What happens to that energy, though? Energy is conserved, even with gravitational waves, correct?
So, what happens to the energy - does some of it get converted into 'normal' potential energy by changing the (amount of gravity? gravitational fields?) of the stuff that it passes through - the weak interaction that you refer to?
And, if it interacts very weakly, does all of the energy eventually get used up this way - do GWs get 'used up' before they travel across the universe?
(Probably a meaningless question): can GWs hit the edge of the universe, and if so, what happens then?
> What happens to that energy, though? Energy is conserved, even with gravitational waves, correct?
Yup. It's like ocean waves carrying energy. The difference is that it's hard to interact with GWs, so instead of "riding" them and capturing their energy, you find them mostly passing through you. They have tons of energy, but very little of it is dissipated back into matter.
Gravitational waves redshift in an expanding universe, so as they propagate out to lightlike infinity, their wavelengths stretch so much that there is no hope of detecting them.
In a flat universe, they go out to lightlike infinity without redshifting, but with the amplitude falling off 1/r rather than the 1/r^2 of light. Eventually they become too weak to be detected unless we can detect a single graviton of a particular frequency (which is going to be unimaginably difficult technologically).
> can GWs hit the edge of the universe?
This is an excellent question! Neither of the above types of universe has an edge; there is a lightlike infinity that electromagnetic and gravitational waves head towards. What's there? Who knows! For all practical purposes, these waves just depart from us and everything we can see, never to return.
We can have an edge to a universe that is contracting rather than expanding, or one that eventually contracts.
This is really hard to think about and I had to look around, and found http://jetp.ac.ru/cgi-bin/dn/e_042_06_0943.pdf [I sadly have had almost no previous exposure to the authors, and somewhat regret it; this paper is from the "Third Soviet Gravitational Conference" in 1972. Wow!]
It will take more time to digest it than is reasonable for a real response, but section 3 is relevant for a universe that is like ours in most ways except that it won't expand forever but rather will eventually collapse. However, essentially (and this matches my intuition), for a typical source the gravitational waves will radiate outwards from the source, slow down, and come back. Depending some choices of Friedmann parameters, they could even return as convergent waves focusing on whatever moved purely timelike from the source (e.g. the remnant of the merger) during the GWs lightlike journey; more likely they'd smear out in a larger region; and possibly they might not actually converge (or smear into the same general region) until very near the future singularity having undergone gravitational blueshifting. After converging they'd depart, and rapidly get lost in nonlinearities. This is not super-different from ripples on a pool that spread out, bounce back and lose structure.
This also raises the question of what significantly blueshifted gravitational waves might do. Drag matter a bit faster towards the future singularity is my guess. It also raises questions about constructive interference, but in that direction lies strong gravity, and there's not going to be an answer to those questions in the linearized gravity that we use to model gravitational waves.
I answered some of your other questions in other comments on this thread, I think. If not, ask again!
Your mention of how it was 'impossible with HTTPS' to inject ads into web traffic made me recall how, two years ago, Lenovo shipped laptops with software ('Superfish') that injected ads into encrypted webpages:
This problem has been noted for some time. Past articles on the subject have shown how the various requirements for passwords come about through a combination of limitations imposed by the system they're being used on, or through misguided attempts at making things easier for users.
I wonder if there has ever been an attempt through a forum like RFCs or ISO to define a worldwide (or at least latin char set) standard for password requirements. Based on what i've seen in forums like this, there seems to be fairly broad acceptance that allowing a large number of characters from a character set with as few limitations as possible bests serves the interest of security. The thorniest issue would likely be about balancing requirements for increased complexity (eg capitals and lowercase, numbers, etc) with ease of use.
Your post was rude, misrepresented GP's argument, and did not contradict any assertion made in GP's post.
GP correctly argued that artists have always created, whether or not they were granted rights under a system of copyright law. He did not focus on or advocate a return to the system of artist patronage from the 16th century.
This same problem happened to the Ethiopian central bank. One batch, which had been bought from a trader, was discovered to be fake fairly quickly; another batch of faked gold, seized from smugglers, had been in their vaults for years.
As he said, 'more than Emacs is at stake here.'.[1]
I presume this refers to Bazaar's status as part of the GNU project, and that RMS did not want to write off part of GNU without being certain he needed to.
Regardless, he has since OKd the switch from bzr:
I don't insist that Emacs should stay with bzr. I chose to support bzr because it was still a contender at the time. [2]
I mean, don't not fixing what ain't broke is certainly a matter of integrity. Fixing something to the latest hippest new fad just to "attract young hackers" detracts from integrity. Making the editor an awesome badass attractive editor should be enough. Otherwise you'll only be attracting groupthink-prone douchebags, anyway.
- personal drug use (of any kind)
- bans on same-sex marriage (which I just looked up, and seems to be legal in Canada anyway)
- any form of gun control
I'm not saying that I do or do not think the above should be legal, but they all are examples of "we know what's best for you". I think that's what the GP commenter was alluding to.
So, what happens to the energy - does some of it get converted into 'normal' potential energy by changing the (amount of gravity? gravitational fields?) of the stuff that it passes through - the weak interaction that you refer to?
And, if it interacts very weakly, does all of the energy eventually get used up this way - do GWs get 'used up' before they travel across the universe?
(Probably a meaningless question): can GWs hit the edge of the universe, and if so, what happens then?