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Space Weather Forecasters Can Count on Jupiter
Abhishek writes "Space.com reports that forecasters who predict the Solar weather can rely on Jupiter now to help them see the part of the sun that is not visible due to Earth's rotation and revolution and sun's rotation along its own axis. Scientists observing the X-Ray emanating from the Jovian atmosphere theorised that those coming from the equator were related to solar activity but it is definitely not a perfect mirror; only one in every few thousand X-Ray photons get reflected. But even that is very useful in predicting the solar weather. 'We found that Jupiter's day-to-day disk X-rays were synchronized with the Sun's emissions,' said Anil Bhardwaj at NASA Marshall Space Flight Center, who led a new study using data from the European Space Agency's XMM-Newton telescope. Their work was detailed in Geophysical Research Letters."
Scientists discover that sun still shines at night due to photons reflected from THE MOON!
Since Jupiter is about 43 light-minutes from the sun, and we're about 8 light-minutes away, the round-trip travel time (when Jupiter is on the opposite side of the sun) will be 43*2 + 8 = 94 minutes.
A lot of information we get from the sun is, naturally, only 8 minutes delayed, but I guess since solar winds travel no faster than about 750 km/s (and usually travel much slower), solar winds take more than 50 hours to reach us -- so an hour and a half delay isn't that bad.
Ben Hocking
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This is only helpful for half of the time. The other half, Jupiter would be reflecting parts of the Sun that we can see because we're on the same side.
If monitoring the far side of the Sun (Don't you just *want* to say "dark side"?) really becomes important, we'd need a spacecraft in the same orbit as Earth, but on the opposite side of the Sun.
Currently, the combination of Jupiter, Saturn, and Uranus do a pretty good job of covering the Sun from all angles. Of course, when the planets line up this won't work so well. But with the pole shifting that happens during conjunction, we'll have much bigger things to worry about anyway. (WHAT?!? There was no pole shift in 2000-2001? Well, it will happen next time.)
Ben Hocking
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Solid as a rock.
Excuse me, but mind explaining why it wouldnt be 70 minutes for the light from the sun to reflect from jupiter...? 43+(43-8) or am I doing something wrong here?
My UID is prime... is yours?
This is measuring the "dark side of the Sun" (couldn't resist). So Sun's between us and Jupiter, photons go out from Sun, hit Jupiter, reflect, come back past Sun to Earth.
Only works half the year, obviously.
>. Thanks for pointing that out :D
My UID is prime... is yours?
If Jupitor is 43 light minutes from the sun, and earth is 8 light minutes from the sun, then the correct equation for the round trip from Sun to Jupitor to Earth is: 42*2-8 which would equal 76.
Huh?
(Somehow, that doesn't sound right...)
First of all, as explained elsewhere (in replies to replies of the reply you're replying to, I believe), the correct equation should be 43*2+8 (since this is helpful when Jupiter is in conjunction with the sun, and is not helpful when Jupiter is in opposition (on the opposite side of the night sky, i.e., on the same side of the sun as us). Of course, 43*2+8 = 94 minutes, which one might be tempted to write as 1 hour, 34 minutes, meaning that I'm off by 4 minutes.
However, if one were to stick to significant figures, 94 minutes = 1.6 hours, so in fact I'm off by 0.1 hours. I throw myself on the mercy of the court. :)
Ben Hocking
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