DR.
RONALD MALLETT: Today I'm gonna address some of the questions that people have an interest
in asking me.
DR.
RONALD MALLETT: [Laughs] You got it.
DR.
RONALD MALLETT: On Facebook, "What movie or TV shows get the closest to a true or realitic
depiction of time travel and time travel mechanisms?"
Well there's two movies I can think of.
One was "Planet of the Apes".
"Planent of the Apes" illustrated Einstein's special theory of relativity.
That is to say according to Einstein's special theory of relativity, the faster an object
moves, the more time slows down.
And this allows time travel in the future.
In "Planet of the Apes" the rocket does go close to the speed of light.
It turns out that unbeknownst to the space travellers, they have actually travelled into
the Earth's future.
That is really a real depiction of the possibility of time travel.
Another more recent one is Star Trek, with the notion of wormholes.
Wormholes are based on Einstein's general theory of relativity, which says that we can
create tunnels in space and use these tunnels in space to actually alter our passage through
time.
So this is a real possibility as well.
So wormholes are on the other side of it.
So those are two that come to mind immediately that illustrate a real possibility of time
travel.
This is from Twitter.
SPEAKMOUTHWORDS asks, "Do you think the many worlds solution to the grandfather paradox
will be testable?
If not, does it even have a place in science?"
The grandfather paradox says that what if you go back into the past and prevent your
grandparents from meeting eachother.
Then they don't have your parents and if they don't have your parents then they don't have
you.
So if they don't have you, how could you have gone back into the past and prevent your grandparents
from meeting eachother.
That's called the grandfather paradox, okay.
It has to be remembered that the many worlds interpretation was not developed to explain
the grandfather paradox.
The many worlds interpretation was in fact to talk about how quantum mechanics relates
to the universe as a whole.
The prob was first addressed by a man named Hugh Everett III at Princeton University in
which he applied quantum mechanics to the entire universe.
The result was was that he found that every possibility that can be played out is played
out.
For example, if you had made a decision today about having a fish sandwich or a cheese burger
then at the moment that you make the decision to have a fish sandwich, the universe splits.
You now have a fish sandwich in this universe, but there's also a universe in which you have
the cheese burger.
And these are independent universes and they split and one of the things is is that there
might be an interference between these various universes.
That is something that might be testable.
That's a possibility.
As far as the grandfather paradox is concerned, David Deutsche from Oxford University said
that if you apply the many worlds interpretation to that, when you go back into the past, you
arrive at a past of a parellel universe.
And in that universe you could prevent your grandparents from meeting each other.
However, it doesn't affect the original universe you came from.
Now the original universe evolves and gives rise to your parents, it gives rise to you.
So that's how the paradox is resolved.
Now, as far as how that would be tested, that would be difficult because even if you set
up the experiment, it turns out that when you do the experiment, you may think your
experiment failed but it didn't because the information ended up in a parallel universe.
If it ends up in your universe, however, that leads to a whole different thing because that
means your universe will change as a result of your saving..getting that information.
So, it could be testable but that's something that's going to have to be developed in much
more detail.
NICKIANDCARRIO asks, "When you travel back in time, does time move forward?
Where do you end up when you go back to the future, where you left off?"
It's a good question.
Thing is is that when you travel back in time, your personal time always goes forward, even
though you're travelling back in time.
So, you continue to age at your normal rate even though you're travelling in the past.
If you try to get back to the future, the question is is that it depends on whether
or not you've ended up in a parallel universe.
If you've ended up in a parallel universe, you can never go home again because once you're
in that parallel universe, you can go to the future of that parallel universe but you can
never get back to your original universe.
Of course, if you end up in the past of the original universe, then there is a possibility
that you could go into the future of the original universe.
However, the future of the original universe will be different than the universe that you
started out in because you ended up in the past and even though you may not think you
affected anything, even if you stepped on a butterfly that could change the course of
history.
ANDREWFOURATT asks, "Since the Earth is constantly moving, how do we ensure that we end up in
our desired place during time travel and not in outer space?"
I'll use the illustration of my work.
When you turn the device on today and it starts creating these loops, these loops don't close
back on themselves.
Think of a device, it's called..a toy device..it's called a slinky, a little children's device,
and imagine that you're holding the base of the slinky here and that the top of the slinky
is being held as time goes on.
So as time goes on, okay, the base of the slinky is here but the slinky is moving with
the Earth, which is connected to the laboratory.
So, at some future time, it's over here.
So, you can actually spiral back along those loops of the slinky back to any point in time
and you'll always end up where the Earth was back in that point in space and time, all
the way back up to when you turned the device on.
So these loops are all connected in that way and so they keep track of where you are in
space and time.
So, you'll never just end up in outer space.
On Facebook, TANISHQ ABRAHAM asks, "I like the theories and science of time travel and
time machines, but I wonder if it's correct morally to change the past or the future of
someone's life.
For example, the discovery of the H-bomb that brought so much destruction to life."
The question is, is it morally something that we should do even if we can do it?
If we can travel in time, should we?
You have to remember that any technology that's developed has the potential for good or ill
and we are the ones that have to determine it.
To mention the simplest thing that you can think of, um..let's say something like a utensil.
A knife can be used to butter bread.
It can also be used to stab someone.
So are we gonna ban knives?
And when we look at something like air travel.
Air travel has brought the planet closer together, but all we have to do is think of 9/11 to
think about the other possibility.
And when it comes to time travel, it's going to be responsible for us as citizens to determine
how time travel is going to be used.
Because, think about it, one of the things that a time machine can be used for is an
early warning device.
Think of what it would mean to have knowledge of the future to save people's lives.
For example, to warm us of disasters like Katrina in New Orleans or the tsunamis in
Japan.
If we could have that kind of knowledge, think of what it could mean for us.
Technology is going to move on.
The thing is is that we, as human beings, have to determine how to use that technology.