How Can We See Galaxies 47 Billion Light Years Away When the Universe is Only 13 Billion Years Old?
This is my second post in the Just Science Week Challenge.
This 2003 paper in Physical Review Letters puts a lower limit on the size of the universe at no smaller than 46.5 billion light years in radius. If the universe is geometrically flat, that is.
In this video I made on the Hubble Deep Field, I mentioned this number and was immediately inundated with questions and comments from people screaming that that number could not possibly be correct. How can the universe be that big if the fastest anything can travel is the speed of light? The universe simply CAN’T be larger than the distance light travels during age of the universe, right?
Wrong.
It is true that the universe is 13.5 billion years old, and it is also true that nothing can travel faster than the speed of light. But it does NOT follow that the size of the universe is simply the distance light traveled in 13.5 billion years. You can’t stop there. Why?
Because the universe is expanding, and has been for 13.5 billion years.
Remember yesterday’s post? Everything in the entire universe is flying away from each other at a rate linearly proportional to its distance. That’s Hubble’s Law. The distance that light has to travel over time is continuously getting bigger and you MUST take that into account.
Technorati Tags: cosmology
Remember in my last post, we’ve established that the universe is expanding at roughly the Hubble Constant, and that number is a function of time. It matters WHEN you take your measurement of the redshifts of far away galaxies. Right now, the universe is expanding at about 71 km/sec/Mpc and is accelerating.
A somewhat simpler way to think of the expansion rate of the universe is that it expands at roughly the age of the universe to the 2/3 power: AgeOfUniverse^(2/3). Unfortunately, it’s not simply a plug and chug formula, since the expansion is occurring continuously, you need to apply some calculus. Here’s the formula, but I’ll go through a simple example a little later:
Illustration Credit: Ned Wright
The above integral just takes the ratio of elapsed expansion time to the age of the universe raises it to the 2/3 power and does this over the entire time the expansion is occurring.
What all of this means is that whenever you discuss the size of the universe, you need to apply a scale factor that is relevant TO THE TIME you are interested in. The issue of when is very important because the size of the universe, and the rate at which it was expanding has changed since the universe began.
So, for RIGHT NOW, the size of the universe has expanded to roughly 46.5 billion light years since the Big Bang.
Let’s break down the above integral into some smaller intervals and watch what happens. Let’s use 13 billion years as the age of the universe and let the universe expand for an average of five billion years at three different points in time: 2, 7, and 12 billion years after the Big Bang:
- At age of universe = 2 billion light years: the universe has expanded by a factor of (13/2)^2/3 = 3.48
- At age of universe = 7 billion light years: the universe has expanded by a factor of (13/7)^2/3 = 1.51
- At age of universe = 12 billion light years: the universe has expanded by a factor of (13/12)^2/3 = 1.08
So combining these scale factors over the two intervals above, the universe has expanded to a size of:
(average distance light travels over interval of interest) * (sum of all scale factors).
Plugging in the numbers (we used an elapsed time interval of 5 billion years):
(5 billion light years) * (3.48+1.51+1.08) = 30.37 billion light years.
The 5 billion light year number above is the average distance light traveled in 5 billion years so the units are in light years.
Now, this is a discreet example, taking only three points in time, but already we have a number bigger than 13 billion light years. Since the universe is expanding continuously, we actually need to do the integral above and when you do that, the answer approaches 47 or so billion light years.
Actually, this is a little misleading, the number cited in the above paper does a different analysis and I’m doing something a little different that what the authors of that paper did, so I’m trying to make a number fit that was derived using different techniques in my example above and it won’t work out that way. Still, the end results are similar and nothing is really lost by doing that.
But, ignoring the details for a minute, what I’m really trying to do here is show that the size of the universe isn’t simply the light travel time over the age of the universe. The expansion of the universe requires that you apply a scale factor as outlined above.
If the math is confusing you, just remember this: that scale factor is important. It accounts for the distance the universe has expanded over the time period you’re interested in. It doesn’t go far enough to say that the size of the universe is simply the distance light travels over the course of the age of the universe. Since the creation of time, everything has gotten farther apart, remember Hubble’s Law: everything is speeding away from everything else, all the time.
So, when the Hubble telescope took the deep field images, it provided us with the deepest views we’ve ever seen into the universe. Those galaxies were approaching the farthest edges of our cosmic home, and they weren’t 13.5 billion light years away, they were much, much farther.
UPDATE: Here’s a good graph I found on Universe-Review.ca, they have kindly given permission for me to post this.
Illustration Credit: Universe-Review.ca
The point that tony has made is correct but the question “How Can We See Galaxies 47 Billion Light Years Away When the Universe is Only 13 Billion Years Old?” is incorrect. Because we cannot see galaxies 47 billion light years away. but we can see what a galaxy that at this very moment is 47 billion light years old looked like when it 13.7 billion light years ago.
Two Galaxies Us and our FriendGalaxy which is 13.7 billion light years away are traveling away from each other increasing speed constantly. Our FriendGalaxy takes a picture of himself and sends it to us in a photonEMAIL which can only travel the speed of light. We Receive our FriendGalaxies email 13.7 billion years later. we have continued to move apart. meaning when we received the email not only has 13.7 billion light years passed we have also moved even further away making the distance between us and our friendgalaxy 47 billion light years away. So we can see what our friend looked like when he was 13.7 billion light years away. but we will never be able to see what he looks like now or any time after 13.7 billion years ago. Hopefully i did not make that more complicated than i originally had it in my head.
and correct me if i’m wrong.
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While it is correct that the photons arriving were produced NO LONGER than 13 billion years ago–however–photons don’t age or have rest mass–we will ALWAYS be able to see that galaxy AND what it looks like “now” EVENTUALLY!!! It is simply impossible for us to “have seen it” and be CONSTANTLY RECEIVING PHOTONS at some PRIOR TIME and then suddenly STOP SEEING THE PHOTONS.
We will simply be able to see what that location looks like NOW (there) in 47 billion years!!!! (at which time it will be, what, at least 94 billion light years away, more likely 200 billion light years away!!!)
It will NEVER DISAPPEAR!!!–unless quantimechanically the solid angle of the source becomes so small that we only see as a packetized source which begins to “flicker”–but that is still DATA about its then/was configuration.
Stop thinking about space as three space and start thinking about the 3 space we see as the surface of an expanding sphere with dark matter being converted into the sphere (space itself) and dark energy proving the energy to expand the sphere–making things blow apart–because they are in the same place in space AND SPACE IS EXPANDING BETWEEN THEM–they are not moving through space–except to the extent that they are governed by the forces we can measure interacting among each other within the space that exists.
Mark,
It would appear that you are saying that although light itself moves at 300,000 km/sec, the expansion of space itself makes the actual distance become the 40+ billion light years and the light, which would have normally travelled some 13 billion light years has appeared to travel the 40+ billion light years in the same time (the 13+ billion light years).
It isn’t that light has picked up speed, but that space itself has expanded which puts an additional “kick” into the speed of light.
This, of course, would not be reflected in a Doppler red shift as the space that light is in makes the wavelengths still the same as they would have been if space did not expand.
This is almost as bad as the the stimulus package which is expanding faster than the speed of light.
We hope President Obama has a way of slowing it down.
DO I HAVE THIS RIGHT?
Steve Garramone,
Melbourne FL
It is the expansion of space that causes the doppler shift. It doesn’t matter to us if the light source is moving away from us or if the space between us is stretched, there is still a doppler shift.
The only way I could think of this is to think of THREE space as actually being the same as TWO space on a sphere. Consider that the big bang was a point and that the explosion burst the point OUTWARDS. There is NOTHING at the center–JUST THE SURFACE. And it is expanding because the “energy” (dark energy) of the explosion is not depleted. That is the only construct I can come up with that provides for the “energy” to have all objects moving away from each other at increasing speeds!!! The “dark matter” is just like the surface of the sphere expanding being CONVERTED into space. It affects light because it is SPACE–just crunched up–not fully stretched space.
The “sphere” metaphor is also good in that the expansion is from the edges. Multiply Pi times 13 billion and you get nearly 46 billion–add the “inflation” and you can get there. There is a lot more complicated mathematics that I don’t understand, but how else can stuff be further away than there is time for if it all started from the same spot?
I hypothesize that there will be no NATURAL interaction between dark matter and ordinary matter because dark matter is being converted into SPACE and has the characteristics of “lumpy” space which disrupts light. As the dark energy wears down it will stretch the lumpy dark matter into smooth ordinary space until there will be nothing left other than the regular matter far away from itself in a smooth energy less/dark energy less space.
You will ALWAYS see anything YOU CAN SEE–AND WE CAN SEE THE ENTIRE UNIVERSE (from the original big bang) because at ONE TIME IT WAS CLOSE ENOUGH TO SEE–zero distance or certainly less than 13 billion light years. Since we DID SEE THEM–and they cannot be moving away faster than LIGHT–WE WILL ALWAYS SEE THEM–just getting dimmer and red shifted away and with a big time delay.
The “seeable” universe is also a falacy because there would be an expanding zone of new seeable stuff as the “seeable” event horizon would be expanding and MORE NEW STUFF would be seen which is not the case.
Imagine the sphere analogy that says you look in any direction to infinity–around the sphere to the other side.
No illegally topologically change the sphere into a flat surface with infinite edges from your perspective–but everyone has the same perspective. Hence everyone sees the universe expanding AWAY from them when it is all connected.
The disappearing universe is a contradiction. Consider I DID SEE YOU. You cannot be moving away from me faster than the speed of light. Hence I will always be able to see you! qed/wzbw Also it follows: We can SEE THE ENTIRE UNIVERSE NOW!!! The far stuff is just getting hard to see and the information is becoming very dated.
On the Obama stimulus package. Just keep in mind one thing: It is the WORK that makes the money strong, not the money that makes work strong. What would your savings or anyone’s for that matter be if we all stopped working tomorrow!? The stimulus package needs to CREATE something of VALUE that can be used to reduce future costs or improve future productivity.
Perhaps the auto workers should GO BACK TO WORK and produce really INEXPENSIVE CARS! Or we should build 50 nuclear plants–if the operating costs/not capital costs are LOWER than producing electricity from coal. Or we could build 5,000 windmills if the operating costs were less than coal!
But as an economist, IT MUST BE THAT even the operating costs of wind power cannot compete with the fully loaded cost of fossil fuels–so dig and drill we do.
The roads and infrastructure of the post war provided for MASSIVE efficiency in goods movement along with CHEAP gasoline. Add to this the benefit of running water and air conditioning to make the southwest habitable AND diesel fued used in farming and you have the economic drivers of the last half of last century.
Women in the work force and computers drove the 80-2000 boom. Thinking everyone was productive and creditworthy caused the financial boom of 90-2008.
Fundamentally, what Obama faces is a means to be sure that the entire population is PRODUCTIVE because it is THEIR WORK that makes the economy strong.
As a physicist, in the auto industry: if wages are the problem for costs in the industry–why would you pay people 80% of their pay NOT TO WORK for two days. Shouldn’t we take all of the auto workers that are being paid AND PUT THEM TO WORK DOING WHAT THEY DO BEST–making cars! Doesn’t having them work FIVE DAYS while paying them FOR ONLY ONE MORE provide lots of productivity!
And the assets in your bank are only as good as the promise to pay (ability to pay and to be productive) of the person borrowing the money. Think of it–when someone “stretches” to buy a house they are actually committing to give 20-30% of their income for 30 years. All of that future value has been converted into an asset we consider as liquid as CASH. (Which of course is only the governments promise to pay you–tomorrow–and your ability to make someone else accept that promise for their work today!) [Of note: did Popeye ever give Whimpy a hamburger today?]
Mark -
I was tongue-in-cheek about the recovery stimulus… I just thought that it was interesting about the similarity in numbers between the National Debt and the age of the universe…
I still cannot wrap brain around this 40+ vs 13+ billion years…
Is the universe 13+ billion years old or 40+ billion years old.
If it is 13+ billion years old but 40+ billion light years in radius from us then light must have travelled at 3 times the 300,000 km/sec or some 600,000 km/sec in order for us to see that far.
OR
Because the universe is expanding so fast that relative to us time slows down (time dilation) and in its own framework the light it ihas travelled for only 13+ years while in our framework that is 40+ billion years
OR
length contraction - same relative reasoning. 40+ billion light years in its own framework is equivalent to 13+ billion light years in our reference.
Thus, we “think” time has existed for some 13+ billion years but in reality, it has existed for at least 40+ billion light years. By your reasoning, it could be virtually limitless as the faster one goes, the more length contracts or time expands so there is no limit as the denominator
sqrt [(c^2 - v^2)/c^2] approaches zero.
(Lorentz Transformations)
That Lorentz guy and the others who worked with him or before him (he was not alone) were bloody geniuses.
Pretty soon our National Debt will exceed any conceivable Lorentz calculated figure, so maybe he wasn’t such a genius after all.
Maybe I am a simpleton
no one knows how old the universe is haha i think its funny how you all think you know so much when really you know nothing at all.
Tony, please help me understand this correctly. I say something, and you tell me if it makes sense.
Are you saying that the universe is bigger *now* than how far the light traveled from the furthest images we can *now* see?
In other words, yes, the light from the deepest part of space that we *now* see took 13.5 billion years to get to us, but because whatever made that light has since moved away from us (Hubble acceleration), those deep space objects are now in excess of 47 billion light years away?
If I give you an example using the principle I am talking about, maybe it will be easier to criticize what I am saying.
Imagine two rocketships traveling in space, one following the other at a current distance of 1 light year. Imagine that the rocketship in front is traveling at 1.5 times faster than the second rocketship. The distance between the two will increase over time naturally. We can treat these two rocketships as stars or galaxies or whatever.
Now imagine that the rocketship in front points a laser beam back towards the second rocket ship. After one year, the laser will reach the second rocketship and the astronauts onboard will observe the light. Of course they will say aha, that laser must have started *at least* 1 year ago, because the second ship astronauts didn’t see it before (imagine they can see light more than 1 light year ahead using their onboard telescope).
However, during the last year, when the laser light was traveling, the first rocketship has since traveled away from the second rocketship at 1.5 times the original distance, the astronauts in the second rocketship are observing light from something that *now* exists much further away than 1 light year.
If we proxy the two rocketships as marking the extremities of the universe, then the example generalizes to mean that the light that we think is coming from objects 13.5 billion years away actually came from objects that are *now* much further away because they have accelerated away from us since they shone the light that we now see!
Am I getting this right?
This is a terrific post. Your description plus the links answered so many questions that I have.
I guess I’m wondering one thing, though. I did a search on what the most distant galaxies we’ve seen are. What I found was A1689-zD1 (http://blogs.discovermagazine.com/badastronomy/2008/02/12/hubble-and-spitzer-find-most-distant-galaxy/) which was viewed by Hubble and Spitzer. But that one is only something like 12 billion light years away and the various articles say it formed just after the “Dark Ages” of the galaxy. So is it correct to say that even though we could theoretically see a galaxy that’s 47 billion light years away, we never will? If a galaxy that is just 12 billion light years away was formed at the beginning of the universe, how could we ever see a galaxy that is farther away? I can’t quite articulate my question, but how do we know that A1689-zD1 is at the beginning of the universe if we could theoretically see something that’s much farther? Sorry for the clumsy question and again, thanks for the post!
correction: I said that A1689-zD1 formed just after the “Dark Ages” of the galaxy. I meant the “Dark Ages” of the universe.
Uh, doesn’t this then violate the principle that nothing can travel faster than light. If the universe is 16.8 billion years old, but it was the size of a pin head before the big bang, but since then (it’s birth) it has spread out to a size of 47 billion light years, isn’t the universe expanding at a rate faster than light travels? Hence moving at a rate faster than light travels?
So I’m interpreting this as the distance from the point where the photon originated might be X light years from us, but because of the expansion, the actual thing we’re observing is now further than that.
So when you say that we’re “observing” something further than 13.5 billion light years, you really mean we’re receiving photons that originated closer than that, but those photons were emitted by and thus represent objects that are now further than that.
Is this an accurate take-away, or is the issue actually more subtle?
Did anyone ever see the “Powers of 10” video where everything microscopic eerily resembles everything astronomic? (http://www.youtube.com/watch?v=A2cmlhfdxuY)
Sorry to crush everyone’s dreams but the big bang was nothing more than a spark plug ignition in someone’s engine, our perceived universe is contained inside one of the engine’s cylinder and the human race is nothing more than parasites on one of the billions of atoms that could be either exhaust or unburnt fuel. What if? What if our perception of our universe is nothing like we try to imagine?
My head hurts thinking about how meaningless we are compared to the scale of “our universe”…
My head is o the verge of exploding when I think about the possibility that we are in someone’s Formula 1 engine that revs at 20,000 RPM, the equivalent of 5,000 big bangs in one minute or 83 big bangs in one second when we are currently living through only one of those big bangs.
I better stop and go to sleep before I cause my self an aneurysm.
tim
Sep 15, 2008 at 3:46 pm
what a dumb page. the answer to the original question is simple… the question is meaningless.
the idiot who asks the question thinks that light ‘years’ are measurements of time instead of disance. the question is fallacious.. exactly like… ‘how can london be 200 miles from liverpool when it’s only 3 hours since i had breakfast’
Oh, yes, Tim got it right that the question itself is meaningless at all.
“At age of universe = 2 billion light years:”
You cannot measure the age in light years!!!!!! Fix this please!!!
This is a hilarious question indeed. Are you trying to confuse people or yourself? You are comparing time with distance? The question is basically similar to this one: how can 3 kilometers larger than 2 hours? How do you answer this question? Isn’t this hilarious?
Let’s not get insulting to each other by denigrating or poo-pooing anything anyone says. After all, none of us were around when this all started.
I have been taught the the unversal constant in the ubiverse is the speed of light, some 300,000 km/sec. One cannot add a linear velocity onto another linear velocity and come up with a final speed greater than c (or 300,000 km/sec). Thus, on the x-axis, and object or frame of reference (call it “A”) travelling to the right at, say 200,000 km/sec relative to the origin, then a second object (call it “B”) travelling to the right with respect to “A” is NOT travelling at 400,000 km/sec with respect to the origin. There is some formula somewhere that tells what it is (obviousy from the Lorentz equations of 1903-4.) But this is beyond my paygrade to know what that is.
So, someone, please help us out. If you answer that question, this mystery will unfold.
The applicable Lorentz transformation is on page 34 “Relativity,” by Albert Einstein (translated from German) but I cannot make heads or tails of it.
Addendum:
That sentence should read, “Thus, on the x-axis, an object or frame of reference (call it “A”) travelling to the right at, say 200,000 km/sec relative to the origin, then a second object (call it “B”) travelling to the right with respect to “A” at 200,000 km/sec is NOT travelling at 400,000 km/sec with respect to the origin.”
USE THE SPHERE ANALOGY. The surface is expanding because the “sphere” is being blown out from the center. Our “universe” is the surface of the sphere (or more complicated conic). It is “expanding” and further points are expanding away faster as the sphere expands the points on the sphere are moving away. We are all 47 billion light years from the furthest point AND THERE IS NO EDGE OR END–just like no edge of a sphere. The energy “expanding” the universe could be the dark energy with the dark matter becoming space–surface of the sphere. It will eventually slow down when the dark energy is dissapated and dark matter has been converted into space. But as long as the sphere is GROWING the universe is expanding and the objects are moving away from themselves faster than they were yesterday.
The time / size question is relevant in that the Big Bang BOUNDS the problem with space and time equal ZERO at big bang. So how does something get to be further away than light and time allow.
Force and energy expanding universe are not acting in THREE SPACE.
Regarding Stephen Garramone’s Addendum:
Why not? Because of Einstein’s Relativity theory that says nothing can travel faster than light?
If the two objects where going in opposite directions, relative to each other, A and B would be traveling at the sum of their speed: 400,000 km/sec, but from the origin they would be appearing to be traveling at 200,000 km/sec in opposite directions. From m understanding, this is the basis of this article, if the universe is 13 billions years old and matter was still traveling at the speed of light since the big bang, from opposite end of the universe we would appear to be 26 billion light years away. It’s the 47 billions number I don’t get…
To Rafman -
Not according to Lorentz. Using his transformation the two objects, travelling in opposite directions at 200,000 km/sec would NOT be travelling away from each other at 400,000 km/sec.
I still cannot wrap my brain around it and I don’t know how to plug numbers into his formula.
Anyone… HELP!
Steve G
Just quickly, to all the people saying it’s a stupid question, you’ve got to think about what it means.
For someone like me, who isn’t “stupid” about this issue, the speed limit of stuff is “c”. A light year is 1year*c. In one year, at speed c, you go a light year of distance at max speed. So, in 13 billion years, stuff can only go 13 billion light-years of distance. So, the universe must be a sphere with radius 13 billion light-years, so stuff must be at max 26 billion light-years away.
This is what the average Joe would know, and one would not be stupid for thinking this, okay? This makes the most obvious sense.
Now I know now that it’s actually a lot more complicated - what with expanding space and RELATIVE speed limit of c (something about “relative to local space”, and Lorentz?). Also, that’s just “how can stuff be 47billion light-years away…?”. ‘Seeing’ these galaxies is more complicated, because are we seeing them as they are now? as they were in the past, and when? how far were they then? how far are they now? does the expanding of the universe help or impede light’s journey from them? what do you mean expanding universe - what does it mean to “add space”? etc.
That is what this article should explain - going into expansion factors and whatnot is all good and well once you’ve settled the more basic confusions for most people - and definitely a lot of the people (including me) posting here.
Further elucidation on Lorentz.
The relative speed of the two spaceships, each travelling at 200,000 km/sec in opposite directions (i.e., the speed of separation) is
(200,000 x 200,000)/[1 + (200,000x 200,000)/(300,000x 300,000)] = 276,923 km/sec which is less than 300,000 km/sec (the speed of light.) In fact, the maximum possible velocity of separation would be 300,000 km/sec.
So, from the Earth’s perspective, 13×10^9 lightyears which would take light 13×10^9 years to travel represents only 13X10^9 light years across from one of the universe end to the other with the earth in the middle and it would still be 13×10^9 lightyears from the Earth to either end.
I don’t know how to say this but. to put it in the colloquial,
This is weird shit!
No such thing as a stupid question but this is still weird, to me. My brain is too limited.
I like topics like these, it pushes our minds to the extreme.
There is something here that does not compute: either the age of the universe is much older or the galaxies that we think are 47 Billion light year away are much closer (some kind of distortion in between is causing the discrepancies perhaps?).
If the age of the universe is 13 Billion light years and let us say it was expanding at the constant speed of light (which is not) then similar to the example of my previous post where if the two objects where going in opposite directions at 300,000 km/sec, relative to each other, A and B would be traveling at the sum of their speed: 600,000 km/sec (forget Lorentz for a moment); however they would never be able to see each other while traveling at that speed because the sum is greater than the speed of light; my point is if the universe is 13 billions years old and matter was still traveling at the maximum velocity, the speed of light since the big bang, from opposite end A and B would appear to be 26 billion light years away (although they would not be able to see each other).
Also if the rate of expansion of the universe is currently increasing, it should never surpass the speed of light according to Einstein’s theory; there is no way we should be able to see galaxies as far as we think they are while the universe is smaller than the straight line distance between us and the this particular galaxy, so either the age of the universe is much older or the galaxies that we think are 47 Billion light year away are much closer.
I am going to sleep, good night.
To The Rafman -
See… it wore you out, too. Lorentz et al are conjectures but so far these hypotheses have been borne out by what limited experimental evidence we have. The slowing of time at high speeds using atomic clocks on GPS satellites, for example.
Is it conceivable that we can have three points in space (L, C, R) and all be equidistant apart and yet opposite from the central point (C)? Yes - on a sphere. In this case CL = CR = LR. BUT, to get from L to R under this paradigm one does not have to go through C, that there is a more direct route across the two dimensions which bypasses C (the common starting point.) This involves going out of the two dimensions into a third dimension, where C does not exist and going directly.
To analogize, in three dimensions, this could be possible that we jump across of fourth dimension to achive the same thing. Take a hypothetical beginning point in 3D whhere space “explodes” as is postulated by the Big Bang and imagine 3 objects traveling out from the center but remaining equidistant apart and with the center -that’s a tetrahedron with the sphere circumventing all four points (the three new points plus the center. Each point can access the other three without going through a common central point yet everything be equidistant apart. That would require a four dimensional “sphere” x^2 + y^2 + z^2 + w^2 = r^2. Lorentz thinks that “w” is time and there are a multitude of equations bringing time into play which imply such a fourth dimensional universe. Yet, we can travel back and fourth against three dimensions but not time, so what gives?
Again, this is beyond my pay grade and I agree with The The Rafman - it is time to “go to bed.”
So as Edward R. Murrow use to say, “Good Night and Good Luck.”
Stephen,
Just because we don’t know how to travel back and forth in time it does not necessarily mean it is not possible, after all we don’t want to be like the ones that claimed that the earth is flat and at the center of the universe.
You make a very good point that we seem to forget rather quickly: ”Lorentz et al are conjectures but so far these hypotheses have been borne out by what limited experimental evidence we have.” … and that includes Mr. Einstein, bless his soul.
No argument…
Einstein sure was a genius with his application of the Lorentz equations and General Relativity proven in May 1919 or was it 1923 (with the total eclipse of the sun and the changing of position of stars behind the sun?)
I don’t think the world is flat… my brain may be, but not the world.
Looks like the universe is 39 billion light years around. Why?, Because it takes 13 billion light years to reach the furthest point, so far, and by Lorentz, if he and Einstein were right, is 13 billion light years from a point on the opposite side - making a perfect circle with the three points being equidistant from each other all 13 billion light years away from each other.
What a concept…
Brand New newcomer:
for some reason this question has been bugging me. am very uneducated in this area, but,
is there any information about the universe ever having slowed down in the past(?) and re-started?
in any explosion there are several phases:why could not the ‘big bang’ have the same pattern?
hope I don’t sound goofy.
Look I am as thick as they come, but how the heck do we come to a figure of 13.7 billion years old for the Universe. It seems to me that everything and I mean everything is either round or formed from round elements and even the elements are formed from round atoms and even the atoms are formed from round, do you get the picture? So if everything is round and the Universe is expanding at an ever increasing rate all you can see to get the 13.7 billion lifespan is a linear observation or have we learned a way to go back 13.7 billion years and then bend time so as to observe around the horizon? It just doesn’t make sense! Clever these scientists unfortunately I think outside the box and do not accept conventional mathematics.
The problem with trying to explain this stuff to Americans is first getting them to understand that they are not the center of the universe!