Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Karen W. on 29/10/2007 17:17:29
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I am not familiar with all the details, but know that Two American Radio astronomers, Arno
Penzias and Robert Wilson discovered a faint uniform background radiation, which reached
throughout all of space and was then identified by them to be remnants of the Big Bang.
How was it that they determined that the So called "cosmic microwave" background was
actually the echo of the big bang itself, having been left over from the fireball of
creation of our universe..
I am really slow to understand the science end of things pertaining to the world around
me, so if in your answers you could give them in simple layman terms for me to understand
then I would much appreciate the time you all give to helping me learn some more about the
world I live in , in particularly how it came about from a scientific view instead of the
religious view I grew up with!
Question #2.. If the universe was one large mass without stars etc etc etc...before the
big bang, then what exactly was it that exploded to cause the Big bang and create the
universe to begin with... there must have been something here in order for something to
explode and break off into pieces to begin with??? I am really confused There must have
already been something in order for something to explode and give us our existing universe
in the way we recognize it now. RIGHT????? Easy explanation PLEASE as you see I am
already quite confused, Which is not hard to do!!! Thanks everyone!
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I am not familiar with all the details, but know that Two American Radio astronomers, Arno
Penzias and Robert Wilson discovered a faint uniform background radiation, which reached
throughout all of space and was then identified by them to be remnants of the Big Bang.
How was it that they determined that the So called "cosmic microwave" background was
actually the echo of the big bang itself, having been left over from the fireball of
creation of our universe..
Essentially for 2 reasons:
1. The radiation intensity is (excepting little variations) isotropic, that is the same in all directions;
2. it has the spectrum of a blackbody.
1. Means that the radiation pervades all the universe.
2. Means that it must have been generated from something hot and dense (a non-dense substance would generate a different kind of radiation).
Now put those 2 things together with the already known (at those times) fact that universe expands, and think "making the movie go backwards". What do you see?
(Question #2 is too difficult for me).
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I understand that the radiation is spaced out pretty evenly everywhere for
the most part, which forms kind of a large black body which evades the
entire universe...
so that means that whatever was here before the big bang was something very
dense and hot because a non dense substance would have created a different
kind of radiation.. does that, mean there could have been like one massive
star like the sun.. very hot,, could it have exploded into many creating all
the stars etc?? So the earth is what part of this intense heated object?
Would it have been the core of the entity? Is it like the growth of life in
the womb??? whatever was here expanded until it had to blow or give birth so
to speak to a whole new universe...???? Like before the big bang there was
this massive existing hot black dense area object.. which was expanding and
growing... was the heat being radiated by its growth or was the grwth
radiating the heat which built up inside before it exploded??? Did it
explode of its own natural evoulution or did something happen beyond its own
evolution to cause the big bang! It seems so much like nature and birth and
rebirth.. something can only grow so big without then expanding if it is
about to outgrow its environment it seems as though something would have to
give in order for the growth to continue... I am really confused but very
interested ..
How do we now come to be living and non living things, was it the explosion
that perhaps changed non living structure into a living variety of plant and
other biological life... HELPPPPPP!
It is difficult for me too Alberto!
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Your image of the early universe being like the sun is very good. That's pretty well what it was like at the time the background radiation was generated. The radiation then was light pretty much like a star and has since then been red shifted by a factor of about one thousand to bring it down to the microwave region.
To step back to your original question why it is considered to be a property of the whole universe and not something about, for example, local isotropic conditions in our own galaxy or solar system. One important feature is that it is not faint and weak needing sensitive instruments to detect it. It is incredibly bright. If you compare the energy coming in from the microwave background to the other radio sources in the universe at these frequencies. I have seen the microwave background likened to Bright moonlight compared with a dark sky the stars and the milky way.
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Going back to the beginning it was just hot gas and it had to expand a lot and cool down a lot before the sort of structures that we are familiar with now, stars galaxies and planets could form. This period is known as the "dark ages" of the universe because all that was the was the fading glow of what is now the microwave background as it went from light through the infra red and millimetre wave regions and eventually reached the microwave region cooling down from around 5000 degrees K to around 20 - 30 degrees K before the first big stars started to form Then quite a lot of stars had to form, run through their lives and blow up before there were enough heavy elements around to make rocky planets like the earth Which has only been around for about a thirds of the period from the big bang to now when the microwave background temperature is around 2 - 3 degrees K.
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It was approximately 3 minutes after the Big Bang that the first hydrogen atoms started to appear. Prior to that it was too hot for atoms to form.
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Going back a bit further is a problem and still the subject of considerable discussion The big bang could have been a one off event that just "happened" as a result of quantum mechanical improbability. What we see could be an extremely tiny part of a whole which has vastly different properties and physical laws from what we see here. The bang could even be a continuous process its just the fact that we are in a quiet bit. I personally tend to favour a different approach.
The laws of physics are incredibly finely "adjusted" to enable stars, atoms chemistry and life to exist. You could put this down to us being in a particular foruitious part, or even that some super intelligence planned it all out and set things in motion in exactly the same way. This latter explanation was used to describe the origin of life on earth until science showed how it could all evolve from simple beginnings. Using this as a parallel it is possible to wonder if the universe and the physical laws have been subject to some sort of evolutionary process.
How could this work? to get evolution functioning it is essential to have some sort of recycling process in which small changes might allow things to develop and reach a level of optimum complexity. It has been suggested that the formation and destruction of black holes over incredible time scales may have allowed this. this could also fit with some of the multidimensional "branes" clashing that other theoreticians favour. One requirement remains that of finding some sort of fractal or "scale independent" process.
We already know that space and time are inextricably linked through relativity and that that includes scale. A black hole is a bit like a tardis because it is effectively indefinitely large inside whatever the size might be outside. A lot of the rest I have already mentioned elsewhere on these pages and really belongs among new theories and not in a balanced resume like this.
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Beaver, strictly speaking it was too hot before then for for protons to form then nuclei of atoms like helium came later. neutral atoms only started to form around the time of the generation of the cosmic microwave background about 300,000 years after the bang because the flash of light was generated by all the electrons joining up to the nuclei to make neutral atoms which then allowed the light at a wavelength long enough not to ionise the atoms to propagate unhindered across the universe.
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My mistake. I meant to put "hydrogen nuclei" which, of course, are protons.
Hey, it's getting late & I've had a long day, OK? [:(!]
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Your image of the early universe being like the sun is very good. That's pretty well what it was like at the time the background radiation was generated. The radiation then was light pretty much like a star and has since then been red shifted by a factor of about one thousand to bring it down to the microwave region.
To step back to your original question why it is considered to be a property of the whole
universe and not something about, for example, local isotropic conditions in our own
galaxy or solar system. One important feature is that it is not faint and weak needing
sensitive instruments to detect it. It is incredibly bright. If you compare the energy
coming in from the microwave background to the other radio sources in the universe at
these frequencies. I have seen the microwave background likened to Bright moonlight
compared with a dark sky the stars and the milky way.
I do not understand the statement about being red shifted..What does that term mean?
What is the microwave region?
Are you saying that it is so strong or bright that it produces energy in approximate
capacity of that of a bright moon or that of the stars in the milkyway against the dark
sky????
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Going back to the beginning it was just hot gas and it had to expand a lot and cool down a lot before the sort of structures that we are familiar with now, stars galaxies and planets could form. This period is known as the "dark ages" of the universe because all that was the was the fading glow of what is now the microwave background as it went from light through the infra red and millimetre wave regions and eventually reached the microwave region cooling down from around 5000 degrees K to around 20 - 30 degrees K before the first big stars started to form Then quite a lot of stars had to form, run through their lives and blow up before there were enough heavy elements around to make rocky planets like the earth Which has only been around for about a thirds of the period from the big bang to now when the microwave background temperature is around 2 - 3 degrees K.
OK I understand the hot gas expanded then cooled repeatedly until what?? It exploded but
what was it enclosed in to begin with and where does the solid matter come from if all
there was was this gas expanding and cooling? Inside of what?? What was the container ???
that held the gas.
Does something happen to gas that is repeatedly heated and expanded? would the gas
eventually burn building carbon wall around the gas or sending out carbon into
surrounding, area, and then becoming more solid base that blows after it eventually
exploded!! Would the carbon build up over time.. and would that eventually be the solid
material?? I am confused.
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Don't run away I have some more questions on the last few posts but me eyes hurt and I need to lay down.. I will come back tomorrow and see what kind of trouble I can get myself into!.. Night all.
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Your image of the early universe being like the sun is very good. That's pretty well what it was like at the time the background radiation was generated. The radiation then was light pretty much like a star and has since then been red shifted by a factor of about one thousand to bring it down to the microwave region.
To step back to your original question why it is considered to be a property of the whole
universe and not something about, for example, local isotropic conditions in our own
galaxy or solar system. One important feature is that it is not faint and weak needing
sensitive instruments to detect it. It is incredibly bright. If you compare the energy
coming in from the microwave background to the other radio sources in the universe at
these frequencies. I have seen the microwave background likened to Bright moonlight
compared with a dark sky the stars and the milky way.
I do not understand the statement about being red shifted..What does that term mean?
What is the microwave region?
Are you saying that it is so strong or bright that it produces energy in approximate
capacity of that of a bright moon or that of the stars in the milkyway against the dark
sky????
Red-shifted: The classic analogy is that of a police car siren. As it passes you the pitch drops noticeably. The same thing happens with light. To say that it has been red-shifted into microwaves means that, in effect, the "pitch" has dropped far enough that it is no longer light, but has moved down the electromagnetic spectrum into the microwave region. This article explains about the EM spectrum http://en.wikipedia.org/wiki/Electromagnetic_spectrum (http://en.wikipedia.org/wiki/Electromagnetic_spectrum)
The bit about the moon is giving a comparison of how strong the CMBR is. If there were none, it would be like a dark night; but the signal is so strong it's like the light from the moon brightening the sky. (We can't see it, though, as it is red-shifted into the microwave region)
Going back to the beginning it was just hot gas and it had to expand a lot and cool down a lot before the sort of structures that we are familiar with now, stars galaxies and planets could form. This period is known as the "dark ages" of the universe because all that was the was the fading glow of what is now the microwave background as it went from light through the infra red and millimetre wave regions and eventually reached the microwave region cooling down from around 5000 degrees K to around 20 - 30 degrees K before the first big stars started to form Then quite a lot of stars had to form, run through their lives and blow up before there were enough heavy elements around to make rocky planets like the earth Which has only been around for about a thirds of the period from the big bang to now when the microwave background temperature is around 2 - 3 degrees K.
OK I understand the hot gas expanded then cooled repeatedly until what?? It exploded but
what was it enclosed in to begin with and where does the solid matter come from if all
there was was this gas expanding and cooling? Inside of what?? What was the container ???
that held the gas.
Does something happen to gas that is repeatedly heated and expanded? would the gas
eventually burn building carbon wall around the gas or sending out carbon into
surrounding, area, and then becoming more solid base that blows after it eventually
exploded!! Would the carbon build up over time.. and would that eventually be the solid
material?? I am confused.
The gas did not cool repeatedly. To begin with, the primordial universe was at billions of degrees Kelvin. That is far too hot for anything interesting to happen (like a heatwave in Texas!). As the temperature cooled, interesting things started to happen - matter de-coupled from energy and, after 3 minutes, protons started to form.
It wasn't for another 300,000 years that it had cooled enough for helium atoms to form. The cooling was caused by the expansion. The universe is still cooling as the expansion continues.
The heavier elements weren't formed simply by the cooling of the universe. A very small amount of lithium was produced, but that's as far as it went. The hydrogen & helium gradually co-alesced to form stars. Heavier elements are formed during the evolution and deaths of stars. I believe iron is the heaviest element that is routinely formed inside stars as they near the end of their life and elements heavier than iron are produced when massive stars explode as novae & supernovae.
As for the container, or whatever... who knows! We can only see the "visible universe". What lies beyond is a mystery; although experiments with the new LHC collider at CERN may produce evidence of further structure such as higher dimensions.
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The 'evidence' - which is the first line of the original post, was that they thought there was some interference getting into their receiving equipment. They were looking, with a large microwave horn antenna, into deep space, for radio sources. Every amplifier introduces electrical noise (random fluctuations due to thermal effects). To reduce the receiver noise, it is usual to cool the 'front -end' amplifier with liquid nitrogen, because the front end introduces the majority of the noise.
They calculated the level of electrical noise that they would have expected in their receiver at the temperature it was operating at and got a higher level than expected.
They first looked at the receiving antenna (a large microwave horn) and found pigeons nesting there. "Hot bodies", they thought - "that explains it- low frequency radiation, causing interference". So they shot the pigeons and cleared out the nest. It made no difference. They looked at local buildings for something to explain the interference - no joy.
Wherever they pointed the antenna (using the Earth's rotation, too) they got the same level of unexplained extra signals. Lots of checks were made on the theory of noise in amplifiers but they eliminated that and still predicted a lower level of background noise than they got.
It had to be explained in terms of a source of radiation throughout deep space.
Good news for Hoyle - bad news for Bondi and Gould - the steady state proponents.
(When I was a lad, the Big Bang hadn't been considered as a serious model for the Universe)
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Doc, Thank you for explaining better, So a proton is made up of what? Atoms? nuetrons electrons??? Which part makes up the protons. Then the molecules.. Wait;;;got to look them up .. I am getting them confused as to what makes up what!...be back have to look them up!
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Well:::
Protons
http://en.wikipedia.org/wiki/Proton
I just shot myself in the foot cause I will never be able to understand all the components of what makes up what without visual aid! I wonder if the kids science store has a proton I can take apart and see all disected.. so to speak.. they all seem like they can be slightly different.. they are not all the same I see. This is science 101 or lower for me... Please be patient!..
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ok I have three more pages to go on the wave particle duality..then I will be back! I NEED TO CLARIFY SOME THINGS IN MY HEAD BEFORE I CAN CONTINUE!
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Protons & neutrons are made of quarks - 3 each. As far as we know, quarks are fundamental (meaning they are not composed of smaller particles). The same is true of the electron. Protons, neutrons & electrons are the constituents of atoms. Protons & neutrons are known as nucleons as they make up the nucleus of the atom. Electrons orbit the nucleus (sort of but not really(ish); but that's delving into quantum physics).
Quarks are held together by gluons - the mediators of the strong force (which is called strong because it is).
Molecules are a collection of atoms that are bound together by co-valent bonding. The electrons in the outer electron shell of the atoms go swapping & stuff so the atoms stick together. OK, being pedantic, it's not exactly like that, but it'll do for now. [:P]
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Thats a lot simpler explanation then my science book! LOL! thanks Doc!
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The real scientists among us will probably take me to task for that explanation; but as a very simplistic view of it, it'll do. If I started talking about electron clouds & probability functions you'd probably throw your hands up in horror and call me names [:X]
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NOT a chance but you would probably be all day and night explaining your explaining! LOL LOL!
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Sophie
"Good news for Hoyle - bad news for Bondi and Gould - the steady state proponents.
(When I was a lad, the Big Bang hadn't been considered as a serious model for the Universe)"
Hoyle was the originator of the continuous creation theory which I found very exciting when he first expounded it on the radio.
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Yes, I think I heard him talk cosmology - I certainly heard Bondi when I was at Uni.i..
Oh, yes - he coined the phrase although he didn't go for the theory. (Quite a daft theory, but for the evidence!) It was Georges Lemaître who started the big bang thing. Amazing for it to be a Catholic priest, bearing in mind all the stick Gallileo got.
I now remember his continuous creation - much more satisfying as it puts off any ultimate questions to infinity, rather than a specific time.
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Wasn't Lemaitre involved in the Copenhagen quantum thingy?
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afaik Lemaitre was a cosmologist and proposed the 'primeval atom' idea.
He published around 1927 - the same time as Bohr proposed the Copenhagen Doctrine, which binds the particle and wave natures together in quantum theory.
The link between them was really, I reckon, in the relevance of expansion to Einstien's fudge (cosmological constant) and the difficulty in unifying quantum theory with relativity.
'They' (I nearly wrote 'we' but that would be presumptious) still have to sort out that one.
Lemaitre wasn't the first 'big bang' proponent, apparently. Charles Darwin's father suggested it as a possible start to the universe. There's nothin new under the sun is there?
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There appears to be no discussion about inflation after the BB. That really blows the mind. By the way how large was the estimated size change during the inflation period?
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There appears to be no discussion about inflation after the BB. That really blows the mind. By the way how large was the estimated size change during the inflation period?
1026. Quite a lot, eh!
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Volume or linear ?.