Posted on 09/27/2017 10:32:15 AM PDT by C19fan
In August, detectors on two continents recorded gravitational wave signals from a pair of black holes colliding. This discovery, announced today, is the first observation of gravitational waves by three different detectors, marking a new era of greater insights and improved localization of cosmic events now available through globally networked gravitational-wave observatories.
The collision was observed Aug. 14 at 10:30:43 a.m. Coordinated Universal Time (UTC) using the two National Science Foundation (NSF)-funded Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors located in Livingston, Louisiana, and Hanford, Washington, and the Virgo detector, funded by CNRS and INFN and located near Pisa, Italy.
(Excerpt) Read more at nsf.gov ...
that means about three solar masses were converted into gravitational-wave energy during the coalescence.
E = MC^2 means three solar masses = mind boggling amount of energy.
Serious question here.
Gravity is a force, yes? It has waves. I understand the constant force of gravity as it relates to mass for conclusive and repeatable experiments and observations in our solar system.
But to what extent can we really be sure gravity is a constant throughout the universe? Is it reasonable to theorize that gravity is different (as it relates to specific mass) in different parts (older or newer) of the universe (assuming expansion)? Is gravity considered energy? Then while it cannot be lost or gained, is it possible that it can be distributed differently across different mediums unrelated to mass?
How does light (photons) affect gravity? Gravity can affect light, so wouldn’t it be safe to assume that something as benign as light can affect gravity? Then what else can affect gravity?
Asking for a friend?
I love the astronomy news. Thank you!
If we just detected it, when did it actually occur ?
One of the assumptions are the laws of physics are the same across time and space. Although there are people working on what is called Modified Newtonian Dynamics that claim the gravitational constant itself can change.
A billion years ago. Gravity waves propagate at the speed of light.
I think this is exactly what I was wondering. If the gravitational constant were not so constant, a great many things could be better explained (Black Holes, Big Bang, Neutron Star masses, etc.)
But it really screws a lot of thing up too. I have also wondered what makes us so sure the speed of light is constant throughout time and space?
What was the speed of light back then? What speed do gravity waves travel at today? What has changed?
The article says 1.8 billion light years in one spot and 1 billion in another. Either way, it’s been a while.
Gravity is one of the four fundamental forces (the others being electromagnetic, strong nuclear, and weak nuclear forces). Cosmologists are reasonably sure gravity is the same throughout the universe, otherwise other parts of the universe would look very different, since gravity is the dominant shaping force of it. But we see that the universe on the largest visible scale is isotropic and homogeneous.
Gravity affects light because according to General Relativity it’s a curvature in space-time. Light follows that curvature as is propagates. So does matter, hence things fall. Gravity itself is not affected by other forces, however. Light only represents energy transferred by the electromagnetic force. The photon is its force carrier, while gravity (hypothetically) has the graviton as its force carrier.
Enough with the negative waves man!
Thank you for that explanation. It is informative and simple.
Now, what about the speed of light as a constant? LOL?
Gravity is a force, yes?
...
Gravity is actually the curvature of spacetime. Technically it’s not the same as a force, but it’s still called that, even within science.
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