# What is the max speed that anything can move?

#### SimuLord

##### Whom Gods Annoy
How fast can something move, or how fast can something be practically moved without deforming or destroying it?

Because an electron can fly around at the speed of light (3x10^6 km/sec), but try moving something like a spaceship much faster than exit velocity and it'll crack up.

NASA managed to get New Horizons up to about .05c (which is way faster than exit velocity, but you don't see everything and its sister going .05c, do you?), but that's as fast as anything bigger than a subatomic particle's ever been confirmed as being able to go.

#### riskroWe

##### New member
It depends on the mass of the object because the heavier it is the more inertia needs to be overcome to accelerate. So tiny particles can go really damn fast, large objects not so much.
Duh.

#### chuketek

##### New member
photog212 said:
owever, the speed of quasars as well as their energy consumption does raise interesting questions about the speed of light and mass.
Umm... not meaning to be an ass, but do you know what quasars are? They don't consume energy to accelerate in any meaningful way. I personally doubt that real superluminal quasars exist, but then again I'm not an *astro*physicist.

slowpoke999 said:
Hmm so if I understand, if humans could live forever and move at that speed, the person who moved that fast would view time as normal and take billions of years in his time, but an outside observer would see it happen in less then a second?

Or is it that if someone travelled 100 lightyears away and then travelled back in 1 minute in his time it would be like 1000 years for anyone not moving that fast?
Explained very simply, things travelling very fast with respect to you "age" more slowly than you. So, someone goes to this star, takes, say 150 years Earth time to do it, then takes another 150 years to get back, he will have aged 240 years rather than 300. If you do it faster, the effect is more pronounced.

The bit that is a little harder to understand is that *relative to the spaceship* the Earth is moving very fast and so ages more slowly than the guy on the spaceship from his perspective. Also, due to length contraction, the star would get closer, so he would not be aware of the 150 years his trip would be taking in Earth time, only the 120 years in his time.

You might be thinking that this would mean that when the spaceship gets back to Earth then how from his perspective could the Earth have aged more slowly AND he aged more slowly, it doesn't make any sense. The trick is that he had to decelerate and re-accelerate backwards to get back, and when he did that the situation changed. From his perspective, during that brief period, Earth would have aged 60 years extremely fast so that after his 240 years, when he arrives back Earth has aged a total of 300 years.

Note that I'm ignoring the fact that our spaceman could only "see" the earth through light which travels at a finite speed. Also these effects are not finite light speed based illusions, in his movement frame the Earth really would age at a different speed, and the star really would get closer. Space and time are much more flexible than we are used to assuming at these speeds and energies.

Shoggoth2588 said:
They say nothing is faster than the speed of light but, darkness is always there first
...
I know that's from something but I can't remember what >.>
Neverending story 2 I think

#### chuketek

##### New member
SimuLord said:
How fast can something move, or how fast can something be practically moved without deforming or destroying it?

Because an electron can fly around at the speed of light (3x10^6 km/sec), but try moving something like a spaceship much faster than exit velocity and it'll crack up.

NASA managed to get New Horizons up to about .05c (which is way faster than exit velocity, but you don't see everything and its sister going .05c, do you?), but that's as fast as anything bigger than a subatomic particle's ever been confirmed as being able to go.
The problem isn't how fast something is moving, it's what is around it and how fast that is moving relative to it.

The main reason you can't have a plane move at 0.05c is that the air rushing past it at 0.05c would destroy it very quickly. If you were in deep space, travelling at 0.5c you might have problems with the stray atoms and molecules crashing into your ship at 0.5c.
If there was absolutely nothing there, you found a way to protect against the stuff that was there, or everything around you was moving with you at the same speed then you could move as fast as you liked (up to c of course).

#### SimuLord

##### Whom Gods Annoy
chuketek said:
SimuLord said:
How fast can something move, or how fast can something be practically moved without deforming or destroying it?

Because an electron can fly around at the speed of light (3x10^6 km/sec), but try moving something like a spaceship much faster than exit velocity and it'll crack up.

NASA managed to get New Horizons up to about .05c (which is way faster than exit velocity, but you don't see everything and its sister going .05c, do you?), but that's as fast as anything bigger than a subatomic particle's ever been confirmed as being able to go.
The problem isn't how fast something is moving, it's what is around it and how fast that is moving relative to it.

The main reason you can't have a plane move at 0.05c is that the air rushing past it at 0.05c would destroy it very quickly. If you were in deep space, travelling at 0.5c you might have problems with the stray atoms and molecules crashing into your ship at 0.5c.
If there was absolutely nothing there, you found a way to protect against the stuff that was there, or everything around you was moving with you at the same speed then you could move as fast as you liked (up to c of course).
You mean like the "forward deflector shields" and other things made of Handwavium in science fiction?

6 miles an hour.

#### chuketek

##### New member
SimuLord said:
chuketek said:
You mean like the "forward deflector shields" and other things made of Handwavium in science fiction?
Bingo
Although if you were simply protecting against stuff then you'd effectively get friction from it which would further reduce the speed, and if you couldn't 100% fully protect against it it'd be like standing your ship in a particle beam. But this is all dependant on the protection your craft offers.
For a human totally unprotected from these particles, I'd guess from a quick calculation that you could survive 0.1c for a small amount of time providing that you only encountered a few stationary protons... which is an extreme best case scenario.

#### not_the_dm

##### New member
azncutthroat said:
99.99c

Basically, anything just under the speed of light. I don't know the exact number...
Maximum speed in a vacumn = c [sub]299,792,458ms[su]-1[sup][/sub]

Edit: "According to special relativity, the energy of an object with rest mass m and speed v is given by ãmc[sup]2[/sup], where ã is the Lorentz factor. When v is zero, ã is equal to one, giving rise to the famous E = mc[sup]2[/sup] formula for mass-energy equivalence. Since the ã factor approaches infinity as v approaches c, it would take an infinite amount of energy to accelerate an object with mass to the speed of light. The speed of light is the upper limit for the speeds of objects with positive rest mass."

Basically if it has positive mass it cannot be accelerated to c. What happens if the object has negative rest mass? Do you need a negative infinate amount of energy to accelerate it to c?

With regards things moving faster than light:

"There are situations in which it may seem that matter, energy, or information travels at speeds greater than c, but they do not. For example, if a laser beam is swept quickly across a distant object, the spot of light can move faster than c, but the only physical entities that are moving are the laser and its emitted light, which travels at the speed c from the laser to the various positions of the spot. The movement of the spot will be delayed after the laser is moved because of the time it takes light to get to the distant object from the laser. Similarly, a shadow projected onto a distant object can be made to move faster than c. In neither case does any matter or information travel faster than light."

#### manicgreenapple

##### New member
Get a cockroach within a foot of me and I'll top any speed you think of.