Philip Plait's Blog, page 36

A billion galaxies lurk in a 10 trillion pixel map of the sky

The sky is big. If you want to map it in detail, you have to think big, too.

Astronomers are good at that. A massive international team has just released a sky survey so huge that I'm having a hard time grasping it.

The map is the culmination of six years with 1405 nights of observations, three telescopes (and one space telescope), and one supercomputer cranking away at the data… because the survey has a total of 10 trillion pixels, and makes up a petabyte of data — a thousand terabytes, or a ...

Happy (Martian) New Year!

Happy new year! If you're a Martian!

When it's Sunday, February 7, 2021 on Earth it will be January 1, 36 (yes, just 36) on Mars: The first day of a new year.

It turns out this is based on science but is also somewhat arbitrary. I know that sounds like an oxymoron, but bear with me. This is fun.

Mars is the fourth planet from the Sun. On average it orbits about 228 million kilometers out, compared to 150 million for Earth. Because of that, it orbits more slowly and has a longer path to cover,...

UPDATES: Phosphineless Venus and dustless Betelgeuse?

I have a couple of updates on some news stories I've been following for quite some time, both of which caused quite a stir when first announced: Phosphine in the atmosphere of Venus, and dust causing the dimming of Betelgeuse in late 2019/early 2020.

The versions of both are: Venusian phosphine may have actually been sulfur dioxide, and Betelgeuse dimming may have been from it getting cooler.

You may recall that back in September 2020 a team of astronomers announced they may have found eviden...

A blue bolt out of the blue: On the edge of space, lightning leaps *upward*

Chances are, you've seen, heard, or felt a lightning bolt erupt in the sky somewhere near you. After all, there are well over a billion lightning flashes on Earth per year. That's about four dozen per second, somewhere over our planet (sometimes in one spot, where an astronomer with a phonecam can get video).

Thunderstorms are a common feature of our planet, and the electrical fields therein are the root source of the power of lightning. But they also generate other phenomena, too, ones that we...

Ancient star, ancient planets… ancient life? Well…

Compared to our usual human notion of time, the Earth is old: 4.5 billion years, give or take a few dozen million. The Sun formed a tad bit earlier, and is about 4.6 billion years old.

We know of stars older than ours, though. Do they have planets, too?

Yes! And a new planetary system just found is incredibly ancient, likely over twice as old as ours. The existence of its planets is surprising, and has all sorts of implications for science and the search for extraterrestrial life.

The star is...

Are neutron stars blasting out dark matter?

One of the most irritating problems in astrophysics right now can be simply stated: What is dark matter?

Simple questions like that can have seriously complex answers. In this case, a team of theoretical physicists propose that superhot neutron star cores are creating and blasting out axions, which then generate high-energy photons when they interact with the blisteringly powerful magnetic fields surrounding the neutron stars, and that in turn can be seen as an excess of X-rays from them.

See?...

Cool: Six-star system found. Cooler: Made of three binaries. Coolest: *Eclipsing* binaries.

This deserves a "whoa": Astronomers have found a sextuple (six-) star system where, if you watch it for a few days, every star in it will at some point undergo an eclipse.

Whoa.

Multiple stars are just intrinsically cool: Unlike our Sun, sailing alone through space, multiples are where two or more stars orbit each other in a stable, gravitationally bound system. Half the stars in the galaxy are in multiple systems like that. Most are binaries (two stars orbiting each other) and some in trinari...

The weirdest binary: Planet and not-a-star barely orbit each other

Astronomers have found a pretty weird binary system about 450 light years from Earth: Neither of its components is a star. Instead, one is a brown dwarf, and the other appears to be a planet orbiting it! Even then, the brown dwarf is on the lower end of things. If it were any less massive it would be a planet itself.

The system is called CFHTWIR-Oph 98, but we'll call it Oph 98 for short. It was found a few years ago in ground-based observations using the Canada-France-Hawaii Telescope's infrar...

Was early Mars wet and warm, or dry and cold? Yes.

We know there's water on Mars. And lots of it.

Thing is, it's frozen. With the polar caps, and under the surface even down to mid-latitudes, when you talk Martian water you're talking ice.

While there may be scattered pockets of liquid water under the surface, if you want copious liquid water on the surface then you need to time travel, back to, oh, say, 3 billion years ago (better warp extra fast around the Sun or bring a few extra banana peels). Back then there was quite a bit of surface wat...

CK Vulpeculae: Something went boom but we don't know what

There are some objects in space that we kinda sorta know what they are, but the details are still fuzzy. For example, CK Vulpeculae is very obviously a bipolar nebula, made of gas and dust in an hourglass shape. We also know it formed in late 1670, when a star in the constellation Vulpecula (the fox) underwent a tremendous outburst of energy, going from invisibility to easy naked-eye viewing.

But... what is it? That is, what specifically caused the star to suddenly grow immensely in brightness ...