Tour of the Universe!. Andromeda:.
Tour of the Universe!
Astronomers in the southern hemisphere are lucky enough to have a clear view of the Large and Small Magellanic Clouds. Those of us in the northern hemisphere are totally out of luck. The Large Magellanic Cloud is a dwarf galaxy located about 160,000 light years away. In fact, it’s the third closest galaxy after the Sagittarius Dwarf and the Canis Major Dwarf Galaxies.
The Large Magellanic Cloud is only about 1/10th the mass of the Milky Way, containing a mere 10 billion stars worth of mass. This makes it the 4th most massive galaxy in our Local Group of galaxies, after Andromeda, the Milky Way and the Triangulum Galaxies.
It’s considered an irregular galaxy, without the grand spiral shape that we see with other galaxies, but it does have a prominent central bar. It’s possible that the Large Magellanic Cloud was once a spiral galaxy like the Milky Way, but a near pass with our galaxy or another distorted its shape, wiping away the spiral formation.
The Large Magellanic Cloud has large pockets of gas and dust, and it’s undergoing furious star formation. In fact, some of the largest, most active star forming regions ever observed are in the LMC. In 1987, a supernova detonated in the Large Magellanic Cloud – the brightest supernova seen in 300 years. For a brief time, the supernova was visible with the unaided eye. The supernova remnant is still being studied as it continues to evolve and expand.
The Whirlpool Galaxy is also known as Messier 51a, and it’s one of the most familiar galaxies. If you’ve seen a picture of a galaxy captured by the Hubble Space Telescope, chances are you were looking at the Whirlpool Galaxy. That’s because this galaxy, located about 23 million light-years away in the constellation Canes Venatici, is aligned almost perfect face on. We have beautiful view of the Whirlpool Galaxy’s entire structure, from its spiral arms to its dense galactic core.
The Whirlpool Galaxy is fascinating for another reason as well. It has a companion galaxy to one side called NGC 5195. The two galaxies interact through gravity, and this gives astronomers a chance to study what happens when galaxies collide.
Astronomers have calculated that the Whirlpool Galaxy measures about 38,000 light-years across, with a mass of about 160 million times the mass of the Sun. This makes the galaxy smaller and less massive than our own Milky Way.
You can see the Whirlpool galaxy with a good pair of binoculars, or a small backyard telescope; although, you’ll want a bigger telescope to see the spiral structure and detect the companion galaxy NGC 5195. To find the Whirlpool Galaxy, located the easternmost star in the Big Dipper. Then go about 3.5 degrees to the southeast. On a dark night you should be able to see a fuzzy spot where the galaxy is.
Astronomers think that NGC 5195 first passed through the main disk of the Whirlpool Galaxy about 500 to 600 million years ago, and then made another disk crossing about 50 to 100 million years ago.