It's considered to be an important discovery that they've actually been observed. Albert Einstein predicted their existence a century ago.
"Gravitational waves carry information about their dramatic origins and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed."
This is a big BIG deal. Wow. I was shocked at the news. They've been looking a long time. The implications and confirmations here are huge. Maybe even bigger than the Higgs boson. What an exciting time to be alive.
Joe Biden … putting the Dem in dementia since (at least) 2020.
Question: "How can you explain gravitational waves to an average person, with little knowledge of physics?"
Richard Muller, Author of [i]Now-The Physics of Time[/i] (2016) wrote:Gravitational waves are what happens when you shake space itself. Just like when you shake a rope, the shake moves down the rope, when you shake space, the shake travels. When it passes by two mirrors, the distance between them changes (because space is being shook), and that's what LIGO (the Laser Interferometer Gravitational-wave Observatories working simultaneously) detects -- a change in the distance between two mirrors. According to theory, gravitational waves travel at the speed of light. This has not yet been verified, but it probably will be verified by future measurements with LIGO.
LIGO detects gravitational waves by measuring light that is bouncing back and forth between those two mirrors. If the distance changes, it affects the light, and that's what is observed.
Incidentally, the reason they are called "gravitational waves" and not "gravity waves" is that "gravity waves" refers to ordinary water waves and other phenomena that depend on gravity. If there were no gravity, and you splashed water, the splash would just stay; it wouldn't move away from the splash point. So to differentiate gravitational waves, they are called gravitational, not gravity. But, among physicists, in ordinary conversation, they are frequently just called gravity waves.
As for some of the implications, at least a few of them involve making instruments with sufficient sensitivity that we can look far enough back in space and time to see the moment of creation, telling us through the radiation detected what exactly caused the big bang that started the universe.
I concur--it is a very big deal...but it isn't going to usher in a new "golden age" of technological or scientific advancement. At least, not quickly, at any rate. The fact that they were detected at all is, itself, a scientific achievement, though--possibly even Nobel-worthy.
The task now is to fine-tune the equipment, detect more instances of gravitational waves, and refine the current models describing reality.
I doubt we have the capability of creating our own gravitational waves but even if we did we couldn't use them for communication because they are still subject to the speed limit of c.
If they are created by the collisions of massive black holes then they should be created by the collisions of galaxies, as well.
Avatar wrote:Nice. But I mean, this isn't going to usher in some amazing new technology or anything right?
--A
No, it's absolutely going to usher in new technology, or at least new science. It's going to open a window on the universe like a deaf person learning how to hear. It opens up a new branch of physics (or astrophysics, or astronomy, or cosmology). Not only was Einstein's general theory of relativity confirmed in a way that even Einstein himself never thought would be possible (due to the technical difficulties), but the implications of new science are huge. This allows us to probe reality with an entirely new tool. This is on the level of discovering warp drive or time travel, something that that might be theoretically possible but technically prohibitive. It's science fiction becoming reality.
Joe Biden … putting the Dem in dementia since (at least) 2020.
Science fiction is reality. We're living in science fiction. But I was under the impression that this was just another corroboration of the theory of relativity? Not an out and out confirmation?
Isaac Newton's approach correctly predicts the gravitational attraction between any two objects but gives no insight into how something here can reach out across empty space and pull on something there. Einstein spent a decade trying to determine how gravity is communicated, and finally concluded that space and time form the invisible hand that does gravity's bidding.
The metaphor of choice, overused but evocative, is to think of space as a trampoline. Place a bowling ball in the middle of the trampoline causing it to curve, and a marble will be nudged to travel along a curved trajectory. Similarly, Einstein professed that near an astronomical body like the Sun, the spacetime environment curves, which explains why Earth, much like the marble, follows a curved trajectory.
It seems to me this only tells us why things move in the particular paths they move in. Which is great, and we can calculate what will happen. But it still doesn't say why things move at all. Move Jupiter toward Earth, and, the closer it gets to us, the more it will change our motion. We know what our new path will be, because we know how Jupiter warps space-time. But why do we travel on that path? Where's the lasso that Jupiter throws around us to pull us toward it? Why don't we just sit motionless on the curve?
All lies and jest
Still a man hears what he wants to hear
And disregards the rest -Paul Simon
That's the question the bit you quoted answers. Things move because spacetime is curved. The presence of matter warps it so that other matter falls toward it.
I see how the bit I quoted answers the question of the path objects will travel along. I do not see how it answers the question of why they bother traveling at all. Why must there be motion? If the Enterprise was big enough to transport an Earth-size planet a few light-seconds from us, space-time between us would be warped like crazy. If I shot a projectile toward the other planet, the path it would take is determined (in part) by exactly how space-time is warped. But why do the two planets move toward each other without being pushed/thrown/shot? What sets them on the path of the warped space-time?
All lies and jest
Still a man hears what he wants to hear
And disregards the rest -Paul Simon
That is what I'm asking. Telling me that space-time is warped is telling me which direction things will move. I do not understand how it is also telling me why they bother moving at all.
All lies and jest
Still a man hears what he wants to hear
And disregards the rest -Paul Simon
Because everything in the universe is falling through space (at the same time) - I'm sure the trampoline/bowling ball/marble metaphor, is slightly misleading. The marble has no effect on the trampoline. However, the marble could affect a silk tablecloth.
Things move because gravity applies an attractive force to objects, pure and simple. Whether this results in a stable orbit or a direct collision depends on what other motion has already been imparted to the objects.
This force can be modeled as a warp in space time. In this model, the amount of force is shown by the steepness of the slope. The steeper the slope, the more the object is impelled in the "downward" direction.
But it's not a real slope. In a real slope (a hillside, for example), a force of gravity pulling downwards imparts a force in a lateral direction - to the left or right. The ball rolls "towards" the downhill direction.
In other words, in a real slope, an ubiquitous unseen force (gravity) moves an object towards another object. In the model of gravity, the two objects attract each other all by themselves.
Are you saying we still don't know "how something here can reach out across empty space and pull on something there"? Einstein gave us a way of visualizing and calculating it, but he did not give us the mechanism? Because that's how it looks to me.
All lies and jest
Still a man hears what he wants to hear
And disregards the rest -Paul Simon
But I mean, this isn't going to usher in some amazing new technology or anything right?
Telling me that space-time is warped is telling me which direction things will move. I do not understand how it is also telling me why they bother moving at all.