Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jeffreyH on 19/11/2019 19:11:44
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Well this is not the question you might think it is. If a spacecraft is falling freely towards a gravitating body, and then starts accelerating towards the body, would an accelerometer show the acceleration?
I have not seen anything about this online. I would say it would. Is there any observational evidence anyone can point to? Have you tried this personally?
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Well this is not the question you might think it is. If a spacecraft is falling freely towards a gravitating body, and then starts accelerating towards the body, would an accelerometer show the acceleration?
I have not seen anything about this online. I would say it would. Is there any observational evidence anyone can point to? Have you tried this personally?
If the ship fires it engines such that the ship accelerates towards the gravitating body at a rate greater than that due to the gravity of the body, then yes, the occupants will sense that extra acceleration. It doesn't matter what direction the ship is pointed, any thrust by provided by the engines will be felt the same way by the occupants. In other words, if the occupants were unable to look outside and had no prior knowledge of their situation in regards to the gravitating body, firing their engines, no matter what their orientation, would not give them any information regarding their situation with respect to that body.
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The Earth is in free fall round the Sun.
Accelerometers work just fine here on Earth.
We are also able to establish that we are rotating and that means we are accelerating.
Some bits of the Earth are always heading towards the Sun.
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Some bits of the Earth are always heading towards the Sun.
What does this mean?
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Some bits of the Earth are always heading towards the Sun.
What does this mean?
It means that, at any time, there is some point on the Earth's surface which is moving towards the Sun.
With a slightly looser definition of "towards" you can say that anywhere on the surface between where it is noon now and where it will be noon in the next 12 hours is moving towards the Sun.
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If you are weightless that is as far as you will get to freefall, as everybody knows gravitational potential goes on forever to infinity. That sort of puts it in the relativity frame of is the elevator rising or building falling etc.
If in deep space your craft accelerates at 9.81 ms your nerve nedings will feel the force acting on them as you are met by the accelerating ship.