Strange

Again, despite popular science articles, there is no communication. I am a bit disappointed that Nature should publish such a poorly written story.

Ummm ... what's the opposite of a fan ?

Despite popular science articles, there is no communication. Why would photons in a bound state constitute an address? What is this new form of matter?

My guess was a few weeks, and it seems to be about right: http://www.popsci.com/node/204957 It seems to be a very common question: https://www.google.co.uk/search?q=how+long+survive+after+sun+goes+out

We already know that your opinion on anything to do with science has no value. That is completely irrelevant because, as it clearly says, it is for galaxies that are not gravitationally bound. As usual, you understand nothing. Change the "we" to "I" and you might get somewhere. Do you have any evidence that the galaxies in a cluster are not orbiting one another? (Your total lack of understanding of physics does not count as evidence.)

That is quite a neat way of representing it. I don't know if it is completely novel (I think I have seen similar diagrams). I tried a Google image search but it didn't come up with anything like it. Maybe you should call it a Vince Chart.

The moderator also provided a link to the story.

Crank? No, you are not the only one. I'm sure that "journal" will be very happy to publish absolutely anything you care to submit. http://rationalwiki.org/wiki/Pierre-Marie_Robitaille

That was to show that a object can (1) pass by another massive object without falling in (which you claim is impossible) and (2) have its orbit changed from an ellipse so it does collide with the object it is orbiting (which you claim is impossible). Obviously, I was not comparing the mass of the comet to that of a galaxy. However, the point about orbits of multiple bodies is equally true whatever the mass. Please prove that it is impossible for two galaxies to move away from one another in the presence of gravity. Please prove that it is impossible for two galaxies to collide. (And incredulity does not count as a mathematical proof.)

According to Stigler's Law, no scientific law is named after the discoverer. Including Stigler's Law. https://en.wikipedia.org/wiki/Stigler's_law_of_eponymy

What bothers me most about this thread is the title. "Discovered" ? Where was it? Up a mountain? Behind the filing cabinet?

I wasn't discussing a binary system, because that is irrelevant to the conditions we are discussing. Not in the case we are discussing. Yes. Please do that. How about you produce a simulation of thousands of galaxies orbiting around each other and prove that they never collide.

That is exactly what I did. I wasn't making any such comparison. Your inability to understand even very simple English may be the problem here.

OK. So let's see the detailed analysis of energy in and energy out (with references to the sources of any data used).

I'm sure he could see exactly what was wrong. But was unable to get you to accept it.

Why? Mathematics works whether mathematical objects exist or not. (And that question probably depends on what you mean by "mathematical object" and "exist".) And physics works, whether mathematical objects exist or not.

Philosophers have been arguing about that since mathematics was invented (or discovered, depending which side of the argument you are on). I'm not sure it really matters.

As well as being directly tested, many of these are so fundamental to other branches of physics that they are implicitly tested whenever any experiment is done. BTW I don't think I would classify chaos theory as physics. It is a mathematical model that apears to have real-world application in many areas.

If anything, the reverse is true. Large scale projects (such as the LHC) generate so much data that it may take years to analyse it all. This is true of many smaller scale projects as well. So the biggest problem with physics today is that there is not enough detail on Wikipedia? Apart from that, I can't see anything on that page that could be described as lacking in evidence. (It doesn't even mention String Theory, which is a common target of this sort of complaint.)

Correct. All we know are their velocities. https://en.wikipedia.org/wiki/Velocity_dispersion

As usual, you are making up nonsense instead of attempting to learn. (But at least you didn't end your drivel with "do you agree" so we may be making some progress.) Consider, as simpler example, a comet in orbit around the Sun. It may pass by Jupiter, which is very massive, but it won't suddenly change its course and dive into the surface of Jupiter. It will have its path changed slightly but continue heading away from Jupiter and towards the Sun. It won't dive into the Sun as it passes, it will pass around it and head out to space again. Because its orbit constantly changes because of its encounters with the planets, the orbit will not be a fixed ellipse (so Kepler is irrelevant, except as a short term approximation). And, eventually, the comet may collide with a planet or the Sun. The situation is similar, but much more complex, in the case of galaxy clusters because you have a large number of similarly sized objects in orbit around one another. (So Kepler is almost totally irrelevant.) There paths will be chaotic but they still won't suddenly change course and dive into a collision with a nearby massive galaxy. The only way to model the paths of bodies in a system like this is through simulation. (Not by random guesswork based on a limited understanding of Newtonian gravity.) Shown to be an incorrect guess by stars and gas orbiting a black hole or neutron star. This is only true in the ideal case of one body orbiting another, with no other masses around. Perhaps you could identify the ellipse in these orbits: Strawman fallacy because no one said that is what is happening. Obviously also false.

Wow. That certainly gives an idea of scale.

I assume you don't understand how hygroscopic materials work. What were you planning to use? Hygroscopic materials will either bind water to the surface (adsorbtion) or dissolve in the water they attract (deliquescence). It sounds like you are thinking of the latter. In both cases, there is a limit to how much water will be absorbed. It will require energy to recover the hygroscopic material (either driving the water away from the material or recovering the salt from solution). That is the energy that turns the wheel. If hygroscopic materials worked as you suggest, then an even simpler method would to simply have a large funnel containing the hygroscopic material. It would attract water which would run straight out of the bottom of the funnel. This could then be used to turn a water wheel. (I hope that shows why the idea can't work.)

Not really. What is 1 litre made of? What is a square metre made of? Or a mile? Or a second? They are just measurements of the distance between things.

I think there have been some studies that show girls tend to do better at single-sex schools (and boys do worse?) - this might be because they no longer seem themselves being treated differently than the boys. Or because they are not intimidated by the boys. Or ...