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UI astronomer: Approaching asteroid will become temporary second moon
An asteroid is approaching the Earth which the experts say will come close enough to be caught in our planet’s gravity well, technically becoming a second moon, at least for a few months.
University of Iowa physics and astronomy Professor Casey DeRoo says this asteroid will be captured by the Earth’s gravitational pull around September 29th, it’ll slow down, then go into a sort of U-shaped orbit.
“For a horseshoe orbit, it’s something that starts off in front of us and ends up behind us as we are orbiting the sun,” DeRoo says. “Really, it’s going to do just a single slingshot around the Earth and sort of an oblong or ellipse, and then carry on its way behind us, having approached from the front.”
The asteroid known as “2024 PT5” is only about 33 feet in diameter, or about as big across as a school bus. While it will come relatively close to Earth, close in astronomical terms, DeRoo says there’s no chance the asteroid will hit us.
“They are easy to pick out, their trajectory versus the stars because they’re the things that are moving more rapidly than the stars themselves, right? And so with just a couple of observations over the course of a few days, you can actually get quite a bit in terms of orbital parameters,” DeRoo says, “and those orbital parameters tell you essentially how that orbit will evolve within our solar system. So we are 100% confident on this kind of trajectory.”
If you’re hoping to catch a glimpse of this wandering space rock, you’re wishing on the wrong star, because even though it’ll be in our orbit, it’ll still be many tens of millions of miles away.
“If you imagine trying to see a school bus from the distance of the moon, that would be the difficulty that you’re trying to actually encounter here. So it is a really faint object,” DeRoo says. “This is the kind of thing that you pick out with dedicated ground-based observatories or telescopes. So you’re going to have a difficult time finding this from the ground, unless you’ve got, say, a two- to three-foot telescope lying around.” By that, he means a telescope with a two- to three-foot diameter lens would be needed.
The experts say the asteroid will slingshot out of Earth's orbit around November 25th, after about 56 days as our looming moon, and it’ll drift harmlessly back into space.
Where did it come from? There are various theories. DeRoo says it could have been created many millennia ago when the Earth and Moon first separated, or it may have fallen out of the asteroid belt that hovers between Mars and Jupiter. We’ll likely never know for sure.
