Are there any stars in between galaxies?

[ChrisBooth12]

Of all the Galaxies out there are there any stars that are just out there in the middle of nowhere that are not in a Galaxy? Would we be able to even see them or would they be to dim?

[Squink]

Here’s one on its way:

One of the fastest moving stars ever seen is challenging theories to explain its blistering speed.

The cosmic cannonball, a neutron star known as RX J0822-4300, was discovered with NASA’s Chandra X-ray Observatory.

Astronomers used five years of Chandra observations to show that the rogue star is careening away from the Puppis A supernova remnant, leftovers of a star that exploded about 3,700 years ago. The neutron star is racing out of our Milky Way Galaxy at about 3 million mph (4.8 million kph).

“Just after it was born, this neutron star got a one-way ticket out of the galaxy,”

Here’s some with buddies:

Clusters of old stars not large enough to be considered galaxies have been found wandering through otherwise sparse regions between galaxies. Most were probably kicked out of their former homes by violent galactic interactions, astronomers said.

The gatherings, called globular clusters, are among the oldest structures in the universe. They contain mostly aged stars that date back to the first few billion years of the universe. As many as a million of these old stars are sometimes huddled into a dense pack that makes a globular cluster.

These galaxies are probably losing many stars to the void.

Single stars are difficult to see at a distance of millions of light years. With so many galaxies nearby, it’s also difficult to prove that a particular star isn’t associated with one or another of them.

[aptronym]

One could also point to the Large and Small Magellanic Clouds, which aren’t “galaxies” per se but exist outside of them.

[Alive_At_Both_Ends]

@aptronym

One could also point to the Large and Small Magellanic Clouds, which aren’t “galaxies” per se but exist outside of them.

Why aren’t they galaxies?

[Sal_Ammoniac]

And to astronomers, is “galaxy” a technical term, or a term of convenience, like “constellation”?

[Napier]

“Galaxy” and “constellation” are both technical terms.

Galaxies are coherent objects in the sense that they are gravitationally bound together and local evolution is driven in part by dynamics on the galactic scale. So, for example, spiral galaxies and elliptical galaxies have different statistical tendencies describing the stars inside of them. Galaxies also do fun things like collide with one another and tear one another apart (though if it were happening to our galaxy now we probably wouldn’t notice except by studying star motions).

Constellations aren’t coherent objects, they’re just visible patterns the stars form in the sky as viewed from here. They get used to name and, to some degree, to find objects for observation and measurements. That is, you might start aiming a telescope by swinging it around so it’s pointed at a constellation where your target is. Increasingly, though, observational astronomy involves more computers and less looking up. I don’t know if constellations would be invented now, had they not been in the ancient past.

[Yllaria]

@Alive At Both Ends

Why aren’t they galaxies?

Is it because they’re too small?

[Polycarp]

Well, aptronym to the contrary, the two Magellanic Clouds have been recognized as* irregular galaxies* for all my life, and apparently for about 20 years previous. If he has some information substantiating his post, I’d love to see it.

[K364]

@Yllaria

Is it because they’re too small?

I think that Alive At Both Ends was casting doubt on the assertion.

They are definitely galaxies .

[Alive_At_Both_Ends]

@K364

I think that Alive At Both Ends was casting doubt on the assertion.

Indeed I was. They’re irregular galaxies, as already noted.

[N9IWP]

Stars found between M81 and M82
http://www.badastronomy.com/bablog/2008/01/08/aas-6-lonely-stars-between-galaxies/

Brian