Philip Plait's Blog, page 19

Galactic death: Some galaxies hit the gas, live fast, and die young

You think the Universe is busy now? Why, back in the day, it was positively overflowing with activity.

If by activity you mean making babies, and by babies you mean baby stars.

When the cosmos was between 2 and 4 billion years old galaxies were just cranking along, converting huge reservoirs of cold gas into stars at a fierce rate, some easily 100 times what we tend to see today in our 13.8-billion-year-old Universe. Because light takes time to get from them to us, we see these galaxies as bei...

A fog of gamma rays permeates the sky. Now we know why.

The Universe glows softly in gamma radiation.

This isn’t anything to be concerned about; we’re not all about to Hulk out. Well, to be more clear, this is nothing to be concerned about unless a) you’re an astronomer, and/or 2) you find the Universe a pretty interesting place and want to know more about it.

Lucky you: I’m #1 (and #2), and if you’re #2 then read on.

The Universe glows in lots of different flavors of light. For example, the Cosmic Background Radiation is a glow all over the entir...

In Jupiter's Great Red Spot, a wind is rising

Jupiter’s enormous Great Red Spot, a huge elliptical rotating storm that has persisted for centuries (at least!) has been undergoing some weird changes over the past few decades. Its color has changed, and it’s been shrinking, too. Now, new results from 11 years of Hubble Space Telescope observations show that the wind speeds around the Spot have increased significantly, too.

Why? That’s not clear (get used to that phrase). Like so many things about this ridiculously huge maelstrom, it’s not un...

Dwarf planets can have rings, too, if they're lumpy or oblate

All four giant planets in the solar system have rings. Saturn’s are the most obvious, of course, but Jupiter, Uranus, and Neptune have them as well.

But they’re not alone. Two minor planets have rings made of countless icy particles as well. Their discovery was a shock to astronomers, because it wasn’t thought that smaller bodies could maintain a ring system. Nature, though, is more clever than we are, and found a way.

But how, exactly? Over time, rings tend to disperse without moons to shephe...

Earth, Venus, and the Moon may all be victims of ancient hit-and-run planetary collisions

A big problem with trying to figure out how the planets formed is that it happened 4.55 billion years ago. The record’s a little blurry by now.

We have a lot of science and understanding of the planet-building processes, and can model them on computers by solving the various equations involved. But these models are only as good as the math and physics that go into them. If there’s some process involved we don’t know about, then the models that don’t include it could very well be wrong.

This ha...

The Molten Ring Galaxy is blasting out a trillion suns worth of infrared radiation

A galaxy billion of light years from Earth is pouring out vast amounts of infrared light, the tell-tale signature of furious star birth.

That’s already pretty cool, but it gets better: As the light from this galaxy traverses the Universe it passes by a massive galaxy cluster that distorts it, amplifying its brightness, cloning it repeatedly, and twisting it into what looks like a river of molten gold.

I mean, seriously. Look at this.

A Hubble image of a galaxy cluster 4 billion light years aw...

The 900-year-old mystery of the missing supernova has finally been solved

A 900-year-old galactic mystery has been solved! The cold case of The Star That Appeared in the Night But Then Disappeared Without a Trace may finally have found its perp.

The story begins in 1181 CE. On August 6, Chinese and Japanese astronomers saw a "new" star in the sky, what they called a "Guest Star." It brightened over time before fading, getting about as bright as Saturn at its peak. In February 1182 it faded from view, having been visible to the unaided eye for six months.

This sounds...

How is an intermediate mass black hole like the Cookie Monster? They’re both really sloppy eaters

If you had to wager on a star vs. a black hole, you’d bet on the black hole to win every time.

But how it wins tells us a lot about it. Your standard-issue stellar mass black hole (one with, say, 5 to 100 times the mass of the mass of the Sun) would tidily (and tidally) pull material off the star and eat it slowly over time. A supermassive black hole (with over 100,000 times the mass of the Sun) could eat a star whole in one gulp, especially the ones at the top of the weight scale with billions...

Lucy's wild ride to Jupiter's orbit… but not to Jupiter

In a little less than a month, NASA will launch an ambitious mission through the asteroid belt and out to Jupiter’s orbit. The spacecraft won’t be visiting Jupiter, though: It will fly by several asteroids that share an orbit with the giant planet, looking to investigate these fossils from the solar system’s early days.

This mission is pretty cool, but the flight it’ll take to get where it’s going is just nuts.

This mission is called Lucy, named after the skeleton of Australopithecus afarensis...

Forget Yellowstone: Thousands of immense supervolcano eruptions buried much of ancient Mars

In one of the single most terrifying articles I have ever read, planetary scientists show that ancient Mars suffered from immense, repeated supervolcano eruptions that buried a huge region under ash as deep as a kilometer, and that these eruptions are tied to vast calderas in a specific spot on the planet.

These supervolcanoes erupted between 1,000 to 2,000 times over a 500 million year period, an apocalyptic era in the Martian past called the late Noachian/early Hesperian, about 3.7 billion ye...