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Asked by eefairgrieve312 to Matt, Kate on 18 Jun 2013.
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Matthew Pankhurst answered on 18 Jun 2013:
I guess the answer would be the universe – because it has everything in it! It’s a really good (and polite!) question, because some things that are big aren’t made of many particles, and some things that are small are made from heaps of particles. This is because not all particles are the same size. Imagine you have a pile of peas that fill a small saucepan – and next to it is a great big saucepan with a one watermelon in it. The saucepan that has the most particles in it is smaller, and the saucepan that has the least particles in it is bigger! Hydrogen is the smallest element in chemistry, and its about ten times smaller than the biggest – an element called caesium.
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Comments
Claire commented on :
Maybe if you had to pick one “thing” in the universe, it would be a neutron star? A black hole would probably have more, but then you have no way of knowing what went into it so you couldn’t say for sure
Sam commented on :
I think I heard the number of atoms in the universe is roughly 10^80 – which is 1 followed by 80 zeroes – give or take a factor of a hundred. But that’s just the universe we can see – we don’t know how big the universe is overall. And I heard that for every atom there are 10 billion photons (light particles). So there’s a lot of light out there!
drogers commented on :
If there is so much light out there, why is it dark at night?
Sam commented on :
Excellent question! Because the universe is very big so all the light is spread thin, because the light is in frequencies we can’t see, because the light from the Sun is much more intense than light from the stars, because many of these photons are absorbed very quickly by things nearby, etc.
Photons are also the particles that carry electrical and magnetic forces – so every time two electrons collide, a photon is emitted and then reabsorbed immediately to pass on the collision energy. This effect is a result of what’s called “Quantum Field Theory”.
There’s also light coming from all directions, but it’s in microwave frequency. This is called the “cosmic microwave background”, and it’s from light arriving from just after the universe was formed and it was still very dense and hot. Scientists use this to find out what the universe looked like very early on and how it’s expanding.