gravity or rather, sudden lack of gravity question

[DrPizza]

Person stands on earth. Suddenly, earth becomes massless (yes, I know it's hypothetical)
The question was, does the person float off into space? My answer was, of course, tangent to the surface of the earth in the direction of motion.

The follow-up annoying part. Earth's gravitational field distorts space-time. Now, that gravitational field ceases to exist (?) What effect does this have on the person as he begins to float off into space.

A) aren't there experiments suggested for detecting "gravity waves" caused by supernovas?
B) what effect, however small, would this have on the person

I keep thinking of all those pictures, using the analogy of the rubber sheet depressed by a mass to show how space-time is distorted by mass. I keep thinking of the sheet suddenly springing back as the mass instantaneously vanishes. Then, my head starts to hurt... Is this a case of over-application of an analogy?
Please comment.
Thanks.

 

[silverpig]

Space would de-warp and you would continue to travel your straight world line, although now you would be travelling in uncurved space. Hence, you'd fly off straight, tangential to the earth's surface (but it'd look like you started floating straight up for a while as the earth still spins.

A) yes. look up LIGO and LISA
B) The effect is to compress and expand a person repeatedly... Assuming convenient geometry, a passing gravitational wave going through you from your chest to your back would make you shorter and wider, and then taller and thinner, and would repeat this way until the wave passed. That's how LIGO works, is by checking for a path difference between two orthogonal arms. It has to be insanely sensitive though, right now it can detect path length differences on the same order as being able to detect if the earth moved closer to the sun by a distance of an atomic nucleus.

 

[DrPizza]

Thanks 🙂
I couldn't remember what the proposed experiments were named. But, I did remember the insane precision necessary.

 

[sao123]

Dont forget you would also end up with some sort of head over heels tumbling motion... in addition to your flight in the tangental plane.


path is exadurated for for this example...

<O

^
O

poof earth disappears

-- >

 

[Loki726]

if earth suddenyl dissapeared, you wouldn't immediately fly off tangentially into space, you would have to wait (speed light)/(distance from the center of the earth to you) seconds before you would stop experiencing the effects of gravity.

 

[sao123]

Originally posted by: Loki726
if earth suddenyl dissapeared, you wouldn't immediately fly off tangentially into space, you would have to wait (speed light)/(distance from the center of the earth to you) seconds before you would stop experiencing the effects of gravity.

which would be.... 0.0000001 seconds....
close enough to instantaneous for all mathematical purposes.

 

[Xyo II]

Originally posted by: sao123

Originally posted by: Loki726
if earth suddenyl dissapeared, you wouldn't immediately fly off tangentially into space, you would have to wait (speed light)/(distance from the center of the earth to you) seconds before you would stop experiencing the effects of gravity.

which would be.... 0.0000001 seconds....
close enough to instantaneous for all mathematical purposes.

well no, because the sun's dent in space time is affecting your orbit- you wouldnt be affected by this a whole lot actually, but if we are considering that the earth physically does not exist anymore, accompanied by its surrounding atmosphere, it still depends on your distance to the moon, and you might come to a standstill as your frozen carcass is pelted by floating debree and natural satellites. and it also depends on your location on earth, and earth's location in its elliptical orbit, because you might be close enough that the sun's gravity will effect your path even more so, and your path may be redirected enough for you to get scorched by a random solar flare. all assuming you dont collide with one of our man-made satellites.
edit: or the two inner-most planets dont get in your way

 

[liquid51]

Correction. There will be no more satellites 😉