The truth is that wormholes are all around us, only they're too small to see.
Wormholes are very tiny. They occur in nooks and crannies in space and time.
You might find it a tough concept, but stay with me.
Way too small for a human to pass through - but here's where the notion of
wormhole time machines is leading.
Some scientists think it may be possible to capture a wormhole and enlarge it
many trillions of times to make it big enough for a human or even a spaceship
I'm not saying it can be done, but if it could be, it would be a truly
So I've combined two of my favourite things to see if time travel from the
future to the past is possible.
Let's imagine I'm throwing a party, a welcome reception for future time
travellers. But there's a twist. I'm not letting anyone know about it until
after the party has happened. I've drawn up an invitation giving the exact
coordinates in time and space. I am hoping copies of it, in one form or
another, will be around for many thousands of years. Maybe one day someone
living in the future will find the information on the invitation and use a
wormhole time machine to come back to my party, proving that time travel will,
one day, be possible.
In the meantime, my time traveller guests should be arriving any moment now.
Five, four, three, two, one. But as I say this, no one has arrived. What a
shame. I was hoping at least a future Miss Universe was going to step through
the door. So why didn't the experiment work? One of the reasons might be
because of a well-known problem with time travel to the past, the problem of
what we call paradoxes.
Paradoxes are fun to think about. The most famous one is usually called the
Grandfather paradox. I have a new, simpler version I call the Mad Scientist
I don't like the way scientists in movies are often described as mad, but in
this case, it's true. This chap is determined to create a paradox, even if it
costs him his life. Imagine, somehow, he's built a wormhole, a time tunnel
that stretches just one minute into the past.
Through the wormhole, the scientist can see himself as he was one minute ago.
But what if our scientist uses the wormhole to shoot his earlier self? He's
now dead. So who fired the shot? It's a paradox. It just doesn't make sense.
It's the sort of situation that gives cosmologists nightmares.
This kind of time machine would violate a fundamental rule that governs the
entire universe - that causes happen before effects, and never the other way
around. I believe things can't make themselves impossible. If they could then
there'd be nothing to stop the whole universe from descending into chaos. So I
think something will always happen that prevents the paradox. Somehow there
must be a reason why our scientist will never find himself in a situation
where he could shoot himself. And in this case, I'm sorry to say, the wormhole
itself is the problem.
In the end, I think a wormhole like this one can't exist.