apophis is shown in this figure. The green line and circle show the Moon's location. The path below the equatorial is marked by a dotted blue line and a solid blue line. Valvano et al 2021.
The closest approach will be on April 13th, 2029. On that day, the asteroid will approach Earth at a distance of over 30,000 km. It will be subjected to both Earth and the Moon at that time. It will be exposed to solar radiation pressure.
It will be so close that its axis of rotation will be altered by tidal forces. The models show that the Earth will cause a lot of damage to Apophis. Some of the particles escaped into a disk surrounding Apophis, but most fell back to the surface.
The scientific astronomy community will engage in a massive observational campaign when Apophis arrives. So will they. Some of the telescopes that are under construction will be operational by 2029. We have a lot to learn about asteroids, and when one comes close it is an opportunity that can't be ignored. The better we understand asteroids, the better we can deal with them.
The authors say that their analyses may contribute to the 2029 observation campaign. The 2029 campaign may improve our ability to mitigate the threat posed by dangerous asteroids.
