Universe

[Doughzer]

Faith in politicians, isn't that what they call a load of rubbish!

[Grunthos]

Dark Matter - something a bit like normal matter you can touch which fills in an make things balance out quite well. There are several suggestions for what it could be, what sort of properties it has, and a lot of astronomy falls apart without it. It solves a whole host of different problems. Its still possible it could be wrong, but right now most people in the field assume it is true.

Dark energy we know hardly anything about - we see it's effects - accelerating the expansion of the universe on big distances, there are one of two suggestions for what it could be, but so far its pretty much a mystery.

So Dark Mass, maybe 80-90% understood, Dark Energy maybe 5-10%.

An excellent summary Juliano.

Anyone wanting a further description might wish to watch the short TED video on dark matter and dark energy.

[Doughzer]

I found this interesting to guys and gals.

BBC News - Survey gets a grip on dark energy

[sparkly]

This is all getting very interesting stuff... I love it when you come to realise how many different ideas and theories can be inter placed and generate new ideas with a mix of science and "personal theories" ( not to be mistaken with scientific theories). I really have enjoyed reading your posts, I have learned something.. And that's good right?. Thanks guys. Kind regards Vince

hi Vince

Theorys have to be visualised first the problem with alot of peeps is that they refuse to think out of the box and just repeat whats allready been discoverd,

“The true sign of intelligence is not knowledge but imagination.”

“Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.”

“We can't solve problems by using the same kind of thinking we used when we created them.”

“Logic will get you from A to B. Imagination will take you everywhere.”

“Imagination is everything. It is the preview of life's coming attractions.”

[Hugechris]

To test if the universe is moving towards something is a very tricky indeed.

The isotropy of the cosmic background radiation points to a very symmetric expansion of the universe all all directions a compelling indication of a big-bang creation.

The inflationary theory of the universe proposes that the universe we "know" could well be one bubble in a whole set of other bubble universes, if there are any influences of these other universes through gravitational attraction (gravity seems to provide the most generic means of interaction) causing movement one would anticipate that other fields could interact with our universe after a long enough period of time. We may have to wait a long time to see (if at all possible) (by see I mean detect the effect using equipment that can only seemingly measure only 4% of the phenomena we observe in our own universe!). If there are no other universes then the concept of absolute motion of the universe becomes meaningless.

One can come up with ideas that the unexplained phenomena in our universe could be the effect of external (to the universe) influences and theorist have and exploring ideas through imagination and testing the status quo is to be encouraged.

Science and the logic of mathematics has given us a means of testing / deducing the implications of our imagination that turn an amazing idea into a great theory.

[Gary Anthony]

Even if there are other universes in the multiverse (in meta-time) there would still not be any kind of absolute motion. Recently some very slight anisotropy in the CMB has been detected that suggests "Dark Flow" toward some humongous attractor. Maybe we are about to collide or re-collide with a "brane" or another universe. Long before that happens and before all the stars burn out, all matter in the universe will fall into supermassive black holes as they are doing right now - before our very eyes! By then, these black holes will be virtually identical and indistinguishable. So, It may as well be that all matter will fall into the SAME black hole because statistically by quantum theory there could be no difference. We may be experiencing the first stages of "The Big Crunch" when we measure the growing mass of the central supermassive black hole in our galaxy.

[Ronnie67]

Wow after reading all yr thesis, beliefs, theories and so on about the universe, its good to know how so many wonder what lies beyond, for hundreds of years scientists have predicted many thing, many of which where flawed. The earth was flat, the sun and planets orbit around earth, earth being the centre of the universe. However today with our technology we know much more about the universe, but we still do not know a great deal. dark matter for instance covers much of the universe and probably the cause of the universe expanding, but what will become of the universe if it continues on stretching, will a tear rip and destabilise the universe, we could even split into two universes, but how do we know this has not happened yet, many predict that there is not one but many universes out there. Black holes could be a doorway into these alternative universes, what exactly is a black hole, we know its a star gone supernova, none knows what lies within the void, its just all speculations and theories as to what's in the centre.

I guess everyone has their theories as to what's out there, I have many

[Earl]

Well i think the universe is moving towards something, well beyond my comprehension,

It might help to define what the universe is, it does not move it only contains all the things that move within it,

Expansion is not like movement although it can appear from a physical point of view that expansion causes movement.

Movement is restricted to the speed of light, nothing can move faster.

Expansion can be faster than the speed of light because nothing is moving. as its the nothing that expands.

The Universe is expanding between out Milkyway and M31 however the Milkyway and M31 are moving closer to each other at a velocity great than the expansion, this is Movement within expansion.

Expansion can be measured by the red shift of light, just as object moving closer to you have a blue shift of light.

[Ronnie67]

We look at the speed of light and say nothing can move faster than the speed of light, but I think this is wrong, as technology progresses in the distant future something more will be discovered and the speed of light could change, we look at the science hundreds of years ago to now. What will happen in another three hundred years.

[Earl]

We look at the speed of light and say nothing can move faster than the speed of light, but I think this is wrong, as technology progresses in the distant future something more will be discovered and the speed of light could change, we look at the science hundreds of years ago to now. What will happen in another three hundred years.

I feel your looking at this the wrong way, Nothing can travel in space faster than the speed of light the recent Cern and neutrinos has been studied in fine detail for whcih it has been solved, for us to be able to travel faster that the speed of light we either need to find a way to manipulate space or travel outside of space/time, (if such a concept actually has any meaning) either way the energy needed to do such tasks is theoritically so immense we have a massive barrier there other than nothing can travel faster than the speed of light.

The Sound barrier was one thing, the fastest train was another, the fastest car, however the fastest particle is something else.

[badgerchap]

The CMB may or may not be a relic of the Big Bang, but seeing as it was predicted (marginally) before it was discovered, and at the correct temperature, there's a good chance it is what we think it is. Otherwise there's a mahoosive hole in the Standard Cosmological Model, which raises even worse problems because the SCM, as incomplete as it is, is highly successful in predicting the behaviour we see in many significant astronomical phenomena.

As for the expansion of the universe, it's a fairly simple thought excercise to bring oneself to the same conclusion as fully fledged (I'm just a student!) astrophysicists and cosmologists:

1: We are all aware of the doppler effect - when a police siren approaches you, the pitch of the percieved sound is higher, when the siren recedes it is lower. An optical version, whilst provable with colour wheels etc., can be inferred from this - as both sound and light propogate as waves (forgetting duality for the timebeing) - i.e. they can be described by the equation x=Acos(wt+phi), then we can assume (and experimentally demonstrate), that indeed this is the case.

2: Thus in the case of light, a receding object will appear redder, as the spectrum of its light is stretched toward the longer wavelength end of the spectrum. An approaching object, conversely will appear blue. This effect can be demonstrated using the sun as an example. The side of the sun that 'approaches' as the sun rotates is indeed blueshifted, and the converse for the receding side.

3: With the exception of galaxies in the local group which undergo significant mutual gravitational interactions, all of the galaxies in the universe can be seen to be receding, as their light is, in all cases, redshifted. This shows fairly simply that the universe is in a state of expansion. This is lucky, because it ties in with predictions of an expanding universe (ignoring for now the cosmological constant - that's a whole other can o' whoop!).

Of course the main issue with all this, which I think may also affect the underlying meaning of your original question, is the term 'universe'. The universe that is commonly referred to is in fact the observable universe. It is this which we can see expanding. Unfortunately, due to the nature of relativity and the light speed limit, there is no way in which we can ever see beyond this visual boundary, and so to suggest any kind of firm knowledge beyond this point would be almost entirely conjecture (alright, 100% conjecture on my part!).

I've also left out Inflation, originally posited by Alan Guth, mainly because a) I'm not sure whether or not I believe it yet and b: I really don't know that much about how one would go about proving it!

What you get into next is all the hoohaa about bubble universes, parallel universes, infinity and M-theory. I can recommend The Fabric of the Cosmos by Brian Greene for a good read regarding these postulations - the book is explained as much as possible in simple every day terms, and more than anything gives the ol' grey matter a good dusting off.

Add to all this the highly solipsist attitude that we really don't know anything and we could all be a bogey up a giant cosmic nostril, and you have the joys of philosophy springing out at you from every angle!

Just a quick P.S. Vince, what you're suggesting is, linguistically and scientifically speaking, a hypothesis. Gravity is a Theory. Evolution is a Theory. Your idea needs a couple more supporters before it's a theory

[Vince1963]

Hi Badgerchap.. Just let me say thankyou for the input, I now have learned more about this topic since posting this topic and now know when to keep my gob shut lol.. I may have my wording a bit off but i think guys knew what i ment. I know you science guys know more about this stuff than me and i respect that and salute you. I just wanted to stimulate a debate and help me get answers (which i got), somethings are just too way out there for me to comprehend but i desperately want the answer, and guys like you are just who i NEED to talk to. may i message you with any questions?.. Kind regards Vince

[Vince1963]

Earl put

It might help to define what the universe is, it does not move it only contains all the things that move within it,

Hi Earl... I find this hard to get my hear round... If the universe doesn't move how is everything inside it expanding?.. If everything inside it is expanding then doesn't it stand to reason that everything will expand beyond the existence of the universe as we know it?.

[Vince1963]

We look at the speed of light and say nothing can move faster than the speed of light, but I think this is wrong, as technology progresses in the distant future something more will be discovered and the speed of light could change, we look at the science hundreds of years ago to now. What will happen in another three hundred years.

Maybe light travels beyond our expectations through Black holes maybe speed is infinite beyond the realms of the event horizon...

either way what ever lays beyond the event horizon absolutely nothing can exist beyond it in a particle sense unless its like some sort of tele-portation and you re-atomise at the other side. (just a thought)

or maybe there is nothing within a black hole at all, and all matter which enters it is obliterated and thrown out ward to the event horizon to join its ever increasing density...

(that's just an idea guys)

[Ganymede12]

Taking of the speed of light I've thought of a simple way to make a photon travel faster than the speed of light!

Run forward with a torch whilst turning it on!

Will the parent velocity of your running, combined with the speed of light that a photon travels at any way, be enough to make a photon go faster than normal? Also, can you make a photon stand still (ignoring the fact that absolute motionless is impossible to achieve)?

[badgerchap]

Ah Ganymede, you've hit on one of the most beautiful and bizarre aspects of Relativity! The truly weird thing about light is that even if the light source is moving towards you at say 1/2 the speed of light, and you are moving towards it at for example a 1/4 of the speed of light, you will STILL measure the photons travelling at precisely the speed of light. I can't remember the precise wording, but it's something like:

"The speed of light remains the same for all observers regardless of the motion of the observer or the source."

As for light standing still, there are a few interesting things which, whilst not perfect, may give you some food for thought:

People often talk about the 'speed of light', but just as with the term 'universe', there's more to it than that. What people are generally referring to is the speed of light IN A VACUUM. Light does indeed travel at different velocities dependant on the material through which it passes. You can see this in a pond or river. When you stand a stick in the water, it looks a bit like the stick is bent, at the water line. This is because the light travelling through the water moves a bit more slowly until it meets the air, where it speeds up a bit. This causes the light rays to bend, causing a distorted image. This is the principle of refraction at work. Materials have been found which take this to the extreme. The speed of light in a vacuum is around 300,000,000 m/s, but in once case, light was slowed down to below 40 m/s!!

Also, light falling into a black hole could become vastly decelerated, stopped and then reversed by the pull of gravity, depending on its path of approach to the Black Hole. Matter falling into BH's rotates, like the water falling into a bath plug, and if an incident beam of light were to approach at an angle opposite to this rotation, it would be very rapidly slowed down, stopped and reversed as it succumbed to the indomitable might of the black hole.

Which brings me neatly back to Vince's question about the SOL in a black hole, and the possibility of exceeding it. Time to bring out Einstein again!

I'm sure that everyone's heard of

e=mc^2,

otherwise known as the energy mass equivalence, where e is the total amount of energy possessed by a moving system, m is the mass of that system and c is the speed of light in a vacuum.

Here's a little thought experiment for you. First assume that c NEVER changes (we're talking vacuums here so its a constant 300,000,000 m/s). Start with m=1. E is already therefore a big number. But if you want to accelerate an object, you must give it more energy. But giving it more energy, as the energy mass equivalence shows, slightly increases the mass. Now it's fairly simple to realise that the more massive an object is, the more energy it needs to reach a certain speed, right? But each time you give it more energy, it gets more massive, so needs more energy and so on....

What all this gobbledygook means is that no matter how you accelerate an object, you will always need a bit more energy to get it to reach the speed of light. Off the top of my head I THINK it takes the same amount of energy to accelerate an object from 0.97-0.99 of c as it does to go from 0-0.97 of c!

So in a black hole, even though the gravity can ensnare the light, it would still never have enough energy to accelerate anything past that magical barrier.

Unless of course the Laws of Physics are different within a black hole, but that, my friends we may never know!

P.S. Apologies for

A) the superior tone, it's a habit I struggle to break when I'm talking about physics - maybe I should be a high school teacher!

Sorry for the capitals all over the place - I'm sending from Tapatalk, so there's no italics. There are probably a dozen typo's too!

[badgerchap]

. may i message you with any questions?..

Feel free! But you must also take everything I say with a pinch of salt - I have a habit of spouting as if I know what I'm talking about, but I'm probably a mile off! I'm only a student (albeit a 'mature' [sic] one), so I'm still learning myself

[badgerchap]

"The speed of light remains the same for all observers regardless of the motion of the observer or the source."

Actually I think it's "The speed of light will be the same for all observers in all possible inertial reference frames", but without a discussion of the meaning of the term 'inertial reference frame', it's a bit jargonish!

[Earl]

Hi Earl... I find this hard to get my hear round... If the universe doesn't move how is everything inside it expanding?.. If everything inside it is expanding then doesn't it stand to reason that everything will expand beyond the existence of the universe as we know it?.

its the nothing that is expanding not everything. there is far far more nothing in the universe than something.

[badgerchap]

its the nothing that is expanding not everything. there is far far more nothing in the universe than something.

Yup - it's the universe that expands, not its contents!

[Earl]

Yup - it's the universe that expands, not its contents!

My waistline is an exception to this rule

[badgerchap]

My waistline is an exception to this rule

Ah, then you must be a believer in the Gastronomical Constant

[Ganymede12]

badgerchap you have given me a lot to think about!

Another thing! Could you create a ray gun by super heating a photon and projecting it like a torch?

[badgerchap]

badgerchap you have given me a lot to think about!

Another thing! Could you create a ray gun by super heating a photon and projecting it like a torch?

One word: laser.

Laser stands for Light Amplified Stimulation of Electromagnetic Radiation. A laser is, in extremely basic terms, excited light. The issue with laser guns or ray guns is that whist they are most definitely possible, they are highly impractical, the problem being that they need an awful lot of power to become as dangerous as you would need for a ray gun. The battery you would need for said weapon would be enormous! However, I reckon give it another decade or so, with improvements made in battery technology, they will eventually become practical. If you want to the the world's most badass laser, check out NIF:

https://lasers.llnl.gov/

Now that is one powerful laser, but at the moment it takes something like the power of the entiire US national grid to power. There was an excellent Horizon episode about this called "Horizon: How to build a star on Earth". I can't find a link but search for it on Google, it was a great episode, Prof. Cox at the helm. Definitely worth a look. But basically, a laser excites photons and concentrates them, just like you asked. There is a lot more to it, but in essence, this is what goes on.

[badgerchap]

Correction: make that "Light Amplification by Stimulated Emission of Radiation".