They also spin so regularly that you can build a clock out of their signals: http://en.wikipedia.org/wiki/Pulsar_clock
Now someone just needs to build an API and and app for the Pebble so there can be a pulsar wristwatch.
The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
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Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#62Earlier quoted context omitted.
Makes me wonder if there will be someday an electrical generator using the rotational energy of a celestial body. (this would need to have a reference in the main star, otherwise it would just spin with the planet)
generator using the rotational energy...would need to have a reference in the main star Nope. You could launch generator pods in a hyperbolic trajectory that would start out escaping the neutron star, but generate electricity from the rotating magnetic field in such a way that it's captured in orbit and comes back to its launch point.
No you can't. Conservation of angular momentum doesn't allow that.
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#63Why do planets, stars and moons spin? Are there any that don't?
It has to do with the total angular momentum of a system composed of multiple smaller bodies. (Like the dust/debris cloud during solar system formation)
This minute physics video (about the shape of the solar system) explains it probably better than I can put into words myself:
http://www.youtube.com/watch?v=tmNXKqeUtJM
The relevent part starts at about 1:03, but I recommend watching the whole thing.
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#64They also spin so regularly that you can build a clock out of their signals: http://en.wikipedia.org/wiki/Pulsar_clock
Not only are they regular enough to make clocks, but they're 5 times more accurate than atomic clocks.
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#65They also spin so regularly that you can build a clock out of their signals: http://en.wikipedia.org/wiki/Pulsar_clock
Don't we already use these as a sort of GPS for interstellar travel? I think the Voyager plaques contained coordinates to Earth based on pulsar frequency.
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#66Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#67Earlier quoted context omitted.
I could not take my eyes off "One Birth" / "One Death" Fascinating - and I think humanity is "winning"
I couldn't take my eyes off of the fact that everytime wikipedia is edited someone dies. How 'bout that for the correlation=causation folks!
Huh, I was more surprised that every time someone dies Wikipedia is edited.
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#68They also spin so regularly that you can build a clock out of their signals: http://en.wikipedia.org/wiki/Pulsar_clock
Not only are they regular enough to make clocks, but they're 5 times more accurate than atomic clocks.
I am assuming you are repeating the claim on the wikipedia page. Or maybe (hopefully) you have another source? I saw the claim on the wiki article and my first reaction was bullshit. My second reaction after stumbling across dead links in two of the three the citations was bullshit. After re-reading the article and the one functioning citation without seeing a accuracy/precision/stability figure my third reaction was also bullshit.
The strontium clock at Boulder loses one second in five billion years. [1][2][3]
Does anyone have any information supporting the pulsar clock claim? I have a sneaking suspicion that the author of this claim --just like the catalog in the chair pocket on airplanes--thinks my radio clock that syncs to WWVB/DCF77 is "an atomic clock."
[1] http://www.theverge.com/2014/1/22/5333324/nist-atomic-clock-...
[2] http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...
[3] http://www.colorado.edu/news/releases/2014/01/22/jila-stront...
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#69They also spin so regularly that you can build a clock out of their signals: http://en.wikipedia.org/wiki/Pulsar_clock
Don't we already use these as a sort of GPS for interstellar travel? I think the Voyager plaques contained coordinates to Earth based on pulsar frequency.
I didn't know that. That's fascinating and "beautiful"!
Re: The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
#70Earlier quoted context omitted.
Wow, that page led me to the fact that there is such a thing as centrifugal force... And all these years spent trying to correct people. Oh well, you live, you learn. http://en.wikipedia.org/wiki/Photon_sphere
The "war on centrifugal force" is pedagogical. If you sit in an inertial frame, all forces you intend to teach are due to interactions between objects. This lets teachers introduce the interactions one at a time in a way that presents minimal opportunity for the "no, that equation doesn't work here for XYZ reasons which you won't understand until after you've taken vector calculus" problem. If you allow rotating refe…
This is what I love about HN - an anti-troll comment. Like most of us I think a generalist knowledge confers the right to an opinion and expressing that opinion.
Comments like this point out just how much I do not know, they sweep their arms across a horizon of maths and hard won understanding and say "only express that opinion after you know what that means"
Anti-trolling.
It's what keeps us honest about our own limitations, and reluctant to spout off crap.
love it. Now going to look up inertial frames and start translating.