[Alan McDougall (OP)]

What would be the consequences of turning off Earths gravity field for a nano second ?

A hypothetical thought experiment?

Alan

[PmbPhy]

What would be the consequences of turning off Earths gravity field for a nano second?

The consequences would be what you'd probably expect, i.e. nothing of great interest. When gravity is turned off (which of course is impossible so you'd be violating the laws of physics) objects in the region of Earth would start to move in the same way that they'd move in the absence of gravity, but only for one nanosecond. That's not enough time to notice it happening. However for those instruments on Earth which are affected by such things and record them then there would be a record of it. Whether such instruments exist is another story but there are far too many labs and scientists working all over the Earth to know what each one is doing and what experiments they have running.

[chiralSPO]

If instead of "turning Earth's gravity off" for a nanosecond, we imagined that everything accelerated away from the center of the Earth at 1 g for 1 nanosecond, this would be equivalent. Surface gravity on Earth is 9.8 m/s², and the acceleration decreases at increasing depth. But let's imagine that everything accelerated away from the center at 9.8 m/s² for one nanosecond, that would impart a velocity of 9.8x10^–9 m/s and a total displacement of 4.9x10^–18 meters, or about 1 billionth of the radius of a hydrogen atom...

As pmbphy says, "nothing of great interest"

[Alan McDougall (OP)]

If instead of "turning Earth's gravity off" for a nanosecond, we imagined that everything accelerated away from the center of the Earth at 1 g for 1 nanosecond, this would be equivalent. Surface gravity on Earth is 9.8 m/s², and the acceleration decreases at increasing depth. But let's imagine that everything accelerated away from the center at 9.8 m/s² for one nanosecond, that would impart a velocity of 9.8x10^–9 m/s and a total displacement of 4.9x10^–18 meters, or about 1 billionth of the radius of a hydrogen atom...

As pmbphy says, "nothing of great interest"

OK point noted and agreed with so lets increase the time of the gravity field being put off to a second?

Worldwide or complete death and destruction.  People/everything else will become unglued from the ground and reach heights over 32 feet in the second, and the living would die from the fall when the gravity turned on again. 

Also massive objects that became unglued would rise up 32 feet fall back and destroy every living thing on the planet, making an atomic bomb look like a puny fire cracker by comparison,   and then there is the inside of the planet from its core upward to the surface , that will emerge above the surface as molten heat to burn up what is left of our late great planet earth.   It would be a very bad second indeed , the end of humanity.

Also all the oceans of the earth will rise up 30 feet creating the ultimate tsunami

"I know! I know! that gravity could never be turned off in an isolated part of the universe, like the earth, if it were then gravity would not exist in the entire universe which would cease to exist alongside earth".

Nevertheless I think it is a fun question to debate!

Einstein imagined himself riding on a beam of light so why not imagine this equally impossible thing?

Alan

[chiralSPO]

That would probably ultimately cause some pretty severe earthquakes. I admit, I don't really see where you're going with this--Of all the impossible scenarios one could imagine, this is one of the least interesting (unless I'm missing something). I think it would be far more interesting if all of the oxygen in the atmosphere somehow became singlet oxygen (https://en.wikipedia.org/wiki/Singlet_oxygen) for 1 second. In addition to killing most non-marine life and destroying most flammable structures on the surface of the Earth, there would be some pretty nifty photophysics as the rest of the singlet oxygen reverted back to the triplet state...

[Colin2B]

I think it would be far more interesting if all of the oxygen in the atmosphere somehow became singlet oxygen

I hesitate to ask what circumstance might bring that about. However, I do agree, far more interesting.

[chiralSPO]

I think it would be far more interesting if all of the oxygen in the atmosphere somehow became singlet oxygen

I hesitate to ask what circumstance might bring that about. However, I do agree, far more interesting.

I don't know how such a circumstance might come to be, but it is at least theoretically possible--there is enough energy from incoming sunlight, and there are several ways that light can be harnessed to convert triplet oxygen to singlet oxygen (in fact plants do this by accident during photosynthesis, and have evolved several ways to reduce this undesirable pathway and mitigate the damage done by singlet oxygen).

I cannot think of any way that gravity could be "turned off" so this singlet oxygen scenario is both more likely and more interesting than that described in the OP (no offense Alan)