# The Naked Scientists Forum

### Author Topic: Would a slow-moving spaceship diffract between two planets?  (Read 1499 times)

#### Daniel Beech

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##### Would a slow-moving spaceship diffract between two planets?
« on: 26/01/2010 19:30:03 »
Daniel Beech  asked the Naked Scientists:

Hi

I have a question for you: if a spaceship was travelling at a very slow speed between 2 planets, would it diffract and if so what would happen to the people inside the spaceship?

Wave particle duality means that something should happen if you are travelling at around 10^-70, which is very slow I know, but putting it into the formula for the De Broglie wavelength with a mass of 10000kg gives a value of 6.63 x 10^32m.

So, if 2 planets where that distance apart and the right shape to cause diffraction, would diffraction occur?

I asked my physics teacher and she didn't know so I'm hoping someone at the naked scientist does.

Thanks
Daniel Beech

What do you think?
« Last Edit: 26/01/2010 19:30:03 by _system »

#### LeeE

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##### Would a slow-moving spaceship diffract between two planets?
« Reply #1 on: 26/01/2010 22:27:39 »
I think you're thinking of the space craft and its occupants as a single particle here, and that's what might be confusing you.  The space craft will consist of many particles, all of which will all be moving at a speed relative to their thermal temperature, so even if the space craft itself is moving very slowly, or is even stationary, if you think about it, the particles making up the matter of the space craft will be moving much faster.  For various reasons you can't cool anything to absolute zero K so that it has zero thermal energy, which is just as well really.

#### yor_on

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##### Would a slow-moving spaceship diffract between two planets?
« Reply #2 on: 26/01/2010 23:17:59 »
I'm kind of losing you there. I guess you want to consider the ship the equivalent of a particle? As Leee says? And then wonder if this 'particle' would show a interference pattern :)

Kind of nice idea. I'm not sure that would be possible. Diffraction is something of a wave property, and here you would have an awful lot of waves to count on, not only the speed of your 'particle' but all those waves making up it too. But I won't swear to it being impossible though. Perhaps there could be a state of averages allowing something strange?

But it is a question that makes me wonder though :)
The speed you're suggesting is a fraction of the speed light have in a vacuum right? And that speed is relative what?

Consider that you always will see light move from you at a constant 'c', no matter your own speed relative a third object (passing space ship, meteor, planet etc)

So when you 'gear down' to that speed, how will you do it, and can you guarantee it as relative that third object to be the correct one?

:)

I think you will like this one

#### The Naked Scientists Forum

##### Would a slow-moving spaceship diffract between two planets?
« Reply #2 on: 26/01/2010 23:17:59 »