In hubble space photo-graphs, or artist's depictions of galaxies, why is the centre always glowing?

Question

Aren't there black holes at the centre of the galaxies that would typically make them 'black'?

Looking for a genuine answer please...

Answer 1

Our galaxy has arms of younger stars and gas that appear to spiral out from the centre. The objects in these spiral arms are in almost circular orbits about the centre of the Galaxy.

About 30 percent of all galaxies have spiral arms. Some have arms that spiral directly from the nucleus, while others have a linear feature, called a bar, from whose ends the arms originate.

We see this in our galaxy, where the Milky Way is divided into two portions for much of its length. Indeed the centre of the Milky Way galaxy is invisible in ordinary light because the interstellar dust in that direction is so thick. Infrared light, however, penetrates the dust, and recent measurements have allowed astronomers to 'see' the Galactic centre.

The Sun takes about 200 million years to complete one orbit around the centre.

Answer 2

There is a vast amount of scale that you must realize when you see a picture of a galaxy. Even our best telescopes can't resolve individual stars in all but the closest galaxies to our own. And the ones that can be resolved are simply areas of light made by supergiant or super bright stars that the Hubble telescope can pinpoint as single sources. Not even the Hubble can resolve an actual solar disk of any star (except for our sun, of course). They are simply too far away.

When you look at the centers of galaxies, you are looking at hundreds of thousands of stars. The light from all those stars makes a glowing haze. A black hole, even a supermassive black hole at the core of a galaxy, is not very large when compared to the light years of diameter you are looking at when you look at just a small part of a galaxy's center. Besides, unless the black hole is actually absorbing matter, it cannot be seen. And even if it was, like I said, it would be impossible to detect, because at those distances even a starfield of 500 thousand stars is just a blur of light to even our finest telescopes.

What can be seen, through radio telescopes, is the intense amount of x-rays and gamma rays emitted by a black hole during a feeding frenzy, or through regular telescopes when a star goes supernova prior to becoming a black hole.

Answer 3

I'd also like to note that a galaxy can have multiple black holes, not just one in the center. as well, the whole "black hole in the center of every galaxy" thing is just a theory.

but someone also said that a black hole is small. that's true. it's ability to suck in light has a range that is much much smaller than the large concentration of stars in the center of the galaxy. so there are plenty of stars in the center which are far enough from the black hole to have their light escape and reach earth.

hope that helps along with the other answers

Answer 4

The concentration of stars is always highest at the center of the galaxy. The black holes at the center of the galaxies are very tiny compared to the size of the galaxy so we see the glow of the central stars that are near it. The galaxy is thousands of light years across and the black holes are smaller than our solar system

Answer 5

The glowing you describe is mostly found in photos of one type of galaxy called 'spiral.' In this kind of galaxy -- our Milky Way is one -- stars, gases and dust are more concentrated in the center. Super-massive black holes are also present in the core of eliptical galaxies but even they aren't large enough to block out the objects there. To some extent these black holes contribute to the central glow by accelerating nearby material to velocities close to the speed of light.

Answer 6

Its simply a perspective issue, yeah the center would be black if you were closer too it, however since we are such a great distance away , the millions and millions of stars closest to the center are what we see.

Analogy

If you were standing right in front of a building in New York City at night , and there were absolutely no lights on in this building, you could see that, but hop in a plane and fly over New York and all you see are the city lights, you can no longer see the building with no lights.

Answer 7

From the distance we are looking, a black hole (even the event horizon) would be so small, it would be impossible to see.

The centers of galaxies generally have the highest concentration of stars. From the distance we are looking at, those individual stars (that we can't resolve anyway), just merge together as concentrated light fuzz. Since there are more of them near the center, it is brighter near the center.

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Answer 8

As others have pointed out, those black holes would be invisibly small.

To answer your top-level question, people take images from Hubble (and other sources), but they add the colors to enhance the image to show more clearly what's going on.

So they'll pick a color to represent a certain temperature range, and use that color where appropriate, using various color to show various features or temperatures or substances.

They do have an eye to making it pretty when they do this, but the images you see, for example, at www.nasa.gov aren't drawn whole-cloth.

They're enhanced photos.

Answer 9

There is just a big mass of stars, and the glow could be 'light pollution' i.e: if you look at a cluster of lights at night from foar away, there is a glow around them.

Hope This Helps!

Answer 10

The black hole is surrounded by a halo of stars. You cannot see through the haze of stars to see the center.