Philip Plait's Blog, page 16

Astronomers spot the construction site for a galactic supercity

It's hard to grasp how big galaxies are.

Hubble takes a series of giant outer planet family portraits

Every year, Hubble Space Telescope is pointed toward each of the four giant outer planets in our solar system — Jupiter, Saturn, Uranus, and Neptune — as part of a program to monitor their atmospheres.

All four rotate rapidly, in well under one Earth day*, so images are taken over the course of several hours to be able to create global maps of the planets, allowing planetary scientists to examine as much of the planets' atmospheric systems as possible. They're also done in as close to the same ...

So, about that black hole found in a nearby galaxy… yeah, maybe not so much

Just a week ago, I wrote about research claiming to have found a black hole in a nearby galaxy based on observations of a star orbiting it.

Yeah, that may not be the case. Just days after the first paper came out a different team of astronomers shows that the second object may be a relatively normal star, and not a black hole.

Bummer.

Get ready for Thursday night's (almost very nearly total) lunar eclipse!

Starting Thursday night/Friday morning, the sky will put on a show: A lunar eclipse, when the Moon passes into and out of Earth's shadow. This one strongly favors viewers in North America, but will be visible in part from Central and South America and eastern Asia.

It's galactic cannibalism all the way down

Our home galaxy is the Milky Way, a truly immense structure over 120,000 light years across. We don't think galaxies as big as ours form all at once, but instead start off as a collection of smaller galaxies that collide, merge, and grow that way.

The last moments of Earth's formation seriously scarred the Moon

There's a popular hypothesis among planetary scientists that, very early in our solar system's history, the migration of gas giants like Jupiter and Saturn threw a huge wave of giant asteroids into the inner solar system. This created a distinctive and cataclysmic blitz of asteroids late in the formations of the inner planets.

A near-Earth asteroid may actually be a chunk of the Moon blasted into orbit!

An asteroid a bit longer than a basketball court is following Earth around the Sun, and new research shows it may be a chunk of the Moon blasted off into space by a giant impact.

Black hole in Milky Way satellite galaxy found as it tosses around its companion

Astronomers have found compelling evidence of a black hole in a cluster of stars that's in a satellite galaxy of the Milky Way, the first time one has been found on a cluster this young. It's an important discovery, as it will help astronomers understand what young black holes are like and how they change over time.

Puzzling planets perpetrating perpendicular paths perplex people

One of the most obvious things about our solar system is that all the big planets orbit the Sun in very nearly the same plane. If you looked at the solar system “from the side” it would look very nearly flat.

*Thirty-five* new black hole and neutron star mergers found, bringing total known to 90

A very large team of astronomers has announced they have discovered 35 new compact object mergers — from black holes and/or neutron stars — adding to those previously found in the past few years, which now makes a total of 90 such events seen. These are among the most colossally energetic explosions the Universe is capable of, but, bizarrely, emit literally zero light that has been seen.