Conquer Club

Okay. I need answers. Cosmology (for me) is an interesting topic and it explains things through the universe, in theories.

Alright. I need some nerds of cosmology to answer me a couple of questions that I'm kind of curious as to know, and then there is a bonus question of personal opinion. I was watching a documentary on dark matter and dark energy, so this has prompted my questions.

1. How is the universe expanding when there is nothing beyond the universe? I don't get it. It's not like a mountain, made by atoms, to fill in space of other atoms. How can something expand into nothing? I thought about it, and I decided that the universe must expand by dark matter and dark energy to expand away, and then other dark matter and dark energy to fill in the space that previous dark matter and dark energy once had. Would this be correct, or have scientists of cosmology not reached a theory for that? It's interesting as to how something grows into nothing beyond.

2. How is a moon formed? I don't know, I've never been taught it, and I'm too lazy to look it up on the interwebs. I know that stars, planets and suns are formed in nebulae (please correct me if I'm wrong), but I don't know how moons, like Luna, are formed. Are they just large asteroids caught in the gravitational pull of a planet, or they tiny planets?

3. What is your view on dark matter and dark energy? What's your view on the graph which some cosmologists have made up of things that make up the universe? 5% atoms, which we can see, 25% (or 20%) dark matter, which we can't see, and dark energy which makes up 70% (or 75%) which is just a theory.

Thanks.

Skittles! wrote:2. How is a moon formed?

I'll have that one...

Skittles! wrote:I know that stars, planets and suns are formed in nebulae (please correct me if I'm wrong)

Yeah, that's roughly correct. In any space where large numbers of atoms are whirling about (such as a nebulae) then there's a chance some of them will clump together and form a mass. Fastforward that process and you soon have a planet.

It's just the same for moons in some cases, small planets that get grabbed by the gravitational pull of a larger one. Sure, they can be passing asteroids (etc) that get caught in gravitational fields, but chances are that a moon is either a small planet that got caught, or a chunk of rock which got caught on its way past.

As for our own moon, the current reigning theory is that it's the result of a large amount of debris that was hurled into orbit after our planet collided with another planet/moon during the formation of our solar system. The colliding planet struck one side of the Earth, and the debris was hurled from the other, which ended up coallescing and forming the moon.

So yeah, moons form pretty muck like planets do; then they just need to drift/hurtle into a gravitational field and stick there.

Skittles! wrote:1. How is the universe expanding when there is nothing beyond the universe?

When people say "the universe is expanding" you seem to be thinking of the universe as a bound thing, constrained. what is actually happening is the matter in the universe is moving outwards (expanding) into space that already exists,. which is arguably either a part of the universe or not. There is still something beyond the universe to expand into; it's just a lot of nothing, if you see what I mean.

This is all theoretical, mind, you shouldn't rule out the possibility that God is creating more universe to expand into too.

Whether the "nothing" exists is actually not a meaningful question. I think.

"Expanding" just means that the distances between objects within the universe grow larger. Not necessarily that there's an outer border that's expanding into something else and pulling the things inside along or something.

MeDeFe wrote:"Expanding" just means that the distances between objects within the universe grow larger. Not necessarily that there's an outer border that's expanding into something else and pulling the things inside along or something.

Yeah but how do you know?

how do you know what? that the universe is expanding?