Speed of Light, and space travel.

Message boards : Science (non-SETI) : Speed of Light, and space travel.
Message board moderation

To post messages, you must log in.

Previous · 1 · 2 · 3 · 4 · 5 · Next

AuthorMessage
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 805228 - Posted: 5 Sep 2008, 9:29:11 UTC - in response to Message 800033.  

The vacuum is not quite empty. It has an average density of a molecule or two, in Quantum mechanics particles and anti-particles are popping into and out of existence all the time.

The Universe expands right now at a speed faster than light --i.e. the farthest reaches of space are receding from us at a speed exceeding that of light. During inflation of the early universe this was also true.

Regards,

Bill


Hello Bill
I have thought on this and still wonder... if space is expanding and it is expanding faster than light, we cant forget that matter is still matter and "theoretically" it cant travel faster than light, so following it through the matter out at the edge of space cant travel faster than light so it cant keep up with the expansion of space so it cant be travelling faster than light... chicken and egg situation. (working on the lightspeed issue for all matter)

So does matter get left behind in the expansion process... or is our current concept of expansion also a misobservation of an unknown event.

If it is true that some parts of the universe are retreating faster than light speed then we have a relativity problem, as matter is matter even if its far away. Or else... there is a faster than light phenomenon and it must relate to the nature of space itself, which says to me we are back to emf issues and atomic bonding.

You could argue that it's the space itself that is expanding--causing the mass (stars) to move away from each other--at great distances the stars are receding from us at a speed faster than light.

Quantum entanglement-a la Schroedinger"s cat-and all claims that the state of paired particles are not determined until an observer looks at one and notes it's spin --this supposedly determines that the opposite spin is now imparted to the companion particle instantaneously. Supposedly the particles are in both states until someone looks. This is hard for me to accept I probably dont know about experiments that might confirm this--but suppose that it is true-in this case no useful information is transmitted since the original observer cannot choose the spin state (so to transmit a 0 or a 1--lets say). It may be more correct to say that information cannot be transmitted faster than the speed of light.

Quantum weirdness is hard to accept --like Schroedinger's cat being neither alive or dead until an observer looks at it. It seems to me that the cat is either in one of the states but that nobody knows it (the information is not available) until someone looks. Seems to me that the cat itself would qualify as an observer anyway.
ID: 805228 · Report as offensive
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 805231 - Posted: 5 Sep 2008, 9:48:14 UTC - in response to Message 805228.  

The vacuum is not quite empty. It has an average density of a molecule or two, in Quantum mechanics particles and anti-particles are popping into and out of existence all the time.

The Universe expands right now at a speed faster than light --i.e. the farthest reaches of space are receding from us at a speed exceeding that of light. During inflation of the early universe this was also true.

Regards,

Bill


Hello Bill
I have thought on this and still wonder... if space is expanding and it is expanding faster than light, we cant forget that matter is still matter and "theoretically" it cant travel faster than light, so following it through the matter out at the edge of space cant travel faster than light so it cant keep up with the expansion of space so it cant be travelling faster than light... chicken and egg situation. (working on the lightspeed issue for all matter)

So does matter get left behind in the expansion process... or is our current concept of expansion also a misobservation of an unknown event.

If it is true that some parts of the universe are retreating faster than light speed then we have a relativity problem, as matter is matter even if its far away. Or else... there is a faster than light phenomenon and it must relate to the nature of space itself, which says to me we are back to emf issues and atomic bonding.

You could argue that it's the space itself that is expanding--causing the mass (stars) to move away from each other--at great distances the stars are receding from us at a speed faster than light.

Quantum entanglement-a la Schroedinger"s cat-and all claims that the state of paired particles are not determined until an observer looks at one and notes it's spin --this supposedly determines that the opposite spin is now imparted to the companion particle instantaneously. Supposedly the particles are in both states until someone looks. This is hard for me to accept I probably dont know about experiments that might confirm this--but suppose that it is true-in this case no useful information is transmitted since the original observer cannot choose the spin state (so to transmit a 0 or a 1--lets say). It may be more correct to say that information cannot be transmitted faster than the speed of light.

Quantum weirdness is hard to accept --like Schroedinger's cat being neither alive or dead until an observer looks at it. It seems to me that the cat is either in one of the states but that nobody knows it (the information is not available) until someone looks. Seems to me that the cat itself would qualify as an observer anyway.

On the Internet nobody knows you are a cat!
Tullio
ID: 805231 · Report as offensive
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 805235 - Posted: 5 Sep 2008, 9:55:10 UTC
Last modified: 5 Sep 2008, 9:57:07 UTC

Hello Tullio,
Bona Sera

Got up a little early this morning--Back to bed now. It's a dog that nobody knows--as per the New Yorker Cartoon.

Ciao piasano

Daddio
ID: 805235 · Report as offensive
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 805248 - Posted: 5 Sep 2008, 11:42:44 UTC - in response to Message 805235.  
Last modified: 5 Sep 2008, 11:52:53 UTC

Hello Tullio,
Bona Sera

Got up a little early this morning--Back to bed now. It's a dog that nobody knows--as per the New Yorker Cartoon.

Ciao piasano

Daddio

You had given me an idea. If Schroedinger's cat were able to transmit a simple signal by pushing a lever (yes means I am alive. No signal means I am dead). there would be no paradox (This was called the dead man's handle in railroads: if nobody pushes the lever the trains stops). How to make him push the lever? Give him some food if he pushes it.Cheers.
Tullio
ID: 805248 · Report as offensive
Profile Keck_Komputers
Volunteer tester
Avatar

Send message
Joined: 4 Jul 99
Posts: 1575
Credit: 4,152,111
RAC: 1
United States
Message 805388 - Posted: 6 Sep 2008, 0:59:58 UTC

Observing a signal generated by the cat is a way of observing the cat.

Relativity may only apply locally. Of course in this case "locally" means about 13 billion light years.
BOINC WIKI

BOINCing since 2002/12/8
ID: 805388 · Report as offensive
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 805469 - Posted: 6 Sep 2008, 8:24:10 UTC - in response to Message 805388.  

Observing a signal generated by the cat is a way of observing the cat.

Relativity may only apply locally. Of course in this case "locally" means about 13 billion light years.


The cat is observing itself--there may be no need for it to communicate to another observer.
ID: 805469 · Report as offensive
Profile tullio
Volunteer tester

Send message
Joined: 9 Apr 04
Posts: 8797
Credit: 2,930,782
RAC: 1
Italy
Message 805488 - Posted: 6 Sep 2008, 10:40:26 UTC - in response to Message 805469.  

Observing a signal generated by the cat is a way of observing the cat.

Relativity may only apply locally. Of course in this case "locally" means about 13 billion light years.


The cat is observing itself--there may be no need for it to communicate to another observer.

Yes but cats don't publish in Physical Review, Nature, Science, Physics, Nuovo Cimento etc. Publish or perish.
Tullio
ID: 805488 · Report as offensive
Profile Graeme Stretton
Avatar

Send message
Joined: 2 Nov 01
Posts: 392
Credit: 349,012
RAC: 0
Australia
Message 810553 - Posted: 21 Sep 2008, 9:51:43 UTC

Hi all.

Just a few points.

1. No one seems to have allowed for time dilation effects on the crew of a near light speed ship. It may be 4 years to the nearest star at light speed but the crew would experience that as a much shorter time. If you could get the ship to light speed it would arrive in 0 time. At less than light speed our heroic 20 year old pilot could arrive back to find his twin brother was a great grandfather.
At light speed, assuming instant acceleration, the ship would arrive at the destination instantly. Or to put it another way, it would arrive at the same time it left.



2. Information can be transmitted faster than light by what Einstein called "Spooky action at a distance". In this 2 or more, particles are placed into a state called a superposition where they have identical but unknown states.
One particle can then be moved a distance away, across the galaxy or even the universe, and when the particle still here is observed the distant particle will assume the same state as the particle that was observed. This occurs instantly no matter how far the particles are apart.

3. Putting all the problems with light speed, if you actually did get to light speed time dilation would become infinite and you would arrive at your chosen co-ordinates at the end of time with no way back. Not a good idea.

4. Another small problem, at light speed the ship would have infinite mass and therefore the universe would start to collapse on you. Ouch.


Well, there's my 2 bobs worth.



Qunpu' lo'taHmo' jIH yItamQo'
ID: 810553 · Report as offensive
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 810611 - Posted: 21 Sep 2008, 15:55:33 UTC - in response to Message 810553.  

Hi all.

Just a few points.

1. No one seems to have allowed for time dilation effects on the crew of a near light speed ship. It may be 4 years to the nearest star at light speed but the crew would experience that as a much shorter time. If you could get the ship to light speed it would arrive in 0 time. At less than light speed our heroic 20 year old pilot could arrive back to find his twin brother was a great grandfather.
At light speed, assuming instant acceleration, the ship would arrive at the destination instantly. Or to put it another way, it would arrive at the same time it left.



2. Information can be transmitted faster than light by what Einstein called "Spooky action at a distance". In this 2 or more, particles are placed into a state called a superposition where they have identical but unknown states.
One particle can then be moved a distance away, across the galaxy or even the universe, and when the particle still here is observed the distant particle will assume the same state as the particle that was observed. This occurs instantly no matter how far the particles are apart.

3. Putting all the problems with light speed, if you actually did get to light speed time dilation would become infinite and you would arrive at your chosen co-ordinates at the end of time with no way back. Not a good idea.

4. Another small problem, at light speed the ship would have infinite mass and therefore the universe would start to collapse on you. Ouch.


Well, there's my 2 bobs worth.

Some recreational thinking ---Well--something to ponder. Since you cannot select the state of the entangled particle you cannot send useful information. Also, if a light beam traveled in zero time to a distant star than why would it take eight years to send and receive a round trip message to this place.

Also if space became flat or zero length at the speed of light then why are we looking back in time as we gaze to the heavens. --shouldn't we being seeing what is happening now as we look towards far away galaxies or is it just the light beam that knows what is happening now ??. Two cents worth here
ID: 810611 · Report as offensive
Profile Graeme Stretton
Avatar

Send message
Joined: 2 Nov 01
Posts: 392
Credit: 349,012
RAC: 0
Australia
Message 811256 - Posted: 23 Sep 2008, 12:52:36 UTC

Some recreational thinking ---Well--something to ponder. Since you cannot select the state of the entangled particle you cannot send useful information. Also, if a light beam traveled in zero time to a distant star than why would it take eight years to send and receive a round trip message to this place.

Also if space became flat or zero length at the speed of light then why are we looking back in time as we gaze to the heavens. --shouldn't we being seeing what is happening now as we look towards far away galaxies or is it just the light beam that knows what is happening now ??. Two cents worth here

You have given me some more to think about. Thank you William.

Not really sure about selecting states etc. I was only pointing out that there are things that occur at faster than light speed.

As for the round trip time, why years? I would send many billions of entangled particles in the first trip then communication could be maintained for a very long time.

As for the light arriving in zero time that is from the photons point of view, from our frame of reference the light would appear to be traveling at it's normal pace.

Or perhaps the slow communication is caused by a really slow ping. P-)

TTFN

Qunpu' lo'taHmo' jIH yItamQo'
ID: 811256 · Report as offensive
Archer

Send message
Joined: 30 May 99
Posts: 20
Credit: 1,106,422
RAC: 0
United States
Message 827962 - Posted: 7 Nov 2008, 20:30:00 UTC - in response to Message 765528.  


Would that not imply that the speed of light through space would be slower than the speed of light in a perfect vacuum?

And by that fact, would it then become possible to exceed the speed of light in an imperfect vacuum such as space?

If, in a vacuum, the speed of light is 26,981,512.2 meters per second, or 90% the speed of light in a vacuum, and a ship accelerates to 99%c, as dictated by the constant 'c', then the craft has essentially exceeded the speed of light.


The only "speed of light" that you're not allowed to exceed is that in a "true" vacuum. Things exceed the speed of light all the time in various media *other* than a vacuum. For example, the Cerenkov (sp?) radiation that you see in the water around radioactive materials is due to particles traveling faster than the speed of light in the water.

ID: 827962 · Report as offensive
Profile William Rothamel
Avatar

Send message
Joined: 25 Oct 06
Posts: 3756
Credit: 1,999,735
RAC: 4
United States
Message 828604 - Posted: 9 Nov 2008, 10:52:04 UTC

If something were to travel faster than the speed of light I don't think that we could see it.

That's why we can't see all of the Universe since at great distances the effect of space expansion causes those parts of the Universe to rush away from us at faster than the speed of light.
ID: 828604 · Report as offensive
Profile ML1
Volunteer moderator
Volunteer tester

Send message
Joined: 25 Nov 01
Posts: 20435
Credit: 7,508,002
RAC: 20
United Kingdom
Message 828632 - Posted: 9 Nov 2008, 14:13:21 UTC - in response to Message 828604.  
Last modified: 9 Nov 2008, 14:13:42 UTC

If something were to travel faster than the speed of light I don't think that we could see it. ...

Instead, you may see whatever form of Cherenkov radiation...

Keep searchin',
Martin
See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)
ID: 828632 · Report as offensive
Profile kasule francis
Avatar

Send message
Joined: 9 Jul 08
Posts: 293
Credit: 104,493
RAC: 0
Uganda
Message 836209 - Posted: 1 Dec 2008, 18:51:10 UTC - in response to Message 828604.  
Last modified: 1 Dec 2008, 19:00:53 UTC

I believe that no matter can travel faster than light for one reason atoms cant exist at that state the fall apart because it may seem its the escape velocity out of atoms orbit just like earth has one as for universe moving faster than light its some kind of illusion been created by some property we are yet to discover possible a mirror of sorts objects seen in a mirror seem faster .
We choose to go to the moon and to do other things, we choose to go to the moon not because its easy but because its hard. kennedy
ID: 836209 · Report as offensive
Profile Lynn Special Project $75 donor
Volunteer tester
Avatar

Send message
Joined: 20 Nov 00
Posts: 14162
Credit: 79,603,650
RAC: 123
United States
Message 836402 - Posted: 2 Dec 2008, 7:50:42 UTC - in response to Message 836209.  

I watched the Universe season three, and according to those wacko physicist sceintists, in the future they think it will be possible to travel faster than the speed of light. Albert Einstein, could be proven wrong. (Hoping)
ID: 836402 · Report as offensive
Profile kasule francis
Avatar

Send message
Joined: 9 Jul 08
Posts: 293
Credit: 104,493
RAC: 0
Uganda
Message 836437 - Posted: 2 Dec 2008, 11:15:21 UTC - in response to Message 836402.  

The problem why traveling faster than speed of light will never be possible is because of dynamics involved its a point that can best be described in terms of gravity and electromagetic properties of electrons,if you use that principle you will beyond doubt see that it can never be possible,the speed of light is like a line dividing what is energy and what is mass i dont know even if particles like neutrons ,electrons,protons can exit at greater than speed of light

if you want a detailed explanation of what exactly goes on at that point so you can see if its true or not i would be willing to send it to you i wont go into detail here coz it may bore some
We choose to go to the moon and to do other things, we choose to go to the moon not because its easy but because its hard. kennedy
ID: 836437 · Report as offensive
Profile Gary Charpentier Crowdfunding Project Donor*Special Project $75 donorSpecial Project $250 donor
Volunteer tester
Avatar

Send message
Joined: 25 Dec 00
Posts: 30719
Credit: 53,134,872
RAC: 32
United States
Message 836755 - Posted: 3 Dec 2008, 17:45:03 UTC - in response to Message 836402.  

We are made of stuff that can't move FTL. It will never be possible for us to travel FTL. That doesn't mean that some things don't move FTL. Pauli exclusion states are one item that does travel FTL. So it may be possible for us one day to move information FTL.

ID: 836755 · Report as offensive
tom-PC

Send message
Joined: 2 Dec 08
Posts: 1
Credit: 137,573
RAC: 0
United States
Message 836772 - Posted: 3 Dec 2008, 20:56:50 UTC

Particles can and do travel faster than light (local definition). That's what causes Cerenkov radiation. Several classic physics experiments depend on having particles which go faster than the local speed of light. The explicit statement of Einstein's prohibition is that "no particle can exceed the speed of light as determined in a vacuum."
ID: 836772 · Report as offensive
Profile kasule francis
Avatar

Send message
Joined: 9 Jul 08
Posts: 293
Credit: 104,493
RAC: 0
Uganda
Message 836890 - Posted: 4 Dec 2008, 6:40:47 UTC - in response to Message 836772.  
Last modified: 4 Dec 2008, 6:46:34 UTC

your still travelling in a given direction but not as a atoms but energy at that state you cant be made of several components theoretically you should go back to your original state when you drop speed.we have to differentiate particles electrons,neutrons,protons may travel at speed of light atoms no.
We choose to go to the moon and to do other things, we choose to go to the moon not because its easy but because its hard. kennedy
ID: 836890 · Report as offensive
Profile Keenan

Send message
Joined: 30 Nov 08
Posts: 4
Credit: 1,730
RAC: 0
Canada
Message 837846 - Posted: 7 Dec 2008, 23:29:40 UTC
Last modified: 7 Dec 2008, 23:35:40 UTC

Cool thread, In biology, a hot topic right now is quantum tunneling in electron transfer chains. Where these electrons tunnel through energy barriers without matching the kinetic energy needed to actually overcome them. This is a really big discovery for the wave aspect of the wave-particle theory of an electron.

(Now back to the foundations) welll electromagnetic radiation moves at the speed of light. These are electrons acting in a manner characteristic of electromagnetic radiation (through energy barriers no less). And electrons have mass.. Conclusion: Quantum mechanics is about to throw a big time wrench in our pretty little machine. Einstein was only wrong on one count, and that was exactly this.. the dual nature of electrons which may allow for instantaneous tunneling. (hmmm preposterous...!;])

There are sooo many applicable theories out there, maybe we're (metaphorically) trying to apply steam power to a situation which requires fossil fuel combustion!

http://en.wikipedia.org/wiki/Quantum_tunneling

But Hey.. I'm a bio major taught this by a chem prof in a post full of physicists, who knows lol.

EDIT: Isn't this what they're doing right now with that giant particle accelerator..? O_o Trying to figure out the nature of mass? Maybe a possible conversion of mass during quantum tunneling? Too bad the thing broke down..)
ID: 837846 · Report as offensive
Previous · 1 · 2 · 3 · 4 · 5 · Next

Message boards : Science (non-SETI) : Speed of Light, and space travel.


 
©2024 University of California
 
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.