Philip Plait's Blog, page 13

In 7176 BCE, the Sun erupted in what may be the biggest blast in 10,000 years

The Universe is scary. There are dangers galore, including black holes, asteroid impacts, supernova explosions, and more. However these events tend to be far away and/or extremely rare, so they're nothing you really need to worry about in your daily life.

And then there are solar storms. If there's any astronomical event we need to take very, very seriously, even more than asteroid and comet impacts, it's these.

So is there liquid water under the Martian ice cap or not?

So, is there liquid water in a subglacial lake under the south polar cap of Mars or not?

Given the brutally cold sub-freezing temperatures on Mars, especially at the south pole, you'd think the answer would obviously be no. But it's not at all that clear, and two papers came out this week arguing on opposite sides of the idea.

There are 40 quintillion black holes in the observable Universe. More or less.

How many black holes are there?

I don't mean near the Sun, or even in the galaxy. I mean, how many black holes are there in the entire observable Universe?

Turns out about 40 billion billion of them.

For those who like numbers, that's 40,000,000,000,000,000,000. In exponential notation that's 4 x1019.

In English, that's holy crap that's a lotta black holes.

Weird chemistry is making the Earth's interior cool faster than thought

Long ago — 4.5 billion years ago, right after the Earth formed — our planet was hot. It formed by essentially getting slammed billions of times by asteroids, and all that energy of impact was enough to keep the Earth broiling.

Eventually heavy elements like iron and nickel sank to the core, and lighter ones rose to the surface. This differentiation created the Earth we see today: An inner, solid nickel/iron core that's nearly as hot as the surface of the Sun; an outer, liquid iron core; the sol...

Stellar intruder makes a grazing hit-and-run on a pair of young stars

The Sun flies solo through the galaxy, the nearest star to us over 40 trillion kilometers away. But that's not the case for all stars.

A thousand-light-year-wide bubble around the Sun was blown by the ghosts of long-dead stars

We've known for decades that our Sun sits near the center of a vast expanding bubble in space, a growing cavity carved out of ambient gas in the Milky Way. But a remarkable new study has come out showing that nearly all the nearby gas clouds that are currently forming stars sit on the thin edge of that bubble — strongly implying that the expansion of the bubble itself triggered that star birth.

Antimatter and matter fall at the same rate. Well, within 3%.

Let's say I'm a mad scientist*. I have a ball of antimatter and a ball of matter, which I have carefully measured out atom by atom to be exactly the same mass in my Matter-Antimatter Doomsday Device Maker. I then hold them both over the ground at exactly the same height, and then let them go.

Will they hit at the same time? Or is there some fundamental property of antimatter that makes it respond to gravity differently than normal matter?

James Webb Space Telescope is now fully deployed! But there's still a long way to go.

Now witness the observational power of this fully deployed and not-quite-yet operational space telescope.

— Emperor Palpatine, kinda

On Saturday morning, January 8, 2022, the eyes of James Webb Space Telescope became fully opened, and the massive observatory now ready to begin its long testing phase to focus its individual 18 hexagonal mirror segments into a single, monolithic vision of the Universe.

Solar UV radiation on Earth's surface may have been more intense eons ago than we thought

About 2.5 billion years ago, the Earth did not look at all like it does today.

Non-baryonic mystery: Where is this galaxy's dark matter?

Speaking of dark matter, astronomers have uncovered a pretty interesting mystery involving it. Or rather, not involving it: They’ve found a galaxy that apparently has little or no dark matter in it.