carl

If you're really interested in this stuff, Stephen Hawking's "A Brief History of Time" is a good place to start with a non-mathematical text. However, I know a lot of people who tried to read it and gave it up as too difficult. I believe there's a simplified version out now -- not that I want to insult your intelligence, but there's no point starting on a version that you're going to give up halfway through.

Some of Patrick Moore's stuff is OK, but he mostly concentrates on observational astronomy and not cosmology.

Nimbus

I take the opposite view. We actually know a great deal about the universe. Not everything, I grant you, but to think that from our small world we have been able to see back (almost) to the begin of the time, been able to determine the laws that govern the movement of the planets, the creation of suns, put forward theories for the creation of the universe itself, probe (in theory at least) down to the smallest level of structure (Quarks and SuperString) as well as the unfamiliar and strange world of Quantum Mechanics, I think we can be pretty proud of ourselves..

Nimbus

I used to think that the "Big Crunch" would be a bad way for the universe to end. All the wonder and glory of the universe crushed out of existence. Now, looking at the alternative, where all matter and energy has been spread evenly through a unimaginably vast and empty universe, so that there are no longer any stars or planets or indeed any structure of any kind. When even the protons themselves start to decay in their constituent Quarks. Now to me, that is depressing....

Leslie

Thanks carl, I take your point about trying to stay with such a publication and I have no doubt that I would find it hard going. I may take look though, maybe the library can supply it. I like Patrick Moore's programs. His stuff is also interesting to me.

Hoppy also has a point of course-what can we actually do to change it?

Les

TopBanana

Leslie, I'd recommend you start with something by Marcus Chown. He's the New Scientist cosmology consultant, but he's written some very approachable books too.

You could try 'The Never-Ending Days of Being Dead'.
Amazon.co.uk: The Never-Ending Days of Being Dead: Books: Marcus Chown

carl

Yes, it always amazes me that we understand pretty well what happened after the first 10^-33 seconds, but it's that first bit that's difficult...

Leslie

Thank you TB-much appreciated.

Les

Hoppy

With respect Nimbus, we know next to nothing about the universe and the more we find out, the less we find we know. None of it can be proven one way or the other. As an academic endeavour, I can see the interest, but not the relevance. And I just don't care - I have tomorrow to worry about.

If we're so smart, how come we cannot agree about climate change or, more to the the point (and rather closer to home than several billion light years) what can we do about it? Nothing

Richard.

Nimbus

With respect Hoppy I contest that we do know a great deal. Saying "we know next to nothing" (your opinion) does a great dis-service to many people who have not only worked out the theories, but in some cases conducted experiments to prove them (warping of spacetime by mass, time dilation, quantum uncertainty). I agree, there's still a lot to learn and every new discovery leads to new questions, but I maintain that we, as a species on a small world, can be proud of ourselves for the discoveries we have made so far. Also, saying "we know next to nothing" implies you know what the total sum of knowledge is and are therefore able to compare what "we" know to this sum..

Regarding climate change. Predicting climate change accurately is a very difficult task, if not impossible. This is because knowing what will happen in future requires detailed knowledge of the current state of the atmosphere, what factors effect it (and by what degree) and reliable models on how the changes will take place. None of these are complete or agreed on. You also have the problem that small differences in starting conditions can lead to large differences further on in time. General conclusions may be drawn, but they they depend on the data and models used. You also have to factor in the politics angle, which throws a whole new factor into the debate are..

carl

Hey, I was looking at the 'popular science' section in my local Waterstones today, and there were two Marcus Chown books but I couldn't remember which you'd recommended so I didn't get either...

But looking at that section reminded me that I have read any of the Richard Dawkings books, nor Roger Penrose's "The Emperor's New Mind".

Maz

iTrader: (34)

What about the theory that says there are an infinite number of universes in existence? This is based on the principle that if we can have a big bang here in our universe, it could be happening an infinite number of times elsewhere.Elvis could really be working in a chip shop somewhere! With regard to the theory you mention above about a lifeless empty universe. Surely gravity would not allow that to happen, when the momentum of the moving galaxies wanes and runs out gravity would pull everything back in.

Hoppy

Do you believe in infinity? That seems to be one of the fundamantals behind cosmology. It's infinite, and apparently expanding. Ininfitely. That is truely weird.

It means that we are not the only planet with life. There are others that have ungone exactly the same process of evolution, and indeed there is a bloke named Hoppy writing exactly the same thing as I am doing now on a website far away. And somebody exactly like you is reading it.

Now get this: not only is there another planet just like ours, but there is actually an infinite number of them. I find this a little hard to take in over my morning coffee.

Richard.

Nimbus

Our cosmos is not infinite. It has no bounds, but that does not mean that it's infinite (back to the ball analogy again. The surface of the ball does not have boundary, but it's not infinite in size). In fact when cosmologists find an infinity, it's usually the sign that their sums are wrong . In our own universe, t's likely that there are a huge number of planets orbiting the billions of stars in each of the billions of galaxies that we can see. However, to say that there would be copies of our world anywhere would be stretching things a little. You would have to have exactly the same starting conditions, exactly the same geological/planetary history (Mass extinction events' anyone???) for things to develop in a way that matched our own. Frankly, the chances are, well, nearly infinite... This is all with our own universe.

With regards to the parallel universe idea though, if there were infinite number of them, than not only is a copy of earth a possibility, it's an absolute certainty..

Time for my second coffee I think...

carl

This a long running debate between the Many Worlds Interpretation (MWI) and the Copenhagen Interpretation schools of thought. Niels Bohr was in the latter group.

Leslie

Without all the deep knowledge of the Cosmos, I still think that there will be other worlds with life on them but I doubt very much that they will be clones of the Earth.

Les

Nimbus

Gravity depends on mass. If there's not enough mass to create a large enough gravitational pull, it won't slow, stop and reverse the outward expansion.

When you are on the Earth, you can throw a stone into the air. Although the initial speed may be high, you know that the Earth gravitational pull will be enough to slow the stone and eventually it will fall back to earth. If you try this on a small asteroid the initial speed may well be enough that the stone never slows enough to fall back. The asteroid's mass (and hence gravity) is too small. This is the currently accepted situation with our own universe. It is expanding at such a rate, that the amount of mass (and hence gravity) is not enough to slow it's expansion. Therefore, it will continue to expand for ever

Hoppy

Something that has no bounds is surely infinite

Going back to my earlier thesis, it is far easier to believe in God than it is to get your head around this kind of science. And your earlier reference to politics in all this is highly relevant.

Not that that gives me any more answers or comfort. Just a headache

Cheers for the responses, though

Richard.

Nimbus

Not so. The ball analogy again. Imagine that you are a 2 dimensional being, living on the surface of a ball. You can move forward/back/left right, but have no perception of up and down. Now, you can travel all around the circumference of the ball, both north/south and east/west. You will never come to a barrier, or "edge" of your world, but it is finite in size. There is only so much surface for you to explore.

This is what I mean. In our 3D (OK, 4 if you count time ) world, we can move forward/back/left/right/up/down. But if we travel far enough (for long enough and fast enough), we will end up back at our starting point. we will not have hit a boundary, or found the edge of our universe, because there is not one. But like the ball, there is a finite amount of space we can explore. That amount of space is getting larger (as the universe expands - imagine the ball slowly inflating), but it's not infinite.

Easier because all you have to do is say, "I don't understand the science, or accept the views/evidence of those that do, therefore I don't "believe" it and instead but my faith into a non-proven/un-provable idea that someone else did it all"...

Just because you don't understand it though, does not mean that it's not right

No probs. Nice to have a good debate on Scoobynet once in a while..

Hoppy

I get the ball alalogy, but...

How big is this ball and if it is expanding, what is it expanding into?

Also, you say that on the surface of the ball you cannot move up or down, but that we can move up and down. Do you mean inside the ball?

Of course, all this is an attempt at applying human understanding to something we do not understand and furthermore I would suggest that mankind will have been extinct for a very long time before we have had a chance to grasp it.

And to cap it all, what good has come of any understanding we may have
(to quote your earlier post) of "warping of spacetime by mass, time dilation, quantum uncertainty?"

Not that I have a clue about what they are but all I know about the benefits of space travel is that it led to the development of non-stick saucepans. This doesn't strike me as best use of some our finest brains.

I guess that's my point - there is no useful purpose in inconclusive hypothesis. And that's not necessarily a serious criticism; I waste a lot of my time in utterly pointless activities and academic endeavour is worthy in its own right. I just think there are more important things to worry about.

Regards,

Richard.

lestippp

Gee guys I can answer all this...... watch Star Wars

It is based on a true story from a galaxy far far away

Release your imagination, all is possible

Maz

iTrader: (34)

The dimensionsal theory is quite interesting. As already stated we have three physical dimensions and time being the fourth. These are tangible (so to speak) dimensions we can comprehend. However some scientists state there are many more dimensions up to seven or eight that we cannot see or touch. Can anyone describe the nature and properties of these hidden dimensions? Another factor to add to the complexities of comprehension is that the laws of physics and chemistry are different in space to Earth. Therefore our findings could all be completely irrelevant when used as a parallel to what happens in space.

jonc

Forget all this, its all there to occupy our brains when the real truth is that all this is just a computer simulation call a matrix.....there is no spoon.......

Nimbus

I'll try to give answers/opinions..

current estimates give the diameter of the universe as nearly 93 billion light years. It's not expanding into anything. There is no "outside" to the universe. I guess this is one of the things that is difficult to explain and understand.

I may not have explained properly. For the 2D beings, there is not up and down. For us, you move up a set of dimensions. So instead of a 2D surface of the ball, we have a 3D sphere of space. The idea remains the same.


There may not be any material benefit for a very long time (if at all) for studying this. But it's in our nature to ask questions and I think the answers as well as the process of discovery enrich our lives.

Maz

iTrader: (34)

Plausible I suppose I mean we could all be hardwired into a mainframe that can simulate every possibility and every detail.

Nimbus

These extra dimension are wrapped up so small they they have no impact on our daily lives. They are the scale of the planck length, which is very small indeed. Put it this way. If an atom was the size of the universe, the planck length would be the hight of an average sized tree.

When I say "wrapped up" think of it like this. If you have a tube like a hose pipe for example, and reduce the thickness of the hose smaller and smaller to the planck length. You will in effect have a one dimensional line. But all along this line you have the hidden curled up extra dimension of the tube. This is what the extra 6 or 7 dimensions are like on our 3D world. They are at every point of space, but so small that we can not perceive them.

Not so. The laws of physics and chemistry are the same no matter where you are. This is one of the principles of Einstein's theory of general relativity. The fact that someone in an enclosed space could not tell if they were in a room on earth, or a constantly acceleratingly space ship prove that. I thought even you should now that one Einstein...

Hoppy

Agreed

But you've lost me. The solar system extends 93 billion light years (diameter?). Doesn't it get bigger everytime we get a more powerful telescope? And it is expanding, apparently into nowhere but is not infinite. Then we have more than our regular three (or four) dimensions in our world but they are quite small. Unbelievably miniscule.

Frankly, there are more plausible fairly stories but I'm not dissing you mate and thanks for your replies.

Richard.

carl

Knowledge for knowledge's sake not good enough?
Quantum theory: directly leads to development of tunnel diodes, quantum computers, interesting effects if you play with 3 polarizing filters
Warping of spacetime by mass (that's general relativity), time dilation (special relativity): they (indrectly) make GPS calculations work because you have to correct for them.

carl

I wrote this last time and a lot of people got upset. It annoys me when people like you rubbish the theories without bothering to do any research to comprehend them. You've done no proper study, not bothered to spend any time doing proper research, but because it doesn't happen to suit your (limited) view of the world, it must be a 'fairy story'.

Fact: spacetime can expand without expanding 'into' anything.
Substantiated theory: higher-order dimensions are 'rolled up' to be very small
Fact: the universe is finite but unbounded. I mean, how difficult is this? The surface of the earth is finite (you can paint all of it) but unbounded (you can't fall off the edge)

If you can't understand this stuff it's not my problem, but don't knock people who can unless you're coming from a position of authority.

Maz

iTrader: (34)

Don't take it personally, I'm sure Hoppy doesn't intend offence. This is a very complex and intriguing subject which I and many others find absolutely fascinating. It is our good fortune to have people like yourself and Nimbus contributing to this thread, and persevering in the face of scepticism and much head scratching. I'm sure people had to face this sort of response in years gone Darwin, Einstein et al. However it didn't discourage them so keep up the posting and educating of the less well informed like me. I only have Einstein as my user name I don't share his great knowledge . Therefore I am quite intrigued and curious about the string theory, that all the fabric of the universe is composed of strings of higher dimensions, and that everything physical is a manifestation of these higher dimensions.


Einstein also said mass and energy were interchangeable, would this explain where all the mass in the universe came from? I mean how can you have all this physical matter come from nothing? The big bang released an (almost) infinite amount of energy which has subesequently become mass, is this the general consensus? Another thing I and many others want to know is what caused the big bang? Was it the the next step in the big crunch? How big was the universe in the very first instance the size of an atom? So many question I know but curiosity and the thirst for knowledge is what makes humans human.

Nimbus

It's the universe that is 93 billion light years across (In fact after a bit of reading up, that's just the observable size. It could be as large as 156 billion light years wide). The Solar System is about 10 light hours across (to the orbit of Pluto) in comparison.

I agree that it can be a bit bewildering the first time you hear this kind of thing, but you've got to remember that all of this is based on either observational evidence or strongly support theories.