Philip Plait's Blog, page 10

For the first time, three supernovae are seen at the same time in a single galaxy!

In an unprecedented event, there are THREE active supernovae simultaneously seen exploding in a galaxy right now!

While two supernovae seen at the same time in the same galaxy has happened before, to my knowledge there has never been three. That’s pretty cool!

DUDE, where's my carbon star?

The star V Hydrae is dying. But it’s dying with style. 

It’s about 1,400 light-years from Earth, and was once similar to the Sun but is now what we call an asymptotic giant branch (or AGB) star: One that has run out of hydrogen fuel in its core to fuse into helium and has swollen up hugely. Stars like this expand and become red giants, and over some millions of years will contract and expand several times, usually getting bigger at each expansion phase. 

Surprisingly high fraction of dead galaxies found in ancient galactic city

Our Milky Way galaxy lives in a small group of others including the Andromeda galaxy and a few dozen much smaller ones. But bigger groups exist: Galaxy clusters can have hundreds of big galaxies in them, all orbiting around their mutual center of mass.

Psst! Wanna see an actual Hubble image of a planet forming around a nearby star?

We now know of over 5,000 exoplanets, worlds orbiting other stars. The vast majority of those were discovered via the transit method, where the planet causes a mini-eclipse and blocks a little bit of its host star’s light.

Timeline of the Milky Way

We live in the Milky Way galaxy, an immense, flat, spiral galaxy surrounded by a massive halo of stars and dark matter. The disk of stars, gas, and dust in which the Sun resides is fully 120,000 light years across; a soul-crushing distance on the human scale. In the middle of the disk is the central bulge, a lozenge-shaped hub of stars.

Follow-up: ORCs are weird, huge, and still mysterious circles in space

ORCs! In! Spaaaaaace!

Hubble sees the farthest star in the Universe

Staring at the same spot in the sky for the better part of a day, Hubble Space Telescope — aided by a quirk of gravity that can massively magnify distant objects — may have spotted the most distant star ever seen… by a huge margin. If confirmed, the star is nearly 13 billion light years away, and we see it as it was when the Universe was only 900 million years old.

Watch as a million galaxies form in the first billion years of the cosmos

Studying the very distant Universe is hard. That’s because — not to be too on the nose about it — it’s far away.

Astronomers discover a huge expanding debris cloud from two colliding protoplanets!

In a planet-forming disk of gas and dust around a young, nearby star, two huge objects recently collided at high speed. The colossal impact was positively apocalyptic in size, vaporizing enough material to make a small planet — at least. Even better, the huge dust cloud created in the event passed between us and the star, eclipsing it twice, allowing astronomers to learn more about this catastrophe.

When is a planet not a planet? When it’s actually a star

In the time since the first planets orbiting another star — called exoplanets — were discovered in the early 1990s, astronomers have found a lot more, and the number has now passed the 5,000 mark.