we can make things go faster tan light i think

[phat tony]

Faster ten the speed of light.

If man A is standing on the south pole and man B is standing on the north pole.

Both men have a satellite phone.

Man A phones man B, he waits for the connection to be made. man B receives the call and says ”hello” man A says “hello” back almost instantly.

Steven Hawkins said in Steven Hawkins universe 3 I think that if you had a super train on earth that was going the speed of light it would do a lap of the earths surface in 7 seconds.

Allow that the circumference of earth is about 40,000 kilometers, traveled in 7 seconds is fast, a lot faster than sound normally.

Now allow that a communications satellite is 35,000 kilometers from earth, man B answers the phone and says hello and receives a hello back almost instantly. That sound is traveling 35,000 kilometers to the satellite then 35,000 kilometers from the satellite to man A so far that sound has traveled 71,000 kilometers, it then makes that journey back again so over all that sound will travel 142,000 kilometers in less than a second.

Steven Hawkins said that nothing can or will ever travel faster then the speed of light but we as a race have made sound travel what looks to be about 4 times faster than the speed of light. Am I right or wrong.

Steven Hawkins also said that the closer you get to the speed of light the slower time gets simply because the universe will not let us break the speed of light barrier. If you get to a just under or equal to the speed of light then time should or could stop. If so then breaking the speed of light by 4 times should or could make time go in reverse.

So if that is true then man A and man B would be defying time and communicating back in time and to me they are not. Any ideas on this one.

I am a little lost because I thought I heard somewhere that Hubble saw the big bang or not far after, but how, I do understand that it would take a very long time for the light to get here but if we could not travel faster than light then the light would have got here before us not billions of years after. If I heard right which I feel I didn’t but if I did then our planet traveled faster than the speed of light.

[nebogipfel]

Faster ten the speed of light.

If man A is standing on the south pole and man B is standing on the north pole.

Both men have a satellite phone.

Man A phones man B, he waits for the connection to be made. man B receives the call and says ”hello” man A says “hello” back almost instantly.

Steven Hawkins said in Steven Hawkins universe 3 I think that if you had a super train on earth that was going the speed of light it would do a lap of the earths surface in 7 seconds.

Allow that the circumference of earth is about 40,000 kilometers, traveled in 7 seconds is fast, a lot faster than sound normally.

Now allow that a communications satellite is 35,000 kilometers from earth, man B answers the phone and says hello and receives a hello back almost instantly. That sound is traveling 35,000 kilometers to the satellite then 35,000 kilometers from the satellite to man A so far that sound has traveled 71,000 kilometers, it then makes that journey back again so over all that sound will travel 142,000 kilometers in less than a second.

Steven Hawkins said that nothing can or will ever travel faster then the speed of light but we as a race have made sound travel what looks to be about 4 times faster than the speed of light. Am I right or wrong.

Steven Hawkins also said that the closer you get to the speed of light the slower time gets simply because the universe will not let us break the speed of light barrier. If you get to a just under or equal to the speed of light then time should or could stop. If so then breaking the speed of light by 4 times should or could make time go in reverse.

So if that is true then man A and man B would be defying time and communicating back in time and to me they are not. Any ideas on this one.

I am a little lost because I thought I heard somewhere that Hubble saw the big bang or not far after, but how, I do understand that it would take a very long time for the light to get here but if we could not travel faster than light then the light would have got here before us not billions of years after. If I heard right which I feel I didn’t but if I did then our planet traveled faster than the speed of light.

Tony, You are making my head hurt a bit but I can tell you that you have got your sums wrong.

The speed of light is approximately 300,000kps

With my simplistic understanding of Relativity nothing can exceed the speed of light becuse mass increases to the point where an infinite amount of energy would be required to go any faster.

Hubble can see a long way back in time towards the big bang but the edge of the visible universe for us is currently about 13.7 billion years. We have no idea how big the universe is (how much further back in time the big bang was) because we cannot (and probably never will) see it.

The cosmic microwave background radiation which can be detected is like an echo of the big bang but again we cannot know it's time of origin.

I think

But I'm sure others with a better grasp of physics can help you more.

[RobH]

The sound isn't going round the Earth faster....the sound is only travelling from your mouth to the microphone in the phone, and then from the speaker in the phone to the ear of the listener. In between, it has been converted into radio waves, which travel at lightspeed.

This signal travels, not at the speed of sound (roughly 300 metres per second at normal temperature and pressure), but at 300,000 kilometers per second, meaning that it circumnavigates the Earth in 0.133 seconds.

Rob

[phat tony]

wow, i got may answer. thank you for the fast reply's. i knew it looked wrong but could not get my head around it. nebo can you imagine how much my head hurts LOL. i have hundreds of things like this bouncing around in my head all the time.

i am learning more here then i could anywhere else, thank you so much nebo and rob.

[phat tony]

hahahahahahaha my poor wife LOL.

[Space Bat]

Groans....

[kniclander]

try reading "A brief history of time" by Stephen Hawking. It might make more sense than this Hawkins fellow you've been reading.

[ollypenrice]

Yes, let's get the great man's name right, at least.

Cracking answer from Rob and a nice response from the OP.

Olly

[FraserClarke]

Steven Hawkins said in Steven Hawkins universe 3 I think that if you had a super train on earth that was going the speed of light it would do a lap of the earths surface in 7 seconds.

Other way round

A super train going at the speed of light would go round the Earth 7 times in one second; about 0.133 seconds per lap as Rob says.

[Grunthos]

.

Cracking answer from Rob and a nice response from the OP.

Vraiment Olly.

Tony postulated a potentially challenging question - a "hypothesis" in the widest definition...

Rob answered with a summary of current scientific, objective status.

Tony then changed his viewpoint based a scientific principle namely that of empirical evidence (what we observe).

Some of us have had a slight discussion about this sort of thing on another SGL thread. It's a pity we can't all be sitting in a cafe/pub "arguing" about this over a bottle of wine or two...

[phat tony]

so true gruntos, it would be great. i would be in my own form of heaven.i have no one to take to about all this stuff and that is why i came to this site but it would be as i said heaven to me to do it face to face. i would see it being one of them chats that go on all night and as long as time would let us. i also feel we would all walk away in need of a very large pack of headache pills.LOL

[Auntystatic]

Here is an example for you, in stargazing live last month there was a live satellite link up to the USA, where they spoke to the last man to leave the moon Eugene Cernan, there was a noticeable delay of around 2 seconds to questions and answers caused by the satellite delay.

Dani

[DaveGarland]

Ah now this thing about seeing the big bang. Now although we can't see this, apparently we can see back about 13 billion plus years, not too long after the big bang. What I can't get my head around is that this light left its source over 13 billion years ago and took that long to get here because it's 13 billion light years away. BUT! The universe is constantly expanding... And 13 billion years ago this source would have been only a fraction of this distance away...

So how has this light traveled 13 billion light years????

Oh we need to find a bar!

[DaveGarland]

hahahahahahaha my poor wife LOL.

Tony, I just put this to my wife.... She just glazed over lol!

[themos]

What I can't get my head around is that this light left its source over 13 billion years ago and took that long to get here because it's 13 billion light years away. BUT! The universe is constantly expanding... And 13 billion years ago this source would have been only a fraction of this distance away...

Don't worry, I have a PhD in theoretical physics and I still have to think slowly about this.

You are correct in all the essentials. The origin of this radiation was indeed closer 13 billion years ago. That's why the farthest thing we can detect is actually more like 47 billion light years away and not 13.7.

The thing is it makes a difference if you talk of the distance "then" or "now". And the light travel time is different again!

Frequently Asked Questions in Cosmology

[mdstuart]

Dave

It does make you realise that despite our advances there are many things we do not understand and cannot explain fully..

Which is why the whole astronomy thing is so facinating..

What I have found interesting recently from reading a specialist books on galaxies is that many "slow burn" stars and globular clusters and even galaxies seem to have formed early (in the first 10%) of the universes history . I also understand most stars have not yet made a 100 orbits around the nucleus of their host galaxies..It almost feels like the universe is still young in a wierd sense...

Mark

[DaveGarland]

Don't worry, I have a PhD in theoretical physics and I still have to think slowly about this.

You are correct in all the essentials. The origin of this radiation was indeed closer 13 billion years ago. That's why the farthest thing we can detect is actually more like 47 billion light years away and not 13.7.

Frequently Asked Questions in Cosmology

Holy Moly! This just makes me even more confused! Everything I ever read suggests the universe is around 15 billion years old tops. But 47 billion light years distant??? Surely this would make the universe closer to 50 billion years old???

[DaveGarland]

Themos, ok I've tried reading this and if I'm honest, it's a mind melt! Lol. But am I understanding this right? Light speed is only relative to the matter around it? So matter at the edge of the universe is traveling away from us faster than the speed of light relative to us, but this is ok because it's slower than the speed of light relative to the matter around it?

But then at the start of the universe everything was very close and the edges couldn't have expanded from the centre faster than light. So the universes expansion is accelerating???

[themos]

Light speed is only relative to the matter around it?

That's not a bad way of putting it. I prefer to think that the notion of "speed limit for relative speeds" only applies to one thing going past another. In other words, they have to pass through the same point. If they are far away from each other, the notion of relative speed is pretty meaningless or, at the very least, problematical.

So matter at the edge of the universe is traveling away from us faster than the speed of light relative to us,

it's very far so we shouldn't be thinking in terms of "speed relative to us". People want to use the Doppler effect analogy and so attribute the redshift to speeds but I don't think that is necessary. All you need is the fact that the space component of spacetime has changed scale since the emission of the light.

ut this is ok because it's slower than the speed of light relative to the matter around it?

Yes, that is true. Nothing was zooming faster than light past anything else over there, back then.

the edges couldn't have expanded from the centre faster than light. So the universes expansion is accelerating??

I don't understand this argument.

Speed is in metres per second

Expansion is in percent per year.

The "edges" of which you speak are only the edges of the observable universe at a particular time.

Let's think slowly about the consequences of this.

[DaveGarland]

I mean at the time of the big bang, the newly created universe was all in the same place. So everything was limited to the speed of light in relation to the matter around it? So how did some matter get to be 47 billion light years away in 13 or 14 billion years? Is the rate of expansion increasing?

Fascinating stuff this!

[themos]

I mean at the time of the big bang, the newly created universe was all in the same place.

We don't really understand the t=0 event. But you can start a millisecond away from the Big Bang, say, and then parts of the universe that now host our galaxy and Andromeda galaxy were far closer to each other than they are now.

So how did some matter get to be 47 billion light years away in 13 or 14 billion years?

Space got "devalued" by a certain percentage per year which is what the "expansion of the universe" is all about.

[Frank the Troll]

13 - 14 or 47 ? thats from our perspective point of reference for the big bang

Just how many billions of years are we from the edge of the expansion front?

Big bang = 0 We are here = 47 Expansion Edge = ??

[themos]

there is no "expansion edge". we can see as far as time elapsed since BB allows. that distance cannot be measured unambiguously as it depends on which "currency" you use as space suffers from inflation (not the technical "inflation scenario", just the % per year that universe expansion suggests). It's like trying to figure out accumulated payments over decades: do you use pounds of 2012 or of 1946?

[Frank the Troll]

yes we are expanding, I know that, but into what, if its nothing, then their has to be an edge, or it could be argue that the nothing we are expanding into, is in some way, a part of this universe

Sry, Im using edge as an abstract concept here

If there was nothing before the BB, then I would like to know where the mass of this universe came from?

As an aside: "god said let there be light, and there was light"

Sounds like the big bang to me, and no, Im not regilous, just curious

[themos]

yes we are expanding, I know that, but into what, if its nothing, then their has to be an edge

You see, that's why I tell everyone that talking about the "expansion" of the Universe is confusing.

There is no expansion. There is just inflation, in the economic sense. Space gets devalued with time.

If there was nothing before the BB, then I would like to know where the mass of this universe came from?

I think the current thinking is that the total energy of the universe is zero and the positive stuff we see is balanced by negative energy that we are just beginning to understand. That way you don't even have to violate conservation of energy at the BB.

But it's also important to realize that conservation of energy is a consequence of time symmetry. At a moment of creation, if there is such a thing, you don't have time symmetry and so you don't have to conserve energy. That would mean your question would have no answer. Now, we usually don't like that! So, we will probably chase a model in which it can be answered.