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Originally Posted by little man
thanks, Aj. do you have any idea what sorts of data are collected and transmitted? also, what sort of use can we put that info to?
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There's actually quite a large number of instruments on the spacecraft.
It's measuring the strength of the cosmic wind. This is going to be important if we ever want to get off this planet on a permanent basis. As it has made passes by the planets it has sent back information on their composition, given us information on the radio signals coming from Jupiter and Saturn*, and is now telling us quite a bit about the outer parts of the solar system.
It has allowed astronomers to have a better idea of not just what the other planets are made of but what their atmospheres**, ionospheres, gravity fields, etc. are like. Because of Voyager we know quite a bit more about the rings of Saturn than we otherwise would, as well as having discovered things about a couple of Jupiter's larger moons that ground based telescopes would never have revealed. For example, Io is a hellhole. It is so close to Jupiter and the tidal forces of Jupiter are so strong that the volcanic activity on Io is because Jupiter keeps pulling at its mantle. Europa, we've discovered, has ice--it appears to be water ice with some ammonia and methane and possibly even some sulfur. Now, what's interesting about that is that underneath that ice there *may* be liquid water. Where there is liquid water, life has a chance to get started. We know, from environments here on Earth, that very, very simple creatures can live quite happily underneath ice packs.
A lot of the value that has been gained from the Voyager has been in giving NASA the expertise to build better and better robotic missions. Cassini, the Mars rovers, are all descendants of Voyager. A lot of what we are doing in space (as opposed to Earth orbit) is still in the 'basic science' stage. Meaning that we are still trying to figure out what is going on at a very basic level. The difference between the two is best explained this way:
Newton describes how gravity works. That is the basic science. Building a rocket that can escape Earth's gravity is engineering. Newton described how gravity works at the end of the 16th century, at that point building a ship to fly to the moon was largely (not entirely) a matter of engineering solutions. Without the basic information, though, of how to calculate if the Earth has X mass and you want to escape its gravitational pull you have to provide this amount of thrust, no rocket would ever have gotten out of the atmosphere except by peer, dumb luck.
*Jupiter and Saturn put out radio signals. Around Jupiter, this is caused by a cloud if ionized gases from Io that get captured by the big planet and then become part of its magnetosphere (the planet's magnet field). The particles get charged and start sending out radio signals. You can hear the radio signal
here. It's important to note that these radio signals are purely a function of physics and that there's no intelligence involved.
**It's important to note here that at no point does Voyager enter the atmosphere, it merely uses a spectrometer to measure what wavelengths are absorbed and reflected back. Since any chemicals in an atmosphere will be opaque to certain wavelengths, transparent to others and reflective to still others, if you can see what the spectral lines are like then you can tell what the atmosphere is made of. That is how we can tell what stars that are millions of light years from Earth are made of--in fact, it's how we first discovered what the Sun was made of.
Cheers
Aj