Philip Plait's Blog, page 28

Incredible image: Gorgeous magnetic chaos in the galactic center

The center of our galaxy is a terrifying maelstrom of matter and energy.

You'd think having a supermassive black hole there would be the major source of the chaos, but in fact it's a bit player. Instead, the frenzy at the Milky Way's heart is created by exploding stars, regions of massive star birth, and streams of hot gas. And pulling the strings on all this — almost literally — are powerful magnetic fields.

The best way to see this is by looking at opposite ends of the spectrum, in this case...

Explaining Saturn's ravioli moons

Saturn's moons are weird.

I mean, really weird. When the Cassini spacecraft showed up at Saturn in 2004 and started doing flybys of some of the inner moons, the images it sent to Earth were so bizarre I actually had to look at them for a moment to even understand the shape I was seeing.

That's because some of them look like, well... ravioli. Yes, seriously.

Saturn’s moons Atlas (left) and Pan (right), both of which have large flattened rims around them, making them look like ravioli. Credit: ...

Landslides on the Moon? Get a Klute.

On the Moon's far side — the hemisphere forever hidden to prying eyes on Earth — lies a crater named Klute (after an engineer who was part of the team that developed the Saturn V rocket engines). Klute is old, terribly old; it's 75 kilometers wide and extremely degraded, eroded by billions of years of subsequent impacts around it, as well as the gradual effect of the solar wind and micrometeorite impacts.

To its immediate northwest is a much fresher crater about 28 km wide, called Klute W. We c...

Radioactive plutonium from a nearby supernova found on Earth

Two and a half million years ago, a cosmic catastrophe unfolded not far from Earth.

In a cluster of young stars just over a hundred light years away, a particularly massive star ran out of fuel. It had gone through its supply of hydrogen, helium, carbon, even oxygen, neon, and silicon. Its core was iron, and that cannot be fused to make energy. The core collapsed, generating a wave of energy so colossal it ripped through the octillions of tons of outer layers of the star, ripping it apart, and ...

A moment of the Universe

Oh, humans.

We go about our lives, scurrying hither and yon, seeing only what’s directly in front of us, and far too rarely taking the time, even a moment, to consider what may lie exterior to our field of view, outside our experience, across the horizon.

Or above it.

So this I offer to you: A chance to see something greater than yourself, something on a scale far larger than you may have known.

The galaxy cluster Abell S0295, a vast structure containing dozens if not hundreds of galaxies. C...

Methuselah's Star is not older than the Universe after all. But it's still pretty frakking old.

There are times in science when you get a result that you know is wrong, but you don't know why. This can lead to some interesting suppositions and many times to very interesting science.

Like, for example, when you find a star that appears to be, um, older than the Universe.

Such is HD 140283, a star similar to the Sun that lies 200 light years from Earth — pretty close as stars go. It's been known for some time to be a special kind of star, one we say is low metallicity.

In a nutshell, the ...

Wait: Do black holes *really* swarm in the core of globular cluster NGC 6397?

Recently here on the blog I wrote about the globular cluster NGC 6397, a collection of a hundreds of thousands of stars in a compact ball, orbiting the Milky Way and currently about 8,000 light years from Earth.

I wrote about it because a pair of astronomers ran statistical models on the way the stars are orbiting in the cluster, and claimed there's a pretty good chance that there's a swarm of stellar-mass black holes in the cluster core, with a total mass of 1,000–2,000 times the Sun's, meanin...

Just how many stars *is* Albireo, and is one of them a black hole?

The star Albireo is a favorite among amateur astronomers. Easily visible to the naked eye in northern hemisphere summer, it marks the head of Cygnus the Swan (or the base of the Northern Cross; you picks your asterisms and you takes your chances).

The magic happens when you look at it through a small telescope. It's easily resolved into two stars: A bright one that shines orange-red (called Albireo A), and a slightly dimmer one (Albireo B) that is sapphire blue.

It was an open question for cen...

A nuclear test creates a forbidden crystal. This is the fivefold way.

In the 1940s, the very first atomic blast deep in the New Mexico desert spawned something that has lain underground all these years, waiting. Something forbidden, something so bizarre that scientists swore it couldn't exist on Earth. They had found it in meteorites, oh yes, from the depths of space that had come. But this was forged in the radioactive fires of The Bomb, something that could only be born when humans arrogantly tampered with the laws of Nature itself, letting loose the terror of…

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Dark matter might heat exoplanets enough to make them glow

We know that dark matter exists, but, irritatingly, we don’t know what it is.

One way to figure that out is to look for signs of it here on Earth, using subatomic particle detectors. But a new idea just published in a scientific journal is that we need to go bigger. A lot bigger: Using entire exoplanets as detectors.

I give them points for thinking originally, for sure.

Dark matter is a form of matter that has mass and gravity, but doesn’t emit light or interact with normal* matter directly. ...