Today's topic: Dwarf/Satellite Galaxies and Galactic Collisions

Dwarf galaxies are the most abundant type of galaxy in the universe. These little dudes contain as few as 1 million stars. As few as one million? Thats right. A normal galaxy, such as The Milky Way, contains hundreds of billions of stars! Because these dwarf galaxies contain much fewer stars, they become increasingly difficult to find in the cosmos. They are small, which makes them easy to pass over when your eyes are being pulled to the glow of larger galaxies. They contain far fewer stars, making them dimmer which makes them hard to distinguish from the normal glow of space and also cuts them off from some pre-specified brightness levels in surveys of galaxies. BEcause of this, we are still discovering more and more of these galaxies all the time. You will find most known dwarf galaxies hanging around larger galaxies, orbiting around the center of these larger galaxies like satellites, hence the name satellite galaxies. It turns out that dwarf galaxies actually outnumber regular galaxies 12:1, so what is considered regular may need revision.

The lifetimes of these satellite galaxies are cut short by the gravity of the larger galaxies in acts of galactic cannibalism where the larger galaxy consumes the smaller galaxy. The Milky Way has a number of satellite galaxies and has already partaken in the consuming of one. This galaxy was called the Sagittarius Dwarf AKA lunch. The remains of this dwarf can be seen as streams of stars orbiting the center of our galaxy looking like this:

Pretty neat right? I mean, it looks cool and all, but it can be very dangerous considering the destruction that can occur when stars and planets collide. But that wouldnt happen close enough to us to where it could affect us right? right?? Well, kinda. The consumption of a dwarf galaxy most likely wont affect us, butttt larger galaxies also collide and combine with other larger galaxies causing literal galactic obliteration

As an example, I'll use us and our nearest galactic neighbor, The Andromeda Galaxy. Currently, Andromeda and The Milky Way are about 2.5 million light-years apart. Remember, 1 light year = 6 trillion miles. Fueled by gravity, the two galaxies are hurtling toward one another at 402,000 kilometers per hour (About 250,000 mph). But even at that speed, they won’t meet for another 4 billion years. Then, the two galaxies will collide head-on and fly through one another, leaving gassy, starry threads in their wakes. For eons, the pair will continue to come together and fly apart, scrambling stars and redrawing constellations until eventually, after a billion or so years have passed, the two galaxies merge and form one galaxy. That is going to look something like this:

Worry not, we wont be alive for this. Not even close. The sun is heating up at a rate that will allow life on Earth to continue for around another 1 billion years. After that, it will be far too hot to support life. So even if we do make it to Mars, it wont matter in the long run. Come on Elon Musk, figure it out already