Earlier quoted context omitted.
You can even do so without going near the speed of light if you build a very massive ship and utilize time dilation of gravity. Arvin Ash has a cool video on this that is probably too complicated to describe in a HN comment: https://www.youtube.com/watch?v=PA66ah9b0U4
As long as we are talking about how far you can go in one lifetime, how would human body react in a spaceship with that much mass? Wouldn't the gravity crush any humans to death. 10% of the sun's mass is more than 30,000 times earth's mass. Add to that the fact that the diameter is only 620 m, and the gravity becomes 1.4e13 g.
Why can’t I go faster than the speed of light?
181–190 of 234 posts
Re: Why can’t I go faster than the speed of light?
#182Earlier quoted context omitted.
If you were watching their lives out the window of your spaceship you’d see them in fast forward vv. they’d see you in slow motion. Everything is relative. The main ”paradox” found by experimention is that the speed of light is a constant, regardless of your velocity. The only way this could be true, if you do a thought experiment, is if time was dialating for you. As for the physical and mathematical “why is this ha…
> If you were watching their lives out the window of your spaceship you’d see them in fast forward vv. they’d see you in slow motion. Everything is relative. Both observers, looking at one another, would see the other moving near c. Neither would know who was ‘actually’ moving. Yet, you assume there would not be a symmetry in their respective views of the other’s passage of time. Explain why. In simpler terms, a twin…
Re: Why can’t I go faster than the speed of light?
#183Earlier quoted context omitted.
You can even do so without going near the speed of light if you build a very massive ship and utilize time dilation of gravity. Arvin Ash has a cool video on this that is probably too complicated to describe in a HN comment: https://www.youtube.com/watch?v=PA66ah9b0U4
As long as we are talking about how far you can go in one lifetime, how would human body react in a spaceship with that much mass? Wouldn't the gravity crush any humans to death. 10% of the sun's mass is more than 30,000 times earth's mass. Add to that the fact that the diameter is only 620 m, and the gravity becomes 1.4e13 g.
Re: Why can’t I go faster than the speed of light?
#184I think a lot of people assume that this means you couldn't go more than a few (~100) light-years in your lifetime... But this is not actually correct. Counter-intuitively you can theorically go any number of light-years (essentially) in your lifetime, as long as you are able to approach the speed of light because when you do so the distance is dilated and hence you're covering far more ground within your reference f…
It his, it just depends on the observer.
An external, stationary observer will never see you go further than 100 light years, but yourself? Assuming you are able to make your ship go any arbitrary speed approaching c, you could be traveling billions of light years.
It's just that when you stop (if you manage to stop), the universe around you will have aged billions of years, while you will only be a few years older.
Re: Why can’t I go faster than the speed of light?
#185Earlier quoted context omitted.
I know this is true, but I never got my head around this, maybe someone can help. So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some decimals. How much would I h…
> So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? From the photon's perspective, it passes earth immediately. From our perspective, it takes 7 or 8 minutes. > And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some…
To go even further: to a photon's perspective, it is able to teleport instantly anywhere in the universe, because time doesn't elapse for it.
Re: Why can’t I go faster than the speed of light?
#186Earlier quoted context omitted.
As long as we are talking about how far you can go in one lifetime, how would human body react in a spaceship with that much mass? Wouldn't the gravity crush any humans to death. 10% of the sun's mass is more than 30,000 times earth's mass. Add to that the fact that the diameter is only 620 m, and the gravity becomes 1.4e13 g.
The solar system is traveling in space and is quite massive but I haven’t been crushed to death yet.
Re: Why can’t I go faster than the speed of light?
#187Earlier quoted context omitted.
> So if a photon is emitted from the sun, it's passing earth immediately? Then why does sunlight need 7 or 8 minutes to get to earth? From the photon's perspective, it passes earth immediately. From our perspective, it takes 7 or 8 minutes. > And let's say, i travel one light-year at the speed of light, that should be instantaneous, right? The odometer would show 1 light-year, my watch would should 0 seconds and some…
just curious... does "time" have a "speed" ? Is travelling at the speed of light, actually travelling a a fraction of the speed of time?
- Time relative to an observer: Designating a non-accelerating massive object ("observer"), you get a coordinate system which assigns a time and distance to each event (point in spacetime). In this coordinate system, the observer moves along the time axis.
- Proper time: For an object taking any path through spacetime, you can measure the "subjective" time which has passed between two points on its trajectory.
The two notions coincide along the path of an observer: For each second of subjective time, the observer moves one second along the time axis in its coordinate system. Observer time moves at one second per second, if you will.
What you usually call "velocity" is distance/time in the coordinate system of some observer. For massive objects, this is always smaller than the speed of light. If you want, you can define another notion of speed, to illustrate the original commenter's point: distance in some coordinate system per proper time. This can be arbitrarily high, because at high velocities the proper/experienced time becomes shorter.
To get back to the speed of time: If you measure coordinate distance per proper time, it is only natural to also measure coordinate time per proper time. If you take earth as the observer and follow a spaceship, this is earth time per spaceship time. For a fast spaceship, time on board passes slower than on earth (time dilation), so reciprocally, the spaceship moves through (earth) time faster than 1s/s.
(Unfortunately, the notion of proper time becomes useless for massless particles moving at the speed of light: proper time along their trajectory is constant. They "do not experience time".)
Re: Why can’t I go faster than the speed of light?
#188Re: Why can’t I go faster than the speed of light?
#189Earlier quoted context omitted.
Apologies, I wasn’t trying to call you a troll, more that your first comment seemed to me like it might have been made in jest, clearly it wasn’t. The articles you’ve linked to are interesting and there are clearly many scientific discoveries to be made by studying the early formation of the universe which will test our current models. However I don’t feel like convention is the right word for laws like the conservat…
>Convention to me would mean something that has been accepted just because it’s always been done that way and people didn’t really bother to question why. You're wrong. The Thermodynamic laws are sort of axiomatic, meaning you really can't explain why energy is conserved. It's just experimentally shown to be maybe true, but no one knows why energy is conserved or has actually proved it to be true. It is totally "conv…
This means, and I assume, we can also base all of our equations on say "energy is not conserved and always increase by 1 Joule", though the physics equations might be much more complex.
Pro-science folks are too enthusiastic about current science to the point that they become unscientific. Pointing out that these theories/laws/conventions might become invalid in the future is getting downvoted.
Newsflash: physics theories/laws/conventions are getting invalidated all the time.
Re: Why can’t I go faster than the speed of light?
#190Earlier quoted context omitted.
Q1b. Are you the same person you were yesterday?
I think yes, and the answer is more concrete for "oneself", since the molecules that make-up oneself are all accelerating and decelerating with you/as you in your own reference frame.
Truly, the Ship of Theseus was inside us all along. (Which is super convenient, considering how often we step into the same river twice!)