Philip Plait's Blog, page 6

Jupiter's moon Europa is getting salty

Well, this is very cool news: Astronomers have pretty much confirmed the presence of sodium chloride — table salt — on the surface of Jupiter’s moon Europa!

NASA mission spots Chinese rocket impact craters on the Moon

On March 4, 2022, an upper-stage rocket booster slammed into the Moon. 

We know this much for sure. But as soon as you dig into this story, it gets weird. 

The central figure in this saga is Bill Gray, a software designer who wrote Guide, a sophisticated piece of programming used by professional and amateur astronomers to calculate the orbits and positions of asteroids in the sky. He wrote about this as the events happened.

We're getting a clearer view of the interior of the Sun

The Sun is a mass of incandescent gas, as They Might Be Giants put it. And not to quibble about it being a plasma and not a gas, they’re right. That also makes it quite opaque, meaning it’s difficult to know what’s going on inside it.

Ryugu was born an asteroid, became a comet, and died an asteroid

In December 2020, after a year’s journey through space, a small capsule from the Japanese Space Agency’s Hayabusa2 mission fell to Earth. Landing in the Australian Outback, it contained just 5.4 grams of the most precious stuff there is: Pristine samples from the surface and interior of an asteroid.

New method significantly speeds up the search for dangerous asteroids

Note: This article was written in part to help promote Asteroid Day on June 30, a global effort to raise awareness about the dangers and scientific importance of asteroids. It’s on June 30 every year, the anniversary of the big Tunguska impact of 1908, and the B612 Foundation mentioned below is one of the founding partners.

Unseen planets kick a ring of debris off-kilter around a nearby star

One of the more amazing things about astronomy is how it acts like a time machine. 

For example, we sometimes see things so far away that it takes light billions of years to reach us, so we see that object as it was when it was young. 

But in another way, we can travel in time by looking at a star that is very similar to but far younger than the Sun is now. It’s not perfect, but it does give us an idea of what our nearest star was in its youth.

Protons are 5% smaller than previously thought

Look around you (or, if you’re sight impaired, touch something). Everything solid, liquid, or gas that you see and feel is made of matter. We sometimes call it “normal” matter, though with dark matter outmassing it 6-to-1 in the Universe which of them is normal?

What happens when a star engulfs its planets?

First, the bad news: In a little under 8 billion years, the expanding red-giant-Sun will engulf the Earth.

Earth’s core is speeding up and slowing down

You’d think, of all the planets in the Universe, the one we’d know best is the one we live on.

But that’s actually part of the problem: Living on it. Earth has 500 million square kilometers of surface area, but a volume of a trillion cubic kilometers. Volume wins, and worse, all that stuff is way down deep inside the planet where we cannot possibly reach it to study.

A comet got really close to the Sun and completely freaked out

The comet 323P/SOHO was discovered in 1999, and has a fire-and-ice orbit: On its profoundly elliptical 4-year orbit around the Sun, it goes out nearly to the orbit of Jupiter, but then falls back down to just a hair over 5 million kilometers from the Sun’s broiling surface. If you were standing on the comet at that point you’d have to hold up both hands to block the Sun, and it would feel like staring down a blast furnace.