Le 15-02-24 11:53, clipka a écrit :
> Am 24.02.2015 um 17:31 schrieb clipka:
>> Am 19.02.2015 um 09:25 schrieb scott:
>>>> I'm building a bubble around my spaceship to protect from "drag" at
>>>> interstellar velocities. This site says that for subsonic craft a
>>>> parabola is a better shape for the nose. However, an ogive is better at
>>>> supersonic speeds.
>>>>
>>>> http://www.aerospaceweb.org/question/aerodynamics/q0151.shtml
>>>>
>>>> Which applies in outer space? Or, should I not use either and use a
>>>> teardrop shape instead?
>>>
>>> What is the speed of sound in space... I don't think any "supersonic"
>>> designs are necessary.
>>
>> In an ideal gas, the speed of sound is proportional to the square root
>> of the pressure... until relativistic effects kick in, I guess.
>
> In numbers: Speed of sound in hydrogen and helium is roughly 10^3 m/s at
> atmospheric pressure. With the pressure in outer space being lower by a
> factor of about 10^14, according to Newtonian mechanics the speed of
> sound in this medium would be about 10^7 times higher, i.e. 10^10 m/s -
> exceeding the speed of light by about 1.5 magnitudes.
>

That would be inversly proportional.

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