time travelling
-
I know that the universe is expanding and that we can see stars that have died now,even some that were created at the moment of the big bang. So surely as we get bigger we can see further back in time and possibly to see if there was anything before the big bang ,it's only a matter of patience. i feel like there is a flaw in what i have said but I don't know what it is,help please.
also to what extent and depth of space does E=mc squared work?Posted
-
by
wassock
moderator
Think your question is basically the ultimate question of life the universe and everything?
Posted
-
by
SEJones
definitely the ultimate question 😃 i'm fascinated by it. i think your 1st question is asking: 'as the universe expands we should see further into space'. based on current understanding , the answer would be no. although we would be still be able to probe deep into space we would eventually become disconnected from places we currently observe relative to us. the problem is the accelerating rate of expansion of the universe which will eventually cause our observable universe (in terms of the light horizon of the observable universe) to be closed off from other regions of the universe. they will no longer have causal connection with each other. what is going on you might ask? well, for seventy years prior to 1998 the consensus was that the universe was steadily expanding due to the effect of a hypothesised big bang. the cosmic microwave background radiation discovered in 1960s gave strong weight to the big bang theory. then in 1998, dark energy was discovered which was found to have the effect of actually accelerating the expansion of the universe.no-one knows what this form of energy is made of apart from the fact it is a repulsive force and is suspected to be a property of space itself. it sounds weird but empty space is not truly 'empty' - something going on within it in the sense that it has its own energy which does not get diluted as more space is generated. hence the accelerating universe. it is estimated that 75% of the mass in universe is made of 'dark energy'. if such a big component you can understand its power and impact on the light horizon of the observable universe.
as for what was happended pre-big bang? no-one knows. there are no data whatsoever to indicate what actual mechanisms created the BB in the first place. there are many theories to do with branes but they tend to be discredited because these are theories that are unfalsifibale. unfalsifibaility goes against the basic principles of scientific methods.
Posted
-
by
Kitharode
moderator
Hello to the curiosity rover.
Wassock and SEJones have it right - you're asking one of those 'ultimate' questions; Why are we here? What came before the BB? Is 'space' a nothingness, or more of a weird 'fabric? And I get the feeling that the bottom line to both their answers is; We don't yet have the answers. (If that's not true, they'll tell us - we kinda know each other 😃
We've all got a picture of 'what we think we know' and it's a good picture. Big bang, lots of hydrogen, star formation, stars make other stuff like oxygen and carbon and the other elements, things settle down and here we are chatting. But it's only a good sketch on the canvas, the details and colour need to be added. I guess that's why scientists break the universe into manageable bits. By concentrating on one bit there's a better chance, perhaps, of picking up these details which can then be fed back into the 'what we think we know' model, which in turn will prove/disprove something, or it won't.
Cosmology, which is what you're into here, is without doubt an awesome subject, but it's BIG one. Good luck!!
E=mc squared as far as I know is one of those 'universal laws', so you can use it anywhere in the universe. Like gravity. As far as we know, you can use the laws of gravity throughout the universe, which is handy. Please bear in mind, however, that if you get 'heavy' about this then all that's not strictly true. If you could get into the inside of a black hole it's likely that Gravity and E=mc2 as we know it just don't work.
One other thing if I may. When we say 'the universe is expanding' we generally all know what we mean. The 'hard scientists' have it in detail, you and I get the picture. But I have it from a very reliable source that we might consider it better to say 'the distance between galaxies is increasing' on the universal scale. (You probably know that galaxies in clusters can move closer together, but on the universal scale these clusters are not much more than the specks of dust in your living room).
The suble difference between the two statements is this: If the universe and everything in it is expanding, the universe is expanding (obviously). But if the universe is infinite (there is an infinity of 'space' available) it is the spreading of the galaxies into this available space that we are observing. Same thing, but different. I've got my favourite, but I've no idea what's right!
Not knowing what level you are at, you'll have to forgive me if this is a little beneath you. However, if you're ever looking for anything like this then these guys come highly recommended. http://www.theplanetearthcentre.co.uk/astronomy-education
Posted