Friday, 31 January 2014

Did you c what I did there?

So how fast do you think things go?
According to our friend Wikipedia a greyhound can travel upto 74 kilometres per hour (km/h), the Onager or Wild Ass (also my nickname for my sister) can run short sprints at 70 km/h. It is pretty well known that the fastest animal is the Cheetah who can travel at an amazing 120 km/h. The fastest human is currently Usain Bolt ran his World Record 100m sprint at just over 10 metres per second, and according to a recent scientific paper can produce more energy than a bullet as it leaves a gun.
But what is the fastest something can go? We've already talked about infinity which is the largest something can be, so is there an infinite speed? Can somethings in space just go as fast as they like? Well through out history scientists had this battle over and over again, is there a cosmic speed limit?
Well yes, yes there is.

All the stars we see in the sky, the light from them has taken hundreds even millions of years to reach us.
*Credit to Wikipedia for the photo

If you can just make out the little red dot there, that is Proxima Centura, our near star friend. The light from this star takes just over 4 years to reach us (4.367 years to be exact). This is because light has a speed limit, it is the fastest thing in the Universe, light can travel at a maximum speed of
299,792,458 metres per seecond (m/s). Some things happen at this limit which I'll talk about at another post.
Why light travels at this speed is another question, it is a constant number that always appears in the maths. Some scientists have suggested that if light could travel at an infinite speed limit it wouldn't exist at all! (See what I mean about the philosophical?!)

What do you think? How does it make you feel to know that we always see the past of stars?

Wednesday, 29 January 2014

Why did I start this?

So I started this blog mostly for myself, it will (hopefully) make me better at what I study if I am able to explain it. But I hope that people reading this will enjoy whatever is on here!

All physics and astronomy explained on here has been checked, but if ever there is anything wrong just drop me a message or a comment and I will fix it!
Also along those lines if there is any topics you want me to cover then I can do that as well. I will probably within the next few weeks deviate into other subjects like book reviews, games and what I find generally interesting!


To Infinity and Beyond?

So one of the things I get asked a lot after telling people I study Astronomy is "How can space be infinite?".
Well it's one of the hardest questions to answer, as not only is it mind boggling and stray a little towards some philosophy, but it is something that we as humans can never experience!
The way that I was always taught to begin imagining it is a balloon with dots on it, you blow the balloon up and the dots move further apart. Now imagine that the universe is like the surface of a balloon, and the dots are the galaxies, or massive clusters of stars. The universe expands like the surface of the balloon and everything gets further apart. Now if we are on the surface of this universal balloon, how will we know when we get to the edge? We don't, it would be like trying to find the edge of the Earth if you are on the surface. So the Universe is massive, bigger than we could ever imagine, but you would be travelling forever in it, trying to find an edge.
Mathematically infinity is define as the biggest something can be, it goes on forever, and is denoted the symbol ∞ (and if you ever have to do many integrals you know the joy of seeing a function that goes to infinity).
So is our Universe infinite? Our best guess is yes, in the way the us humans perceive the world anyway. That is the wonderful thing about something being infinite, there is always gonna be more of it.
So as our favourite Astronaut says 'To infinity and beyond'.