# Something fun: What if we could travel faster than the speed of light?

Discussion in 'Pseudoscience' started by wegs, Aug 21, 2013.

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3. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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Well let's throw some numbers at traveling at twice the speed of light and see if the numbers add up:

Say a star was 100 light years away from you. It emitted light in the year 1911, and the light arrived at your position in the year 2011. Just as the light reached you, you started traveling towards the star at 2c (twice the speed of light). As you traveled towards the star you would be encountering younger and younger light from the star that was emitted after the original light that emitted in 1911 that reached you when you started traveling.

When you get to within 50 light years of the star, you will have traveled for 25 years, and traveled a distance of 50 light years. So the year is 2036, and the light that hits you there was emitted 50 years ago, so the light left the star in the year 1986.

When you get to within 25 light years of the star, you will have traveled for 12.5 more years (37.5 total), and traveled a distance of 25 light years (75 light years total). So the year is 2048.5, and the light that hits you there was emitted 25 years ago, so the light left the star in the year 2023.5.

When you get to within 1 light year of the star, you will have traveled for 12 more years (49.5 total), and traveled a distance of 24 light years (99 light years total). So the year is 2060.5, and the light that hits you there was emitted 1 year ago, so the light left the star in the year 2059.5.

When you get to the star, you will have traveled for .5 more years (50 years total), and traveled a distance of 1 light year (100 light years total). So the year is 2061, which is 50 years later than when you left in 2011, because you traveled for 50 years.

Yup, the numbers add up. Just like clockwork!

5. ### kwhilbornBannedBanned

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If speed is relative to something the we are moving at the speed of light from a photons perspective. Walk toward the light and we are moving faster than light.

Not.

The photon would pass a walking us at same light speed.

Just a funny way to look at things.

7. ### wegsWith brave wings, she flies . . .Valued Senior Member

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lol thank you for taking our 'fun' seriously here.

I was hopeful someone would come up with examples.

Great! So....Would we be able to actually see into the past like a time machine by traveling farther and farther into the Universe?

(just looking at it from the perspective you give, with your examples)

If so...that'd be wild.

8. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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You probably noticed that in my example, regardless of the speed at which you travel (2c in the example) that time is cumulative. In other words, it takes time to travel. So regardless at what speed you travel, time is always accumulating, hence it's therefore impossible to go "back in time." Time accumulates no matter what. In the example, traveling at twice the speed of light to a star that was 100 light years away means 50 years elapsed. Time did not reverse, it accumulated as usual.

9. ### wegsWith brave wings, she flies . . .Valued Senior Member

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I understand, thank you…I wasn’t ‘thinking’ cumulative, for some reason. I gotcha!

Let’s have some more fun:

http://spaceplace.nasa.gov/review/dr-marc-space/time-travel.html

Let me make a disclaimer here—I'm not "arguing" for time travel lol
It's just fun to play with the hypotheticals of the what if's of physics.

Last edited: Aug 21, 2013
10. ### river

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We could go faster than the speed of light , if we have a shield against both friction and the gaining of mass

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I hear ya.

12. ### river

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The thing is though most light from distant galaxies and stars is already here , our observations

So if you travel faster than light , you see the dispersal or diffusion of light and see the interactions

13. ### AlphaNumericFully ionizedRegistered Senior Member

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Friction has nothing to do with it, the obstruction to going faster than light is more intrinsic than that. And it isn't like relativistic effects are something you can build a shield against, they aren't 'beamed in' from anywhere, they are viewed as a core property of space-time itself.

14. ### river

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Well I take issue with this

If you develop a shield from space-time , outside influences , then the object will not be affected , in and of its self

15. ### dumbest man on earthReal Eyes Realize Real LiesValued Senior Member

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Since we are having fun.
May we ponder this "what if"?

What if - using the scenario espoused in Post #2 : "Say a star was 100 light years away from you. It emitted light in the year 1911, and the light arrived at your position in the year 2011. Just as the light reached you, you started traveling towards the star at 2c (twice the speed of light)."

97 years after the star that emitted the light perceived by you in 2011, that same star goes "Super-Nova".

What would happen to you, traveling at 2c (twice the speed of light), when you encounter the "blast effects(?)" of the "Super-Nova"?

It's just a "what if", but, it is, indeed, fun at times to play "what if"'s!

16. ### wegsWith brave wings, she flies . . .Valued Senior Member

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No takers I see.

Interesting website...pretty much sums up that we would surely die traveling near the speed of light. Even if we had secure technology to do so.

http://gizmodo.com/5957697/super fast-space-travel-would-kill-you-in-minutes

Last edited: Aug 23, 2013
17. ### Janus58Valued Senior Member

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That's like trying to develop a shield from left/right-forward/back.

18. ### Janus58Valued Senior Member

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This statement from the article is misleading :

I've bolded the offending part. It is not hydrogen in the craft that causes any danger, it is the interstellar hydrogen outside of the craft. In effect, you would be running into hydrogen atoms at high speed. This is old hat, and hardly a surprising revelation.

19. ### Janus58Valued Senior Member

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Here's the pitfall of such questions:

From our present understanding of the universe, FTL travel is not possible. When you try to assume that it is, you are also assuming that our present understanding is wrong. While it is not impossible for this to be the case, nothing in the statement "you started traveling towards the star at 2c (twice the speed of light)" tells s anything about how our present understanding is wrong. IOW, what are the "new rules" that allow for FTL travel?

It all fine and dandy to say that we are just speculating here, but even speculation has to start from somewhere. Without knowing what the rules are, we have nothing to base our speculation on.

It's a bit like asking, "If 2+2 does not equal 4, what does 3+3 equal?" It's not that you can't imagine a math in which 2+2 does not equal 4, it's that there are too many ways that you can imagine this, and they all don't give the same answer for 3+3.

For example, I can offhand think of two kinds of "math" where 2+2 doesn't equal 4: base three and base four. In base three, 2+2=11 and in base four, 2+2=10.

As far as 3+3, in base four it equals 20, and in base three the question has no meaning because the numeral 3 doesn't even exist.

20. ### wegsWith brave wings, she flies . . .Valued Senior Member

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On your first point, Janus, could be poor word choice.

To your point about speculating...agree, again...with the caveat that it can be fun (to me at least) to talk about 'why' something will never be possible. (as much as it is fun to 'play' with some hypothetical examples) I don't think we have to assume that our present understanding would need to be wrong, as much as ...with our present understanding, can such things ever be possible, if technology was to afford it? The answer would still be no. Just a 'fun' discussion from that slant. (to me)

21. ### dumbest man on earthReal Eyes Realize Real LiesValued Senior Member

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Okay, Janus58, just for fun, using any "math" of your choosing : - What would happen to you, traveling at less than "c"(the speed of light), when you encounter the "blast effects(?)" of a "Super-Nova"? - Just for a "what if" type of fun!

Last edited: Aug 23, 2013
22. ### sculptorValued Senior Member

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let us assume that you could reach .9725C
and that mass increases with speed
then
slowing down has got to be a bitch?

23. ### billvonValued Senior Member

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As much of a bitch as speeding up in the first place.