Philip Plait's Blog, page 29

The eerie, unearthly sight of polar stratospheric clouds

I am something of a nephophile — and before you get all snickery and snarky, it comes from the Greek nephos, for "cloud"* — and I truly enjoy seeing images and videos of interesting and unusual clouds.

I live east of the Rocky Mountain foothills, and the wind patterns here generate a lot of unusual-looking clouds. I've seen all manners of them, including fluctus (another snicker-inducing name), mammatus (a snicker-inducing formation), lenticulars, and more.

I've also seen my share of iridescen...

What created this enormous spiral in the Martian north pole? Wind. And Time.

In some ways, the north pole of Mars is like Earth's. Brutally cold, covered in water ice, yet chillingly beautiful. A big difference is that Earth's arctic area is ocean, while that of Mars is built up on solid ground.

Another big difference is that the Martian north polar cap has an enormous spiral-shaped trough system in it, covering an area of a million square kilometers — 50% bigger than Texas.

The Martian north polar ice cap has a spiral trough pattern in it, possibly due to erosion. Thi...

New pix of Jupiter will rock your (very very large) world

Jupiter never disappoints.

11 times wider, 300 times more massive, and 1,300 times the volume of Earth, it's truly enormous. It's bigger than some stars! So there's a vast amount of room on our solar system's biggest planet for interesting things to see.

On January 11, 2017, both the Gemini North Telescope in Hawai'i and the Hubble Space Telescope orbiting above Earth were pointed at this gigantic world, taking images nearly simultaneously in different wavelengths to probe Jupiter's atmosphere...

Supermassive stars might be born in the chaos around supermassive black holes

If you asked me where the most massive stars in the Universe might exist, the last place I'd guess would be in hellish accretion disks around supermassive black holes.

Yet a new paper looking at how stars would behave near these black holes shows exactly this. According to this theoretical work they can either form there and grow huge, or form nearby and be captured, whereupon then they'd grow huge.

I can't remember the last time I read a journal paper and muttered “holy crap” under my breath ...

More evidence that Mars is volcanically active right now. Today.

New research looking at images and other measurements made from orbit strongly suggests that Mars may still be volcanically active now. Like, today now. This fits in pretty well with other indicators that the Red Planet may not yet be the Dead Planet.

The observations were made using various instruments on board the wonderful Mars Reconnaissance Orbiter (or MRO), which has been circling the planet since 2006. The images targeted an area called Elysium Planitia (literally the Plains of Heaven), ...

A huge cloud of expanding supernova debris was found hidden in plain sight

When a massive star explodes at the end of its life, it creates one of the most ostentatious displays in the Universe: a supernova.

This is a colossal release of energy that propels the outer layers of the star outward at speeds of an appreciable fraction of the speed of light. For a brief time, this single object can outshine an entire galaxy of billions of stars.

So you'd think hiding the results of one would be tough. But, it turns out, that can in fact be the case. Astronomers just discove...

Don't panic, but a big Chinese rocket will make an uncontrolled re-entry this weekend

Sometime over the weekend, the 30-meter long 20+ ton first stage core booster of a Chinese Long March 5B rocket will re-enter Earth's atmosphere in an uncontrolled manner, with pieces of it crashing somewhere on the planet.

The thing is, we don't know where.

Now, don't panic. It's a big planet, and the odds of it hitting anyone are low… but not zero. To be more clear, this is a worrisome event but not one to be freaked out about.

Why don't we know where it will hit? There are several factors ...

Another clue for Boyajian's Star: Still not aliens, but maybe a companion

Remember Boyajian's Star (what )? This star undergoes episodes of rapid and dramatic drops in brightness that are, even to this day, still unexplained. What made it most famous was the idea that it could be getting blocked by pieces of an alien megastructure being assembled around it.

Oh yeah, that star. The dips we see in the star's brightness are weird, because they appear to be semi-random (if they do happen at regular intervals they're not super strict about it...

A black hole tore a star apart and played with the debris

On April 9, 2019, the light from a cosmic catastrophe reached Earth: A star ripped apart by a black hole. Everything about this event is terrifying and amazing, including the colossal energy emitted, the stream of debris from the star circling the black hole, and how the spin of the black hole may be flinging that debris off like batter from a kitchen mixer blade.

The event caught the attention of two different sky survey observatories (ZTF and ATLAS) just days apart, and was at first thought t...

NASA extends the Mars helicopter mission, testing it for actual mission ops

Droning on and on is usually boring, but in this case it's actually pretty exciting: NASA is extending the mission for the Mars Ingenuity helicopter drone! And it's entering a new phase, too, going from technology demonstration to operations demonstration, meaning it's not just seeing if the new technology works on Mars at all, but actually showing that it can be used to aid in the exploration of the planet.

This new mission phase starts with Flight number six, which should take place in a coup...