How fast can we humanly possibly go in space?

originally posted by: tanka418
a reply to: stormbringer1701

I'm sorry y'all...But, I'm afraid that I don't view the speed of light quite the same way. For those equations to even begin to work, "C" must be some sort of hard limit in things, and logically, it can only be a cognitive limit...kind of like "speed of observation".

Anyway, I don't really want to argue that...

Although, many of the responses I've seen here reflect archaic thinking. One of the primary reasons that Terrestrial space vehicles can't accelerate to any reasonable speeds is because of the gas propelling it...the "nozzle velocity" of the rocket is the limiting factor. You can have all the fuel you want and it can't help.

Ion drives are better for attaining high velocities, but will take a very long time due t lack of thrust, even IF the "nozzle velocity" is higher.

There is some science for a sort of "field drive":
www.hpcc-space.de...

I've pointed this tech out before, most try to dismiss it based on really poor data. I bring it up here because, a field drive does not need fuel, nor does it's "drive" capabilities decrease as the mass of the vehicle it is driving does. It's kind of like it scales all on its own, never requires additional energy, fuel, etc.

No it is quite physical. nothing about relativity has been disproven by observation or experiment. relativity works and works quite well. and Relativity says that as velocity increases so does mass and therefore so do the requirements for ever more energy to go any faster. it is an exponential relationship and at C itself the energy requirements are infinite. And well before then it becomes physically impossible to carry enough fuel.

So the light barrier is quite real for anything dependent on the rocket equation. that does not mean we cannot find loopholes. it does not mean there are no realms where relativity does not apply. But to say light speed is not a real barrier is just wrong.

originally posted by: deltaboy
I was just reading the news about the launch of the probe to space heading to Pluto about 36,000 mph. Can we go faster if we can push the momentum to let say 100,000 or 1,000,000 mph? Can the humans withstand that type of speed in space? After all I see astronauts in earth's orbit doing spacewalk going about what 8,000 miles per hour? I forgot so anybody can help correct me.

Its not the speed that's the problem its the acceleration that can kill.

We could go right up to the speed of light and be safe as long as the acceleration is slow enough.

originally posted by: stormbringer1701
So the light barrier is quite real for anything dependent on the rocket equation. that does not mean we cannot find loopholes. it does not mean there are no realms where relativity does not apply. But to say light speed is not a real barrier is just wrong.

No more than sound was...

And of course relativity works. It works quite well right to the limit of observation...then it quits.

The limit of observation is a sliding scale, but, lots more science need to be done before it will move...

originally posted by: tanka418

originally posted by: stormbringer1701
So the light barrier is quite real for anything dependent on the rocket equation. that does not mean we cannot find loopholes. it does not mean there are no realms where relativity does not apply. But to say light speed is not a real barrier is just wrong.

No more than sound was...

And of course relativity works. It works quite well right to the limit of observation...then it quits.

Sorry Tanka but you're wrong. The speed of light is an actual physical speed limit. We have tried to accelerate particles at the speed of light but as you probably know (or maybe don't know) the amount of energy needed to accelerate any physical mass to the speed of light becomes infinite.

So in particle accelerators we can accelerate particles near the speed of light but never to it or beyond it.

We've also looked for faster than light particles called tachyons which would in theory not violate relativity since they would ONLY travel faster than the speed of light. Nothing. They don't exist.

As stormbringer said, that doesn't mean there aren't other ways around the speed limit but it will not involve accelerating mass faster and faster like Chuck Yeager breaking the sound barrier.

Instead it will involve traveling slower than light while warping, bending, folding space/time itself so that the distance between two points briefly becomes closer than normal.

a reply to: JadeStar

What if there was some way to negate or cancel out the mass or inertia of an object? Then we could go superluminal.

originally posted by: BASSPLYR
a reply to: JadeStar

What if there was some way to negate or cancel out the mass or inertia of an object? Then we could go superluminal.

By that reasoning then we would have faster than light neutrinos and photons of light but they don't exist. It's also probably a lot easier to warp space/time than "cancel out" mass.

originally posted by: BASSPLYR
a reply to: JadeStar

What if there was some way to negate or cancel out the mass or inertia of an object? Then we could go superluminal.

Photons are massless (if you don't count their kinetic mass), and they only travel at the speed of light.

Quite apart from the infinite energy hurdle, going faster than light speed has some unusual consequences regarding the flow of time. The equation for relativistic time dilation involves the square root of a variable that approaches zero as you approach the speed of light. At the speed of light, the variable is zero, meaning that your local time stops completely. At faster-than-light speed, the variable is a negative number. Normally, a negative number cannot have a real square root. However, mathematicians came with with the so-called imaginary numbers to acommodate square roots of negavite numbers. Can we then say that, at faster-than-light speed, time becomes "imaginary", and what exactly would that mean? Does the traveller's local time turn backwards? Does it branch off into a parallel timeline?

originally posted by: JadeStar
Sorry Tanka but you're wrong. The speed of light is an actual physical speed limit. We have tried to accelerate particles at the speed of light but as you probably know (or maybe don't know) the amount of energy needed to accelerate any physical mass to the speed of light becomes infinite.

So in particle accelerators we can accelerate particles near the speed of light but never to it or beyond it.

We've also looked for faster than light particles called tachyons which would in theory not violate relativity since they would ONLY travel faster than the speed of light. Nothing. They don't exist.

As stormbringer said, that doesn't mean there aren't other ways around the speed limit but it will not involve accelerating mass faster and faster like Chuck Yeager breaking the sound barrier.

Instead it will involve traveling slower than light while warping, bending, folding space/time itself so that the distance between two points briefly becomes closer than normal.

Way back in the later 1970's I did some consulting for SLAC (Stanford Linear Accelerator Center), I was much more of a hardware type back then. Anyway, I clearly remember discussions with the Physicists there about Tachyons specifically. They seemed rather certain that they had seen the decay products of Tachyons, course that was the late 70's and they may have misidentified what they were seeing.

It is also important to understand just how an accelerator does it's accelerating...As I'm sure you know it is done with magnets, and seriously high potential differences...So, basically they are trying to accelerate these heavier particles (protons, etc.) using, wait for it, Electromagnetic quanta, a.k.a. photons. So of course there is no possibility of ever accelerating past that point.

As for whether Tachyons exist or not...logically, there must be something past the limits of light. Truth is we simply don't know yet...perhaps LHC will help out one day.

originally posted by: wildespaceCan we then say that, at faster-than-light speed, time becomes "imaginary", and what exactly would that mean? Does the traveller's local time turn backwards? Does it branch off into a parallel timeline?

You rotate partially out of Einsteinian space-time. If you go completely imaginary, you're detached from status spacetime and can't get back, and it's time for the sad bagpipes, and you're on the Flying Dutchman In Space.

I'm the only tar who's e'er jumped ship from Vandervecken's crew...

originally posted by: JadeStar

By that reasoning then we would have faster than light neutrinos and photons of light but they don't exist. It's also probably a lot easier to warp space/time than "cancel out" mass.

If the speed of light's a limit, change the speed of light.

a reply to: Bedlam

Sneaky! I see what you did there!