Scientists are trying to work out the number of galaxies in the whole of our universe, and so far they have surveyed about 3% of our sky. They have found around 3 million galaxies in that section of the sky, so if the number of galaxies is the same around the whole of the sky, there is around a hundred million galaxies in the universe.
There are around a hundred million stars in a galaxy.
So, this means that there are around a hundred million galaxies, in each of which are a hundred million stars. This means there are 10,000,000,000,000 (or ten quadrillion) stars in the universe. Each star has “on average … at least 1.6 planets.”
That’s 16,000,000,000,000 (16 quadrillion) planets out there. And people say we’re the only ones to exist.
There’s actually something called the Drake Equation which estimates the number of extraterrestrial civilisations in just our Milky Way galaxy, and you can find more information about that here.
This is an infrared picture of the galaxy. It’s 300 billion light years across. Scientists can zoom into the centre of the galaxy, and see high velocity stars orbiting a dark space, showing the location of a black hole. It’s hot gas orbiting a massive black hole (called an accretion disk), and so the light coming from that region shows astronomers precisely where the black holes are. A few pixels on your computer screen cover an area 27 million miles across, and the black hole they orbit is 4 million times the weight of our own sun.
This is why I want to take astrophysics. Because I want to try and understand stuff which no one has yet to understand. I want to find out the very meaning of our world; what made it, why it came to be and exactly what is in everything. It’s literally going to the edges of the universe.