What is at the center of a galaxy?

A supermassive black hole?

As regards the Milky Way: the distance from the Sun to the galactic center is now estimated at 26,000 ± 1400 light-years while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass (named Sagittarius A*), strongly suspected to be a supermassive black hole. Most galaxies are believed to have a supermassive black hole at their center.

Sagittarius A* (pronounced "A-star", standard abbreviation Sgr A*) is a bright and very compact source of radio emission at the center of the Milky Way Galaxy, part of a larger astronomical feature at that location (Sagittarius A).

Recent observations have determined the mass of the object to be about 3.7 million solar masses within a volume with radius no larger than 6.25 light-hours (45 AU). This is compatible with, and strong evidence in support of, the hypothesis that Sagittarius A* is a supermassive black hole.

Sagittarius A* is "associated" with the supermassive black hole; what is seen is not strictly the black hole itself. The observed radio and infrared energy emanates from gas and dust heated to millions of degrees while falling into the black hole; the black hole itself emits only Hawking radiation at a negligible temperature, on the order of 10^-14 kelvins.

A supermassive black hole is a black hole with a mass of an order of magnitude between 10^5 and 10^10 (hundreds of thousands and tens of billions) of solar masses.

Supermassive black holes outside the Milky Way

In May 2004, Paolo Padovani and other leading astronomers announced their discovery of 30 previously-hidden supermassive black holes outside the Milky Way. Their discovery also suggests there are at least twice as many of these black holes as previously thought. It is currently believed that every galaxy contains a supermassive black hole at its center, with most of them being in an "inactive" state not accreting much matter.

Some galaxies, Galaxy 0402+379 for example, have two supermassive black holes, forming a binary system. Should these collide, the event would create strong gravitational waves.

This is a subject that you and I both need to read up on to understand it properly!

Good thinking..! There's good evidence that a super-massive black hole exists at the center of not only our galaxy but other spiral galaxies too, like M101. Based on the motions of stars closer to the Milky Way's core, the mass of the central black hole is estimated at 4-million times more than our sun.

A galaxy is an end point in the evolution of the universe. some cosmologist declare that a black hollow inhabits the galactic center. The galactic center is being pushed via something that tactics count number,such that it is going out of existence. A black hollow could purely engulf all stars in our galaxy and sit down doing no longer something invariably some variety of neutron celeb interest is probable driving the galactic center.

Theoretically, a black hole.

The spirals are formed from the fact that the centre of the galazy is the entire galaxy's centre of gravity, so it is the point around which everything in the galazy ultimately revolves.

Exactly wot is there isn't really important, although the huge gravitaional forces seem to imply that it's a extremely massive object, which would almost have to be a black hole, but it has never actually been observed.

Looking at the previous answers I hope to give you something more substantial than posh or becks....

Scientists fall into 2 categories.... they either believe that Neutron Stars or Black holes are at the centre of Galaxies. If a Neutron star has a mass of over 5 solar masses then gravitational collapse will occur, inevitably producing a black hole. As time passes the likely hood of the object being a Neutron star diminishes - Q.E.D -The older the Galaxy the more likely there is to be a black hole at the centre! Hope this helps!

each galaxy and solar system has its own star or sun (they are both the same thing) in the center..

nothing in the middle spin fast to cause the spiral.. the explosion of a star a long time ago might have cause this..

it is not a black hole. if it is, the galaxy might have already disappeared..

How about if the center of a galaxy is a nucleus of an atom. And everything spinning around makes a molecule which is part of a compound that is just part of a table leg. We are not so big then ha!

I believe the current theory is that individual galaxies were formed by material ejected by massive supernova's and that evidence to back this up is emerging in the form of black holes being found at the centre of each galaxy.

I also read that the "expanding universe" model may well be incorrect and that the observation of expansion may in fact be the individual galaxies being drawn towards their black holes, hence the RELATIVE increase in distance.

In our case as is with all that we know of (no exception found yet) is a supermassive black hole. Galaxies spiral out from the center.

I've been told a really freakin' huge black hole.

Makes sense, I guess it's kinda like a whirlpool, drawing all the galaxy inward in a spiral.

Maybe?

Well I'm not like an astrophysicist or anything but I mean that's just a guess for yah.