# Tag Info

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Kip Thorne said that the detection puts an upper limit on the mass of the graviton at the announcement press conference. I'm not sure of the number, but I think he said it was in the paper.

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Since we can choose the frame of reference in which to calculate, we can use the inertial frame corresponding to the initial motion of the spinning object. In this frame its centre of mass is stationery, and so you question becomes "will a rotating mass start to move?". I hope it is clear that there is no reason for it to move in any particular direction, ...

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In principle yes, but in practice they would follow the same trajectory. At least if you want to be able to actually use them for something useful. The reason a spinning ball curves is due to its interaction with the air. If the ball is spinning clockwise as seen from above, and it is moving toward 12 o'clock, this pushes the incoming air a bit to the left, ...

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The impact of this measurement on the status of quantum gravitation is exactly zero. The proper statement of the incompatibility of general relativity and quantum mechanics is that the quantum field theory of general relativity is not renormalizable. Renormalizability essentially means that the theory is well-defined at all energy scales, which seems like a ...

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Another question, how can we identify the ripple's origin (let's say that if it's the result from the big bang or another big event)? (I'm just answering this part of the question, as James has already answered the main part about GR vs QM.) LIGO have produced an image which shows their best estimate of where these two black holes were: All they can ...

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No more than the observation of light waves disproves quantum mechanics. Light has properties of both a particle and a wave. At low energies, the particle nature of light is hard to detect: radio waves are made of photons, but individual radio wave photons are pretty hard to detect. I'm not sure that we have directly detected individual photons with ...

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In some sense, the answer is trivially 'yes': Due to spacetime curvature, there exist no circular orbits below $\frac{3}{2}r_s$, with $r_s$ the Schwarzschild radius. So whenever you get an object sufficiently dense, that its radius is below its $\frac{3}{2}r_s$, the mass equivalent to any nonzero rotational energy overcomes the centrifugal force of an orbit ...

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Think at the surface of a ball. A straight line within this curved surface is a great circle. Take some point on the ball. Draw two great circles (apparent straight lines in the surface) starting in this point, with some non-zero initial angle. The two apparent straight lines intersect at the opposite side of the ball. Wrongly assuming the surface of the ...

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Since the collision is perfectly elastic, the ball's velocity goes from -80 km/h from the train's reference point (negative being towards the train) to +80 km/h from the train's reference point, a speed increase of 160 km/h. For a stationery observer, therefore, the velocity goes from -30 km/h (towards the train) to 130 km/h, an increase of 160 km/h. ...

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Time As I understand time will slow for the observer, inversely the rest of the universe will seem to speed up. The observer will ultimately observe everything running faster and faster, plants will spin in a blur, then their orbits will eventually too. Ultimately galaxies will be going like tops and colliding with each other. This will continue to ...

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If an observer is falling toward a black hole with his face away from singularity then what will he observe after crossing the event horizon? Nothing. The reason that why I am asking this question because as far as I know for an outside observer, the falling observer appears to freeze at the event horizon i.e. time appears to stop for the falling ...

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Your premise is incorrect: The external observer's view does not imply anything about an observer within the event horizon. The event horizon itself is just an indicator of the edge of the region where light can no longer escape. Light can head inwards as you would expect. So an observer inside the event horizon will be able to see light reaching them as ...

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