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This video is all about galaxies. We won’t go to far into the details of how they form or work, we’ll concentrate on actually seeing some in the sky. For that, we’ll need to take viewing conditions into account. Looking at the sky for late this November, it isn’t perfect. With a Full Moon, there’s plenty of extra light in the sky, and that can make fainter objects harder to see. Even without the light of the Moon, light pollution is a big factor in cities. Most cities around the world are so lit up that it’s impossible to even see our own galaxy, the Milky Way, and it’s harder to observe other galaxies as well. If you have a telescope, it is possible to see other galaxies with some pollution, but we don’t need to worry about that.

Moving into the countryside, to a location with almost no light pollution, certainly gives us a better view, but the light of the Moon is still a factor. With a Full Moon, the Milky Way is certainly a little obscured, but parts are still visible. Fainter objects like the Andromeda Galaxy are even more difficult to see. Moving into early December gets the Moon out of the picture here, but this may be different in other years. With the Moon gone the Milky way is obvious, arcing up through the Summer Triangle, Through the W of Cassiopeia and down the other side of the sky. In a recent video, the constellation of Pegasus and the asterism of the Square of Pegasus were described, as well as how they are related to Andromeda. They are pointed out again here, and with the one triangle of Cassiopeia, we can use the shape to find the Andromeda Galaxy.

It may just look like a fuzzy spot, but this is a galaxy just as big as out own, with a trillion stars. It seems much smaller due to the distance, it lies 2.5 million light years away. Its a very far distance to be able to see, but it is possible with such a big bright object. We can see the Andromeda Galaxy because it’s our closest neighbour. 2.5 trillion kilometers is far for us, but pretty close for galaxies, large ones at least. Smaller galaxies do exist, dwarf galaxies, and we can see one orbiting Andromeda in the close up. There are dwarf galaxies orbiting the milky way as well, but they are much smaller. The Andromeda Galaxy isn’t our only close large neighbour, the Triangulum Galaxy is always quite close and almost visible to the naked eye. It’s also quite close to the Andromeda Galaxy in the sky, just a little bit past Andromeda coming from the point of Cassiopeia. The Triangulum Galaxy is another spiral galaxy, like Andromeda and the Milky Way.

These galaxies show how the thinner edges are often blue. This blue colour comes from bright young stars, burning at a high temperature. Spiral galaxies often create a lot of new stars, thanks to the gas that their gravity draws in. The gas and dust around the core of a galaxies often gives this region a darker reddish colour, and there are often bands of gas through or between the arms. We can also see that the core at the center is thicker than the arms and disc around it. All of these features are visible for our Milky Way as well. Of course, we are looking at the Milky way from the inside, but we can still see the thin, paler, bluish arms thicken up and darken into the core. galaxies do come in other shapes, but these are some reasons that we’re confident about the shape of our galaxy, even though we haven’t seen it from the outside yet.

The rest of the galaxies certainly aren’t visible to the naked eye, so finding them can be a little bit trickier. Luckily, there are several around the tail of Ursa Major, the bottom or handle of the Big Dipper or the Plough. This part of the sky has some particularly clear galaxies. The Whirlpool Galaxy in particular is grand design galaxy, one where the arms are particularly clear and visible. It is also a nice galaxy to observe because we can see it consuming a dwarf galaxy. The aptly named Whirlpool is sucking in a smaller galaxy that once orbited it. The Whirlpool Galaxy was also called Rosse’s Galaxy, after the first person to sketch its spiral structure. The Earl of Rosse in the 1800’s used the largest telescope in the world at the time to observe the galaxy. The equally aptly named Leviathan Telescope stood in Birr, in County Offaly in Ireland. It was the largest telescope in the world from 1845 until it was taken apart in the early 1900’s and the bigger Hooker telescope was built in 1917.

There is a group of galaxies here in Ursa Major, with the Whirlpool Galaxy just below the end of the tail, the Pinwheel Galaxy just above the end of the tail, and the Sunflower Galaxy on the opposite side of the Whirlpool from the Pinwheel. These galaxies are all named for their distinctive spiral shape, and if you are high enough in the Northern Hemisphere, they are visible all year round. Given the visibility of the Plough or Big Dipper, they are also some of the easiest to find.

The next galaxy isn’t quite as easy, but it is particularly interesting. Taking a look into the constellation of Corvus the Crow, just below Virgo, we find the Antennae Galaxies. These galaxies certainly look different from the others we’ve seen. Rather than a bigger galaxy consuming a smaller one, this is the result of two more equal galaxies colliding. This is the future that awaits the Milky Way and Andromeda in the distant future. Galaxies are mostly empty space, so even though a lot of gas and some stars get ejected, not many things actually collide with each other. Most stars don’t crash into each other or blackholes, although some surely do, most survive the collision relatively unscathed. The gravitational pull of the galaxies eventually joins them together into a new shape.

We take a look into the Virgo Group next. Between the top of Virgo and the end of Leo, there are loads of galaxies to be seen. Really, loads and loads of them, its a very rich part of the sky. We’re looking for a particular type of galaxy. Not the spiral ones we’ve see, but a lenticular or elliptical one. The one we find is M59. It doesn’t have a common nickname, probably because it’s just a huge ball of stars. It’s believed that these larger galaxies are the result of smaller spiral galaxies colliding, losing their shape in the process. It also seems like the galaxies lose a lot of their gas and therefore a lot of their star forming ability as well. Some of these rounder galaxies are huge, and may be the result of further mergers.

There is a lot to galaxies, but here are a few spots you can look to find them and a little about their shapes and how they get them. The “M” numbers, such as M59, M31 for Andromeda, M51 for the Whirlpool Galaxy, these are numbers from the Messier catalogue, and will be explained in a future video. For now, I hope you gat a chance to find and observe these galaxies in the real sky, and that you’ll join me back here next time.