MovieChat Forums > Into the Universe with Stephen Hawking (2010) Discussion > Dont get the time travel

Dont get the time travel

posted 11 years ago by iruleall15
3 replies | jump to latest

Am I the only one who doesnt think the time travel makes sense?

Lets take the part where they said it takes 16 minutes to go around the black hole. But it goes around in 8. They are going half the time than Earth. Or that people around the pyramids are not going as fast as those away from it.

They dont explain how the hell that is. It doesnt make sense. time isnt an object. The body would still age at the human rate on Earth even when in space near a black hole. I dont see how that makes sense. Someone please explain to me how the hell going fast changes time.

[–] Torn2013 11 years ago

Speed increases mass. The more mass, the more gravity. Increased gravity will affect the speed at which time passes.

To the people in the ship everything seems normal (in terms of time passed), however if they were to observe people on earth, everything they see on earth would appear to be moving faster than normal.

Ultimately it comes down to: More mass = more gravity = slower passage of time. Which is why if you traveled from earth at the speed of light, you'd essentially age at a slower rate than everyone on earth. So when you arrive back on earth after 1 week (1 week of your time on the space ship), the earth would have aged by about 100 years.

Pretty wacky stuff to wrap your head around.

[–] davidwile 11 years ago

Hey Iruleall15,

You are not alone. I think it was Einstein who said, "Fast clocks run slow." Einstein's relativity ideas use term such as "time dilation" and "changing the fabric of time" and it really pretty much just goes right over my head. What I was able to understand was his concise statement that fast clocks run slow. I may not understand the "why" of it, but for some time now scientists have shown the effects of speed on clocks by actually taking very precise clocks into space and finding on return to Earth the clocks are measurably slower than the same clocks that remained on Earth.

While I may kind of get the idea of fast clocks running slow, there are so many things like black holes, worm holes, and much, much more that I will never be able to understand. That does not mean I reject as wrong anything I do not understand. It also does not mean that I accept any concept proposed by a scientist. What it does mean is that I am a simple human with a limited amount of knowledge and a limited ability to understand things. I accept that some folks are smarter than I, and some folks have talents I do not possess.

I am thankful for those folks who are smarter than I and can come up with ideas that I am unable to do. I am also thankful that I can listen to the ideas of others and recognize that some of those ideas make sense and some of them are most likely wrong.

No, Irulealll15, you are not alone in not understanding these complicated concepts.

Best wishes,
Dave Wile

[–] padzok 9 years ago

The body would still age at the human rate on Earth even when in space near a black hole. I dont see how that makes sense. Someone please explain to me how the hell going fast changes time.

In short, it's all relative.

So the person on the ship perceives time pass at the normal rate for themselves, and they do get older at the normal rate for themselves.

Meanwhile, the person on Earth perceives time pass at the normal rate for themselves, and they do get older at the normal rate for themselves.

However, due to the effects of being nearer the black hole, a person on the ship has experienced 5 years as measured by a clock on the ship (and got older by 5 years) but the person on Earth has experienced 10 years as measured by a clock on Earth (and got older by 10 years).

He didnt include the full explanation in this show (although he has explained it slightly more fully in other episodes) because he was mainly trying to analyse the consequences rather than the reasons. Check out - say - Cosmos (preferably the Carl Sagan original series) for a full, clear explanation.