space questions

[whp.blue]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

I can't do the maths for that but what speed is the expansion happening at then?

 

[Dalian Blue]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

May I ask for a link, quotes, etc., where did you get this information from?

 

[BlueBearBoots]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

And what's there, at the end?

 

[west didsblue]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

May I ask for a link, quotes, etc., where did you get this information from?

Have a look at the observable universe wiki page

 

[west didsblue]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

And what's there, at the end?

The unobservable universe

 

[west didsblue]

We don't know how far the edge of the universe is from us.

The edge of the observable universe is about 13 billion light years away.

That means the oldest light we have detected from stars are that far from us. Doesn't mean there isn't stuff beyond that though.

Actually the edge of the observable universe is about 46 billion light years away due to the expansion of space, even though the universe is only 13 billion years old.

I can't do the maths for that but what speed is the expansion happening at then?

Don't think there's a simple answer to that due to relativity but it's many times faster than the speed of light. Damocles is the expert in this sort of thing and would provide a much better explanation than I could.

 

[BlueBearBoots]

So it just carries on but we can't see it?



Very difficult to comprehend what was there before and infinity - my head hurts :/

 

[Skashion]

Repost from another thread:

It might be worth explaining this to the layman actually. OK, Pominoz (and anyone else interested), pull up a chair. The size of the observable universe is 93 billion light years. A lot of people always ask how can the observable universe be that big when we've only been around 13.7 billion years and light can only travel at the speed of light. The reason for this is that light now reaching us was emitted by an object much much closer than 13.7 billion light years away and the expansion of space has meant it's only just arrived. We can calculate pretty accurately how far those objects are away now because of the expansion of space, and the limit of the furthest is called the observable universe.

The observable universe gets bigger with time as light from places billions of light years away will arrive given a shit load of time and will also be moving away. You can work it out quite easily, although this is the mega simplified back of a fag packet calculation. It would need hefty calculus to work it out properly and I've only got GCSE level maths. However:

Speed of light = 299,792 Km per second
Expansion of space = 67.8 Km per second per megaparsec
Megaparsec = 3.26 million light years

299,792/67.8 = 4,471.7 Megaparsecs
4,471.7 x 3,260,000= 14.4 billion light years

That means light emitted right now from an object 14.4 billion light years away will never ever reach us because the space in-between is growing faster than the speed of light. However, because light emitted within 14.4 billion light years region will reach us, even if it takes many hundreds of billions or trillions of years to reach us due to the expansion of space effectively 'slowing' the speed of light to a crawl in its effort to reach us, the observable universe will grow for a long long time yet.

 

[BlueBearBoots]

Thank you for the detailed response as always skashion and I do understand what you are saying, however in your opinion, what is the universe expanding in to? Apart from your scientific mind what does your imagination think was there before the Big Bang or in fact at the edge of the expanding universe?

 

[Skashion]

Thank you for the detailed response as always skashion and I do understand what you are saying, however in your opinion, what is the universe expanding in to? Apart from your scientific mind what does your imagination think was there before the Big Bang or in fact at the edge of the expanding universe?

I don't find the question of what came 'before' the Big Bang, very interesting in all honesty.

Firstly, it is wrong even to say what came before. Time comes from laws of physics, most specifically thermodynamics. We perceive time because of entropy. Entropy came to exist in the Big Bang and therefore so did causality. Unfortunately humans have a tendency to try and apply human perceptions into physics. Frequently physics makes a fool of us, especially at the quantum level. Things don't work like we would like them to. They work they way they do.

Even if that wasn't true, I'd find it disinteresting anyway. Logically, either something has always existed or something came from nothing. What came before the Big Bang? Something? What became before Something? Another Thing. And what became before Another Thing? A dreadful boring cycle to which we cannot know the boring answer.

A better question might be what else is there? One of the theories put forward that I find appealing, due to our knowledge of quantum probabilities where every possibility has a probability, is that many universes exist each with their own laws of physics different to ours:

[bigimg]http://images.nationalgeographic.com/wpf/media-live/photos/000/777/cache/multiverse-magazine-illustration-01_77755_990x742.jpg[/bigimg]

As to your question about the geometry of the universe, I find it tricky too. Damocles very kindly attempted an explanation for me a while back which might be worth reading: <a class="postlink-local" href="http://forums.bluemoon-mcfc.co.uk/viewtopic.php?f=5&t=298878&p=7634485" onclick="window.open(this.href);return false;">viewtopic.php?f=5&t=298878&p=7634485</a>