“It surprises me how disinterested we are today about things like physics, space, the universe and philosophy of our existence, our purpose, our final destination. It’s a crazy world out there. Be curious.” -Stephen Hawking
One of the most existential questions humanity has ever asked is the question of our origins: where do I come from? Inspired by Ben Kilminster's writings, here's the entire history of the Universe -- that's led up to the existence of you -- in just 10 sentences*.
Image credit: Amber Stuver of http://www.livingligo.org/.
1.) At some point in the distant past**, the Universe consisted of empty spacetime with a large amount of intrinsic energy bound up in itself, and was in a state of exponential expansion known as cosmological inflation.
Image credit: Me.
2.) About 13.7 billion years ago, a region of spacetime that would contain our entire observable Universe saw inflation come to an end; the energy that was bound up in spacetime itself was transferred*** into matter, antimatter and radiation, marking the first time the Universe can be described accurately by the Big Bang model.
Image credit: Retrieved from http://case.ntu.edu.tw/hs/wordpress/?p=41808.
3.) The energetic, matter-antimatter-and-radiation-filled Universe now cools as it expands, and a fundamental asymmetry**** between matter-and-antimatter leads to a slight, 0.6-parts-in-a-billion dominance of matter over antimatter.
Image credit: Me.
4.) As the Universe continues to expand cool, the excess matter annihilates away with the antimatter, and the radiation shifts to progressively lower energies, allowing the formation of protons and neutrons, stable nuclei, and eventually -- after the radiation becomes low enough in energy so that normal-and-dark-matter now dominate the Universe's expansion rate -- neutral, stable atoms form for the first time.
Image credit: Universe Adventure, © 2005 LBNL Physics Division.
5.) With the Universe now dominated by dark-and-normal matter, gravitational collapse proceeds, and the great cosmic web begins to form, with the first stars in the Universe igniting after a period of 50-to-75 million years.
Image credit: NASA / JPL-Caltech / Spitzer Space Telescope.
6.) The light from these stars reionizes the Universe, making it transparent to light, while the Universe hierarchically forms star clusters, galaxies, clusters, and superclusters of galaxies on the largest scales.
Image credit: Jim Misti (Misti Mountain Observatory).
7.) As time goes on, the most massive first-generation stars run out of fuel and die in supernova explosions, triggering the formation of new stars and enriching the surrounding interstellar media with progressively heavier and heavier elements.
Image credit: X-ray: NASA/CXC/SAO/D.Patnaude, Optical: DSS.
8.) Finally, after generations of stars being born, living, burning through their fuel, and dying, the interstellar medium is sufficiently enriched with enough of the elements for complex chemistry that all new stars and star systems that form will have substantial amounts of the elements and molecules necessary for life.
Image credit: NASA, ESA, CXC, SSC, and STScI.
9.) About 9.2 billion years after the Big Bang, a small region about 1/3 of the distance from the center of our Milky Way -- one of a few hundred billion galaxies in our Universe -- forms a new population of around a thousand stars, one of which -- out of the hundreds of billions in our galaxy -- forms with a protoplanetary disk that collapses into eight planets, four rocky inner worlds and four outer gas giants.
Image credit: Avi M. Mandell, NASA.
10.) After a few hundred million years, complex chemical life takes off***** on the 3rd world in this solar system, and a vast diversity of lifeforms evolve over billions of years and trillions of generations; a scant few years ago, grown initially from the joining of two cells, a veritable Universe-within-the-Universe of 1028 atoms -- left over from the Big Bang and forged in the crucibles of long-dead stars -- came together, for a brief while, to exist as you.
Image credit: Ernst Haeckel's Paleontological Tree of Vertebrates (c. 1879).
And that's how the Universe came from nothing, to create you, in just 10 sentences.******
* - Not every aspect of how each of these events happened is fully understood. The asterisks are here to show you the events that are currently still being investigated.
** - It is not clear how the Universe came to be in this state, and whether that state was eternal to the past or whether it came into existence in some fashion.
*** - The particulars of how inflation ended (the "graceful exit" problem) and how the energy was transferred into matter, antimatter and radiation (the "cosmic reheating" problem) do not presently have universally agreed-upon answers.
**** - We don't know the exact mechanism of what caused the observed asymmetry between matter and antimatter; an illustrative example is here.
***** - We don't know whether life originated on this world or on another world or in interstellar space; we only know that it took off on this world some 3+ billion years ago.
****** - Fine, ten sentences, two semicolons, and six footnotes.
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I think the original title definitly sounds better than ten sentences, two semicolons, and six footnotes.
Love it!
Great article.
Looking at the time scale(Rhys Taylor) simple questions are arising to me:
Space is expanding.
Is time, on a certain observer's point, also changing in time? How was the time-flow(Entropy) at the Big Bang ?
Are we(Our Universe) actually slowing down or do we accelerate?
How do we find out? Consequences?
Thanks for your posts.
nice article.
My only remark is the image below no.2 section
Images like that give such a wrong message about BB that all the writings can't fix.
After all these years people still think of it as starting from one point in spacetime because of those pictures. They think of it as an explosion.
Other than that.. nice post :)
Unless someone invents a 4-D monitor, there's no way to get the image across without leaving the option for misconception.
perhaps an image of CMB is better... uniform everywhere, not starting from a single point.
Good idea for a post and very good execution.
Ten sentences, two semicolons and six footnotes would not be a good title for this, but it would be a great name for a band.
It would never work: the artist title would never fit on an iPod screen.
Apparently I'm not missing anything by not owning an iPOD. (I do have a Galaxy S3 with big screen: I think the name would fit on that.) :)
I still don't think this explains how there is no such thing as nothing.
doesn't having such a thing as nothing violate the Uncertainty principle? If there was nothing, then you would know the energy state and position of a region of space? essentially knowing both position and momemtum?
You can't have nothing in an existant universe.
Before you have one, is another matter.
Why does this seem perennially difficult for some?
"I still don’t think this explains how there is no such thing as nothing."
What "this" are you talking about?
Above the line, Ethan only uses the word once in the title and once right at the end, neither saying it is going to explain how there can be no such thing as nothing.
dean, they'd just make the font size 24pt (and because "it's designed", you can't change it).
The reason for the lack of interest in physics today is because physics is not a science; it is a religion. The Big Bang is absurd ridiculous nonsense. The Big Bang is religious dogma.
'Was the universe born spinning?'
http://physicsworld.com/cws/article/news/46688
"The universe was born spinning and continues to do so around a preferred axis"
The Universe spins around a preferred axis because the Universe is, or the local Universe we exist in is in, a jet; a larger version of a black hole polar jet.
'Mysterious Cosmic 'Dark Flow' Tracked Deeper into Universe'
http://www.nasa.gov/centers/goddard/news/releases/2010/10-023.html
"The clusters appear to be moving along a line extending from our solar system toward Centaurus/Hydra, but the direction of this motion is less certain. Evidence indicates that the clusters are headed outward along this path, away from Earth, but the team cannot yet rule out the opposite flow. "We detect motion along this axis, but right now our data cannot state as strongly as we'd like whether the clusters are coming or going," Kashlinsky said."
The clusters are headed along this path because the Universe is, or the local Universe we exist in is in, a jet.
The following is an image analogous of the Universal jet.
http://aether.lbl.gov/image_all.html
The reason for the 'expansion' of the universe is the continual emission of aether into the Universal jet. Three dimensional space associated with the Universe itself is not expanding. What we see in our telescopes is the matter associated with the Universe moving outward and away from the Universal jet emission point. In the image above, '1st Stars' is where aether condenses into matter.
Dark energy is aether emitted into the Universal jet.
It's not the Big Bang; it's the Big Ongoing.
I think the image at the top does a good job of representing the idea in a 2-d format. A picture of an explosion shown from another vantage implying that there IS a vantage in space from which to view the explosion is very hard to interpret in a way other than the "explosion in space" misconception.
But it's just a picture, obviously not a scientific diagram. So once told about the idea of space itself expanding rapidly, it shouldn't cause any confusion. Well, unintentional confusion that is.
The image at the top represents the Universal jet we exist in; a larger version of a black hole polar jet.
"The reason for the lack of interest in physics today is because physics is not a science; it is a religion. The Big Bang is absurd ridiculous nonsense. The Big Bang is religious dogma."
You have cause and effect reversed. The reason you think cosmology is dogma is because you have no interest in physics beyond your own fancies and imaginingings. You have on idea why the Big Bang cosmology is preferred, and it's because of evidence, not dogma. Originally it was derided by scientists just like it's derided by you. But they, unlike you, understant physics and value evidence. Not just vague and ephemeral analogies to singular misinterpreted data points, but extremely specific predictions of theory and extremely specific measuremensts confirming them.
There is no greater hypocrisy than calling this dogmatic. It is an opinion formed in a void of ignorance because it pleases you to believe it, and you will not so much as bother seeking out the real history that might contradict it. The very height of dogma.
People like you have no interest in physics because they'd rather believe in the power of their egos than a reality that might show them up.
There's no point in arguing about it. Your first paragraph amply demonstrates everything I'm saying, and you can't un-post it. HAND.
"You have cause and effect reversed."
You are standing on the shore next to the mouth of a river. A bunch of objects floating down the river move away from one another as the exit the mouth of the river and enter the lake.
I explain to you that the objects existed in an infinitesimally small point in the distant past and there was a 'big bang' when the objects now existed and are moving away from each other.
Do you accept this explanation or do you understand the objects are moving away from one another because the objects exited the river and entered the lake?
The 'Big Bang' is no different. It is mysticism. There is zero evidence of a big bang. What there is evidence of is most of the matter in the Universe is moving away from each other. To consider this evidence of a Big Bang is religious faith, not science.
All of the evidence is evidence we are in a larger version of a black hole polar jet. This evidence exists whether your religion allows you to understand it or not.
De.Brogle:
Nice straw man. If the observation that all objects in the universe are separating were the only evidence for the Big Bang theory, then you might be correct in attacking it. However, you conveniently ignored all the other evidence for it.
To wit:
1. The overall abundance of light nuclides, especially the relative abundances of hydrogen, helium and lithium, is consistent with the prediction of the big bang theory.
2. Big bang cosmology predicts that there was a time in the history of the universe when the universe suddenly became transparent to radiaion due to the combination of charged particles into neutral atoms. The radiation that suddenly permeated the universe would still be visible today, and it is in fact observed. Further, not only the existence, but the spectral properties of this radiation are right in line with the big bang theory.
3. As Ethan posted right here on this blog not long ago, observation of distant objects should yield evidence that the universe was hotter in the past. This is in fact what is observed.
These are just a few of the lines of evidence in favor of the big bang. Come up with another theory that explains ALL of the evidence better than the big bang, and you'll be taken seriously. Continue to knock down straw men, and you will not.
@ de broigle..
you are on a good jet to get banned.. again. please constrain yourself to post your pseudo-science in the appropriate topic you've been referred to before by others.
@CB
it isn't respresenting expansion of spacetime. it's representing the point where "primordial" energy became matter and radiation of our universe (that's section 2). But that happened simultaniously everywhere at once.
it's just MO that an average non-physicist is not aware of that. And when he sees and image of an explosion, it further reaffirms the wrong view.
Sean T,
Nice straw man. However, you conveniently ignored the evidence which refutes the Big Bang.
‘Was the universe born spinning?’
http://physicsworld.com/cws/article/news/46688
“The universe was born spinning and continues to do so around a preferred axis”
‘Mysterious Cosmic ‘Dark Flow’ Tracked Deeper into Universe’
http://www.nasa.gov/centers/goddard/news/releases/2010/10-023.html
“The clusters appear to be moving along a line extending from our solar system toward Centaurus/Hydra, but the direction of this motion is less certain. Evidence indicates that the clusters are headed outward along this path, away from Earth, but the team cannot yet rule out the opposite flow. “We detect motion along this axis, but right now our data cannot state as strongly as we’d like whether the clusters are coming or going,” Kashlinsky said.”
'Massive Quasar Cluster Refutes Core Cosmology Principle '
http://www.icr.org/article/7246/
"Astronomers recently found a distant collection of quasars. But those quasars shouldn’t exist. And while they certainly appear connected, they’re spread too far across space for standard secular models of the structure and origin of the universe to accommodate."
You also ignore the fact that the Big Bang is irrefutable. Whenever there is evidence which refutes the Big Bang the Big Bang simply changes its story.
'Dwarf galaxies suggest dark matter theory may be wrong'
http://www.bbc.co.uk/news/science-environment-14948730
"Research on dwarf galaxies suggests they cannot form in the way they do if dark matter exists in the form that the most common model requires it to. ... But he believes he has found a solution to the CDM problem. He proposes that instead of "cold" dark matter that formed within the first one millionth of a second after the Big Bang, the Universe may instead be filled with warm dark matter (WDM)."
Not to mention you have no idea what dark energy is.
All in order to maintain your religious belief in an unsupported Big Bang.
All in order to not understand we exist in a Unversal jet.
"However, you conveniently ignored all the other evidence for it. "
It's exactly as I described -- exactly as THEY described. Their religion prevents them from examining all evidence, ignoring it by not looking for it. They only look until they find one thing that supports their imagination, and then stop. And declare everyone ELSE to be dogmatic.
Sinisa:
Oh yes, I misunderstood the purpose of the image. But I guess if it was rendered correctly it would be a flat white image of little interest. :)
The thing I was getting at in my previous post, though, was that the "it happened everywhere in the universe" view is not something that would occur naturally to the average non-physicist. So, you really only need to worry if the image is misleading in the context of explaining the real view. I'm not sure that it is.
"you are on a good jet to get banned.. again. please constrain yourself to post your pseudo-science in the appropriate topic you’ve been referred to before by others."
My bad. I keep thinking physics is supposed to be about understanding what occurs physically in nature.
I realize that is impossible when you choose to believe in absurd nonsense such as, "“primordial” energy became matter and radiation of our universe (that’s section 2). But that happened simultaniously everywhere at once. "
The Universe is a larger version of a black hole polar jet.
Matter is condensations of aether. The aether emitted into the Universal jet builds up the pressure which causes the aether to condense into particles of matter.
However, I realize an actual correct physical explanation as to what occurs physically in nature is not as cool as believing in religious dogma such as '"premordial" energy becoming matter" which is word soup for you don't have a clue as to what occurs physically in nature.
Oooh, is it a DC7????
Bloody kook.
Mr. Pilot.wave,
You are free to talk about whatever you like -- including your ideas on the aether, religion, the Big Bang, etc. -- on this page: http://scienceblogs.com/startswithabang/2012/09/23/weekend-diversion-yo…
That page also contains my comments policy, which I suggest you (re-)read.
You are free to believe whatever it is you want when it comes to understanding what occurs physically in nature, and to share those beliefs with the world on the appropriate thread, which I linked to, above.
The comments section below each article is for a conversation about the science in the article, which is -- surprise! -- not what you are doing. As the comments policy clearly states, if your comments are deemed to be unrelated to the post and a detriment to the discussion by another user/commenter, you do not argue; you move your conversation.
This is your personal warning from me to adhere to the comments policy. Another violation on your part -- which includes talking about your views on the aether on any thread other than the one you were directed to -- will get you permanently banned from commenting on this blog.
Right. With time going left to right.
We don't have problems with a family tree looking like it's actually roots, or that it looks like we're dangling under our ancestors, do we?
So why the sudden misapprehensions of a diagram that showed how the universe evolved?
Of course some barnpots want to make a fuss (chelle here for example).
@ CB
"But I guess if it was rendered correctly it would be a flat white image of little interest. :) "
- that's true :)
@Wow
"So why the sudden misapprehensions of a diagram that showed how the universe evolved?"
- nah.. not misapprehensions... just talking. :)
I am confused by #6. I thought the universe became transparent when all the free electrons combined with the various nuclei (as soon as everything cooled down enough) so that they could no longer scatter photons.
Deuce,
That's when the Universe became transparent to the photons (mostly infrared at the time) that now comprise the cosmic microwave background.
But neutral atoms absorb / are opaque w.r.t. visible light; the Universe requires reionization to be transparent to starlight, which doesn't happen until the first stars form and emit enough UV radiation to re-ionize the intergalactic medium.
Sinisa Lazarek #22
"it isn’t representing expansion of spacetime. it’s representing the point where “primordial” energy became matter and radiation of our universe ..... But that happened simultaneously everywhere at once. "
I'm sure I've seen explanations (from mainstream physicists) saying that the big bang created space (and time?). If that was so there would be no everywhere before BB.
And all the space we now see was created by the expanding universe. Or to rephrase, I thought it was argued that space (or extent if you like) doesn't exist independently of the universe created by BB.
"If that was so there would be no everywhere before BB."
So who is saying there was an everywhere before BB? SL says that AT the BB, it happened everywhere at once. Nothing there about BEFORE the BB.
"I thought it was argued that space (or extent if you like) doesn’t exist independently of the universe created by BB."
Yes, and it's still being argued here like that.
@ Peter Dugdale
there is a sequence of events that led to our observable Universe. This sequence is represented by Ethan with sections 1-5. But things 1-3 are what we were talking about and, seems to me, confuse you a bit.
What you are talking about is actually section 1. What I was talking about is section 2.
Weather or not spacetime existed before or started at some point is irrelevant now. What we start with is spacetime. And this spacetime which undergoes exponential inflation is filled only with pure energy. But nothing of the sorts we have now. That's why I called it "primordial". It's the energy where every symmetry still exists.
Then section 2 happens. For reasons unknown, that exponential inflation of spacetime stops in our observable region. And that energy (somehow) undergoes a change. Drops to a lower energy state if you will. Symmetries are broken, fields are created, matter is created (quarks, gluons etc...). But the important thing (and that which confuses you). This last thing didn't begin in one spot and then spread throughout the spacetime. It happened everywhere within spacetime at once.
IMO, the confusion arises with who calls what big bang, and what does he/she mean by it.
If you call BB the very beginning of describing anything, then yes.. you might say it originated at some point. Then again, spacetime on it's own might have existed indefinately, before all this fuss about our Universe. We just don't know. In any case, there is nothing banging anywhere. For all intense purposes it's just "emptiness" expanding on it's self.
Or you can call BB the moment that energy and matter as we know them began. That point where "intrinsic" energy as Ethan calls it, became energy and matter that we know. "let there be light"... in a way. But this, as I said, happens everywhere at the same time. Not in one point that spreads.
Hope this clarifies it a bit.
p.s. If it (our matter/energy) stage happened in one spot that spread, there is no way/time, for our universe to be in a thermal equilibrium that we see now.
The footnotes say far more than the fanciful scenario.
Sinisa Lazarek #36
Well, thanks for trying to straighten me out, although I'm still not sure I've got it. Will have to peruse things a bit more.
@Peter Dugdale You got it right in your first post. It all boils down to if you want to believe the basis of physics is as Sinisa Lazarek says, 'let there be light' or if you think physics should be based on what occurs physically in nature.
@ de broglie..
well, unlike your posts about aether, mine are entirely based on cosmology and physics of today. You were warned by Ethan to talk sceince or refrain from pseudo-science. Since we all saw you have no clue about science... that leaves the other part...
The best thing about this is all the "we don't know exactly" or "there is no agreed-upon position" provisos in the footnotes. Renders the whole 10-sentence enterprise a bit questionable.
@Sinisa Lazarek
You stated ‘”premordial” energy becomes matter and energy which we know, “let there be light”… in a way.
That is not a physical explanation. All you are stating is that there was something that we don't understand that now appears as it does when we look through our telescopes.
@ Molly
yes, it's best, because it means there is a long way to go in understanding the Universe. It's an honest answer. No, we don't know everything, but we have made huge progress in last 100 or so years.
@ de broglie.
it is not a place of comments section to post the whole lectures about inflation and the very early stages of Universe. Even if it were, I'm not qualified enough to do that. I tried to be brief and put as little physics terminology as possible. Go to wiki and read if you want details. Or buy books on cosmology. No one is stopping you.
But one thing is certain. You are a fraud and a fake. Regardless, you won't get more physical explanations since we don't have physics that explain it fully yet. We don't have a unification of GR and QM needed to explain this stage. We don't know how unified forces behave exactly because we can't replicate them on earth at the moment... etc etc. You just whine and troll without any reason and you bring nothing useful to the table.
p.s.
" there was something that we don’t understand that now appears as it does when we look through our telescopes."
Wrong! Sorry dude, but you really need to learn some physics before you can start to participate. NO! It's doesn't now appear... Almost everything that happens once the forces separate is experimentaly observed and mostly in very precise agreement with theory. What we don't know precisely is what happened before that. So what's the big deal? Guess what.. we are not all knowing. There are things to discover. This is not the end of the road.
What are you trolling about. Think you can do better? No problem... write a paper, make an experiment, and if indeed it works... great.. you just got famous. Stop trolling on this blog.
@Sinisa
"... and you bring nothing useful to the table"
Not necessarily. I happened to find de Broglie's posts the most interesting of all comments.
@Sinisa Lazarek
What about the evidence which refutes a 'big bang'? Such as there being a preferred spin to the Universe and directionality to galaxy clusters and massive galaxy clusters that shouldn't exist and the way dwarf galaxies form?
---Repeated links removed---
How much evidence which refutes the 'big bang' must there be for you to understand there never was a 'big bang'?
There is an explanation which is supported by all of the existing evidence. And we have plenty of evidence of this physical process throughout the Universe, just a smaller version of it.
SInesa Lazarek,
I suspect that Mr Pilot.Wave is typical of those who spew pseudo-science woo. He seems to think that the fact that there are questions for which the best answer currently is "we don't know" somehow is a weakness of the currently accepted science. That's just projection; for most purveyors of pseudoscience, "I don't know" DOES indicate a weakness. Of course, when real science runs into a "we don't know" question, that's just an indication that further work needs to be done, and that there just might be (hopefully!) some ingenious person out there who can figure it out. "I don't know" is a challenge, not a weakness.
@Sean T
It's beyond 'we don't know'. I like 'we don't know'. It's a sign of strength. What is a sign of weakness is sticking to a theory which is refuted by the physical evidence or just continually changing a theory which is refuted by the physical evidence.
—Repeated links removed—
With all of the evidence which refutes the 'big bang' a more correct explanation as to why the Universe is the way it is is 'we don't know'.
de.Broglie.pilot.wave,
This is your last chance.
Again, you are free to talk about whatever you like — including your ideas on the aether, religion, the Big Bang, etc. — on this page: http://scienceblogs.com/startswithabang/2012/09/23/weekend-diversion-yo…
Your comments on this thread are unwelcome henceforth, and if you cannot be anything other than a counterproductive participant peddling disinformation you will be banned from this blog.
This is your final warning to adhere to my comments policy.
The universe spinning about a preferred frame of reference is not peddling disinformation. However, it does refute the big bang.
The directionality of moving galaxy clusters is not peddling disinformation. However, it does refute the big bang.
A massive quasar cluster is not peddling disinformation. However, it does refute the big bang.
The way dwarf galaxies form is not peddling disinformation. However, it does refute the big bang.
bye bye
Not bye bye.
Good riddance.
de.Broglie.pilot.wave will not be commenting here any longer. Thank you to the community for your diligence.
If the Cosmological Principle is valid then what does an observer located in a galaxy 13 billion light years from our own "see"? Perhaps another galaxy 13 billion light years away/ago along the same line?
Einstein et. al. state that the velocity of light in vacuum is a constant, never to be exceeded. Later discoveries in Quantum Field Theory and experimentally confirmed by Casimir hold that there is no real complete vacuum, but rather that it has some density. What then is the index of refraction of the vacuum and might this account for the Hubble effect?
@Roy
"If the Cosmological Principle is valid then what does an observer located in a galaxy 13 billion light years from our own “see”? Perhaps another galaxy 13 billion light years away/ago along the same line? "
- according to the cosmological principle, yes. If the homogeneity assumption is correct. Even an observer 100 billion light years away, should see more or less the same galaxy distributions on large scales that we do. Not the same galaxies of course...
"... hold that there is no real complete vacuum, but rather that it has some density. What then is the index of refraction of the vacuum and might this account for the Hubble effect?"
- no, because QFT doesn't say vacuum has a density. It says that is has certain energy. It's not filled with matter like water or air are. And yes, it's theorized that some of that energy comes from virtual particle production. But those virtual particles "exist" at some plank times that we can't detect or observe. Hence the name "virtual" and not "real".
As for refraction index... well it's still 1. Beceause you are dividing speed of light in vacuum with speed of light in a medium (in this case again vacuum).. so you get 1.
But your question is sound. Vacuum does have some properties which are directly linked to "c". Check electric and magnetic permiability of vacuum. and you will see that vacuum itself puts a limit on c.
Hope this helps.
p.s.
in other words, speed of light is what it is, because of certain properties of vacuum. If those were different values then what is measured, c would have different value.
You could in theory argue that certain constants from classical physics are not constant and vary across the universe. But you would have to put up a really good reason and experimental proof.
Why is it so hard to consider the notion of God? Simply means there could be an answer for order that's beyond us.
@Sinisa
Thank you for responding.
It seems to me that the Cosmological Principle implies a universe that is infinite in extent. Does it also imply a Universe infinite in time?
I know that the nature of the vacuum is generally discussed with respect to its energy density but since this energy is commonly thought to be a product of virtual particles, rather than massless virtual photons, it implies a mass of the vacuum (e=mc^2). I also understand the by definition the index of refraction is 1 but functionally would it not affect either the wavelength of photons or perhaps their absolute velocity as a function of distance? Perhaps in a manner analogous to the spin flipping involved in the 21cm hydrogen line. Note that we cannot actually measure the terminal velocity of photons from a single measurement but only their energy.
Regards,
Roy
It neither implies a universe of infinite extent nor infinite in time.
@wow
I wrote "If the Cosmological Principle is valid then what does an observer located in a galaxy 13 billion light years from our own “see”? Perhaps another galaxy 13 billion light years away/ago along the same line?"
Extend the example. Iterate. That galaxy beyond the one we observe (the party of the third part) should also observe another galaxy another 13 billion light years away/ago. Und so weiter ad infinitum. There then arises the question of time - did that second galaxy exist 26 billion years ago? And the next 39 billion years ago?
Regards,
Roy
James Rearick,
Fine, let's consider God. However, keep in mind that we are talking SCIENCE here, so the rules of engagement are probably different than what you're accustomed to when you consider religious questions.
For instance, tell me what you would observe that would make you conclude that God has nothing to do with the universe. What observation or combination of observations would be totally inconsistent with the idea that "godddidit".
That's the essence of what it means for an idea to be scientific. If you can't falsify it, you can't test it. If you can't test it, it's not science. To the extent that religious people have put forward scientifically testable claims, science has considered these ideas. Be forwarned, however, should you decide to proceed with this notion; I can't recall ANY testable religious claim that actually has managed to successfully stand up to the rigors of scientific investigation. So far, all religious claims are either untestable (ie. God is omnipotent, he can do anything, so the universe was created just as it says in the Bible, but indistinguishable in appearance from an old universe that has developed according to scientific theory), or actually falsified. Maybe you can do better. Good luck.
Oh, and BTW, when you are talking about testable claims, you must provide EVIDENCE for them, and Biblical verse does NOT count as evidence. Only observation of the universe counts.
"There then arises the question of time – did that second galaxy exist 26 billion years ago? And the next 39 billion years ago?"
No.
That 13 billion light year old galaxy is not 13 billion light years from the centre of the universe.
@ Roy
"Extend the example. Iterate. That galaxy beyond the one we observe (the party of the third part) should also observe another galaxy another 13 billion light years away/ago. Und so weiter ad infinitum."
Yes the consequence of that simple induction is clear, but you have to look at your assumptions.
You're assuming that the universe is flat. Other geometries can be finite, but still have no 'boundary' so you can do the above induction, but eventually the 'next galaxy' seen will be the first one in your inductive chain.
Now as Ethan has written before, the universe appears really really flat, which means that if spherical it must be many times larger than the visible universe (I forget the order of magnitude). Which is fine. So it is not clearly implied that the universe is infinite in extent.
"There then arises the question of time – did that second galaxy exist 26 billion years ago?"
Here you're assuming that the distance/age relationship holds constant, which it doesn't in the presence of universal expansion (which was the first hint that the universe had a finite age). The farther away a galaxy is, the faster it is expanding away from us, and so the farther it appears relative to its age. So its quite possible for a galaxy 26 billion light years away being 13 billion years old.
These are good questions, btw! Just not new ones. Scientists have been pondering the universe and whether it is infinite or not for a long time (indeed, a static universe stretching infinitely back in time was one of the preferred theories prior to the CMBR putting the Big Bang theory in the lead).
@ Roy
"I know that the nature of the vacuum is generally discussed with respect to its energy density but since this energy is commonly thought to be a product of virtual particles, rather than massless virtual photons, it implies a mass of the vacuum (e=mc^2). "
It doesn't matter if it's photons or some other particle for this purpose. You have a common misconception, which is that the "m" is E=mc^2 is the same mass that is referred to when we say "photons are massless". It isn't.
Photons don't have REST or INTRINSIC mass -- this is the type of mass a particle has when it isn't moving. This is the m0 in the relativistic energy equation E^2 = (pc)^2 + (m0*c^2)^2. That "0" is significant. m0 != m.
"m" is the RELATIVISTIC mass, and as given by E=mc^2 is literally equivalent to the Energy of a system times a constant -- choose units where c = 1, and you have E=m. Relativistic mass is the kind of mass that is always proportional to energy. It's also the kind of mass that is relevant to gravity and inertia, and which you measuring with a scale. A proton has a much greater mass than just the rest mass of the quarks that comprise it. A molecule that is in a lower energy state than its constituent atoms weighs less than those atoms. If it's hotter, then its heavier, and so on.
This is all confusing because normally you think of "mass" as the thing matter has and which light does not, but also think of "mass" as the thing that you measure on a scale.
So when it is said that the vacuum has energy, this does indeed imply it has mass regardless of what form that energy takes. But it's the kind of mass that is the same as energy, so we just say "energy".
@CB
Thanks for responding.
I am familiar with non-Euclidean geometries. I did rather well in my academic studies of same. However, the only reason to posit that the universe as a whole is a closed geometry is that it is a necessary condition for big bang cosmology. Big bang cosmology hinges on one assumption - that the cosmic red shift is a Doppler effect. This assumption was based on the Michelson Morley experiment which was premised on the belief that light was a wave phenomenon, later shown by Einstein to be incorrect, and before Quantum Field Theory and the discovery of the 21cm hydrogen line.
I guess I'm back to questioning the basics because BB cosmology has come to resemble a Rube Goldberg machine, with ad hoc inventions such as inflation and undetectable substances the physics of which lie far outside our comprehension.
I apologize for being an old, curmudgeonly iconoclast. I attribute my current state to a wasted youth of revelry and debauchery. Maybe not wasted, after all.
Regards,
Roy
@ Roy
"the Michelson Morley experiment which was premised on the belief that light was a wave phenomenon"
The MM experiment was conceptualized in an environment where light was believed to be a wave phenomenon, but it is not premised upon it. As in removing that assumption does not invalidate the experiment and its results. The experimental setup is still a valid test of the frame-dependent velocity of light, and the results perfectly in line with Quantum Field Theory, because QFT is a relativistic theory as all modern theories in physics are.
It's not as though the MM experiment was never revisited after the development of Special Relativity and Quantum Electrodynamics. On the contrary, it and many other experiments have been performed that confirm those results and they are clear: The speed of light is constant in every inertial reference frame.
"I am familiar with non-Euclidean geometries. "
That just means it's even less excusable to make the unstated assumption that the universe is flat. I'm okay with you making it, but it's important to be clear that you've made them. Even if this was true:
"However, the only reason to posit that the universe as a whole is a closed geometry is that it is a necessary condition for big bang cosmology"
This is not true. The Big Bang theory actually makes no prediction on the shape of the universe -- closed, flat, and open are all possibly geometries in a Big Bang universe. However it DOES predict what the fluctuations in the microwave background should look like depending on the geometry. It wasn't until WMAP that we were able to compare and see that according to the BB the observable universe was very close to flat.
In an Inflationary universe, it is expected that the universe would be extremely close to flat, particularly on the scale of the observable universe, but it still is not required that it be exactly so. The universe MAY be infinite in extent. But we don't know that, we can't prove that, and saying that it is would just be an assumption.
"ad hoc inventions such as inflation"
Granted but what's wrong with that? Most theories are ad-hoc. It's very rare that you have something like Special Relativity where the entire theory is the direct consequence of three simple assumptions.
"undetectable substances the physics of which lie far outside our comprehension."
Referring to Dark Matter? Some would view the BB prediction on amounts of baryonic matter vs other forms of energy matching the amount needed to fit galactic and cluster rotation to be an argument FOR the theory.
@Roy,
Maybe part of your misunderstanding results from your misunderstanding of the cosmological red shift. It is NOT a doppler effect. It is a consequence of the fact that the space between us and distant objects is expanding. I'm not an expert in this field, but my best understanding of it is that since space stretches, the wavelength of the light travelling through that expanding space also gets larger, hence the redshift.
Also, BB cosmology is NOT ad hoc. Inflation is an addition that was proposed to explain the horizon problem and the flatness problem, which it does very well. It is not, ad hoc, however, as inflation does yield testable predictions independent of the phenomena is was devised to explain. For instance, certain inhomogenities in the cosmic microwave background are predicted based on the inflationary universe model. So far, so good, as far as testing these predictions.
Similarly, dark matter and dark energy both yield testable predictions, which have so far been shown to be consistent with what is observed. That's why they are accepted as part of our cosmological theories. Of course, who knows maybe in the future we'll find out that all these ideas were wrong. As of now, however, this is the best explanation of all the data.
If you believe otherwise, then you'll have to come up with a better one. A better explanation would, for starters, explain the existence, the power spectrum, and the inhomgenities in the CMB. It would have to explain the abundances of the light elements. It would have to explain why the universe is expanding. It would also have to make quantitative predictions on all of these things which are more accurate than the predictions of BB cosmology.
BTW, I was using ad hoc in the non-judgmental way meaning "for this", and it applies since inflation was added to BB specifically to fix the problems you mentioned. It's a good theory because it also makes testable predictions, but could still be called ad hoc. That's not how Roy was using it, but my goal was to de-fuse the negative connotation.
Oh and personally I'd be very impressed with a BB alternative that was simply able to explain the CMB and its temperature and magnitude. I recall reading about one such theory on this blog (the universe is filled with millimeter black holes) which succeeded in getting the temperature right but was many orders of magnitude off on the amplitude.
@CB,
I didn't see your post when I posted my reply to Roy. I guess we were writing at about the same time, or it was still in the queue. Anyway, I am not a physicist, but I have done some study of philosophy of science. My understanding of what constitutes an ad hoc hypothesis is that it is an addition to an accepted theory that is made SOLELY to make that theory agree with a new observation that would otherwise falsify that theory or at least result in the theorey's prediction becoming inaccurate quantitatively.
For instance, Ptolomaic astronomy, with its geocentric focus and circular orbits, was a perfectly scientific theory. It certainly made testable predictions, namely the positions of the planets. However, the retrograde motions of the outer planets were completely at odds with Ptolomaic astronomy. Adding epicycles to the simple circular orbits solved the problem of retrograde motion. Further epicycles were added to make predictions of planetary positions more accurate. However, these were an ad hoc addition to the theory. Nothing within the theory suggested that such epicycles would exist. There was no observable phenomenon that could be used to test the idea of the epicycles.
Contrast that to inflation, for instance. There was a mechanism proposed to explain inflation. Inflation also yielded testable prediction OUTISIDE of the phenomena it was invoked to explain (Horizon and flatness problems). In essence, it actually was a new hypothesis, not an ad hoc addition to the original theory. Inflation is much more speculative than big bang cosmology, but that doesn't mean it's an ad hoc addition.
I'm ignorant of any scientific definition or typical usage for "ad hoc". If it's as you say, then absolutely it does not apply to inflation.
If you believe otherwise, then you’ll have to come up with a better one. A better explanation would, for starters, explain the existence, the power spectrum, and the inhomgenities in the CMB. It would have to explain the abundances of the light elements. It would have to explain why the universe is expanding. It would also have to make quantitative predictions on all of these things which are more accurate than the predictions of BB cosmology."
The universe is, or the local universe we exist in is in, a jet; a larger version of a black hole polar jet.
@universal jet,
Fine. Now show me the detailed calculations based on that idea that determine how much deuterium, beryllium, lithium, hydrogen and helium should be present in distant stars. Why, based on that idea does the CMB exist and why does it have the spectrum it has, and why are its inhomogenities the way that are observed? Why is the Hubble parameter observed to be what it is? What prediction would your theory make for this parameter? Why is the temperature of the CMB higher for more distant celestial objects, and what is the dependence of the CMB temperature on distance. I want calculations, not assertions. If you can't give them, then your idea doesn't deserve serious consideration.
There isn't really a scientific usage for "ad hoc". It's not a scientific term. However, it does have a negative connotation. It really should only be so regarded if it's used in the sense that I've outlined above, namely an idea that has no justification other than to save a pet theory. If it's an idea that was added to a theory, yields new testable predictions and those predictions are shown to be true (such as inflation), then obviously, the negative connotation should go away, and IMO the term "ad hoc" really should not apply any more. If "ad hoc" is used in other senses, then the negative connotation of that term really should not apply.
Ethan, the ban doesn't seem to be sticking.
Sean T: Partly it's because I work in a field where "ad hoc" is not looked down upon, and partly because I'm a big fan of context and dissuading people of the notion that connotations are the same as definitions, but in any event I think "ad hoc" should be a fine name for a theory built to answer certain specific problems. The word for a theory built this way that doesn't make any testable predictions shouldn't be "ad hoc" but rather "shitty theory". Or maybe, if I may coin a term, "Epicyclean"
On another topic -- your demand to see actual detailed predictions born out by actual data instead of just accepting the argument-by-analogy as true and existing detailed-data-backed theory as false just means that your religion won't allow you to acknowledge reality. Obviously. Like, duh.
P.S. If there was a jet, we wouldn't see objects receding from us as quickly in the direction the jet is coming from. We see objects receding at equivalent distant-proportional rates in all directions. Ergo...
Yeah... universal jet is same person as pilot wave
Guess he doeasn't have a permanent IP, so filter can't work.
"All of the evidence is evidence we are in a larger version of a black hole polar jet. This evidence exists whether your religion allows you to understand it or not."
Heh. broglie seems to start out 'well' in his posts, then ends up with absurd assertions like this. Here's a model broglie post:
"- Link to some new science suggesting we may need minor refinements to the BB model
- Another link to some new science suggesting we may need minor refinements to the BB model
- Another link to some new science suggesting we may need minor refinements to the BB model
THEREFORE, the entire BB model should is bunkum and this is all PROOF of some nonsensical alternative, yours truly Broglie"
If we're in a 'black hole polar jet', surely things wouldn't be expanding away from us in all directions. At least entertain something slightly more plausible, like the 'cosmic void' alternative.
The new science is interesting, and it may eventually lead to either refinements of the BB model or even some radically different model .. but currently, BB fits the evidence we have very well, and nothing else fits better. It's fine and well to conjecture up dramatic alternatives, but then they need to fit the evidence, and nobody can claim evidence that is not in existence at this point in our history.
For me the more interesting part of this article is the Hawking quote .. the current lack of interest in science and space is beyond incomprehensible. I think part of the problem is that we've lost leaders like Carl Sagan, who could inspire the imagination and curiosity of Joe Public in an optimistic way.
The other interesting question to me when looking at "where are" in context, is "where do we go from here". We've had a couple hundred thousand years as 'modern humans' alone - just think how much we could achieve still in another couple hundred thousand years - could we colonize a bunch of neighboring stars if we're just patient and positive and focus our efforts? I think so. We've had at least a couple million years as 'tool-using' 'humans'. How much could we achieve in another two million years?
I think in the long-term we must. Natural selection acts on a cosmic scale too, as the dinosaurs discovered ... if we just sit around, we're ultimately consigning our evolutionary fate to be the same as the dinosaurs. Natural selection must eventually select for space-faring species.
"Extend the example. Iterate. That galaxy beyond the one we observe (the party of the third part) should also observe another galaxy another 13 billion light years away/ago. Und so weiter ad infinitum. There then arises the question of time – did that second galaxy exist 26 billion years ago? And the next 39 billion years ago?"
Roy, you're missing something, and it's the following. When we say we observe a galaxy that is 13 billion years old, what we mean is that we are seeing the light that was emitted from that galaxy 13 billion years ago -- waaaaay back, when the universe was much younger. So if there were alien life forms on those galaxies 13 billion years ago, then what we would now be seeing them "seeing" (ie what those ancient observers would be seeing) would be A VERY YOUNG UNIVERSE.
BUT, in the meantime, during that 13 billion years that the light we are NOW seeing was pottering its way across the observable universe toward us, another 13 billion years HAS PASSED on that galaxy - in other words, that galaxy TODAY looks COMPLETELY different, and has completely different generations of observing alien life on it. Everyone on it 13 billion years ago (the ones who long ago saw the VERY YOUNG universe) have long since died out.
(We cannot see these new observers of today in those other faraway galaxies, because their light is only being emitted today, by the time it reaches us we'll all be long dead as it will be billions of years in our future.)
The observers TODAY in the other far-off galaxy see a 'new universe' close to them, but a 13 billion year old universe far away from them. I.e. if they looked our way, they would now be seeing our Milky Way galaxy as it looked 13 billion years ago.
@Roy Lofquist "did that second galaxy exist 26 billion years ago? And the next 39 billion years ago"
I've created a diagram to try help visualize this:
http://postimage.org/image/b3wamgvrj/full/
What you need to keep in mind is that on these scales, light moves incredibly slowly. Those orange/red light beams in the diagrams were emitted way back when those galaxies were very young, and very slowly plodded its way along, taking 13 billion years to arrive at us. The observers in the "old" galaxy that we NOW see, would ONLY see an extremely young universe, while any observers alive today in galaxies now much older would just see something similar to what we see.
"Inflation" is not an "invention", it's an observation - mainly, that the further a galaxy is, the more red-shifted its light.
Apologies, I've corrected a mistake/ambiguity in the diagram, here's a new one: http://postimage.org/image/w2jz06hlj/full/
Ethan, how much of the first 3 steps is known? Last I heard, inflation was fairly speculative and we only know the state of the Universe with a high degree of certainty from something like a picosecond after the Big Bang. Do we know that the Big Bang was the result of inflation from a quantum fluctuation with the same degree of certainty (and I'm aware there's always some uncertainty in science) as we know, say, Big Bang nucleosynthesis or the age of the Earth?
"Do we know that the Big Bang was the result of inflation from a quantum fluctuation with the same degree of certainty "
The short answer to that is "no".
However, inflation we DO have strong evidence for. There are older threads on here about "How we need Dark Matter" which will get you some of these requests.
Use the "Search This Blog" and have a look at the results.
Great article!
I think it is really interesting how the basic structures that created something as big as our universe also create the basic structures we use in daily life. Examples being. protons, electrons, neutrons, and gases. Obviously, the has changed greatly since the beginning of its creation, such as structures such as stars bursting and planets getting farther apart. It would be interesting to see predictions on what might happen years down the road from now.