When a new asteroid is discovered, the first thing to do is to try to determine its orbit.
That's what they've done now in connection with this asteroid just passing Earth, says Eric Stempels, researcher in astronomy and space physics at Uppsala University.
The asteroid in question has been given the name YR4 and is 40-100 meters wide. It was first sighted as late as the end of December, writes the European Space Agency, ESA, in a press release.
New observations in 2028
According to current estimates, the asteroid's orbit is expected to coincide with Earth's on December 22, 2032. With almost 98 percent probability, the two celestial bodies will only pass close to each other. But the risk of collision is not ruled out. In January, ESA estimated the risk to be 1.2 percent, and now NASA in the US estimates it to be 2.3 percent.
Now it's on its way away from Earth and is expected to pass again in November 2028, says Eric Stempels and continues:
It's only then that we can establish a proper orbit and a message about how it will go in 2032. This percentage risk of collision is thus based on what we know today, and will change with new observations.
"Must keep track"
When assessing the risk of an asteroid, it's about both the probability of it colliding with Earth, and where on Earth it would hit.
There are many links in this chain. Partly if it's so big and made of a material whose impact would have consequences, partly if it even collides with Earth. And then at a place where there are people. All these steps are unlikely in themselves.
Eric Stempels says the asteroid is relatively small, but emphasizes the importance of following up on its orbit.
As long as we can't rule out anything, we must keep track.
