a change in the weather
Jul. 28th, 2013 09:13 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
twoeleventhere were a few recent news stories about voyager 1 reaching a new point in the sun's magnetic environment as it leaves the solar system, but none of the ones i saw had anything but qualitative descriptions of the difference. i finally had the time to read the original papers, which had some striking graphs of the change:
voyager 1 went from feeling the breeze of the solar wind to feeling a sleet of high-energy particles from elsewhere in the galaxy:
galactic cosmic ray nuclei and galactic cosmic ray electrons in red, two different energies of protons (galactic and mixed solar wind/galactic) interacting with the sun's magnetic field in blue.
galactic cosmic ray protons in black, different components of the solar wind in color.
(the numbered dates are julian, and the second graph has months marked, so that's last june thru august)
i would have thought running these graphs with just a little explanation of what's what on them (curves that abruptly fall are the solar wind, curves that abruptly rise are stuff from outside the solar system) might make it clearer why astronomers care about the change. it is rather sudden.
voyager 1 isn't completely outside the sun's magnetic environment, as the third paper in the set explains (and its graphs aren't as dramatic). that's appently coming soon, though voyager 1 is already so far into terra incognita that we have no idea when. astronomers hope voyager 1's power holds up until then. (like most deep space probes, the voyagers are powered by heat from the radioactive decay of plutonium. there's no way to turn off that battery, so it steadily runs down over the years.)
voyager 1 went from feeling the breeze of the solar wind to feeling a sleet of high-energy particles from elsewhere in the galaxy:
galactic cosmic ray nuclei and galactic cosmic ray electrons in red, two different energies of protons (galactic and mixed solar wind/galactic) interacting with the sun's magnetic field in blue.
galactic cosmic ray protons in black, different components of the solar wind in color.
(the numbered dates are julian, and the second graph has months marked, so that's last june thru august)
i would have thought running these graphs with just a little explanation of what's what on them (curves that abruptly fall are the solar wind, curves that abruptly rise are stuff from outside the solar system) might make it clearer why astronomers care about the change. it is rather sudden.
voyager 1 isn't completely outside the sun's magnetic environment, as the third paper in the set explains (and its graphs aren't as dramatic). that's appently coming soon, though voyager 1 is already so far into terra incognita that we have no idea when. astronomers hope voyager 1's power holds up until then. (like most deep space probes, the voyagers are powered by heat from the radioactive decay of plutonium. there's no way to turn off that battery, so it steadily runs down over the years.)