December 27, 2013

Source: fromquarkstoquasars.com 

Galaxies. The Universe is littered with them. They have speckled the
vast darkness of intergalactic space for 13-billion years with their
numerous stars and planets.

Galaxies are grouped within three size variations: dwarf galaxies, mid-range spiral galaxies, and gigantic elliptical galaxies.

Dwarf galaxies – these are the smallest galaxies that have been classified. And they are rather small (relatively speaking; they’re still unbelievably large in “human terms”). Many of these galaxies are only about 200 light-years across, and contain only a few tens-of-millions of stars, weighing only slightly more than a star cluster.

The second grouping includes the Spiral galaxies, such as our very own Milky Way (more specifically, it’s a barred spiral galaxy). These are the most common galaxies observed in the Universe, making up 60% – 75% of all galaxies ever found.

Now we approach the largest galaxies – the Ellipticals. They range in shape from nearly spherical to nearly flat, and they can contain as many as a trillion stars.

Image Credit: NASA

Let’s get to the feature of this article – IC 1101. Shown in the image, IC 1101 is the single largest galaxy that has ever been found in the Universe. It is located almost a billion light-years away.

Just how large is it? Prepare to have your mind blown, because this galaxy has a diameter of 6-million light-years and a mass of about 100-trillion stars. It is nearly 50x the size of our very own Milky Way galaxy and 2000x as massive. If our galaxy were to be replaced with this super-giant, it would swallow up both Magellanic clouds, the Andromeda galaxy, the Triangulum galaxy, and almost all the space in between. That is simply staggering.

Over billion of years, galaxies the size of our own have collided and combined together to form this immense structure. Telescopic observations have also revealed an interesting fact about the stars within this galaxy. Normally, blue-tinted galaxies signal active star formation, while yellow-red hues indicate a cease in the birth of new stars. IC 1101 is giving birth to very few new stars. Unless it continues to collide and join with other younger galaxies, IC 1101 will eventually fade away.