The Lonely Galaxy in The Void
Hubble’s most advanced camera is producing its best images ever including an image of one of the loneliest nearby galaxies, NGC-6503
As you can see, NGC-6503 is a striking galaxy. It is a dwarf spiral located 18 million light years away in the constellation Draco (Latin for Dragon). It’s a relatively little guy only 30,000 light years across or one third the length of the Milky Way.
If you’ve seen earlier images of it you may be surprised at how much more impressive it looks now. This is due to the Hubble Space Telescope’s new camera called the WFC3 (Wide Field Camera 3) which can see a wide range of the electromagnetic spectrum from ultraviolet down to the near infrared. The previous camera, the WFPC2 (Wide Field and Planetary Camera 2) was nice but clearly did not have the resolution and wide field of view the new one has. Its various filters brings out a surprising number of colored structures like the pinks and blues of newly forming stars, the reds denoting patches of gas, and even the browns signifying the obscuring dust found in most galaxies.
This new image was part of the Hubble Legacy ExtraGalactic UV Survey (LEGUS) which maps details about galaxies and their constituent stars. This particular survey consumed 154 orbits of the Hubble around the earth compared to typical 3-10 and the extra time seems well worth it.
NGC is more than a pretty face however. It’s most striking characteristic is probably its location more than anything else. It sits in a parcel of space called The Local Void. This fascinating area of near-nothingness is a huge chunk of space 150 to well over 200 million light years across. It’s not completely empty though; a smattering of galactic filaments have been spotted but it is severely under-dense compared to typical regions of space. It’s so devoid of matter that a paper was written with the hilarious title: The Local Void is Really Empty.
NGC sits towards one side of this void all by itself. This makes it especially notable since galaxies are usually bound to others in either clusters or groups. This lonely position in such a void prompted Stephen James O’Meara to call it the “Lost-In-Space galaxy” in his 2007 book, Hidden Treasures.
Our relatively close proximity of this void means that our local group of 50 or so galaxies actually bounds one side of this empty(ish) area of space. Our local group is also a part of a broader expanse of galaxies all sharing very similar velocities and directions of movement. Taken as a whole, this is called the Local Sheet and this sheet, as well, forms one of the walls surrounding the Local Void.
So the next time you’re feeling lonely or isolated, remember poor NGC-6503. It’s really out in the boonies.