One of my usual blog stops is over at Phil Plait’s Bad Astronomy blog, and this morning he has an exceptional astro photo and a small write up on this enormous galaxy. Andromeda has been one of my favorite objects to view through a telescope for many years, and I can spend up to 30 minutes at a time observing it before I move on to other night sky treasures. His blog post got me to thinking about Andromeda, so I thought I’d throw some cool Andromeda stuff out there.
What is the farthest object you can see with no optical aid? Andromeda of course. It lies 2.5 million light years away and is visible as faint smudge in the sky on a clear night.
(EDIT EDIT EDIT: My big dumb ass just came in from outside (it’s dark) and the moon is past 1st quarter which I should have checked on before I went all smartypants with this post. You see it takes a moonless night for these naked eye objects to be easily seen. As well it helps to dark adapt your eyes for 15 or 20 minutes before you attempt to hunt them down. Also it helps a LOT to be far away from city lights, a fairly dark location is very helpful. So keep these things in mind if/when you decide to take a shot at finding them.)
Where do I look? To the NE sky anytime around 9-10 PM will do. This location won’t be too far from the horizon this time of year at that timeline. Later in the night it will climb higher in the sky. Here is a wide look at the region. Just about everyone knows the familiar constellation of the beautiful goddess Cassiopeia. There is a handy pointer built into Cassiopeia pointing you in the general direction.
Cassiopeia to the upper left, with it’s built in pointer pointing towards the constellation Andromeda, which just happens to border, and share a star with the Great Square of Pegasus. I always have looked at the Andromeda constellation simply as an extension of Pegasus, being the mighty winged horse’s back legs. That isn’t how it is supposed to be, but if you look at it that way it gives a nice fluidity to the Pegasus constellation that I like.
Now that we have a sense of where we are looking and what we are looking at, follow those hind legs of Pegasus halfway out from the Great Square. There is a pair of easily visible stars lined up there, these two stars are my line of sight to finding the Andromeda galaxy. Take note of the separation between the two stars, and double it (heading upwards in this chart.) Bingo! There lies the galaxy. The chart shows the location of one of Andromeda’s companion galaxies, M110, but not the location of Andromeda itself (M32) which is odd. The location for M110 will be roughly the same for M32. However when you are looking at that part of the sky all that matters is those two stars, double the distance, and you will hit Andromeda. 🙂 …You have no idea how difficult it was to find a chart that was useful for pointing out this location. Sure there are hundreds of charts out there, but many with too much info such as gobs of constellation lines, and gobs of stars, and such. And many with too little information, or too close in of a view, or a view too far out. This post was an exercise in dedication! Anyway…
On a good clear night the Andromeda galaxy is just a small fuzzy spot by naked eye observation. But, knowing that what you are seeing is a huge galaxy 2.5 million LY away makes it a pretty neat experience. Move up to a pair of binoculars and it really comes alive, becoming a much larger fuzzy spot. (yeah, us astro geeks get thrilled when a small fuzzy spot turns into a larger one) but now you can identify a brightening core at the center. Moving on up to a small telescope more details can be teased out of the view including a dust cloud in one of the spiral arms. Using my 12.5″ Dobsonian telescope the view is breathtaking. The galaxy is huge, requiring the necessity of slewing the telescope around to take it all in. Now 2 dust lanes are easily visible instead one one, and there are two companion galaxies close by that are always on the target list. Like I said before, I can spend a lot of time observing this object, it is easily one of the top 3 objects us amateurs enjoy.
More cool stuff…
Oh my gosh, it’s heading right for us! (South Park reference) But it really is, at about 70 miles per second! (or if you prefer 250,000 mph!) They believe in around 4.5 to 5 billion years it will collide with our galaxy. By that time our sun will have gone red giant anyway, so this collision will doubtless go unnoticed by us puny humans. At least from the perspective of this planet, and that notion is probably far too optimistic for our species, given the state of the world today.
Will 2 enormous galaxies colliding make for all kinds of star collisions, and orbital dysfunction? Probably not so much. You have to understand the vastness of space, think about standing atop a hill. Now imagine a guy with a shotgun that has gravity defying pellets. This guy is standing 100 miles away and shoots the shotgun right at your location. Will you get hit? By the time those gravity defying pellets spread out over 100 miles it would be extremely unlikely you would get hit by one. Same for the stars in our galaxies, they are so far apart the likelihood of a collision is small. Following the shotgun with gravity defying pellets analogy, now imagine two shotgun wielders pointing their shotguns towards each other at a 100 mile range. Again the pellets will be so widespread, there is very little chance of any colliding. There will however be an interaction between the the dust, and gases that both of our galaxies harbor. These dust clouds would interact very agressively, making for a huge burst of star formation, too bad we won’t be here to see it…
The Andromeda galaxy was huge in Edwin Hubbles research. First he discovered that Andromeda was actually another galaxy like our own, and not another object within our own galaxy. His observations also helped us to understand the distances between our two galaxies, and distances between other objects. Later in his career, by making critical observations, and submitting a paper on the subject, he was credited with the observational proof that our universe is expanding. At an incredible rate to boot. His work also led to our understanding of redshift velocities being consistant with Einsteins Relativity Theory. Which in turn led to observational support for an expanding universe. A notable distinction between a hypothesis with no evidence, and one with verifiable evidence! No wonder this guy got an incredible space telescope in his honor.
Well, if you have followed me this far, there is another smudge in the sky you can also see with no optical aid. It is known as the Double Cluster. Find Cassiopeia again, and follow the constellation lines from right to left on the chart. Those last two stars will help you spot the cluster. Use those two stars to form a slightly elongated triangle, (heading SW on the chart. Note that the chart may not line up exactlywith the sky you are looking at, you have to adjust your point of reference to the chart.) There lies the smudge. This object is a star cluster within our galaxy. Actually two small clusters. You will need binoculars or a small telescope to resolve them beyond a smudge. But you can see it is there with the naked eye.
Well that wraps this one up. I hope if anyone gets a chance, go have a look. Looking up has its benefits.