Into the Universe with Stephen Hawking

[Trekker4747]

Discovery Channel started a new series this past weekend with a series called "Into The Universe with Stephen Hawking" which pretty much features, and is partly narated by, the brilliant scientist and his theories. I forgot I was set to record it and missed the first episode (talking about life on other planets, I believe) but I did watch the great second episode (talking about time-travel.)

Very well done series. As I said it's partly narrated by Hawking it shows him in his chair and his computer-voice reads some lines of (dialogue) which eventualy fades to the narrator who speaks as Hawking over the CGI/animated stuff explaining the sceince stuff. The time-travel episode dealt with, and explained, a handful of ways of time travel including wormholes, gravitational effects and time dilation from traveling at great speeds.

Very, very, awesome series I highly reccomend it. (Not sure when it is re-airing this week but The Discovery Channel is nortorious for re-airing this stuff during the week and even in the future.)

Pending approval and support from posters (and mods) here I'd like to run a weekly-discussion thread on the series (or if not weekly but "new episode"-idly.... )

Thoughts, comments and opinions?

 

[Trekker4747]

Sooooo... No, then?

 

[iguana_tonante]

I would prefer going Into the Universe with someone with a brisker stride.

Ops.

 

[diankra]

Not turned up in the UK yet, that I've spotted. Hope it does, as it'll be worth watching.

 

[BolianAuthor]

I saw this... a very well-done series, and easy to follow/understand. Stephen has some great ideas, and I was very impressed with what I've seen so far. I taped both episodes.

The ONLY thing he talked about, which I didn't really agree with was the "Grandfather Pradox"... where a time traveler goes back in time, and kills himself before the time machine is fully realized. Put simply, this is impossible, because it is a wholly self-destructive premise... as soon as the past version of the traveler is killed, the time machine ceases to be, and thus, there is no means for the future version to go back and commit the murder, so the entire scenario never plays out to begin with. Since that's the case, such a trip is utterly pointless, because of its inherent self-destructive nature.

But again, all of the rest was remarkably well-made and presented.

 

[Trekker4747]

I kind of agree on the Grandfather-Paradox thing. It'd have been interesting to do the whole "One Time Line" thing which could open whole avenues on whether or not free-will exsists.

The best example of this I can think of is in the movie "Bill and Ted's Excellent Adventure."

In the movie two loser high-school students are given a time-machine by a utopian future society (whose foundation is built on the music Bill and Ted's band will one day write) to ensure that they can pass a history report (were they to fail, Ted would be sent-off to military school, the band will never form and future utopian society would not exsist.)

Their "mentor" from the future, arrives, and shows them the time machine. B&T are cautious until, they arrive having just completed their journey -before leaving again to go to tomorrow but that's another issue not related to this topic.

The "idea" the movie tries to set-up is that even though Bill and Ted have not yet left for their "excellent" adventure they soon will and will arrive at that moment to talk to themselves and Rufus. Simply put, the past came first. If you're destined to travel to the past strictly speaking you've already been there and whatever actions you took caused this time-line to exsist. So in the movie, the various historical figures B&T kidnapped had always been kidnapped and the future they live in is based on that having happened.

For example. In the movie they kidnap Abraham Lincoln. Now, say Abraham Lincoln at one point during his time in 1987 discovers he'll be assinated while attending a play he will soon visit. He thinks "Crap! I can't let that happen!" So he changes his theater plans. But, since in 1987's past Lincoln did die whatever Lincoln does will cause his death, not prevent it. His change of theater plans (say he goes to a different theater, a different showing, changes his seats) will be what needed to happen to ensure Booth's success where he otherwise may not have been able to pull it off.

Similarly people always say they'd do things like "save JFK" well, again, it could be argued that whatever you do to try and save JFK will actually cause JFK's death. Why? Because the past came first. If you're ever destined to go there then you've really already been. (Again, B&T demonstrates this nicely when they "set up" things to occur by simply by saying they'll travel to past to do it. Ted's father is talking during the first part in the movie about having lost his keys. We find out later that B&T will eventualy travel to the past, steal the keys, and hide them so that "they" can find them and make use of them.)

Really, it's amazing how such a silly movie did a pretty interesting job of potraying time-travel.

Simply put you can't go back in time to kill yourself (or your mother, father, whoever) because you didn't.

It'd of been nice (or it would be nice) to see Hawking talk about this theory (which I believe to be the "correct" one) if time-travel to a past before the time machine was invented is possible. It may be possible to travel to the past using wormholes or something, but you can only travel back to a point when your machine exsisted -to be the other end of the wormhole. To name another silly movie where this is shown nicely, Austin Powers 2.

 

[trekkiedane]

I've seen the aliens and the time travel episode, it is indeed nicely done; fabulous CGI without too many repetitions and Stephen Hawking has even included a couple of funnies in the narration.

I found it a bit too populistic for my taste but, hey, it's just television -very well made television at that, and everyone should be able to follow what is said and shown -even those whataretheycalled? 'non-geeks' out there in TV-land

Thanks for pointing this out, Trekker

 

[FordSVT]

I kind of agree on the Grandfather-Paradox thing. It'd have been interesting to do the whole "One Time Line" thing which could open whole avenues on whether or not free-will exsists.

Which is why many physicists (and me) are so keen on the idea of parallel and multiple universes, it really does take a lot of the kinks out of things.

That or physically travelling back in time is impossible.

 

[Jadzia]

or physically travelling back in time is impossible.

This makes the most sense to me. I've never really bought into parallel universes.

We've had discussions here before about time travel into the past. My argument against it, predicting "inevitable time loops" and the illogicality of anything trapped in a time loop, made sense to me... even if no-one else followed it.

 

[Lindley]

The ONLY thing he talked about, which I didn't really agree with was the "Grandfather Pradox"... where a time traveler goes back in time, and kills himself before the time machine is fully realized. Put simply, this is impossible, because it is a wholly self-destructive premise... as soon as the past version of the traveler is killed, the time machine ceases to be, and thus, there is no means for the future version to go back and commit the murder, so the entire scenario never plays out to begin with. Since that's the case, such a trip is utterly pointless, because of its inherent self-destructive nature.

I believe that's why they call it a paradox.

<stuff>

I think Daniel Faraday said all that much more succinctly on Lost: "Whatever happened, happened."

 

[ProtoAvatar]

The ONLY thing he talked about, which I didn't really agree with was the "Grandfather Pradox"... where a time traveler goes back in time, and kills himself before the time machine is fully realized. Put simply, this is impossible, because it is a wholly self-destructive premise... as soon as the past version of the traveler is killed, the time machine ceases to be, and thus, there is no means for the future version to go back and commit the murder, so the entire scenario never plays out to begin with. Since that's the case, such a trip is utterly pointless, because of its inherent self-destructive nature.

I believe that's why they call it a paradox.

The problem is, no one has been able to demonstrate that nature forbids time travel into the past and paradoxes.

On the contrary - relativity seems to allow travel into the past - for example, flying around a spinning singularity can allow you to travel into the past.

So - how do you reconcile travel into the past with the paradoxes that arise (of which the grandfather paradox is only an obvious one)?

 

[Lindley]

I don't think closed time-like curves really permit paradoxes of that sort....they simply allow you to return to the same space/time location you left later on.

It's all a bit above my head though.

 

[ProtoAvatar]

I don't think closed time-like curves really permit paradoxes of that sort....they simply allow you to return to the same space/time location you left later on.

It's all a bit above my head though.

Assume you have detailed knowledge of past events and are able to travel into the past.
How are paradoxes avoided, if the laws of physics allow you to travel into you own past?

By creating a parallel time line?
By changing probability?
By you becoming immaterial into the past, much like a ghost?

Lost's 'whatever happened, happened' can't work if you have detailed knowledge of past events. All you have to do once you reached the past is go right instead of going left (as you know you originally did).

 

[Lindley]

Or perhaps it only looks like you're traveling to the past to an outside observer. Given the odd ways relativity seems to work, that's as likely as anything.

 

[ProtoAvatar]

Or perhaps it only looks like you're traveling to the past to an outside observer. Given the odd ways relativity seems to work, that's as likely as anything.

You could very well have been that outside observer, before you accelerated and left that frame of reference, when, due to relativity of simultaneity and frame dragging (or another spatial distorsion), you have a 'door-way' for travelling into the past (as perceived from that outside frame of reference). Then you decelerate, reaching your initial frame of reference and voila! You're into your own past.

 

[publiusr]

I like the look of the spacecraft as done by the series.

 

[trekkiedane]

I'm seriously wondering what it takes to become a journalist these days! It used to be that you needed to have quite a bit of background knowledge about the subjects of your articles, but this article about the Discovery Channel series has me wondering:

The question according to Stephen Hawking isn't if, but when mankind begins to travel in time. The method, we'll use to travel in time, is in a super fast space ship, so it all depends on how long it'll take us to develop a space ship that travels faster than light.

My translation, article here.



Needless to say; I have mailed the journalist about it.

ETA: She just mailed me back to let me know the error has been corrected