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IC 1101
Let’s talk about size (astronomically speaking).
Our galaxy is 100,000 light-years across. That’s
pretty big, but it’s not the biggest galaxy in our
astronomical “neighborhood”. The Local Group
(our “neighborhood”) is comprised of 54 galaxies
(dwarf galaxies included) that are gravitationally
bound to each other. The biggest in the group
Andromeda, 2.5 million light-years away from us,
visible to the naked eye as a fuzz patch (in dark
skies) in the constellation Andromeda, and some
220,000 light-years across. Okay, our Milky Way
still holds its own as the second largest galaxy in
our Local Group. Our Local Group is a whopping 10 MILLION light-years across! That is huge, Now, let’s turn
our attention to the largest known galaxy in the universe. Way out in the distance, 1.07 billion light-years away
in the constellation Virgo, in the large galaxy cluster Abell 2029, lies an enormous galaxy: IC 1101. This gargantuan elliptical is over half the diameter of our entire Local Group of 54 galaxies—nearly 6 MILLION light-years
across! But wait, there’s more! The Milky Way contains roughly 200 billion stars. IC 1101, by contrast, contains
an estimated 100 TRILLION. Absolutely MIND-BLOWING!!! but it makes sense considering it’s a group of 54 galaxies. Just to give an idea of the types of galaxies out there, there are three major classifications: dwarf galaxies, spiral galaxies, and giant elliptical galaxies. Dwarf galaxies are small, like the Milky Way’s satellite galaxies,
the Large and Small Magellanic Clouds. These can be as small as 200 light-years across and are not much larger
than star clusters. Spiral galaxies, like our Milky Way and Andromeda, are the most common types of galaxies.
ICY SCIENCE | WINTER 2013- 2014