Re: Why doesn't the center of the galexy light up the sky?

Olbers' Paradox or why is the sky dark at night?

You may recall that one of the suggested resolutions of Olbers' Paradox is that there is dust in the Universe, and this dust absorbs starlight. This answer does not solve Olbers' Paradox. If there is an infinite number of stars uniformly distributed throughout the Universe, then the dust will be uniformly exposed to star light. As a result it would quickly heat up, eventually reaching the temperature of the surface of a star, and begin radiating just as bright as the stars.

While dust does not solve Olbers' Paradox, it does answer your question. There are great clouds of dust (hundreds of thousands to millions of times larger than the solar system) between us and the center of the Milky Way that absorb the star light coming from the center of the Galaxy. This is not in contradiction to the explanation above because the dust is effectively being heated only from one side, but radiating in all directions.

A dramatic example of this dust can be seen in this image of the constellation of Sagittarius. All of the dark patches and stripes through the image are where dust is blocking out stars behind it. In fact, toward the very center of the Milky Way, the dust is so good at absorbing light that the light coming from stars at the center of the Milky Way is 1 trillion times dimmer than if there was no dust!