Originally posted by StoicLike I said. Not true.
Someone once said that if an object made of pure iron the size of a football stadium hit a planet moving at the speed of light, that it would destroy our entire universe. The Flash would be moving multiple times that speed based on his top speed feats in comics. Which would also make him far larger in terms of mass than a planet, and with the Speed Force shielding him, he would be far sturdier than iron. Just something to think about. [
Originally posted by Black bolt z
Whoever said that was wrong.
Technically they were somewhat right, but the way it's phrased here is disingenuous.
Any amount of mass moving at the speed of light will have infinite energy, and if it hits something it would release a blast of infinite energy expanding in every direction at the speed of light.
Now this wouldn't actually destroy the universe, at most it would destroy everything in the universe (which is different from destroying the universe itself, i.e. the space-time continuum). Even so, as the blast would only expand at the speed of light, it would take billions of years to do so.
However even allowing for billions of years, there are parts of the universe that are expanding away from us faster than the speed of light (this is possible because it is not matter or energy which is moving at that speed, but the space-time they are embedded within). So even given infinite time, such a blast of infinite energy would not even manage to consume the entire universe.
Now there are many characters/objects/entities in fiction that can move at the speed of light. Could any of them actually do such a thing? Well, apart from cosmic - type beings that actually have universe - level feats and stated to have "infinite power" (like Cosmic Cubes), I doubt it.
In fiction, there is usually some kind of "cheat" against relativity that allows lightspeed travel for objects with mass, such as space/time warping, hyperspace/other dimensions, speedforce, etc.
Another part of the post seemed to imply that something going faster than light would be even more powerful/dangerous, when that is not true. As, according to our current understanding of physics, it's impossible for any mass/energy to accelerate to a speed greater than lightspeed, we don't know how much energy such an object would have. Equations for kinetic energy break down past that barrier, and give you nonsensical answers (like imaginary/complex numbers).
So, in real life, if the Earth was hit by an object moving at twice the speed of light, what would happen?
We don't know.
It could destroy the universe, or it could just pass through the earth harmlessly and nothing would happen at all. Or any one of an infinite amount of other possible outcomes.
Originally posted by Black bolt z
Like I said. Not true.
A complete relativistic relation is
E2 = (m c2)2 = (m0c2)2 + (pc)2
where pc = momentum in energy units (divide by c to get momentum) (note: the mass used in the momentum is the relativistic mass)
E = total energy
m = relativistic mass
m0 = rest mass
Example problem: If a moving neutral particle decays into two photons, a 500-MeV photon and a 600-MeV photon, with an opening angle of 60 degrees, what is the rest mass of the neutral perticle?
After balancing transverse momentum, the longitudinal momentum (pc units) is
pc = 600 cos(27 degrees) + 500 cos(33 degrees) = 953.94 MeV
E = 500 + 600 = 1100 MeV
Therefore
m0c2 = sqrt[11002 - 953.942] = 547.72 MeV
The closest particle is the eta meson, with a rest mass of 547.30 MeV.
The momentum beta of the neutral particle = 953.94/1100 = 0.8672
So velocity v = .8672 x 3 x 108 meters per sec = 2.599 x 108 meters per sec
I'm not that smart, but I can understand what is being said here, although I do not know how to figure the solution to higher rates of speed when trying to figure out the higher rates of velocity vs mass. But since you appear to know, why don't you do the math, and get back to me once you figure it out.
Originally posted by Endless MikeSee. An explanation that actually makes sense. And is true.
Technically they were somewhat right, but the way it's phrased here is disingenuous.Any amount of mass moving at the speed of light will have infinite energy, and if it hits something it would release a blast of infinite energy expanding in every direction at the speed of light.
Now this wouldn't actually destroy the universe, at most it would destroy everything in the universe (which is different from destroying the universe itself, i.e. the space-time continuum). Even so, as the blast would only expand at the speed of light, it would take billions of years to do so.
However even allowing for billions of years, there are parts of the universe that are expanding away from us faster than the speed of light (this is possible because it is not matter or energy which is moving at that speed, but the space-time they are embedded within). So even given infinite time, such a blast of infinite energy would not even manage to consume the entire universe.
Now there are many characters/objects/entities in fiction that can move at the speed of light. Could any of them actually do such a thing? Well, apart from cosmic - type beings that actually have universe - level feats and stated to have "infinite power" (like Cosmic Cubes), I doubt it.
In fiction, there is usually some kind of "cheat" against relativity that allows lightspeed travel for objects with mass, such as space/time warping, hyperspace/other dimensions, speedforce, etc.
Another part of the post seemed to imply that something going faster than light would be even more powerful/dangerous, when that is not true. As, according to our current understanding of physics, it's impossible for any mass/energy to accelerate to a speed greater than lightspeed, we don't know how much energy such an object would have. Equations for kinetic energy break down past that barrier, and give you nonsensical answers (like imaginary/complex numbers).
So, in real life, if the Earth was hit by an object moving at twice the speed of light, what would happen?
We don't know.
It could destroy the universe, or it could just pass through the earth harmlessly and nothing would happen at all. Or any one of an infinite amount of other possible outcomes.
Careful Stoic, you're veering into using real world logic and applying it to comics...
But EndlessMike is right. As you approach lightspeed, you approach infinity.
Twice lightspeed does not mean twice infinity, and even if it did, its kinda meaningless.
Back to the issue at hand. Although Flash travels at multiples of lightspeed, I don't think it means he has multiples of infinite mass behind his punches. So it would do the same damage as a lightspeed IMP, IMO.
Originally posted by DarkSaint85
Careful Stoic, you're veering into using real world logic and applying it to comics...But EndlessMike is right. As you approach lightspeed, you approach infinity.
Twice lightspeed does not mean twice infinity, and even if it did, its kinda meaningless.
Back to the issue at hand. Although Flash travels at multiples of lightspeed, I don't think it means he has multiples of infinite mass behind his punches. So it would do the same damage as a lightspeed IMP, IMO.
This is where I would have to disagree with Mike. There is a number placed on the speed of light, and it can and has been clocked. Infinity has no cap. There was simply no other way for me to express how hard the Flash would hit, and therefore I was forced to bring physics into this, even though I sucked at the subject, and cheated like a bastard to get through it.
Originally posted by Stoic
This is where I would have to disagree with Mike. There is a number placed on the speed of light, and it can and has been clocked. Infinity has no cap. There was simply no other way for me to express how hard the Flash wold hit, and therefore I was forced to bring physics into this, even though I sucked at the subject, and cheated like a bastard to get through it.
If you really wanted to calculate how much energy an FTL object would have, you would have to:
- Observe FTL objects hitting things in real life
- Develop a mathematical formula from those observations
- Use it to calculate the energy
According to all the physics we know, matter/energy moving FTL just isn't possible. So we can't calculate how much power/energy an FTL object would have.
You might as well try to use science to attach a number to Mr. Mxyzptlk making 2 + 2 = fish.
Originally posted by Stoic
This is where I would have to disagree with Mike. There is a number placed on the speed of light, and it can and has been clocked. Infinity has no cap. There was simply no other way for me to express how hard the Flash would hit, and therefore I was forced to bring physics into this, even though I sucked at the subject, and cheated like a bastard to get through it.
It has a finite number, because physics needed it in order to create the concept of the metre.
HISTORY TIME!
What is a metre? It is the distance travelled by a beam of light in a vacuum in xs of a second (can't be bothered to look it up now). So if you work backwards from that, it gives the speed of light.
Originally posted by Endless Mike
If you really wanted to calculate how much energy an FTL object would have, you would have to:- Observe FTL objects hitting things in real life
- Develop a mathematical formula from those observations
- Use it to calculate the energyAccording to all the physics we know, matter/energy moving FTL just isn't possible. So we can't calculate how much power/energy an FTL object would have.
You might as well try to use science to attach a number to Mr. Mxyzptlk making 2 + 2 = fish.
Agreed, and understood.
Originally posted by JakeTheBank
If you apply real world physics and logic to characters who clearly defecate on them through virtue of existing, then they're going to become gods in "forum mode".
Agreed, so there should most certainly be a rule against making CISless Flash threads, because his speed would never be able to be beaten. I mean who could ever outfight him, or react in time to stop him from beating them into molecules?
Originally posted by JakeTheBank
If you apply real world physics and logic to characters who clearly defecate on them through virtue of existing, then they're going to become gods in "forum mode".
Well certain things can be quantified, just not things that our physics has no way of accounting for.
This doesn't mean anything against the laws of physics can't be quantified in any way, for example.
I've already explained why FTL is impossible, but in a comic if there is a distance that light takes 2 minutes to cross, and someone crosses it in 1 minute, we can pretty safely say he's moving at twice the speed of light.