Philip Plait's Blog, page 12
February 22, 2022
The Dead Red Planet Part 1: If ancient Mars had oceans, where exactly were they?
We know that Mars had liquid water on its surface long ago.
February 21, 2022
280 million years ago a huge asteroid slammed into the Wyoming/Nebraska border
It wasn’t a dinosaur killer, because it happened just before they arose. But the idea is the same*.
February 18, 2022
Our Milky Way galaxy’s last big collision still leaves clues 10 billion years later
Our Milky Way galaxy is huge, 120,000 light years across its flat disk, and two million light years across its immense halo, a cloud of stars surrounding the disk in a vaguely squashed spherical shape.
But it wasn’t born that way. Instead, it grew via cannibalism.
February 16, 2022
Quadruple asteroid!
We've known for a long time that asteroids can have moons — heck, in a few months NASA is slamming a probe into a tiny moon to test the idea that we can move one out of the way should it be headed for Earth — and it's estimated that a significant fraction of asteroids have smaller ones orbiting them.
February 14, 2022
Was GW190521 the result of eccentric, non-aligned black holes merging?
On May 21, 2019, a ripple in the fabric of spacetime swept over Earth at the speed of light.
These pass through us all the time, but this one was strong enough to warp space noticeably, at least to the detectors used by the LIGO/Virgo collaboration. As the waves passed, they compressed and rarefied a set of lasers beams, causing their lengths to change by a tiny, tiny amount: About 1/1000th the size of a proton. But it was enough.
February 10, 2022
A third possible planet for Proxima Centauri, the closest star to the Sun!
At just over four light years distant, Proxima Centauri is the closest star to the Sun in the entire Universe. We know it has one planet, called Proxima b, and there's decent evidence of a second, called Proxima c.
A team of astronomers has announced there might be a third planet, now too! If confirmed it will be called Proxima d, and would be one of the smallest and lowest-mass exoplanets ever found.
Yeah, this may be a big deal.
February 8, 2022
These two asteroids are extremely young… and used to be just one asteroid
Congratulations! It's a bouncing baby asteroid!
Wait... wait... it's twins!
Well, kinda.
February 4, 2022
Line of sight
As much as I love gazing out into the night sky and taking in the beauty of the stars, there is one thing that is robbed from us when we do so: Our sense of distance.
February 3, 2022
Astronomers find the first rogue black hole wandering the Milky Way!
Exploiting a bizarre property of black holes and gravity, astronomers may have made the first unambiguous detection of an isolated stellar-mass black hole in our galaxy, including a measurement of its mass and distance! If this pans out it will be the first rogue stellar-mass black hole found anywhere that wasn't detected via violently eating a star or some other object.
February 1, 2022
8 highlights of radio astronomy in 2021
The human eye is an amazing piece of equipment. It's so useful it likely evolved dozens of time independently — as my friend Julia Sweeney says (paraphrased), "What good is half an eye? Probably about half as good as an eye." — and allows us a way to sense the world and Universe around us with decent precision.
