Philip Plait's Blog, page 8

Breaking down the structure and history of a nearby — and weird — galaxy

How are galaxies built?

Stellar hypoxia may help make more massive black holes

It seems like a bit of a non sequitur, but new research implies that if a star doesn’t make enough oxygen, it can become a massive black hole when it dies. 

Yeah, that seems like an odd connection. But here’s how it works. 

Invisible dirty dry ice frost avalanches on Mars

In an ongoing attempt to be the weirdest planet in the solar system, Mars apparently has dust avalanches on steep slopes caused by whisper-thin winds generated as dry ice frost mixed in with the regolith sublimates at sunrise and leaves behind dark streaks.

So yes, let’s break this down a bit, shall we?

No planets seen for Sirius B, the nearest white dwarf to Earth

Well, this is a bummer: It looks like Sirius B doesn’t have any extant jovian gas giant planets.

Sirius B is the closest white dwarf to Earth, the leftover innards of a star like the Sun after it goes all red giant, blows off its outer layers, and reveals its dense core to space. And I do mean dense; Sirius B has the mass of the Sun packed into a ball about the same size as Earth.

Lunar horticulture: Plants grown in lunar “soil” for the first time

For the first time, scientists have grown plants in lunar regolith, the mixture of rock and dust that covers the surface of the Moon*. 

This is very cool. 

Exocomets swarm around an alien star… yet seem oddly familiar

One of my favorite stars in the sky is Beta Pictoris — Beta Pic to its friends. I’ve never seen it myself, but I still like it because it’s one of the very first, decades ago, suspected to have a forming planetary system.

Incredible images as astronomers see material swirling around the Milky Way’s supermassive black hole for the very first time!

Astronomers have, for the very first time, taken extreme close-up observations of the supermassive black hole in the center of our Milky Way galaxy.

After a fiery embrace, some stars undergo metamorphosis

In astronomy, broadly speaking, there are two kinds of Mysterious Objects: Ones we see and don’t understand, and ones we predict from our theories but we’re not sure what they look like in a telescope.

It’s a pretty good day when you can point at one class of Mysterious Observed Objects and say they’re also one of the Mysterious Theoretically Predicted Objects.

Electrostatic repulsion may be lofting small rocks off the asteroid Bennu

Why is Bennu spitting rocks into space?

A pulsar is firing a 7-light-year-long antimatter stream into space

There’s an aphorism I’ve seen used here and there which goes, “Nature never draws in a straight line.”

It turns out that’s only mostly true, because sometimes it does, or gets pretty close. For example, a tiny BB of a star just a couple of dozen kilometers across has shot out a pretty straight beam of matter and antimatter that stretches for a staggering 7 light-years — 70 trillion kilometers!

That’s… very long. Even from our distance of 1,600 light-years the beam is half the apparent size of ...