4 of 16
4
Faster than the speed of light?
Posted: 17 October 2007 11:12 AM   [ Ignore ]   [ # 46 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  573
Joined  2007-08-21

It would be cool if within our posts we could insert sort a whiteboard in which we could draw on. Then we could draw little physical representations of our ideas as needed.

 Signature 

Vi veri veniversum vivus vici

Profile
 
 
Posted: 17 October 2007 01:38 PM   [ Ignore ]   [ # 47 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29

Hmm, I can’t send the email to Krauss. It wouldn’t be fair to Narwhol. They are both physicists and just because Krauss is more famous than Narwhol doesn’t necessarily mean that Krauss must be right and Narwhol wrong. That said, Narwhol, it would be great if you could explain your argument a little more clearly. Please!

Profile
 
 
Posted: 17 October 2007 02:15 PM   [ Ignore ]   [ # 48 ]
Administrator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  15305
Joined  2006-02-14
George - 17 October 2007 01:38 PM

Hmm, I can’t send the email to Krauss. It wouldn’t be fair to Narwhol. They are both physicists and just because Krauss is more famous than Narwhol doesn’t necessarily mean that Krauss must be right and Narwhol wrong. That said, Narwhol, it would be great if you could explain your argument a little more clearly. Please!

Why wouldn’t it be fair? You don’t have to accept what either of them say (you could even decide that Narwhol’s is better reasoned!), but two opinions are better than one. Also, we do know that Krauss is a physicist. I will take Narwhol at his word that he is a physicist as well, but just keep in mind this cartoon ...

wink

 Signature 

Doug

-:- -:—:- -:—:- -:—:- -:—:- -:—:-

El sueño de la razón produce monstruos

Profile
 
 
Posted: 17 October 2007 03:11 PM   [ Ignore ]   [ # 49 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29

LOL  LOL

Would you believe me if I told I was a physicist? And does it matter anyway? The fact that Schliemann was a businessman and not an archeologist didn’t prevent him from finding Troy.

Profile
 
 
Posted: 17 October 2007 03:15 PM   [ Ignore ]   [ # 50 ]
Administrator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  15305
Joined  2006-02-14

Exactly. But in the case of physics, which is something of a complex field of study, I will take the word of the physics community. When I hear something that sounds patently false, as I have here, I will ask for clarification and other opinions/evidence from the relevant community, however.

 Signature 

Doug

-:- -:—:- -:—:- -:—:- -:—:- -:—:-

El sueño de la razón produce monstruos

Profile
 
 
Posted: 17 October 2007 03:38 PM   [ Ignore ]   [ # 51 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29
dougsmith - 17 October 2007 03:15 PM

physics, which is something of a complex field of study

I just want to add that this is the reason why I wouldn’t hold it against Narwhol if he was not capable of describing his argument “more clearly” (as I stated previously) to a 5-year old (that’s me). If you do have something to add, Narwhol, please speak to Doug; I’ll try to follow if I can.

Profile
 
 
Posted: 18 October 2007 09:41 AM   [ Ignore ]   [ # 52 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29

I am wondering if the mass (my fingers) required to produce enough energy to hold and move the pencil would be so dense that it would have to resolve in creating a black hole.  How big would my hand have to be so that I could distribute the necessary force needed to move the pencil without creating a black hole? Bigger than the sun?

I think I am going mad… grrr

Profile
 
 
Posted: 18 October 2007 10:04 AM   [ Ignore ]   [ # 53 ]
Administrator
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  15305
Joined  2006-02-14

Well, I don’t think you need a lot of mass to move this huge pencil. What you do need, however, is a lot of energy.

But again, let’s assume the pencil is in the vacuum of space and is 93 million miles long. You would be able to move the end closest to you back and forth without difficulty. Wood is flexible and would bend. But any work you put into it at your end (as a normal human) would not go very far before petering out, I think.

 Signature 

Doug

-:- -:—:- -:—:- -:—:- -:—:- -:—:-

El sueño de la razón produce monstruos

Profile
 
 
Posted: 19 October 2007 03:56 PM   [ Ignore ]   [ # 54 ]
Member
Avatar
RankRankRankRankRankRank
Total Posts:  137
Joined  2007-09-28

My 2 pence,

the message will move at the speed of sound in a pencil.

According to f=ma, to move any object instantaneously would require infinate ammounts of energy. now unless the guy getting the good tan has really been working out, I think that unlikely.

if this really were going to work, we would be doing it already on earth!!!!!

Ski.

 Signature 

hmmmmm  π

Profile
 
 
Posted: 19 October 2007 04:27 PM   [ Ignore ]   [ # 55 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29
SkiCarver - 19 October 2007 03:56 PM

the message will move at the speed of sound in a pencil.

Not possible. Imagine a train that is one kilometer long. (Not impossible in reality, I believe.) The moment the locomotive moves, the last car will move simultaneously (obviously the wagons need to be touching each other perfectly). Now imagine an aircraft flying at Mach’s number. It would take the aircraft almost three seconds to make it across the distance of one kilometer.

[ Edited: 19 October 2007 04:33 PM by George ]
Profile
 
 
Posted: 19 October 2007 04:49 PM   [ Ignore ]   [ # 56 ]
Member
Avatar
RankRankRankRankRankRank
Total Posts:  137
Joined  2007-09-28
George - 19 October 2007 04:27 PM
SkiCarver - 19 October 2007 03:56 PM

the message will move at the speed of sound in a pencil.

Not possible. Imagine a train that is one kilometer long. (Not impossible in reality, I believe.) The moment the locomotive moves, the last car will move simultaneously (obviously the wagons need to be touching each other perfectly). Now imagine an aircraft flying at Mach’s number. It would take the aircraft almost three seconds to make it across the distance of one kilometer.

my bold above.

this is incorrect. assuming that the links are ‘perfect’ as you say. the ‘message’ that the locomotive has started, will be transmitted to the last carrage, via through the other carrages, at ‘the speed of sound in a train carrage’. ALL, materials have elasticity - that is every material, substance, matter… whatever in the universe. as the loco pulls the first carrage it will stretch ever so slightly. that stretch will propagate through the first carrage, to the next, and so on, at the speed of sound in a train carrage.

imagine a solid bar of steel. if you push on one end the ‘signal’ of that push will travel at the speed of sound in steel. so if you hit the end of the bar (which is NO different physically from a simple push) the sound will NOT be heard at the other end instantly. the impulse will travel down the bar as a compression wave.

FYI, the speed of sound in a solid (steel for example) is, i believe, roughly 15 times that of the speed of sound in air. so the analogy with the plane is incorrect.

the only reason we do not notice this train carrage propagation normally, is that steel is VERY stiff. if we made a train out of rubber, we can all imagine that the first carrage will stretch when pulled, then the second will stretch, then the third and so on. it is the same with steel or any other material, except in degrees.

Ski.

 Signature 

hmmmmm  π

Profile
 
 
Posted: 19 October 2007 04:49 PM   [ Ignore ]   [ # 57 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  731
Joined  2007-06-20

Steel stretches.  Steel springs and steel rail cars stretch.  The difference is a matter of degree.  Pull on one end of a Slinky toy and the other end will move after a noticeable delay.  The delay in the long train isn’t easily noticeable but it is there.

http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm

 Signature 

PC

Profile
 
 
Posted: 19 October 2007 04:52 PM   [ Ignore ]   [ # 58 ]
Member
Avatar
RankRankRankRankRankRank
Total Posts:  137
Joined  2007-09-28
the PC apeman - 19 October 2007 04:49 PM

Steel stretches.  Steel springs and steel rail cars stretch.  The difference is a matter of degree.  Pull on one end of a Slinky toy and the other end will move after a noticeable delay.  The delay in the long train isn’t easily noticeable but it is there.

http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strength.htm

sorry dude, i beat you to it!!!!

Ski.

 Signature 

hmmmmm  π

Profile
 
 
Posted: 19 October 2007 05:20 PM   [ Ignore ]   [ # 59 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  731
Joined  2007-06-20
SkiCarver - 19 October 2007 04:52 PM

sorry dude, i beat you to it!!!!

Ski.

Well, I had to write my response using a 93 million mile long pencil while sitting in the very last rail car.  I’m surprised it got through at all.
wink

 Signature 

PC

Profile
 
 
Posted: 19 October 2007 06:50 PM   [ Ignore ]   [ # 60 ]
Sr. Member
Avatar
RankRankRankRankRankRankRankRankRankRank
Total Posts:  9282
Joined  2006-08-29
SkiCarver - 19 October 2007 04:49 PM
George - 19 October 2007 04:27 PM
SkiCarver - 19 October 2007 03:56 PM

the message will move at the speed of sound in a pencil.

Not possible. Imagine a train that is one kilometer long. (Not impossible in reality, I believe.) The moment the locomotive moves, the last car will move simultaneously (obviously the wagons need to be touching each other perfectly). Now imagine an aircraft flying at Mach’s number. It would take the aircraft almost three seconds to make it across the distance of one kilometer.

my bold above.

this is incorrect. assuming that the links are ‘perfect’ as you say. the ‘message’ that the locomotive has started, will be transmitted to the last carrage, via through the other carrages, at ‘the speed of sound in a train carrage’. ALL, materials have elasticity - that is every material, substance, matter… whatever in the universe. as the loco pulls the first carrage it will stretch ever so slightly. that stretch will propagate through the first carrage, to the next, and so on, at the speed of sound in a train carrage.

imagine a solid bar of steel. if you push on one end the ‘signal’ of that push will travel at the speed of sound in steel. so if you hit the end of the bar (which is NO different physically from a simple push) the sound will NOT be heard at the other end instantly. the impulse will travel down the bar as a compression wave.

FYI, the speed of sound in a solid (steel for example) is, i believe, roughly 15 times that of the speed of sound in air. so the analogy with the plane is incorrect.

the only reason we do not notice this train carrage propagation normally, is that steel is VERY stiff. if we made a train out of rubber, we can all imagine that the first carrage will stretch when pulled, then the second will stretch, then the third and so on. it is the same with steel or any other material, except in degrees.

Ski.

Are you saying that if I were to hit one-kilometer long steel pole with a hammer, the impact (not the sound, I don’ care about the sound) would be felt on the other side after three seconds? This is absurd…

Profile
 
 
   
4 of 16
4