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How to get to the stars…

The Alcubierre drive (or Alcubierre metric see: Metric tensor) is a speculative idea based on a valid solution of the Einstein field equations as proposed by Miguel Alcubierre by which a spacecraft might achieve faster-than-light travel, making travel to other stars a possibility. However, it should be understood that this is different from a ship actually exceeding the speed of light within its local frame of reference. Rather, the ship would traverse distances due to the expansion and contraction of space behind and before the ship, respectively, as indicated in the diagram to the right.

Don’t look at the diagram – it only confuses matters. Basically it contracts space ahead and elongate it behind. Basically it works like this (there shall be some maths a-coming) but this is in principle the guts. The key word is “metric”. Relativity forbids travel faster than light which is a pain if you really want to go anywhere fast. But it doesn’t ban spacetime itself moving faster than light. Now if you can do that you can have a weekend trip to Proxima Centauri. Now that is much more fun than Southend.

And this is how it works… This is the metric…

It gets better. I actually understand this which shocks me…

That is gorgeous. And BTW tanh is pronounced “than”. It is the hyperbolic tangent.

If we can harvest enough “exotic matter” it can be done. Windmills obviously won’t do it. Now the maths is tricky but did you really think tricking the light barrier was “simples” as the Meerkat said?

Oh, there is a problem. And it is potentially a biggie. The fact that the Alcubierre metric is a valid solution of the Einstein Field Equations means it is merely mathematically valid. It does not mean it applies to our universe. For example the Goedelian solutions to the EFEs are mathematically correct but almost certainly don’t apply here. Interesting but not correct.

6 Comments

  1. Mr Ecks says:

    If the MACH effect (see Next Big Future blog) is also valid that would give us a space drive for planetary transit (in Star Trek terms “impulse power”) and the Alcubierre could give us intersteller travel. All that’s needed is a power source–fusion-hot or cold and we’re off and running.

  2. Sam Duncan says:

    Forgive me if I’m talking pish here (I got all my eddycation on this from Carl Sagan, James Burke, and the bloke who wrote The Science of Star Trek), but isn’t there a bit of a problem in that there isn’t enough exotic matter?

  3. Leo G says:

    Finally got a grasp on black holes, when someone told me about space being sucked in at a speed faster then light. That is when the bulb went off!

    Could this idea be used to maybe observe the Big Bang?

  4. jameshigham says:

    Just had breakfast and you do my head in. Ouch.

  5. NickM says:

    Leo,
    Probably not.

    Sam,
    You hit the nil. exotic matter is well exotic.

  6. NickM says:

    I meant “nail”. Bloody Lenovo!!!

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