Can a Science "Brain" Answer my Question About Hubble?

Okay , my friends and I (we aren't the brightest sparks in the Science bonfire) have been puzzling over this when we had supper.

Apparantly Hubble telescope has just taken a pic of the universe about 600 million years after the big bang.

So, how could it do that considering we are some time after that and this galaxy didnt even exist then. AND - the cruncher - how did they know where to point the telescope to get the pic of teh baby universe?

My friend who's a drummer says it isnt so - just like the men in the moon malarkey but I believe in aliens so I keep an open mind. Aliens are cool. (If any aliens can read this somewhere in a galaxy far far away, I liek you)

It's like sound.

Say your drummer friend is banging on the drums a kilometer away. You'll hear what he was playing a few seconds ago.

If he just started one second ago, you won't know about him. But if he was at it for a while, there would be plenty of racket from his direction.

It's like getting ripples in a lake from far away. It doesn't matter if you just got to the lake or not. The ripples were on their way coming out here anyhow.

Or in other words - light only travels so fast.

It takes light eight minutes to get from the sun to here. So when we look at the sun, we are seeing it as it was eight minutes ago. When Hubble looks into the farthest reaches of the visible universe (not just our galaxy, but a LOT farther) it is seeing light from 13 billion years ago (give or take a few hundred million).

Or as late comedian Mitch Hedberg said: Why do people say "Here is a photograph of me when I was younger?" EVERY photograph of you is when you were younger.



.

Actually, yes our galaxy is that old also, we have measured the age of globular clusters in our galaxy at 13 billion years. Our Sun is not that old (4.5 billion or so), but it's a second generation star.

The light has been on its way all that time (13 billion years or so). The galaxies they are looking at are 13 billion light years away, and since light travels one light year per calendar year by definition, it had to have left that long ago to arrive here now.

To find early galaxies like that, mostly they need to point Hubble anywhere there isn't something closer in the way. They call these type of photos "deep field", because they are looking as deep into space as possible, and you will find galaxies in formation pretty much any direction you look when you look that far back.

Hubble uses the same technology as digital cameras (charge coupled devices, or CCDs), except the optics are *way* bigger (2.4 meters across), it's in space, so the atmosphere is not in the way, and they can hold the telescope *very* steady, for days if they need to, to take really long exposures.

You can look further back in time with an ordinary television with rabbit ear antennas. Just tune to an empty channel in the UHF range. Part of the snow on the screen comes from the "cosmic microwave background" which dates back to 400,000 years after the Big Bang. The old ATT&T used microwave antennas to carry phone conversations cross country, and a couple of their research guys were checking out noise in those frequencies cause it interfered with long range signals. They found it in every direction they looked. Turns out the noise was coming from the birth of the Universe, and they got a Nobel Prize for discovering it.

Siince it's the whole universe that came into existence at the Big Bang, the fireball from that is in all directions It was white hot at the time the light was emitted (around 2700C), but it has been redshifted by a factor of 1000 by the expansion of the universe since then so it appears in the microwave band now.

The early galaxies are a little later, but they also are found in all directions, as are other, closer galaxies. Its just by being closer, the light left them later, so we see them closer to what they are today. Andromeda is 2 million light years away, so the light we see it by now left that long ago. Andromeda is the furthest thing you can see with your own eyes, in a really dark location on a clear night. And that light left when your ancestors were trying to figure out fire and pointy rocks

Also, they used ultraviolet, visible-light and near-infrared wavelengths to see those distant galaxies, as the visible light was too faint to pick up by itself

And to further boggle the mind- before the Big Bang happened, everything in this entire universe (all matter & energy) was all in a teeny-tiny little ball, smaller than a marble.

The answer is simple:

299,792,458 m/s

It's more correct to say the visible part of the universe was once the size of a marble. We don't actually know how large the universe is, because light from parts further away than 13.7 billion light years has not had time to get here yet. Since we don't know how large it is *now*, we also don't know how large it was *then*, only that a thumb sized patch of it grew up to what we see now.

We have information what was going on 3 minutes after the Big Bang from the ratios of various elements (Hydrogen up to Lithium). At that time things were hot enough to form heavier elements by nuclear reactions. From the ratios we actually see, we have an idea of how hot and for how long.

It's been a long time since I studied astrophysics in college, so I would have to look up how far before those first three minutes we have actual data and when it dissolves into theory and speculation.

Look at it this way, if you could magically teleport yourself 234 light years away from the earth instantly, turn around, and look at the earth through a telescope powerful enough to see all the way back to the earth, you wouldn't see the earth as it is today, but you could see the signing of the Declaration of Independence.

Speaking as an alien, I'm shocked that you people can cam into my galaxy.

Back in the days when we had a WTC, sometime before anyone considered bombing it with a truck, let alone a plane, I used to stand at the windows of the 104th floor with binoculars watching a new building go up. I could see a construction worker bang on the copper roof and hear the bang of his hammer a second or so later.

It's even more correct to say it is thought that the visible part of the universe ....

There are a number of mutually exclusive Big Bang theories, and that's all they are - theories.

Thanks you very much everyone for sharing your knowledge. I even asked on Forum IM last night coz I was confused.

I am no math genius. Or science. I made people laugh (I think) when I told them how I was so stuck in a Physics class exam that I made up my own question and wrote about jet engines. The trouble is I hadnt a clue how they work. So I drew a pod shape (like an engine) and made squiggles inside that for engine parts. Then I derw arrows at teh entry point and wind signs (they are wavy ones) and then wrote "Whoooosh!" at teh exit. I then made up all sortsa nosense about why engines drink gas. I failed the exam.

Yes...but everyone pretty much agrees that there WAS a Big Bang. That the universe began very very small and dense, and expanded into what we see today.

The competing theories are all trying to explain, mathematically, what the universe was like in the first few minutes of its existence. Ultimately, we'd like to know how did this all happen in the first place? That it DID happen, we know. The details of the very early universe, and even back before time=0, are not yet clear. (Nor is it clear if the questions, "what happened BEFORE the Big Bang?" and "how did that little marble-sized universe happen in the first place?" are knowable, or even if they are meaningful questions.)

Jig

If you ever find yourself contemplating jet engines again, I can help.

There's a big fan in the front that sucks in air, and compresses it. Inside the engine, fuel (kerosene, not gas) is burned in the compressed air.

This creates a lot of pressure (just like burning fuel and air in your car creates pressure in the engine cylinders, driving the piston down and turning the crankshaft).

The pressure is released by letting the hot gas shoot out the back end (whoosh!). In technical terms, it's expanded, trading the energy of heat and compression for the energy of motion.

As the gas shoots out the back, it turns a turbine wheel, which is coupled to the compressor up at the front. This turns the compressor, so more air is pulled in and compressed, in a continuous process. The turbine only takes a little bit of the exhaust's energy...the rest goes to push the airplane, just like the air escaping from a balloon pushes it around the room.

Like everything else, a jet engine is a series of tubes.

I just want to say that I'm getting all hot and bothered reading all this cool science stuff you folks know, and can explain.

*goes to take a cold shower*

Wow, I never knew.

*runs to buy a physics textbook*

Yes, the Big Bang theories agree that there was a big bang, but not all scientists and theories agree that there was one. The idea that there was a big bang is only a theory - it isn't known.

What there was before the big bang is usually thought of as a meaningless question because time is thought to have started at the big bang, so there was no 'before' it. But, again, it's all theoretical and a helluva lot of money is spent on it without any chance of it benefitting anyone other than increasing scientific knowledge.

This video might give you a little perspective, Jig.

http://www.youtube.com/watch?v=17jymDn0W6U

If you want to be pedantic, yes, all of science is hypotheses and theories, some of which have better confirming data than others, but which are always subject to revision or replacement if new data comes in. Observation always trumps theory. So anytime a scientist says something "is this" it's shorthand for:

"A lot of observational data matches this theory, the theory fits with all the other well observed theories, and no other theory is anywhere close".

There is also a progression of hypothesis --> theory --> law based on how many ways something has been observed to match the data and how good the mathematical underpinnings are. The "Theory of Relativity" matches observations well, but is known to be incomplete because it does not account for quantum mechanics (which has it's own set of even better observations). Dark Matter is still in the hypothesis stage, we know *something* funny is going on (the motions of galaxies internally and in clusters does not match what we expect based on how many stars we see and their gravity). But there are several proposed explanations for what is doing that, and until we actually find and observe what that is, it remains an unconfirmed theory ie hypothesis.

In the case of the Big Bang, it's hard to explain galaxy red shifts increasing with distance, the cosmic background radiation, the maximum age of globular clusters, and light element abundances without a theory that includes "the Universe was very small and hot about 13.7 billions years ago and has expanded ever since". A valid theory has to explain *all* the known observations, not just some of them.

I'm such a closet geek,I'm actually enjoying reading this thread.

Your life is one of our favorite sit-com's!

I think it is up for an Emmy this year.

Right, a common mistake made (in speech only, I hope) even by astronomers.

Also, the universe might be infinitely large. If so, it was at the time of the big bang, too.

Fun stuff, eh?

Right, and the theory of gravitation is just a theory too. All the evidence points to something like a Big Bang, with the exception of the fluctuating branes theory. Of course, the evidence matters to those who care about evidence. And also, the evidence is interpreted in the light of currently popular theories, like general relativity and quantum mechanics. The interesting thing is how many "predictions" made by the big bang theories have been satisfied with further observations. Admittedly, some were contradicted, leading to new wrinkles like rapid expansion and negative pressure, which surprisingly resolved nagging questions that the earlier Big Bang theories couldn't answer.

That's one interpretation; there are others.

An important point about most Big Bang theories is that the laws of physics predict that they have nothing to say once the density goes higher than a certain amount. So, those theories can't possibly be used to predict what happened before things expaneded enough to go below that density. They're similar to the theories that say we can't tell much about the state of matter before it went into a black hole, by looking at the black hole and what it radiates. There are competing ideas about that, too.

Yes - but I'm being pedantic And I think it's good to be because many people believe that things are true without realising that they are just theories.

As you said, it's difficult to ascribe those things to anything other than a very small universe way back, but not long ago, whoever would have thought that time is unique to each individual, or that space is warped (and it still doesn't explain gravity), or that one particle can instantly affect the properties of another partical no matter how far away it is? So even the Big Bang theory, with all the evidence for it, isn't cast in stone as many people actually think.

Don't forget the all-important sonic orifice: the compressed air goes through this before being burned. It's going faster through there than the speed of sound, so the pressure from the burning can't go upstream and shoot out the front of the engine. If that happens, it ruins your whole day.

The German V2 "buzz bomb" jet engines used "trap doors" rather than sonic orifices; thus the very loud buzzing. That was before my time, though.