In determining the trajectory of near-Earth asteroids, the main difficulty is the need to quickly determine their distance. Two years ago, scientists proposed a new way to do this quickly, and recently proved its effectiveness.
Distance to asteroids
Information that asteroid 2024 YR4 may collide with our planet in the future has renewed interest in studying the possible threat from these space objects. In this regard, a group of scientists recalled that they developed a new way to quickly determine the distance to the asteroid two years ago, and now they are ready to demonstrate its effectiveness.
In total, scientists know about 37,000 objects approaching the Sun closer than 1.3 a.u. today. Most of them are called near-Earth asteroids, although there are a few comets among them. One way or another, all of them could change their trajectory to one that would cause them to collide with our planet.
The only problem is how to define this trajectory and track its changes in real time. This is usually done by observing the asteroid over many nights and, by comparing its position in photographs and brightness, determining the point in space at which it was located each day.
This works for Main Belt asteroids that are measured in kilometers in size. However, among near-Earth asteroids there are many with a size of 200-400 meters. There can actually be millions of them, and each one is capable of destroying an entire city, or even a country. And finding them several days in a row is difficult because of their size, so determining distance can take a long time.
New method
A new method utilizes the same phenomenon as the standard method — parallactic displacement. It consists of observing an object against something distant, such as stars, and knowing how the position of the point of observation changes or does not change in space, it is possible to calculate the change in distance to the asteroid.
In the usual case, scientists take into account the earth’s orbital motion. However, parallactic displacement occurs when the Earth rotates about its own axis on a daily basis. And that’s exactly what the researchers propose to use in the new method. All we need is the observation of one telescope throughout the night, or several located on different sides of the Earth. This is enough to determine the distance.
The effectiveness of this method was recently proven using an experiment with simulated asteroids. In total, the researchers obtained data on 19 fictitious rocks that could have been obtained if they were really close to Earth. And they were able to determine the distance to them.
Now we need to do the same with the data about real objects. The telescope at the Vera Rubin Observatory is scheduled to begin operations in July 2025. It is better suited to test this method in practice.
According to phys.org
