If you saw it, did you get the joke? They included it!
Ok, here it is:
So whenever you mention the History Channel, the image that springs to everyone’s mind (not without justification) is that if you ever flip past that channel, there’s something on about World War Two, with images of tanks and German soldiers, and Hitler, and so forth. Right?
But since the History Channel has made this departure into programmes about the science of the universe, this won’t happen during those programmes… Right?
Well, Laura Verklan (writer/director of the show) and I were chatting about this image that the channel has, during a break between shooting my contributions to the “Cosmic Holes” episode. We were talking about how, if you could make a wormhole (and I explained the immense theoretical and practical difficulties in doing this) even in principle, then it is easy to see from simple consequences of Special or General Relativity, that you can make a wormhole into a time machine. You’d be able go in one end and come out the other end in the past, for example. All science fiction as far as we know now, of course, but an interesting possibility to consider and study on paper at least.
Well, it hit us: A time machine. Ah…! We saw the opportunity for a big on-screen wink at the History channel audience…
You see the joke, right? During the show, soon after the possibility of time machines is mentioned, in the voice-over leading up to a break, the program asks (I paraphrase) “Can humans use time machines to go back in time and change history?”, and then, yes, they run some images of German soldiers, Hitler, and so forth…
I’m sorry, but I can’t help it – I think that’s just hilarious…!
-cvj
Hi,
There are no dead comment sections. Or, better put, they are all equally dead, or equally alive.
And the answer to your question is: No. The total mass energy in the universe has not changed in that process. The mass has just been moved around, as happens in ordinary mechanics.
Best,
-cvj
Hi,
this is probably a dead comment section,
but heres a worm hole question:
if mass leaves time A and appears at time B
isn’t that a violation of conservation of mass/energy ?
thanks
jpd
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Ryan, that’s not really correct. You can go in both directions. So it depends upon when and how the time machine was made. If someone had (somehow) made such a time machine back then (you know, a friendly alien species with extraordinary technology did it and left it lying around in the back of an old wardrobe or something for us to find), you’d be able to pop back to that period.
Cheers,
-cvj
Stricly speaking, the only time period you would be able to get to through a wormhole would be the future, as through a wormhole, in theory, time would slow down for the people inside, but carries on at regular speed for everything outside the wormhole, and so when the people inside arrive, many thousands or even possibly millions of years might have passed since the wormhole was entered.
But also i thought the joke was hysterical
‘Making History’ by Stephen Fry is a great read on precisely this theme.
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Yes, I got the joke. Good one.