Sure we can see stuff that is 13 odd billion light years away, but what if the light from places that are further away just hasnt got here yet?
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Don't they (the clever people) look at the speed that the universe is expanding and then work that backwards to the point where it, erm, wasn't expanding.
You know how if you heat soemthign up if glows red, then white etc
Well thats because the more energy something emits the higher the frequency of the radiation from it, so it glows infra red , then red, white, blueish (think car hedlamps, projectors etc), then eventualy microwaves, gamma rays etc.
Now assuming that the start was infinate energy, you find the background 'noise' in the universe with a radio telescope, measure its wavelelngth, and you know how much energy is left, and form that you can infer how old/big the universe is.
Dunno. But I know a a man who does.
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😀 @ oldgit...the concept of infinity just gives me a headache.
There's a label with cleaning details on the south west corner. If you scan the barcode it should give you a date of manufacture.
😉
And if the universe started from a single point and is expanding into infinite space - how is Andromeda going to collide with the Milky Way?
These are questions that arise from my dream last night.
As is - if we can see 13 billion odd years in one direction, how far can we see in the other direction?
Aren't there also other clues to the other age, such at the abundance of heavy elements which are formed when stars die. These are quite important for life too, so theres a theory life (similar to ours) couldn't have occurred much earlier.
wooobob - Member
Dunno. But I know a a man who does.
me too 😉
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How do "we" "know" how old the universe is
"we" don't categorically know, but we can make educated calculations, which'll become more accurate over time as our knowledge & understanding develops
There are quite a few ways that all corroborate each other loosely.
One is to use red-shift. Because of the way the universe is expanding (like a balloon being inflated) the further away something is from any point, the faster it is moving away. So the more its light is red-shifted (due to the Doppler effect). We can check this for closer objects by measuring their distance another way, which involves measuring their apparent position 6 months apart when we are on the opposite side of the sun and triangulating.
Measure the red-shift, measure the distance. Some stuff is x billion light years away, but nothing can travel faster than light, so the (current) universe cannot be any older than x billion years.
As for galaxies crashing into ours - let me swap the balloon analogy for a slightly more complicated one. Imagine a conical bowl. If you fill it with water from a hole in the bottom, the surface area of the water gets bigger as you fill, of course. Now as it's filling, put some.. I dunno.. polystyrene beads on the surface, and give it a swirl. On the whole, the surface is still expanding and most of the beads are getting further apart, but locally as the water swirls some of the beads will inevitably move towards each other and some will end up sticking together (in this case because of the water's surface tension, but in the case of galaxies gravity creates a similar effect but over a longer range).
"but nothing can travel faster than light" nothing that we are aware of.If the universe is infinite light speed would be pretty slow.
Speed of light cant be used as a constant in that context though. There are a few theories that the speed of light has changed over the life of the universe. The main reasoning for this it's the universe is bigger than it should be
"but nothing can travel faster than light" nothing that we are aware of
Well yes but if something could then all the rules we've been verifying all these years would be completely wrong. Possible but not particularly likely 🙂
Re the speed of light changing. The speed of light in a vacuum is (traditionally) contstant, but the early universe couldn't really be described as a vacuum could it?
Plus gravity seems to operate faster than light, maybe instantly, nobody knows yet
Edit, nobody actually seems to know what gravity is!
Also quantum entanglement, perhaps.
I still want to know [url= http://www.singletrackworld.com/forum/topic/is-the-universe-hollow ]if the universe is hollow[/url]. 🙁
Thats the thing with science, no absolutes. Infinite possibilites in an infinite universe.
indeed, which could turn out to be another form of gravity, or vice versa
the universe is bigger than it should be
what's the recommended size for a universe?
is there an international standard?
(just in case I ever get round to creating one)
Plus the direction of light can be changed by the mass of quite big objects. And naughty black holes will even steal it and not give it back. Or tell you where it has been hidden! Naughty!
TFM are you a real scientist or the armchair variety? 🙂
the universe is expanding (like a balloon being inflated)
I thought the universe was doughnut shaped?
Or possible saddle shaped?
If it's balloon shapes, is it one of those long sausage-shaped ones, because that would mean one end is moving away from the other a lot faster than the sides are moving awat from each other.
Christ - I won't sleep tonight.
Where's the Anadin?
this subject is far too demanding for my peanut brain, especially on a friday - lets talk about beer please...
in an infinite universe
so now the universe is infinite?
in which case trying to measure it's size is stupid and pointless ...
TheFunkyMonkey - MemberPlus gravity seems to operate faster than light, maybe instantly, nobody knows yet
That's not true.
What I don't understand is this:
EDIT I think I just realised my mistake, as you were 🙂
so now the universe is infinite?in which case trying to measure it's size is stupid and pointless ...
We did this yesterday. The maths boffins maintained that there were different sizes of inifinity..
like infinity and infinity+1 ?
🙄
sounds like someone's making things up to explain something they've no idea about
How do you measure the speed of gravity ?
You can switch on a light source and measure how long it takes the light to get somewhere.
How do you instantly switch on a gravity source ?
yes, so you're still getting bigger no matter how much you diet.So if space is expanding then surely all points are moving away from each other
All explained in full
MidlandTrailquestsGraham - MemberHow do you measure the speed of gravity ?
You can switch on a light source and measure how long it takes the light to get somewhere.
How do you instantly switch on a gravity source ?
I don't know but I think it would invalidate the general theory of relativity if it did so.
mol, you answered that question yourself earlier! space is expanding, but gravity causes objects locally* to be attracted to each other.
* on a universal scale
EDIT: ignore the above, mol has edited his post
molgrips, as the light source is 'moving away' from us and the speed of light is constant, the wavelength increases and shifts to the red end of the spectrum, hence red shift.
Blue shift is due to the wavelength decreasing and moving towards the 'blue' end of the spectrum.
(I think...)
Just to be annoying, the universe is expanding faster than the speed of light. So we may never get there.
Just to be annoying, the universe is expanding faster than the speed of light. So we may never get there
To be a pedant, current favoured theory is that at some point at the beginning, it did expand faster than the current speed of light but it is not expanding that fast anymore. Either way this is correct:
So we may never get there.
But what if the universe were on a massive conveyor belt.......?
Why not just cut in half and then count the rings?
does anybody know what the universe is expanding into?
Itself.
Why not just cut in half and then count the rings?
or count the candles on it's cake
is there anything beyond the universe ?
God knows
gravity has no speed that is like asking what the speed of magnetism is. It is a force that has a power and a range
You do get different size infinities so we know some infinites are larger than other infinities.
The grains of sand on a beach may be infinite as are the grains of sand in the world. However we still know which is the larger of the two infinities.
it's about 37 years old give or take a few months..
Dunno where this 13 billion figure came from as it's clear from the bible that the universe was created about 6000 years ago.
Of course that doesn't mean that god created a brand new sparkly, straight out of the box universe then. He might of made a pre-aged one to spice things up a bit.
MidlandTrailquestsGraham - Member
How do you measure the speed of gravity ?
You can switch on a light source and measure how long it takes the light to get somewhere.
How do you instantly switch on a gravity source ?I don't know but I think it would invalidate the general theory of relativity if it did so.
Gravity is an accelerating force of attraction which is a function of the mass of an object. Gravity is a force of attraction and therefore a non mass entity so the speed of acceleration due to gravity i.e. how 'fast' it works could mean that acceleration due to gravity is > than the speed of light however the speed of the object being attracted will not exceed the speed of light.
The limitations of the 'speed of light' is a bit of misnomer as even a photon can only travel as at a fraction of the speed of light albeit it 99.99999rec% of that speed. Only a non mass particle (tachyon) could exceed the speed of light.
But when you start talking about size, and dimension and time etc in universal and quantum terms you need to realise that these terms are not the same as you think of in a day to day 4 dimensional universe.
does anybody know what the universe is expanding into?
The best way to imagine the universe is to imagine a balloon with points on it for stars which are becoming more distant as the universe expands. However then you have to realise that the universe isn't expanding [u]INTO[/u] anything it just is and you have to account for the fact that it exists in more than ten dimensions...
Dunno where this 13 billion figure came from
Perhaps you might want to do a little research then, instead of talking gibberish about the sky fairy.
Dunno where this 13 billion figure came from as it's clear from the bible that the universe was created about 6000 years ago.
Of course that doesn't mean that god created a brand new sparkly, straight out of the box universe then. He might of made a pre-aged one just to test our faith.
True, and a 'day' as referred to in Genesis may or may not be a 'day' as we understand it ...
He might of made a pre-aged one to spice things up a bit.
like a sort of massive intergalactic pair of stonewashed jeans?
Perhaps you might want to do a little research then
But science is just a feeble way of trying to understand and explain what God created, hence the 'aged' universe theory could be correct
molgrips, as the light source is 'moving away' from us and the speed of light is constant, the wavelength increases and shifts to the red end of the spectrum, hence red shift.
Yeah but.. say you were measuring the light with a ruler - your ruler would be getting longer all the time too - so you'd not see any increase in wavelength.....
To consider the quantum side of things as the photos interact with your eye - for them to be redder, they would have to have less energy - where's the energy gone?
gravity has no speed that is like asking what the speed of magnetism is. It is a force that has a power and a range
If you have two bodies, there's an attraction between them, say they are both attached to spring balances. If you remove half of the first mass - how long does it take before the spring balance on the second mass shows a change in its reading?
The limitations of the 'speed of light' is a bit of misnomer as even a photon can only travel as at a fraction of the speed of light albeit it 99.99999rec% of that speed. Only a non mass particle (tachyon) could exceed the speed of light
Photons have no mass, that's why they do travel at the speed of light!
[i]"But science is just a feeble way of trying to understand and explain what God created..."[/i]
Oh dear, I can't see this ending well.
But science is just a feeble way of trying to understand and explain what God created
Here we go again. Next, you'll be saying something like "If we come from monkeys, how come there's still monkeys" to "disprove" the fact of evolution.
Get a brain. I'm outta here. 🙄
leggyblonde, from NASA
Thanks for your question. It is true that nothing can go faster than the speed of light. And it is also true that our universe is expanding faster than the speed of light today. This sounds like a contradiction, but actually it is space itself that is expanding faster than the speed of light, driving objects further apart at an increasing rate. The concept of space expanding faster than the speed of light is not in contradiction with the limit for zero mass particles, ultimate speed. A nice discussion of this can also be found at: http://curious.astro.cornell.edu/question.php?number=575
and you have to account for the fact that it exists in more than ten dimensions...
that is theoretical and not fully accepted yet. The evidence for SST is not conclusive [ either way]
SST= super string theory which suggest varies numbers for dimensions depending on person /theory/particles[fermions [10] v bosons[26] for example]
Am I alone in not understanding why anyone gives a **** about stuff like this?
But science is just a feeble way of trying to understand and explain what God created, hence the 'aged' universe theory could be correct
you are aright an highly innacuarte book is much stronger than feeble science.
Anything "could" be right but we ned to look at probabilities and decide which is "probably" right. I see little point in having this debate if you have faith as you dont need facts to support your view , which is handy as there are none hence the use of "aged" universe to explain the inaccurate nature of the lords word.
Your ruler would get so big that it would be unrecognisable due to the increasing distance between the atoms that it's made from.
Yeah but.. say you were measuring the light with a ruler - your ruler would be getting longer all the time too - so you'd not see any increase in wavelength.....To consider the quantum side of things as the photos interact with your eye - for them to be redder, they would have to have less energy - where's the energy gone?
Imagine the light is a spring. The further you strech it, the lower the frequency of coils for a set distance. To strech this spring you need energy, which reduces the frequency.
Makes sense in my head. Need a coffee now...
sslowpace that's an interesting link, cheers.
Every bloody question answered opens up about 100 more questions!
Photons have no mass, that's why they do travel at the speed of light!
Or do they as they can be acted on by a large enough mass?
Just to be annoying, like 😀
If we are using general relativity as our explantion of gravity then gravity isn't a force its the manifestation of the curving of spacetime.
Therefore you can't think of gravity as travelling faster than the spead of light, gravity doesn't travel through space, it is space
Am I alone in not understanding why anyone gives a **** about stuff like this?
I sure there are plenty of OK magazine readers who agree with you GW
leggyblonde, love this stuff too 😀
GW - Member
Am I alone in not understanding why anyone gives a **** about stuff like this?
Exactly......
.......Meaning of life - hmmmm I'd rather ask an artist, poet or philosopher than some particle jockey 🙄
[i] I see little point in having this debate if you have faith as you dont need facts to support your view[/i]
The problem is that you put too much faith in your 'facts', forgetting that the FSM uses his noodly appendage to alter the results of all scientific experiments.
Exactly.............Meaning of life - hmmmm I'd rather ask an artist, poet or philosopher than some particle jockey
now that's the most common sense [i]ever[/i] to be posted on the subject..
IanMunro - MemberI see little point in having this debate if you have faith as you dont need facts to support your view
The problem is that you put too much faith in your 'facts', forgetting that the FSM uses his noodly appendage to alter the results of all scientific experiments.
Ramen, brother.
Photons have no mass, that's why they do travel at the speed of light!Or do they as they can be acted on by a large enough mass?
Just to be annoying, like
Thats because gravity curves the space through which the photons are travelling. They can still have no mass but be deflected by the curvature of space
But science is just a feeble way of trying to understand and explain what God created, hence the 'aged' universe theory could be correct
Logically perfectly admissible, but a pretty useless position to take imo.
Or do they as they can be acted on by a large enough mass?
Just to be annoying, like
Au contraire - gravitational lensing doesn't work by the mass of the star attracting the photons in a Newtonian kind of way...
Meaning of life - hmmmm I'd rather ask an artist, poet or philosopher than some particle jockey
Fail - the particle jockeys aren't trying to figure out the meaning of life of course, they are trying to figure out how the universe works. Totally different thing.
worrying about either = fail
there is no meaning to life and how the universe works makes **** all difference to anyone. now who's Jordan shagging this week? 😉
Ian, stop it. You know that's naughty 🙂
richmtb & molgrips
Cool
But theoretically, is it photons that would act on a solar sail? And if so, would they have to have mass to propel it through space?
molgrips - MemberFail - the particle jockeys aren't trying to figure out the meaning of life of course, they are trying to figure out how the universe works. Totally different thing.
Semantics Molly, semantics 😉
Meaning of life/how the universe works/where did we come from/how did it all start - same question different spin, bottom line is none of the current theories are testable with current knowledge/technology and the possible explanations have been reverse engineered from slightly fragile data sets.
Not too mention the occasional imgainary particle or new form of undetectable matter which is needed to balance the books ! It's all academically stimulating I agree, but perhaps not the most pressing area of research funding in current times.....
.....and I'm not sure if the Universe 'works', last I heard it was on benefits and putting in a claim for a bigger house due to expansion
Meaning of life/how the universe works/where did we come from/how did it all start - same question
Is it hell. Completely different questions.
IanMunro - Member
I see little point in having this debate if you have faith as you dont need facts to support your viewThe problem is that you put too much faith in your 'facts', forgetting that the FSM uses his noodly appendage to alter the results of all scientific experiments.
Thats quantum physics, that is....... 😆
molgrips - Member
Is it hell. Completely different questions.
But all equally meaningless when answered by a scientist 🙂