Pints all around!
Here is an explanatory pic.
A team of astrophysicists has announced a sighting of gravitational waves – formed in the first trillionth of a trillionth of a trillionth of a second after the universe as we know it blinked into existence. The breakthrough discovery throws enormous weight behind the famous inflationary Big Bang theory. The boffins must be …
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"Barraco Barner" Hate to own up, but back in 2007, on the first few times I heard his name on the radio (before I saw it written down) I thought the man running for president against John McCain was called Barry Cobalmer. And I can still never be quite sure whether it's McCain or McClane who was in a Die Hard movies.
I thought this was an observation of distant possible effects that very closely match theoretical predictions - not a true "detection" as such. The detection would be made (if ever) by those very long interferometers with laser beams at right angles to each other, where the compression of space by a passing gravitational wave would be 'detected'?
True but - GRAVITY WAVES IN SPAAAAAAACE would!
Anyway, why is everybody just talking about the Big Bang this is about Inflation after the BB.
The skewed polarization of the CMB by gravity waves is a prediction from one of the Inflation Hypothesis models. The observation matches that prediction and thus is a 'smoking gun' for both inflation and gravity waves.
Another box ticked for Relativity, wasn't Einstein a clever chap.
Yep this would seem to be more indirect evidence of gravity waves (which we have plenty) but I guess measuring a change in the CMB is as good as measuring a change in matter to some. Also it is largely confirming the Big Bang which is pretty much been accepted for quite some time now. Its good to make it official and to add more evidence but a breakthrough (except perhaps for the neat measuring technology) is a bridge too far imho.
That's right. Until now, gravitational waves have only been inferred by observing the motion of binary systems (a bit like watching boats bobbing up and down in the water). This research shows something a bit more like a mark a wave left when it passed by a very long time ago.
So it is not outright detection, i.e., observing a gravitational wave passing by today, but it is very interesting none-the-less.
Beers all round.
I'm going to go ahead and speculate now that we are never going to directly observe a gravity wave. It is just too weak.
The scales - both large and small - are mind boggling. The discussion is at the level of planck lengths and planck time. We're talking about a time when the granularity of dimensionality itself leaves fingerprints.
You know the observable universe is big and heavy - hundreds of billions of galaxies a hundred billion lightyears across. Imagine you had two of them right next to each other. They would affect each other by gravity, right - at least at the edges? Now shrink the pair so small that trillions of the pair lined up would not span the width of a single proton and they're still right next to each other so the gravity is so much more intense by proximity. One of these is our observable universe, and one of these is a mass that has now fallen outside our "light cone". Now move the second one 16 degrees across what will someday be our sky in 1x10^-44th of a second. That is the scale of gravity wave we're talking about. Entire observable universes worth of energy density swinging whole degrees across the sky because at a scale that small, that is the indivisible increment of a meaningful distance.
It is horrifyingly beautiful.
One quick and dirty way that gets the idea across, if crudely, is "space was unfolding so fast that objects in space would seem to recede from each other at greater than the speed of light." If, you know, there were "objects" during the inflationary period (which there weren't) or you could see them (which you couldn't).
"would seem to recede from each other at greater than the speed of light"
Not seem. They did. And still do.
The speed of light is only a limit on objects as they move through space. The movement of space itself, however, can make the speed of light seem slow. Nothing can move through space faster than light. Space however can move as fast as it wants as it has no mass. Even now parts of the universe that are very far apart from each other are moving apart faster than light.
> Not seem.
Yes seem. No object is moving at more than light speed, which is a good thing as that is impossible.
Let's say you're walking forward inside a train moving at 200 km/h. Inside the train, in your reference frame, your walking speed is 2 km/h like it's always been, but to an observer outside the train it might seem as if you're walking at an incredible 202 km/h.
An example: the most distant galaxy found is roughly 30 billion light years away, but the universe is only 14 billion years old, and light clearly can't move faster than the speed of light in vacuum -- so how could the light have reached us? Because the universe, the ruler you're measuring the distance with, is expanding.
"Let's say you're walking forward inside a train moving at 200 km/h. Inside the train, in your reference frame, your walking speed is 2 km/h like it's always been, but to an observer outside the train it might seem as if you're walking at an incredible 202 km/h."
But if the train was moving at c (the speed of light) relative to an observer, it would seem to the observer that you're both moving at c; even though to you you're moving forwards along the train to the observer you're frozen still.
Relativity has wierd effects, but none of them (AFAIK) produce a measurable "greater than c" velocity for an object.
> But if the train was moving at c (the speed of light) relative to an observer, it would seem to the observer that you're both moving at c; even though to you you're moving forwards along the train to the observer you're frozen still.
Relativity has wierd effects, but none of them (AFAIK) produce a measurable "greater than c" velocity for an object.
You're taking issue with a simple example where a changing reference frame lead to odd conclusions. If you can suggest a better everyday analogy in which changes in the dimensions of space produce easily observable effects, I'm all ears -- I admit I struggled. I toyed with a rewrite of the 'rabbit and the tortoise' paradox, which is based on manipulating time, but it didn't make things clearer.
The expansion of space itself is both why we can see objects further away than the age of the universe, and why the light from them is redshifted (the wavelength of the light has been increased by the expansion of space itself). If you could backtrack the light, you'd find that even though it has covered 30 billion light years in 14 billion years, it has never moved faster than c. Neither the object nor the light is moving at greater than c, it's the reference frame, space itself, which has changed.
"Relativity has wierd effects, but none of them (AFAIK) produce a measurable "greater than c" velocity for an object."
The key word is measurable. For instance if you launched two objects in opposite directions at light speed, clearly they are travelling apart at twice the speed of light relative to each other. There is just no way of observing that from one object to the other...
" For instance if you launched two objects in opposite directions at light speed"
SR allows a 3rd observer to 'see' 2 objects moving together or apart at >c but from the perspective of one object the other can never be moving (towards or away at >c). It's one of the problems with trying to understand relativity by analogy with everyday experience.
In the LHC the protons beams each reach close to c relative to the machine but from their perspective only collide at <c
"As it already says above "There is just no way of observing that from one object to the other...""
The two objects don't move apart at >c that's the whole point. 2 objects traveling at say 0.99c each mutually away from an observer at a point will still only see each other separating at <c.
The observer will see them traveling away from the starting point at -0.99c & 0.99c That's the kind of thing that makes relativity seem so counter-intuitive
If nothing with mass can reach c in any ref. frame then the observer can only see each object as moving with velocity less than c and the same applies to the objects whether they are moving away or towards each other.
"Yes seem. No object is moving at more than light speed, which is a good thing as that is impossible."
No - ARE. Light cannot move IN SPACE fast than light speed. But Space CAN move (expand) faster than light speed as it has no mass. QED - very distant objects can and are actually be moving apart faster than the speed of light relative to each other as space expands, even if it impossible to directly observe it.
> Space CAN move (expand) faster than light speed as it has no mass
Space does not move. Space is the dimensions of the universe: length, breadth, height, time (plus the little squiggly ones). They're the axles on the graph in which objects in spacetime are plotted. They can change, but to say that e.g. "length" moves is nonsensical.
"Space does not move. Space is the dimensions of the universe: length, breadth, height, time (plus the little squiggly ones). "
Space does effectively move - we know that the universe is expanding - and that we can see light from distances further away than we should be able to if space was not moving.
We also know that the Big Bang for instance exceeded the speed of light during it's initial expansion - that is only possible if space also moved.
> Space does effectively move - we know that the universe is expanding - and that we can see light from distances further away than we should be able to if space was not moving.
No, that's confusing the apparent effects on objects in spacetime with spacetime itself. Spacetime isn't an object, it's the set of coordinates, axles in a graph, we use to describe the position of objects in the universe.
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No, much, much smaller than a galaxy cluster. From nearly bugger all (proton size) to about the size of a decent grapefruit. Note that the BB had already expanded to proton size before inflation kicked in; the expansion from nowt to proton took nearly three times as long as inflation lasted.
The CMB shows that there are warmer and colder regions (still all bloody close to 0K) mixed together but this temperature motteling is uniform in all directions. Inflation smoothed it out to be so. Average CMB temperature is equivalent to 2.7K IIRC.
I don't know anything about science, but this research goes against my core believes and therefore it is wrong!
You'll just have to keep doing it over again until you get it right (ie: Your results say what I want them to say).
Way too many people who think their opinion is as valid as your facts.
For non-Americans: In baseball, a "home run" is when a batter hits the ball far enough within an area defined by lines drawn from home plate (being the vertex) to the first and third bases (foul lines) into an area that is not retrievable (either the outfield or "over the fence") in the time it takes him to run around the three bases of a the baseball diamond and return to home plate.
A "grand slam" is when first, second and third bases are occupied by previous batters at the time that a fourth batter hits a home run, thus allowing all four players to run to home plate and score.
So yes, a grand slam is very good.
"After getting the first results in the team then spent three years going over its data to make sure that there was no other possible explanation for what they were seeing. They report a confidence level greater than 5 sigma, meaning the odds are less than one in 3.5 million that they are wrong.
Sadly, that long checking process has left a lot of scientists somewhat out of pocket. In 2004 British bookmaker Ladbrokes offered 500-to-one bets that gravitational waves wouldn't be discovered by 2010 and so many scientists rushed to lay down money that the odds were cut to 10 to one."
Three years ago from now would still be after 2010, so no payout. Unless I've missed where it said detection happened more than three years ago?
Yes the three years confirmation mentioned is confusing but if any scientist detected this before 2010 then they better get down the bookies. Just because you didn't have confirmation back then doesn't mean what you detected only becomes a gravity wave at the time of confirmation. It was and will evermore have been a gravity wave detected pre 2010.
The question makes no sense, because the Big Bang was the beginning of time itself, and thus there was no "before" because there was no time for it to be in.
This is based on the Big Bang being a "perfect" singularity, so if we were to find evidence of a "before" it would mean that the Big Bang was not perfect - which would be very exciting indeed.
Nobody has found any evidence at all though.
I'm a mathematician rather than a scientist (I believe in /real/ proof ;) ), but I'm curious: "before" is just implying outside in one particular dimension (time) which you say doesn't exist outside of the Universe, and I get that. Does it in any way make sense to ask what could be outside the Universe (in any "dimension")?
There are lots of references to what "size" the universe was at various different stages, and the expansion of space, it all seems very enclosed. I'm quite happy with the idea of a geometry being self-contained and non-infinite but... embedded within further dimensions it does kind of make sense to consider things not in that geometry.
> "before" is just implying outside in one particular dimension (time)
The problem is that it implies an earlier point in time, like "lower" implies a lesser altitude and "shorter" implies less distance. But in our universe there is no point in time earlier than zero, just like there is no distance shorter than zero. The question then becomes "are there other universes", which brings you solidly into the realm of free speculations like the Multiverse theory and the 'the universe is a computer simulation' theory.
> The problem is that it implies an earlier point in time, like "lower" implies a lesser altitude and "shorter" implies less distance. But in our universe there is no point in time earlier than zero, just like there is no distance shorter than zero.
This is not disputed.
> The question then becomes "are there other universes"
Does it? How is that argued?
> Well surely an observer experiencing time and being outside our universe, has to be in some other universe?
Who said anything about an observer experiencing time? We're talking about "outside" our universe -- why do we even think what's outside is another universe?
I think "surely" is not going to convince me!
Err ..Not so fast. A while ago I came across an interesting argument by a maverick Israeli physicist (I forget his name). I didn't understand all the details but essentially he calculated the spacetime dilation resulting from the extreme acceleration that the early universe encountered during this rapid inflation phase. It is well known that extreme acceleration does funny things to time and his estimate was that time would be "stretched" by a factor of approximately 10^12.
The age of the universe is generally set at somewhere around 13 to 16 billion years, depending on who you ask.This "stretching" means that the true age of of the universe, as seen by an "outsider" (Whoever that may be), must be divided by this "stretching" factor. What do you get when you divide 16 billion years by 10^12? Well, near as dammit, it's 6 days.
Religion: Eleventy Billion! Science: Also Eleventy Billion! (because they seem to agree!)
Of course, if the actual age of the universe was only 13 billion years then I suppose that means God got to knock off early on the last day.
How would time dilation in our universe be observable to an observer in another universe? There's an event horizon between us.
Also, if the idea is that our universe has moved so fast that it's suffered time dilation, then time runs slower in the other universe, and (assuming the figures are right) you have to multiply our 14 billion years with 10^12 to get how long the outside observer thinks our universe has existed.
As I understand it (the maths is a bit beyond me, so I may not be quite right), the "inflationary" phase in the expansion of the early universe requires a brief period of NEGATIVE gravity, hence the rapid expansion. Since General Relativity says that acceleration and gravity are more or less the same thing, this means that the effect on time dilation works the other way round i.e. time slows down instead of speeding up. Also, I think the physicist was speculating on how it would appear if the Observer (capital letter intended) was outside of ALL universes, instead of just living in another "nearby" one.
I suppose the only way you can get your head around that is by visualising the entire multiverse as a giant computer simulation. Perhaps we really are trapped inside The Matrix!
By the way, since we have a "devil" icon, could someone come up with a suitable "opposite" one (an angel, perhaps) to cover this type of posting.
> Science: Eleventy Billion!
> Religion: 0
And here's how *any* subject on ElReg can be turned into the most preposterous "Us vs Them" argument. :(
Bet you think you come across as funny, taking merit from one group to which you do not belong to attempt to demerit another group that's nothing to do with you.
Don't be another fucking zealot mate, just live and let live. If people want to believe in God or Michael Jackson or whatever that's a personal thing and none of your--or mine--business.
For the purpose of this speculation lets call it The Dark Margy. TDM
IF Expansion of the universe was briefly faster than light.
TDM may be what escaped from the edges of expanding universe when it slowed down.
Dark Penguin cos I was right Linux is goin places when playing with it about 20 years ago.
If they've spent 3 years checking the results, then it's probably correct and would certainly be Nobel prize material - absolutely amazing. But polarimetry is hard (I used to do it) and the ways you can cock it up are legion, so confirmation from other groups is going to be really important,
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