Philip Plait's Blog, page 15

The newly formed Moon may have tidally heated the Earth

Sometimes the rising Moon looks huge over the horizon, big enough that you could almost fall into it. That's an illusion, though. Your brain is tricking you into thinking it's bigger than it really is.

A satellite galaxy to the Milky Way has a way too big black hole at its heart

Our Milky Way galaxy is one of two big galaxies (Andromeda is the other) in a small clutch of galaxies we call the Local Group. There are dozens of smaller galaxies in the group, many of which can be considered satellites of Andromeda or us.

A superhot superdense superfast mini-Earth… and it's practically next door

Speaking of weird exoplanets, astronomers have another oddball planet, and it's seriously oddballish. It's smaller than Earth but extremely dense, and it orbits its host star very close in, so its "year" is far less than an Earth day. The good news is it's pretty close to us, galactically speaking, so follow-up studies should be possible.

Watch a black hole tear half a dozen stars to shreds

One of the sweatiest apocalyptic events you can get on a stellar scale is a star torn apart by a black hole.

Closest monster supermassive black hole pair to Earth found in a nearby galaxy

A team of astronomers has made a pretty exciting discovery: They have confirmed the existence of a relatively tight pair of supermassive black holes in a nearby galaxy, making them the closest such duo known!

Black holes up to about 100 times the mass of the Sun are called stellar-mass black holes, but far bigger ones exist. In the centers of all big galaxies lurk monsters: supermassive black holes, with millions and some with billions of times the mass of the Sun.

How massive is the Milky Way?

We live in the Milky Way galaxy, a decently large spiral-armed stellar city that has a flat disk roughly 120,000 light years across, a giant halo that extends for a million light years, and a central bulge of stars shaped vaguely like a Tic Tac.

Another Tatooine-like exoplanet found orbiting a binary star

Astronomers have found a new exoplanet in a fairly weird way — not because of its orbital motion around its host star, as is usually the case, but because of the motion of its host stars around each other. Yes, stars, plural, because it orbits two stars that orbit each other.

Being thankful: Hubble sees a baby star's shadow play

Today is Thanksgiving, a holiday where Americans traditionally take a moment to reflect on the good things in life, and be thankful for them. It takes many forms for different people — family, friends, health, food, and sometimes just a general appreciation for life.

In those terms, let me say I'm thankful for Hubble Space Telescope.

There are lots of reasons, including having the pleasure and honor of being affiliated with it, getting a degree and a job working with it for some years.

Uncertain future: Is Andromeda going to collide with the Milky Way or not?

In 2012, astronomers announced a startling result: The had used Hubble to very carefully measure the motion of the Andromeda galaxy, and found that it appeared to heading very nearly directly toward the Milky Way at 100 kilometers per second. They predicted that in about 4 billion years the two galaxies would collide, and chaos would ensue.

Two zombie stars are eating their companions and creating cosmic chaos

In a fun coincidence — if cosmic mayhem is your idea of fun* — two news stories just came out about zombie white dwarf stars destroying their companions and the ensuing chaos this has caused.