So I wanted to start What I Like About Space with a bang, so here is a list of my top five favourite things about space!
5. Space is Big.
Space is mind-bogglingly big. Space is so big you could travel your entire life in a spaceship going as fast as we know how to make it go and not even reach the closest star. And there are a hundred billion stars in our galaxy alone. Wow.
Space is so enormously huge that astronomers had to come up with a new measurement of distance to describe just how far away things are. They took the fastest stuff in the universe, light, (which travels at roughly 300,000,000m in a second!) and calculated how far it traveled in a year. That’s 9,460,528,405,000km (5,878,499,814,210.01miles). Our nearest neighbour, Alpha Centauri, is 4 light-years away. I can’t even begin to wrap my head around how far that is. Our galaxy is an even more mind-numbing one hundred thousand light-years from side to side. The biggest galaxy close to us, Andromeda, is over two million light years from the Milky Way. And the edge of the visible universe is approximately 13.5 billion light-years away.
Wow. The universe is huge. We’re absolutely miniscule. And I love it.
4. Space is Old.
Image credit: Hubble Deep Field, NASA
The human race has been around for about 10,000 years. But that’s not even a blink in the cosmic scale of time. It’s more like one eyelash starting to fall downward. The universe began about 13.5 billion years ago in a sudden expansion of time and space that gave birth to the galaxies, stars, and everything within our infinite universe. The first galaxies didn't appear for another almost billion years, and those took several billion years to reach anything remotely like our Milky Way. The earth has only been around for 1/3 of the entire age of the universe, and life as we know it has existed for about 3.5 billion years. Wow. Took quite a while to get to humanity.
3. Space is empty.
Okay, we know space is really big. But how much stuff actually is there?
Image credit NRAO
So we can only really see about 4% of the universe. This is cool, this is good. What do we see?
All the stuff in the universe that emits light is made up of baryonic matter. Baryonic matter is protons, neutrons, electrons, quarks, all the stuff that makes up everyday, ordinary matter. It's what makes up you, your coffee cup, your soda can, and the computer or cell phone you're reading this on. The thing is, baryonic matter tends to form little clumps like stars, planets and galaxies with huge stretches of space virtually devoid of it. Which begs the question, what makes up the rest?
2. Space is Full.
About 22% of the universe is made up of what we call "Dark Matter." Ominous, no? Dark matter is around and in all galaxies, mucking things about and making galaxies turn like discs instead of slowing down round the edges. It acts as a scaffolding between clusters of galaxies, making them stick together in clumps.
So what is it?
The best scientists can say is, it's stuff. Just that. It's some sort of stuff that appears to only interact gravitationally. It flies through and in between baryonic matter, and we can so far only detect it by its effect on galaxies and because it acts as a gravitational lens that distorts the light from faraway objects. We don't know what it is, we just know what it does. Cool, huh?
The rest of the universe is made up of some even weirder stuff we call dark energy. What is that? Well again, scientists haven't a clue. It's some weird form of energy that seems to be speeding up the expansion of our universe, flinging galaxies willy-nilly away from each other. There's not much more I can say because there's not much more I or anyone else know.
1. We don't know a heck of a lot about space.
For all that we know about the universe, for all the galaxies and stars we've seen, we still know so little about the universe. Scientists can only do so much with their handful of observatories on earth and in space. What's really cool is that anyone with a decent pair of binoculars or a small telescope can make observations and contribute to science! There's tons of resources both online and in the form of local astronomy clubs. Even if you can't get out to look at the stars, there's a ton of online citizen science projects like Galaxyzoo out there where you can get involved in research. If you are at all interested in astronomy, check it out. Amateur astronomers have discovered exoplanets, new galaxies, and even entirely new classes of astronomical objects. I've done my best to get involved,and I encourage you to do the same.
So there are my favourite things about space and my reasons for thinking so. I hope you like it, and come back for more!