Traveling the Speed of Light

xcellerate said:
we didn't discover dark matter. Its a theory to explain why galaxies act the way they do. You see, galaxies like spiral galaxies don't contain enough mass (that we can see) to explain why they stay together and not spin out.

In the Inflationary theory, average density of matter is equal to exactly the amount required to create a closed universe. Most matter we see is only 10% of the critical density.

The shape of the universe could be explained by einstein theory of relativity which says that the gravity curves space into 3 dimensions, much like placing a bowling ball on a spring mattress which has ball bearings on it. The bowling ball depresses the mattress and the ball bearings come to the bowling ball. So according to einstein the shape of the universe is determined by the average density of the matter.

If this is true, then the universe will never fly apart, nor will it grow back.

Now, if the average density of the universe is greater than the critical density then the universe will be pulled back together by gravity. Omega > 1

However, on the other end if the average density of mattrer in the universe is less than the critical density then the universe will expand foreever, and eventually fly apart. Omega < 1

NOW, if the Omega = 1, then the universe will expand untill the average density equals the critical density and will remain there forever. This means the universe has a curvature of 0.

Universes that have a negative curvature or are flat extend forever, and therefore explain why we have only been able to see such a infinitly small % of the universe.

NOW, if you follow inflationary theory then omega = ~1, which means the average density almost equals the critical density, however when we add up all the visible matter it only equals between 5 and at most 10% of the universe. SO this theory of dark matter was created to explain where the other 90% of the density comes from.

Just to clarify some more, the big bang is pretty widley accepted as how the universe began right? I mean i cant think of better reason, but there are some problems with it.

Having the entire universe compressed into a single point singularity 3*10^-24 cm across. At the level of compression the universe was at the equations we have don't work, so it creates problems for solving.

The big bang is basically when the universe doubles from 3*10^-24 every 10^-33 second, following a doubling acceleration curve. If the average density of the universe had been greater than the critical density during the big bang, omega would have either shot to infinity or dropped, and the universe would have quickly expanded, too fast for anything to form, or collapsed on itself. However, since we are still here it must not have happened. Inflation says that the rapid expansion of the universe forced the universe to flatten out.

woo.
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This is only appliable if the universe is actually expanding. As far as we know, the universe could always have existed, and be infinite. The big bang could just have happend as a fluke, with all the matter haning in a blob in the universe, and now the expanding of the universe is actually just the infinate shockwaves of the bigbang.
 
I believe that we wont be able to accelerate anything bigger than a particle/photon etc at or above the speed of light, but we could travel above the speed of light when compared to it.

One Theory that has always interested me is the N Dimensional Jump (where N is a given dimension), or Hyperspace. Time and Space are perceptions, and are not constant on every plane of existence.
If we 'travel' or 'transfer' to another dimension, we could move a short distance, return to our dimension, and have moved a very large one, or indeed, vice versa. The same could be said for the passage of time in that dimension.

If we can find the right dimension, which fits our wanted perception of time and space, it could be used for transport (i suppose).

i looked for some stuff on the interhyperweb, but gave up after 15 minutes.
 
Traveling at the speed of light causes an increase in the mass of an object. If we were to continue to send it at the speed of light, we would need an infinite amount of energy. Since there is not an infinite amount of energy, we cannot travel at the speed of light for an elongated amount of time.
 
Nice topic (should be in offtopic forums BTW) but I'm not in the mood to read it all right now. However I wonder. If the Universe is infinite and is a sphere or donut shaped and at some point you actually come back to where you've been, what is outside the sphere (donut)? Nothing? It is just something that we are unable to understand. If I sticked my head out of the sphere (lol, just imagine me doing that =)) what would I see? Nothing? Well, how would that look like? How does "nothing" look like, or what does it do if it doesn't look like anything?
 
stinger.aim92 said:
Nice topic (should be in offtopic forums BTW) but I'm not in the mood to read it all right now. However I wonder. If the Universe is infinite and is a sphere or donut shaped and at some point you actually come back to where you've been, what is outside the sphere (donut)? Nothing? It is just something that we are unable to understand. If I sticked my head out of the sphere (lol, just imagine me doing that =)) what would I see? Nothing? Well, how would that look like? How does "nothing" look like, or what does it do if it doesn't look like anything?
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I imagine that there are other Universes out there. I believe that our Universe was created in much the same way as a galaxy just on a much larger scale. I don't feel like going into the details but if your interested take a look at Edwin Hubble's research,classification, and formation of galaxies.
 
I imagine that there are other Universes out there.
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Ah... that's called a metaverse... it was mentioned on Jet Li's movie... though I forgot the title of it...
 
The movie was called The One and they really didn't stick to the science. Our universe is part of a Multiverse made of an infinite amount of other universes. Discover had an aritcle about a Type 3 civilization being able to travel to other universes which was really informative, as you can tell I like science journals and magazines.
 
can someone explain how scientists know how big is the universe? isnt the only answer "guess?"
 
If you are travelling at the speed of light, how the hell do you stop? parachutes!
 
You can't travel at the speed of light. It's not possible.

If you could, you'd be converted to energy, so there would be no more you, anyway. ;)
 
[46] pushit [2] said:
I know this message doesn't belong here, but sense HL basically revovles aroudn physics, I think it' srather fitting. And I think that it would be a nice break from "1000001 Poses using Gary'smod" (no offense, they are pretty damn cool...) and "STEMA IS TEH SUX, I HATE HL2 NO STROY"

Anyway, I was searching through the forums for "quantum physics" and read an interesting thread on traveling the speed of light. Instead of bumping a 3-month old thread, I decided to create a new one...

First of all, let me say that I am not claiming to be an authority on ANY of this material, and most of the ideas were taken from books I've read and other people. I take no credit for these ideas, I'm just regurgitating them with some of my thoughts.

First of all, many people think it is impossible to travel the speed the light. This has not been proven. Many people bring up Einstein to argue this point, and his theory of relativity. Well, Einstein never actually said you couldn't travel the speed of light, he said you couldn't accelerate to the speed of light. This is because if you ever got going that fast your mass would bascially disentegrate into nothing (...I think, one of my friends said that your mass would have to increase nearly the size of the universe....I don't know which one is correct). In other words, there could be other ways to travel the speed of light that have not been discovered or that our human brains just cannot comprehend.

Also, since the early 90s the idea of quantum physics has been researched and experimented with. I know little about this area of physics, but am fascinated by the theory. Sadly, it basically contradicts Einstein's theory of relativity and our idea of the physical world, meaning there could be a whole new door out there that has yet to be opened. And think about this, in the end of the 19th century, many well-renowned scientists said that basically everythign about physics and our physical world had been discovered with a few holes yet to be found. The idea of fiber optics, computers, wireless applicances, microwaves, travelling to the moon, satellites, etc. etc. was impossible. My point is, think of what is yet to come in the next decades...we really cannot even begin to know what might happen and what might be discovered. I only hope I am aroudn to see it.

Please add any comments, and keep it to a mature level.

Mind-boggler: Our range of planets takes up about 1/trillonth of the space of our galaxy...This can give you an idea about how f--king huge our universe is (take into account that there are at least 50 billion visible galaxies...
Click to expand...

Man, I´m sure you´ve already heard of Star Trek ......... I don´t think we´re too far from having Warp Drive Engines.........
 
the multiverse is a cool idea, theres even an experiment! The slit experiment is used to "prove" the multiverse.

Basically, (youve probably all heard it before), you take a piece of paper and cut 2 slits in in very close together, behind the paper is extremely sensative sensors that can pick up the contact of even a proton. You then fire protons one at a time and you end up with a pair of vertical lines made by each proton hitting the sensor. However, if you remove one slit you end up with just a wide band of hits in a diffuse pattern.

The idea that two slits make a pattern of vertical lines when only 1 proton is being fired, is the idea that the other multiverses are interfering with our universe. Because only 1 proton is fired on our universe we can not explain why it forms vertical lines.
 
We need space-folding 'heighliners' from the DUNE books.
 
xcellerate said:
The idea that two slits make a pattern of vertical lines when only 1 proton is being fired, is the idea that the other multiverses are interfering with our universe. Because only 1 proton is fired on our universe we can not explain why it forms vertical lines.
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Actually, a particle can intefere with itself on a probability basis - because like the cat, we don't know it's state until we detect it.

I hate that cat theory and never believed it was true, and neither did Einstein, but seeing as the proved it a while back that shut me up (it didn't shut Einstein up, he shut up ages ago. About when he died).

Oh, and to clear up a common misconception: your mass DOES NOT increase when you go faster - it looks like it does because as you get faster, more force is needed to increase your speed, as if your mass had increased. What actually happens is time goes all relative (that's physics boffin talk for up excrement creek). If you push someone else along near the speed of light for a year, to them you've only been pushing them for a fraction of a second. If you draw a graph of speed and force, you can never quite reach light speed, only get closer and closer - imagine being near a target and constantly moving 50% of the difference between you and it, you can't quite reach it.

And on the subject of a closed universe, as opposed to infinite - there is apparently a way to test for it, which they are supposedly doing. If the universe was say a sphere, travelling to the edge of it would make you "wrap" to the other side of the universe - go far enough in a straight line and you end up where you started kind of thing.
 
Driftlight said:
Actually, that's completely wrong. Say you accelerate up to 99.99% of light speed. According to our natural instincts regarding physics, that photon over there should be at about a dead stop, right? WRONG. Light always moves at light speed, no matter what. This is a basic principle of relativity. Light always moves at the same speed, no matter how fast you're going. So everything would look normal.

Theoretically, if you could somehow accelerate past light speed, then yes your little timetravel thing would work. But you can't. It might be possible to bypass lightspeed using wormholes and such, but it's not possible to accelerate faster than light.
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Yes, as he said, light always moves at the same speed. If I am moving at c/2, then the light in front of me will STILL appear to be going at c. I can't believe how many people pretend they know what they are talking about.
 
Traveling as fast as light is impossible in theory, let alone practice. Tending towards the speed of light is theoretically possible but I'd like to see someone condense the power of the Earth into a ship and somehow multiply it.

Although mathematics has proven over 9 dimensions, which of course unbelievably primitive human brains cant begin to comprehend, using these to somehow travel through our 3 would be nearly impossible, even though it may be one relative millimeter in the 9th dimension to circumnavigate the universe; infinite 3 dimensional energy is required to do so, not to mention the "travel in a straight line" problem, see if you stray even 1/1000,000,000,000th of a meter from a straight line in another dimension seeing as there’s no actual units of measurement your where no where to be found ever.

As for all the bubble theories and the likes, how do you control something which you cannot ever possibly comprehend? With string? Magnetic fields? Ether? It’s not going to happen fellas.
 
ktimekiller said:
can someone explain how scientists know how big is the universe? isnt the only answer "guess?"
Click to expand...

The radius of the universe can be extrapolated from Cosmic Background Radiation. Basically, a bunch of radiation was expelled from the edges of the universe toward the center at the moment of the big bang, and has continued to move inward during the universe's growth. Based on the intensity and other properties of the radiation we see, we can determine at what time after the big bang started that the radiation was emitted (based on what mean temperature the universe had at what time), and thus know how old the radiation is. Then we can relate that to how far away the edge is, and thus make a good calculation as to how big the universe is.

xcellerate said:
the multiverse is a cool idea, theres even an experiment! The slit experiment is used to "prove" the multiverse.

Basically, (youve probably all heard it before), you take a piece of paper and cut 2 slits in in very close together, behind the paper is extremely sensative sensors that can pick up the contact of even a proton. You then fire protons one at a time and you end up with a pair of vertical lines made by each proton hitting the sensor. However, if you remove one slit you end up with just a wide band of hits in a diffuse pattern.

The idea that two slits make a pattern of vertical lines when only 1 proton is being fired, is the idea that the other multiverses are interfering with our universe. Because only 1 proton is fired on our universe we can not explain why it forms vertical lines.
Click to expand...

You've read The Fabric of Reality by David Deutsch, haven't you? :)

I don't believe him, because as ZoFrex said, a photon can interact with itself and will still move in a wave fashion. Besides, the idea of multiverses seems too convenient for me.

As for all the bubble theories and the likes, how do you control something which you cannot ever possibly comprehend? With string? Magnetic fields? Either? It’s not going to happen fellas.
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Not to mention the fact that there's no such thing as absolute position.


and as for the John Titor thing... oi.
 
Considering the fact that we only are using at most two types of matter as a reference point, that leaves all the other types yet to be found and dissected. There are "things" that can get from A to B a lot faster than light :)
 
Grumpy said:
Considering the fact that we only are using at most two types of matter as a reference point, that leaves all the other types yet to be found and dissected. There are "things" that can get from A to B a lot faster than light :)
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What do you mean by "types" of matter? There really aren't types of matter, there's just matter. And still, nothing can travel faster than light, sorry.
 
time to be a little less serious, first off, guys in an infinite universe almost anything is possiable right? Because infinite space= infinite chance for galaxies/planets/stars to exist = infinite chance of someone exactly like you of existing, etc. Sure we're all special, however when you place it over infinity.

p.s. the infinite improbability drive owns j00.
 
I haven't seen anyone post this yet so here goes:

Scientists have already made particles travel faster than the speed of light. I read an article recently where they shot a particle across a measuring plate and saw that it had arrived before it actually left the other side.

So it can be done. Here is a link to another article supporting my statement. In this article when a particle travels faster than light it actually creates a new form of radiation and emits a blue light.

http://www.physlink.com/Education/AskExperts/ae219.cfm
 
Spugmaster said:
I haven't seen anyone post this yet so here goes:

Scientists have already made particles travel faster than the speed of light. I read an article recently where they shot a particle across a measuring plate and saw that it had arrived before it actually left the other side.

So it can be done. Here is a link to another article supporting my statement. In this article when a particle travels faster than light it actually creates a new form of radiation and emits a blue light.

http://www.physlink.com/Education/AskExperts/ae219.cfm
Click to expand...

What you're failing to mention is that the particles are surpassing the speed of light in a medium. It is a known fact that light takes longer to travel from point A to point B in a medium that is more dense than another. The speed at which the particle is moving through the medium is greater than the speed at which the light is moving through the medium. What has neglected mention in all previous posts is that when someone says "nothing can move faster than the speed of light", what they mean is that nothing can move faster than the speed of light in a vacuum.
 
You know that thread you found..I started it.. I think ;)

Anyway..I really enjoy these topics because it sparks alot of conversation about the nature of the universe and it challenges the theories of some very smart people (like Einstine..hope I spelled it right :p ). I've read many things about this and I am very interested in some of the theories. Here is what I believe:

Infinite does not exist..or rather..it is an unknown that we will not achieve because infinite means "forever". I work in a lab enviroment (involving circuits and transmission lines...stuff like that,) and in a lab enviroment people are always trying to achieve an "ideal" microchip or an "ideal" transmission line.

For example: Ideal means if you have a transmission line (lets say some coaxial cable) there would be no losses of any kind, which means the signal would pass through the cable with no resistance and end up at the end of the cable at the exactly same amplitude as it was at the beginning of the cable. This of course will not happen..we can get close but there will not be anything that will be perfect.

What I am getting at is the speed of light would imply perfection. Einstein said that you can't go the speed of light because in order to do so you would have to have an infinite amount of energy to do so. Also you would take up the mass of the entire universe..which is kind of redundant. So in order to go the speed of light you would need a sort of perfect space ship (which will not exist). We can get close just like the coaxial cable but it will not happen. It's true that everybody who works for a computer chip company or any company that works with electronics is trying to make the first ideal device...you know what that implies??..Perfection and so does the speed of light.
 
I think Tesla said it best by calling the theory of relativity "absurd".
 
antaydos said:
What you're failing to mention is that the particles are surpassing the speed of light in a medium. It is a known fact that light takes longer to travel from point A to point B in a medium that is more dense than another. The speed at which the particle is moving through the medium is greater than the speed at which the light is moving through the medium. What has neglected mention in all previous posts is that when someone says "nothing can move faster than the speed of light", what they mean is that nothing can move faster than the speed of light in a vacuum.
Click to expand...

Things can appear to go faster than light by bending spacetime, but nothing can go faster than light. Light is always going at it's speed but sometimes spacetime is manipulated so that it appears to be going slower, it is just traveling a further "distance."
 
it is impossible to accelerate anything with mass up to or beyond the speed of light. The faster a body is moving, the more mass it gains, hence at light speed you would need an infinate force to accelerate the body.
Einstein never said that there aren't things going faster than the speed of light, there may well be something completely uncomprehendable on the otherside of c, who knows.


i just got one question tho, the thing i still don't quite get.....
lets say, your in a ship travelling at 0.8c towards a person. You then shine a light towards that person, the light travels away from you at c but travels towards the person at c aswell, is it just me or is this strange?
 
That's what the Special Theory of Relativty is all about, light to every observer, is always traveling at c, no matter what.
 
Nezill said:
Things can appear to go faster than light by bending spacetime, but nothing can go faster than light. Light is always going at it's speed but sometimes spacetime is manipulated so that it appears to be going slower, it is just traveling a further "distance."
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Yeah ok...lets continue that thought.

How could light appear to be going a slower speed, but ‘really’ be going its normal speed? Light has no coalition to time.
In fact, time itself does not exist; it is simply a human-derived measurement.

Also, how are you certain the speed of light is constant? And what would be the driving force?
 
I love these discussions. Its nice to see that there are some people out there that actually enjoy discussing what others would call a boring topic.

There are some great articles in the latest Astronomy magazine detailing Einsteins life and his theories. From what I've read, its pretty good.

Anyone read Kip Thorne's Black Holes and Time Warps?
 
2 posts up.
c is constant, the speed of light is not.
light can be slowed down, e.g. when it passes through glass or air it is infact travelling slower than when it passes through free space.
light is thought of a wave and particles, the particle-wave duality theorem or whatever, my brains on summer holiday. i may just have dig out some of my notes.
 
The speed of light is constant, not proven, but nothing ever is proven.
There is a strong amount of evidence to suggest it is constant.
Michelson Morley Experiment, to show the speed of light is constant, there is no Ether, or the Ether has immeasurability.
Whatever speed you are moving, you always observe light to be moving at c.
In a medium the light may slow down (see Snell's Law, etc), but c is constant, so other light speed particles, eg neutrinos, travel faster than light through this medium. Maybe it would be better to call c the speed of neutrinos?

When a supernova happens, the neutrinos reach us before the light, because the light needs to pass through the vacuum, which can be considered a low density plasma.

Also time is real, what is with the people who say it isn't.
No it's not a tangible object, but tangibility does not define reality.
If you say time isn't real you can go on to say that space isn't real and therefore the apple isn't real, and get into a matrix style arguement. But reality for me is just the world around me. Let's not get into a matrix (reality/simulation) debate.
 
ktimekiller said:
can someone explain how scientists know how big is the universe? isnt the only answer "guess?"
Click to expand...
I think they're using the hubblespace telescope in order to have a galactic map... :cool:
 
You have to stop seeing things in human terms. You all see light as the defining indicator of speed in our Universe. Light is a by product, a subset of a process that shares a common function across all bi-phasic matter. It is human intellect that puts tags on all things seen and unseen in our world, but the Universe does not care. While nothing can travel faster than light from A to B, things can get from A to B quicker. The Universe is big and mysterious, and unless you listen as well as look, you shall forever be blind.
 
Grumpy said:
You have to stop seeing things in human terms. You all see light as the defining indicator of speed in our Universe. Light is a by product, a subset of a process that shares a common function across all bi-phasic matter. It is human intellect that puts tags on all things seen and unseen in our world, but the Universe does not care. While nothing can travel faster than light from A to B, things can get from A to B quicker. The Universe is big and mysterious, and unless you listen as well as look, you shall forever be blind.
Click to expand...

My problem with what you've been saying is that it's all seemingly hogwash. You're not citing anything to back up what you're saying, nor is there anything to be cited. They're merely your own speculations.

kirovman said:
The speed of light is constant, not proven, but nothing ever is proven.
There is a strong amount of evidence to suggest it is constant.
Michelson Morley Experiment, to show the speed of light is constant, there is no Ether, or the Ether has immeasurability.
Whatever speed you are moving, you always observe light to be moving at c.
In a medium the light may slow down (see Snell's Law, etc), but c is constant, so other light speed particles, eg neutrinos, travel faster than light through this medium. Maybe it would be better to call c the speed of neutrinos?

When a supernova happens, the neutrinos reach us before the light, because the light needs to pass through the vacuum, which can be considered a low density plasma.

Also time is real, what is with the people who say it isn't.
No it's not a tangible object, but tangibility does not define reality.
If you say time isn't real you can go on to say that space isn't real and therefore the apple isn't real, and get into a matrix style arguement. But reality for me is just the world around me. Let's not get into a matrix (reality/simulation) debate.
Click to expand...

What he said.
 
TigerRei said:
You're right, E=MC^2 is the formula to show how much mass can be converted into energy and vice versa, but it is also an equation to show relativity.
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Well, as I understand it, E=MC^2 is Standard Relativity, which shows how much energy you can get from matter, while the stuff about apparent mass increase at high speeds is dealt with by Special Relativity, which uses a different, though related, set of equations.

As for the very small black holes, correct. But they're made by particle accelerators that smash very small particles at extremely high speeds (near the speed of light) into each other. These black holes however decay within a billionth of a second. This was first done in 2003 in Switzerland. Basically it just proves my point about black holes having mass, not all of them being infinitely massive.
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I was merely widening the stated size range.

And as for the warp bubble theory, it doesnt have any substantial evidence to show how quick it can move objects, or any real evidence that itll work yet. It's just that, theory. The Higgs Boson right now is just a theory. It's what I was explaining.
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And I wasn't impugning it. Merely stating that 3000C is a nifty speed to be swishing around at.
 
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