Why airplanes taxi

writes:

Fixed-wing aircraft taxi because their wheels reduce friction as they
move forward on the ground.

So, logically, spacecraft in the frictionless environment of outer space
should immediately accelerate to the speed of light.

On Feb 6, 10:24*am, Mxsmanic wrote:
writes:
Fixed-wing aircraft taxi because their wheels reduce friction as they
move forward on the ground.

So, logically, spacecraft in the frictionless environment of outer space
should immediately accelerate to the speed of light.

Space isn't frictionless dummy.

writes:

Space isn't frictionless dummy.

Where does the friction come from?

On Feb 6, 10:36*am, Mxsmanic wrote:
writes:
Space isn't frictionless dummy.

Where does the friction come from?

Molecules

On Feb 6, 10:39*am, wrote:
On Feb 6, 10:36*am, Mxsmanic wrote:

writes:
Space isn't frictionless dummy.

Where does the friction come from?

Molecules

And to answer your next post before you post it:

What molecules?

http://en.wikipedia.org/wiki/Outer_space

writes:

And to answer your next post before you post it:

What molecules?

http://en.wikipedia.org/wiki/Outer_space

"While not being an actual perfect vacuum, outer space contains such sparse
matter that it can be effectively thought of as one. The pressure of
interstellar space is on the order of 10 pPa (1×10-11 Pa)."

So, no molecules. And no friction.

Even if you don't wish to consider the hard vacuum of space as perfect, with a
pressure that is 10,000,000,000,000,000 times lower than that of Earth at sea
level, the friction should be also that much lower, and thus the speed of a
taxi should be trillions of times faster. The speed of light is only fifteen
million times faster than a 40-knot taxi, so nearly the speed of light might
well be achieved long before any residual friction could have any effect.

Gee, where would the energy come from to cause the acceleration?

On Feb 6, 2:00*pm, Mxsmanic wrote:
writes:
And to answer your next post before you post it:

What molecules?

http://en.wikipedia.org/wiki/Outer_space

"While not being an actual perfect vacuum, outer space contains such sparse
matter that it can be effectively thought of as one. The pressure of
interstellar space is on the order of 10 pPa (1×10-11 Pa)."

So, no molecules. *And no friction.

Even if you don't wish to consider the hard vacuum of space as perfect, with a
pressure that is 10,000,000,000,000,000 times lower than that of Earth at sea
level, the friction should be also that much lower, and thus the speed of a
taxi should be trillions of times faster. *The speed of light is only fifteen
million times faster than a 40-knot taxi, so nearly the speed of light might
well be achieved long before any residual friction could have any effect.

Mxsmanic wrote in
:

writes:

And to answer your next post before you post it:

What molecules?

http://en.wikipedia.org/wiki/Outer_space

"While not being an actual perfect vacuum, outer space contains such
sparse matter that it can be effectively thought of as one.


A bit like the inside of your skull.

Bertie

On Feb 7, 6:00*am, Mxsmanic wrote:
writes:
And to answer your next post before you post it:

What molecules?

http://en.wikipedia.org/wiki/Outer_space

"While not being an actual perfect vacuum, outer space contains such sparse
matter that it can be effectively thought of as one. The pressure of
interstellar space is on the order of 10 pPa (1×10-11 Pa)."

So, no molecules. *And no friction.

Even if you don't wish to consider the hard vacuum of space as perfect, with a
pressure that is 10,000,000,000,000,000 times lower than that of Earth at sea
level, the friction should be also that much lower, and thus the speed of a
taxi should be trillions of times faster. *The speed of light is only fifteen
million times faster than a 40-knot taxi, so nearly the speed of light might
well be achieved long before any residual friction could have any effect.

The resistance is a function of the density of gas molecules not
pressure
density is related to pressure by
D=PM/RT
M=molecular wt
P=pressure
R=gas constant
T=temperature ( absolute )
ie the lower the temperature the higher the density
so what is the temperature in interestella space?

Resistance is also a function of the velocity squared.
think about how bit a number is c sqaured.

Terry
PPL Downunder

writes:

Molecules

There aren't any molecules in space. It's a hard vacuum.