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A Fourth Gravitational Wave Has Been Detected (theguardian.com)
An anonymous reader quotes a report from The Guardian: Astronomers have made a new detection of gravitational waves and for the first time have been able to trace the shape of ripples sent through spacetime when black holes collide. The announcement, made at a meeting of the G7 science ministers in Turin, marks the fourth cataclysmic black-hole merger that astronomers have spotted using Ligo, the Laser Interferometer Gravitational-Wave Observatory. The latest detection is the first to have also been picked up by the Virgo detector, located near Pisa, Italy, providing a new layer of detail on the three dimensional pattern of warping that occurs during some of the most violent and energetic events in the universe.
A tiny wobble in the signal, picked up by Ligo's twin instruments and the Virgo detector on 14 August, could be traced back to the final moments of the merger of two black holes about 1.8 billion years ago. The black holes, with masses about 31 and 25 times the mass of the sun, combined to produce a newly spinning black hole with about 53 times the mass of the sun. The remaining three solar masses were converted into pure energy that spilled out as deformations that spread outwards across spacetime like ripples across a pond. Detecting these tiny distortions has required detectors sensitive enough to measuring a discrepancy of just one thousandth of the diameter of an atomic nucleus across a 4km laser beam. A paper about the latest discovery has been accepted for publication in the journal Physical Review Letters.
A tiny wobble in the signal, picked up by Ligo's twin instruments and the Virgo detector on 14 August, could be traced back to the final moments of the merger of two black holes about 1.8 billion years ago. The black holes, with masses about 31 and 25 times the mass of the sun, combined to produce a newly spinning black hole with about 53 times the mass of the sun. The remaining three solar masses were converted into pure energy that spilled out as deformations that spread outwards across spacetime like ripples across a pond. Detecting these tiny distortions has required detectors sensitive enough to measuring a discrepancy of just one thousandth of the diameter of an atomic nucleus across a 4km laser beam. A paper about the latest discovery has been accepted for publication in the journal Physical Review Letters.
How about, uh, the last 48 hours. Seriously guyz, to the extent that you're able to divulge, what the hell happened? https://www.theregister.co.uk/2017/09/27/faulty_data_center_takes_out_sourceforge/ Because we're glad you're back, but we really missed you.
Sounds useful, moving one thousandth of the diameter of an atomic nucleus every 2 weeks.
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Gravity moves at the speed of light. This is one of the reasons why Einstein developed the theory of general relativity. Newton's formulas only work when the speed of gravity doesn't matter. I don't know too much details though.
What I also wonder is, why do we detect gravitational waves? Are they only moving the matter, but not so much the photons if the laser beam? If they would move everything in the same way it should be quite difficult to detect something. Though I think some theorists said the same until the first detection
The space that the photons are in is what changes size. To measure it they have two perpendicular "arms" in each detector. When the distance of space changes as a wave goes by, the change in each arm is different; they compare the two and that's when they can detect the ripples.
On the one hand you take life too seriously, and on the other, you do not take playful existence seriously enough. Seth
If you acknowledge that space and time are linked by the fact that it takes time to traverse space, it is therefore only logical to conclude that manipulations in space also cause manipulations in time. This is what the gravity waves are and why LIGO detects them the way it does. The shape of space changes which causes a disruption in the timing of laser pulses going down tubes.
Your example of the Sun and Earth is complicated. Don't view the Sun as a beam simply transmitting gravity to Earth. Gravity waves are radiating outwards in 3D space in all directions at all times. The plane on which the Earth resides looks like an outward moving disc. As each pulse of gravity reaches Earth, it pulls Earth slightly towards the Sun and into the path of other gravity waves that would have been emitted right after the initial one. This process happens over and over and over and what you get is the elliptical orbit that we see today. The angles and speed of transit change as the rate at which the Earth passes through these gravity waves changes and you get an asymmetric version of the underlying phenomena.
The mirrors they had for reflecting the beam back down the tunnel have been SIGNIFICANTLY upgraded. They can measure how much the reflector swings on its pendulum by the impact of said laser itself.
The Hanford LIGO facility can detect a tractor-trailer moving down I5. The effects of these and any other distortions or disturbances are very similar in nature to the waves they're trying to detect, so much of the early work was spent on identifying these and filtering them out. The mirror upgrades helped. (This all comes from a tour of the facility)
So, in essence, yes. Upgrades. Physical equipment, sensors, hell, probably even people.
Don't view the Sun as a beam simply transmitting gravity to Earth. Gravity waves are radiating outwards in 3D space in all directions at all times.
Well said. I would just add something someone told me once when I was pondering the same question. If the sun instantly disappeared, the Earth would continue in its orbit undisturbed for roughly eight minutes. And, of course, it would continue to be heated and lit for the same time.
Did I read it correctly that 3 solar masses were converted to energy? Over what period of time I wonder. Our own sun's total output would not consume all its mass over billions of years.
How big a blast zone did that leave? I can imagine star systems for light years around could have been burnt, destroying civilizations. Has anyone done the numbers?