ВНИМАНИЕ! На форуме начался конкурс - астрофотография месяца ФЕВРАЛЬ!
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Две с половиной недели назад был официально запущен проект Einstein@Home, участники которого, анализируя данные, полученные с трёх интерферометров, будут искать доказательства существования гравитационных волн.
ЦитатаДве с половиной недели назад был официально запущен проект Einstein@Home, участники которого, анализируя данные, полученные с трёх интерферометров, будут искать доказательства существования гравитационных волн.Я только вчера присоединился к проекту, а то SETI мне малость поднадоела.
Ну и как?
ЦитатаНу и как?Сама идея поиска гравитационных волн мне понравилась, да и заставка довольно красивая - вращающийся виртуальный глобус.
Если не сложно, обьясните как именно реализован поиск гравитационных волн?
StarCharter,Thanks for the "nice guy" remarks. I'll take the Fifth Amendment on whether or not they are true.Yes, it does help to read the front page. However, we know that it would also be nice if we had some more explanation handy. There are plans to do that; for example you will see some questions in the FAQ that is being constructed. But the main priority at the moment is making sure the code actually does what it's supposed to. (It basically does, although if you read the help desk you'll see there are still plenty of bugs to clean up.) In the meantime, Ian Jones and I can answer a few questions here and there.That museum link was nice in general. Here's a little more specific Einstein@Home info that addresses some of the questions you and Dennis asked.Einstein@Home isn't really looking for an interference pattern between different points, but that leads to an explanation of interferometry which I think I'll postpone for another day.The LIGO Science Collaboration is implementing several pulsar searches, but the one Einstein@Home is running is the "all-sky pulsar search" as you will see at the top of every WU page. This is not a search for the known pulsars whose locations you see on the screensaver. This is a systematic search of the sky, one location at a time, for any periodic gravitational wave coming from that location. It has to be done for each location because the frequency shifts (Doppler shifts) due to the Earth's motion are different for different sky locations. There are additional Doppler shifts for pulsars in binaries, but the current application is only looking for isolated pulsars.Most of your CPU cycles are going into Fourier transforms. If you don't know, a Fourier transform is a way of looking at a time series as a sum of sine waves at different frequencies. Pulsar signals should be nearly sinusoidal after the Doppler shifts are taken out, so Fourier transforms pick them up pretty easily. Fourier transforms are numerically pretty efficient, but there are an awful lot of them to do in an all-sky search. That is why Einstein@Home is doing this particular search, and not for example the searches for known pulsars which can be done pretty quickly on a single computer.Later on Einstein@Home might do some other searches, but the consensus was that this was the best fit (at least for now) because (1) it is the most expensive in CPU cycles, and thus the best use of the enormous power you all are donating, and (2) people would probably be more excited about going after something brand spanking new than a pulsar that's been seen in radio, x-rays, etc for years. I think also that (3) we know where the radio pulsars etc are, but a previously unknown one (whose radio beam isn't pointed towards Earth) might happen to be much closer and thus a much stronger source of gravitational waves. We set our long-term goals by the sources we already know, but we cross our fingers and hope for a pleasant surprise.Hope this helps,Ben