How To Understand The Difference Between A Solar System And A Galaxy
Galaxies are huge collections of
I'm Robert Massey and I'm here from the Royal Astronomical Society which is one of the biggest astronomical organizations in the world and we look after the interests of astronomers not just in the UK but across the world. What I'm going to do today is give you a few pointers to get you started in astronomy which I think is one of the most incredibly interesting subjects there is. There's sometimes confusion between the definitions of the solar system and the galaxy. But in many ways, they couldn't more different at least in terms of scale. Our solar system is straightforwardly the sun and the planets and the other things that orbit around it. There are many examples of this sort of strewn across the universe that there are probably many stars and planets going around them. But typically, a solar system like the one we live in might be as big as, if you're generous, one light year across and that means that it would take like a year to travel across it. Now if you compare that with a galaxy, even the galaxy we live in, the Milky Way might have as many as 300,000 million stars and it's something like 100,000 light years to cross which means that it would take a ray of light, a hundred thousand years to cross it. So, you can see straight away that we're talking about objects that are really in different leagues. Galaxies are much much much bigger than a solar system. They're a huge collection of stars that dominate the universe. So to be clear, solar systems are things like the sun plus the planets whereas galaxies are huge collections of stars and they make up most the material that we can see in the universe and they're much much bigger than the solar system. .