What is a wormhole? A wormhole is a passageway between points in a 'folded' universe. Imagine a big piece of paper, with A written at one end and B written at the other…

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## Wormholes

#### by Linda Baxter

Have you ever read Carl Sagan's 1985 science fiction novel 'Contact'? Or have you seen the film of the same name starring Jodie Foster? If you have, then you will remember the scene near the end of the film, when the heroine travels to the star Vega, twenty-six light years away from Earth, through a wormhole in space. Just a story, you think. But is it?

The truth is that the scene described above is a serious scientific picture of travel through space-time using a wormhole. When Sagan was writing the book, he asked an American scientist, Kip Thorne, to give him an idea for a way of travelling long distances through space that was scientifically possible. Thorne thought about it for a long time and then had the idea of using a wormhole. He then looked again at Einstein's theories and the accepted rules of physics and was surprised to see that wormholes really could be used to travel through space.

### But what is a wormhole?

A wormhole is a passageway between points in a 'folded' universe. The easiest way is to imagine a big piece of paper, with A written at one end and B written at the other. It will take a small insect a long time to walk from A to B. But now fold the paper in half, so that A and B are near to each other. Now connect A and B with a small tube pushed through the paper - the wormhole. The distance between A and B is now only a few millimetres, and the insect can walk along the tube and make the journey in a fraction of the time. So distances of many light years in space could become just a few metres.

### So, did Kip Thorne invent wormholes?

No he didn't. Kip Thorne proved that there is nothing in the laws of physics and the general relativity theory to say that they're not possible. Einstein talked about 'folds' in the universe. He also thought that if these folds existed, then there might be passages, or shortcuts connecting them. He thought that there might be passages like these connecting two black holes, so that something could enter one black hole, travel through the wormhole and come out again at the other end. He called them 'bridges'. But for some reason, nobody thought very much about them until the 1980s.

### But isn't it impossible for anything to escape from a black hole?

True. A black hole has such strong gravity that nothing, not even light, can escape from it. Everything is crushed at the centre point of the black hole. But mathematicians have proved that things are different if the hole is rotating. Then, it may be possible for a doorway to open at the centre point, where the wormhole begins. And some people believe that white holes exist too. These are the opposite of black holes. Instead of holding everything inside, a white hole pushes everything out. So you could enter a rotating black hole, travel through a wormhole, and then come flying out of a white hole at the other end.

### But is it really possible?

Theoretically, yes. But there are a few problems. Wormholes are not very stable. They only exist for a few seconds before they collapse. And something travelling through one would probably make it break up anyway. And a wormhole would be full of x-rays and gamma rays, which would burn you. And of course, you would never be sure where you were going and almost certainly, you wouldn't be able to come back again the same way. So if we can find a natural wormhole, we then need the technology to control and stabilise it. Which is exactly what the advanced civilisation in 'Contact' were able to do.

### Could we use wormholes to travel through time?

There are people who think exactly that. Einstein's equations treat space and time in exactly the same way. So a wormhole can link two different times as well as two different places. According to Einstein's theories, time travel would be difficult but not impossible. Scientists now take the idea very seriously. But there are some big problems of logic. For example, if you went back in time and killed your grandmother, you would then never be born. So you never existed, so you couldn't travel back in time because you didn't exist! To explain this problem (known as 'the granny paradox') people have invented theories to say that you can only travel back in time to the moment when the time machine was invented. This theory also explains why we don't have lots of 'time travel tourists' visiting us now.

So, in conclusion, wormholes have never been found in nature. No astronomer has ever seen things come flying out of one in the middle of space. But we do know that, according to the rules of physics that we use, they are possible. And if we could find one and control it, travel through space and maybe even time would be a real possibility.

### Tags

I’m sure that we can’t travel in time even thought our means of transport or technologies, the travel in time means that we can know what it will happen in future or in past and that is impossible, according our knowledge only and just our God who know all of this.

Do you think that it will ever be possible to travel through time?
I don’t think it will ever be possible to travel through time. Although I also wish to travel through time but it seems more like a dream. Well dreams may come true if you follow them but this is one like that one is willing to learn English without going through the learning process and by using some trick. “Learning process” is like traveling the whole page A to reach the page B, and trick is the Tube from the magazine that is used to resemble wormhole!
I have a confusion that in time travel whether I am allowed to make any impact or it would be just watch-only travel that I can just travel to different times but I can’t make any impact to them. So, if I am allowed to do whatever I want to then I see so many complexities in time travel, suppose if I travel to some other time and marry some woman and become father then which time the baby would belongs to. So my every action would result in a different end and this means that I have a copy of myself in each time and consider if myself from two or more different times met at some other time!

If you could travel through time, where would you travel to? Why?
I would like to go to the time when this world is going to end. I want to see the end of this world. It’s like a game where you feel you can’t or don’t have time to clear every round, and you wish to see the end. I want to see the progress the human race is able to make till the end of world. I want to see the inventions that we have made, and whether we are able to find any aliens, and to what extent we have explored the universe and the concept of religion, is it still there or we have something else. I want to see the judgment day. Well I wonder whether I will be allowed to see the judgment day procession!

Hi British Council,

First of all thanks for organizing and maintaining the website. It's an easy and best tool for self learners.

Under heading "Could we use wormholes to travel through time?", the example sentence is in past-tense whereas preceding ones are in present-simple. Sentence is: "For example, if you went back in time and killed your grandmother, you would then never be born. So you never existed, so you couldn't travel back in time because you didn't exist!"

My question is, would it be OK, if I say the above mentioned sentence in present-simple. E.g. "For example, if you go back in time and kill your grandmother, you will then never be born. So you never existed, so you couldn't travel back in time because you didn't exist!" - If no, then could you please tell me the reason, or is there anything else that I am unable to understand - actually I am unable to digest why writer has changed the form.

Hi Sajed Karim,

The author is talking about something which is not possible and is speculating about an unreal or imaginary situation. Therefore the form which is used is [if + past + would verb].

Changing it to [if + present + will] would mean that the author thinks the situation is a real possibility. Sadly, our technology is not (yet) sufficiently advanced for this!

You can read more about various hypothetical forms on these pages: here, here, here and here.

Best wishes,

Peter

The LearnEnglish Team

Interesting fact! I've always wondered if we can ever successfully build a practical time machine. Imagine how our lives will be if we can travel through time!

If I was able to travel back in time I would had traveled to the year 2000 to correct a horrible mistake but again thanks God for not allowing that  possible for the life is good the way it is going on now and it is our responsibility to learn from our mistakes and avail  from life,s lessons .

I think it,s totally immature  to consider traveling back in time as a scientific possibility ,the idea itself is good for film makers and fiction books writers etc...
In my opinion  it is some sort of a joke seriously, nevertheless creating such material for argument is quite an idea.

Very interesting article. It will take just a few more decades for our space scientists to achieve the technological development required for long distance space travels or through a wormhole if one actually exist.