Can We Physically Handle Extreme Speeds in Spacecraft and Simulated Gravity?

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Discussion Overview

The discussion revolves around the physical implications of traveling at extreme speeds, specifically near 99% of the speed of light, within spacecraft. Participants explore concepts related to acceleration, gravity, and the effects on human physiology in such conditions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that at a constant speed of 99% of the speed of light, the experience inside the spacecraft would be similar to being stationary in a living room, emphasizing the importance of acceleration rather than velocity.
  • Others argue that without gravity, objects inside a spacecraft would not remain in place when the spacecraft accelerates, referencing a thought experiment involving a balloon and a lightweight object.
  • There are claims that when no external forces act on a mass, its speed remains constant, and that acceleration leads to increased speed, with some participants discussing the implications of approaching the speed of light.
  • Some participants assert that it is impossible to reach or exceed the speed of light, referencing established physics principles and experiments like those conducted at the LHC.
  • There are discussions about the mathematical implications of reaching the speed of light, with one participant suggesting that it could be viewed as an infinite velocity in a theoretical context.
  • Concerns are raised about the effects of microgravity on human health, with references to the need for exercise among astronauts to mitigate muscle atrophy during extended space travel.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement, particularly regarding the nature of acceleration, the implications of traveling at relativistic speeds, and the effects of gravity on human physiology. No consensus is reached on several points, particularly those involving the speed of light and its implications.

Contextual Notes

Participants discuss various assumptions about gravity, acceleration, and the behavior of objects in motion, but these assumptions are not universally accepted or resolved. The discussion includes references to both classical and modern physics without a clear resolution on how they interrelate in the context of extreme speeds.

wilsonb
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Can we hold on..stand up inside spacecraft that close 99% speed of light and can our physical effort to hold on that speed?
 
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Sure, if it is constant 99% speed of light, it is no different than sitting in your living room.

The danger is in the acceleration you experience reaching this speed.
 
Velocities aren't important, as edgepflow noted; it's the acceleration. That's why if you're on a bullet train going 250mph, you'd only know it by looking out the window and that's why everyone just walk around drinking tea and reading the newspaper inside one.
 
Pengwuino said:
Velocities aren't important, as edgepflow noted; it's the acceleration. That's why if you're on a bullet train going 250mph, you'd only know it by looking out the window and that's why everyone just walk around drinking tea and reading the newspaper inside one.

Well, like we stay on the plane with speed, but we manage to walk inside without force back. But its gravity where let us stay on and walk. What bout space without gravity? Example: a tiny object with barely no weight, put inside of a big balloon, then try to pull the balloon ahead with speed, the object without gravity will be force backward inside the balloon... Sine the object wasn't stay or touch the balloon...
 
wilsonb said:
Well, like we stay on the plane with speed, but we manage to walk inside without force back. But its gravity where let us stay on and walk. What bout space without gravity? Example: a tiny object with barely no weight, put inside of a big balloon, then try to pull the balloon ahead with speed, the object without gravity will be force backward inside the balloon... Sine the object wasn't stay or touch the balloon...

That's only because you're accelerating the balloon. Once you reach whatever speed you're looking for and stop accelerating, the object will float in the balloon. As for the airplane, yes gravity does provide a practical means to move around, but if you turned gravity off, you wouldn't be flung backwards if you're going at a constant velocity. You simply wouldn't be able to actually move anywhere because you need some sort of friction (or you could strap a small rocket onto you to get around).
 
my opinion is:
when no other force apply on a mass, its speed will be constant.
when acceleration applies, speed increases.
more acceleration = more speed -> until speed is near to infinity

light is nothing more than a combination of magnetic & electronic wave with tremendous traveling speed. because it is the fastest thing human beings have found so far, einstein could only come out with the m c square before he died.

Newton's theories cannot be applied on quantum theories, which was proposed 300 years later. we shall see 300 years after the accurate measurement of speed of light what equations the scientists will come out with.
 
wilsonb said:
my opinion is:
when no other force apply on a mass, its speed will be constant.
when acceleration applies, speed increases.
more acceleration = more speed -> until speed is near to infinity
All good except for that last step. Regardless of its proper acceleration, the ship will never reach, much less exceed, the speed of light.
 
Doc Al said:
All good except for that last step. Regardless of its proper acceleration, the ship will never reach, much less exceed, the speed of light.

Yea, he used the word infinity. A good choice that also gets your point across.
 
wilsonb said:
my opinion is:
when no other force apply on a mass, its speed will be constant.
when acceleration applies, speed increases.
more acceleration = more speed -> until speed is near to infinity

light is nothing more than a combination of magnetic & electronic wave with tremendous traveling speed. because it is the fastest thing human beings have found so far, einstein could only come out with the m c square before he died.

Newton's theories cannot be applied on quantum theories, which was proposed 300 years later. we shall see 300 years after the accurate measurement of speed of light what equations the scientists will come out with.
No matter how much you have accelerated in the past and no matter what speed you will have attained relative to your starting condition, the speed of light will still be just as unattainable as it was when you started. You won't be able to tell any difference between starting and after you have accelerated, except that lots of things will be flying past you (hopefully, instead of hitting you, which would put an end to your endeavors).
 
  • #10
wilsonb said:
light is nothing more than a combination of magnetic & electronic wave with tremendous traveling speed. because it is the fastest thing human beings have found so far, einstein could only come out with the m c square before he died.

Newton's theories cannot be applied on quantum theories, which was proposed 300 years later. we shall see 300 years after the accurate measurement of speed of light what equations the scientists will come out with.

This is incorrect. It is PROVEN that c is unreachable and is a universal constant. The LHC in Geneva accelerates protons to greater than 99.99% the speed of light. The amount of energy it takes to get them up to speed agrees exactly with our calculations and predictions. Not only that, but e=mc^2 agrees with how much energy and mass are lost and gained in any chemical or nuclear reaction. If c was not correct then it would NOT work. The constant c is much more than simply a speed limit.
 
  • #11
wilsonB said:
my opinion is:
when no other force apply on a mass, its speed will be constant.
when acceleration applies, speed increases.
more acceleration = more speed -> until speed is near to infinity
Doc Al said:
All good except for that last step. Regardless of its proper acceleration, the ship will never reach, much less exceed, the speed of light.

True Doc Al, but there is a sense in which infinite velocity applies mathematically. If one could attain speed c, the cosmos shrinks to a plane figure, and one then travels a finite distance in zero time. So speed c plays the role of an infinite velocity in STR. Yes? But then, I suppose "said one" may not even be considered to be moving at that venture, and would move (at c) only per sub c folks.

GrayGhost
 
  • #12
wilsonb said:
Can we hold on..stand up inside spacecraft that close 99% speed of light and can our physical effort to hold on that speed?

When I do it, my legs fly out about 88.1 degrees wrt the horizontal :)

On a serious note, so long as you are not accelerating, you would float freely in your vessel just as the shuttle astronauts do in orbit. If you are not accelerating, you may consider yourself stationary.

GrayGhost
 
  • #13
GrayGhost said:
True Doc Al, but there is a sense in which infinite velocity applies mathematically. If one could attain speed c, the cosmos shrinks to a plane figure, and one then travels a finite distance in zero time. So speed c plays the role of an infinite velocity in STR. Yes? But then, I suppose "said one" may not even be considered to be moving at that venture, and would move (at c) only per sub c folks.

GrayGhost

I can only point to the (fact?) that a photon has no frame of reference.
 
  • #14
wilsonb said:
Can we hold on..stand up inside spacecraft that close 99% speed of light and can our physical effort to hold on that speed?

But you are moving at this speed right now in some reference frame. And I see you are holding up pretty good.
 
  • #15
Can gravity be manipulated?
gravity.. Space was 0 to gravity. Can we build a machine or what ever to provide gravity? Although we can build space ship, there won't be any gravity wouldn't it? Any proof or article where gravity can be produce? Human will getting weak if no gravity, that's why astronaut need to do exercises often when they in the space. When they come back to earth, they are weak because they have stay long time at space without gravity...
 
  • #16
wilsonb said:
Can gravity be manipulated?
gravity.. Space was 0 to gravity. Can we build a machine or what ever to provide gravity? Although we can build space ship, there won't be any gravity wouldn't it? Any proof or article where gravity can be produce? Human will getting weak if no gravity, that's why astronaut need to do exercises often when they in the space. When they come back to earth, they are weak because they have stay long time at space without gravity...

The only thing that can generate gravity is mass however you could http://en.wikipedia.org/wiki/Artificial_gravity#Rotation".
 
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  • #17
ryan_m_b said:
The only thing that can generate gravity is mass however you could http://en.wikipedia.org/wiki/Artificial_gravity#Rotation".

An easier solution to muscle entropy attributable to zero-g is using resistance training methods. The Coriolis effect has some pretty weird side effects! Saying that the rpm can be a lot less and still produce a simulated gravity field.

There is a very interesting couple of paragraphs in Arthur C Clarkes Rama novel - while a science fiction its tends to be more "hard" sci fi and raises some interesting questions on how we would mentally as well as physically deal with a simulated gravity environment. Perception of motion and up/down etc. Not fact obviously but from a scientifically very credible author so raises real concerns.
 
Last edited by a moderator:
  • #18
Cosmo Novice said:
An easier solution to muscle entropy attributable to zero-g is using resistance training methods. The Coriolis effect has some pretty weird side effects! Saying that the rpm can be a lot less and still produce a simulated gravity field.

There is a very interesting couple of paragraphs in Arthur C Clarkes Rama novel - while a science fiction its tends to be more "hard" sci fi and raises some interesting questions on how we would mentally as well as physically deal with a simulated gravity environment. Perception of motion and up/down etc. Not fact obviously but from a scientifically very credible author so raises real concerns.

I don't think resistance training would cut it I'm afraid. Bone mineral loss, heart muscle atrophy, fluid loss etc. The human body evolved to live in a specific environment, it doesn't bode well for drastic changes!

On the subject of Coriolis forces I wonder how people's perception would change with larger diameters?
 

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