#科技头条#【时间旅行通过黑洞成为可能?】

【时间旅行通过黑洞成为可能?】近日,学者们针对时间旅行展开了有趣的对话。当我们观看恒星和行星,就会不自觉地把星体放在过去来观看。对于行星来说,这种时间上的延迟可能只有几分钟,但是对于恒星,可能是几千年的时间。通过用世界上最先进的望远镜观察微弱的星系,可以回顾整个宇宙的历史。在一个旋转黑洞的内部区域,空间和时间是混合的,时光旅行是非常有可能实现的。http://www.dailymail.co.uk/sciencetech/article-4534572/Time-travel-possible-black-holes.html

Time travel MIGHT be possible through black holes and 'a cunning plan', experts claim

  • When we look at the starts and planets, we see them as they were in the past  
  • For planets, this delay is only a few minutes, but for stars, it's thousands of years
  • By observing the faintest galaxies with the world's latest telescopes, we can look back through time and watch the whole history of the universe unfold
  • In the inner regions of a spinning black hole, space and time are mixed so that travel back in time is tantalisingly close to possible

Literature professor Simon John James and physicist Richard Bower were both involved in the curating the exhibition, Time Machines – the past, the future, and how stories take us there.

Their conversations quickly revealed to them the many, wildly various, meanings of 'time travel'.

Here, they discuss how time travelling in literary and scientific terms might, one day, coincide.

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Simon John James: Richard, what does the term 'time travel' mean for a physical scientist?

Richard Bower: Time travel is the basis of modern physics, and, for anyone that looks up at the night sky, an everyday experience.

When we view the stars and planets, we see them, not as they are now, but as they were in the past.

For the planets this time delay is only a few minutes, but for most of the stars in the night sky, thousands of years.

For galaxies, faint smudges of light made up of very distant collections of stars, the delay can be millions or billions of years.

 

By observing the faintest galaxies with the world's latest telescopes, we can look back through time and watch the whole history of the universe unfold.

But this is not the most satisfying kind of time travel.

It allows us only to gaze into the past as remote observers.

One of the key challenges for modern physics is to determine whether it is possible to influence the past.

One of the key concepts of Einstein's Theory of Relativity is that objects exist in a long line in 4D spacetime, a unification of time and space.

Although all observers agree on the length of the world line that connects two events, they may have different views about whether the events occur simultaneously, or at the same location but at different times, or a mixture of both.

 

For example, while I sit at my desk to eat lunch, then work a little and get up to go home several hours later, a (very) fast-moving observer will see me whizz by eating lunch and immediately getting up to go home.

In Einstein's theory, time and space are mixed together: we cannot think of them separately.

It therefore makes best sense to think of myself as always moving along that 4D world-line, travelling into the future at the speed of light.

But is it possible to cheat the safeguards of Einstein's theory and to travel backwards through time?

Perhaps the most famous time travel text is The Time Machine (1895) by HG Wells, which was the first to imagine humans travelling in time through the use of technology

Perhaps the most famous time travel text is The Time Machine (1895) by HG Wells, which was the first to imagine humans travelling in time through the use of technology

At face value the answer is no, but then again, the science of earlier generations would have said it was impossible for mankind to fly.

Perhaps all scientists need is inspiration and a cunning idea.

SJJ: Well, you can find a lot of inspiration and cunning ideas in fantastic fiction, of course.

Perhaps the most famous time travel text is The Time Machine (1895) by HG Wells, which was the first to imagine humans travelling in time through the use of technology.

Other of his imaginations have been realised – he imagined and wrote about the technology of powered flight before science made it possible in real life, for example.

Wells's innovative idea led to modern time travel stories such as Back to the Future or Doctor Who.

But many different kinds of stories travel in time: Aristotle observed that a good story has a beginning, a middle and an end – but they do not have to be in that order.

Even a text as ancient as Homer's Iliad does not begin with the judgement of Paris, but with Achilles sulking in his tent in the ninth year of the Trojan War, and the story unfolds from there.

Whodunnits usually don't tend to begin with the murder, but with the discovery of the body, and the plot is reconstructed by the detective as the story moves both forwards and backwards.

This is the temporal freedom of narrative time.

RB: What's freeing in the literary device is for practical time travel the central obstacle.

原文链接:http://www.dailymail.co.uk/sciencetech/article-4534572/Time-travel-possible-black-holes.html


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