When Voyager got there it was like night and day. They had these beautifully detailed pictures—it was like mixing candy or something, all these marbled patterns in the atmosphere of Jupiter especially. Saturn didn’t have so much of that, but Jupiter did. At that time I was just out in the general community, looking at the pictures and thinking, “Oh, wow, those are really great.”
But the big thing was Io, at least from my point of view. All of the Galilean satellites—I mean, it was the first time they had ever really taken pictures of that. When they saw Io they were just flabbergasted, because it didn’t look anything like they expected. It’s got all these little volcanoes on it. Brad Smith, who was also at the Lunar Lab, was the head honcho of the Imaging Team, and he said, “My God, what kind of satellite is this? I’ve seen better looking pizzas!”
Then for Uranus and Neptune, there wasn’t quite as much publicity in the general media, because Uranus and Neptune weren’t as spectacular as Jupiter and Saturn were. Uranus in particular, in the visible-eye pictures, was quite featureless. They really had to crank up the contrast to see anything.
But for science, they were quite spectacular because, as I said, we really didn’t know anything about those satellites before, and a lot of what we knew was wrong. During the close part of the encounter, which lasted about three or four days, we were all at JPL. We’d have general meetings where all the groups would come together and report their results for the last six hours or something like that.
It was like walking out of the darkness into a clearly illuminated space, because we knew almost nothing, and then in the space of two or three days suddenly we knew an enormous amount about these planets. It was really an incredible experience. It was like you’ve been wandering around in a darkened forest and suddenly you come out into Yosemite Valley in bright sunlight. It was just astounding, a revelation; both Uranus and Neptune.
I wasn’t there for Jupiter and Saturn, and they already knew quite a bit more about Jupiter and Saturn, but I imagine it was to a lesser extent the same thing for them, because they did discover an immense amount about Jupiter and Saturn, certainly about the satellites which they knew almost nothing about before, and learned quite a bit about the planets too.
That was really a tremendous thing. From the point of view of a very narrow group of space physics enthusiasts, Voyager is doing that again in slow motion because it’s at the edge of our solar system, where the solar wind is piling up against the interstellar gas, which is very, very tenuous, but then the solar wind is tenuous too. It slams into it and creates a shockwave, and it kind of bleeds off around the outside.
People have been speculating about what’s out there for 50 years, and now they’re actually finding out what is happening out there, thanks to Voyager. Lyle’s instrument is contributing a little bit to that even though they can’t point it. They pick a direction to stare, and it’s just staring in that direction. They can see when the Sun brightens up in the extreme ultraviolet; that changes the reflectance off the interstellar gas, and so forth.
So that’s all going on, and it’s very interesting. But the excitement of the old days has passed on to the younger generation. The Mars missions are very exciting to Mars geologists, and there’s a mission going out to Pluto and whatnot. Those of us in the old guard are not part of that. Bill Sandel is probably the most connected to the current discoveries. He’s still in there pitching; the rest of us are all basking in our old glory days.
Right now the Voyagers, the Voyager spacecraft, are punching through the boundaries of the heliosphere. I’m heavily involved with understanding what’s going on there. That’s going to last another decade I think. There’s still enough radioactive power on those things that they’ll be sending data back. We’re right at the farthest we’ve ever been and there’s new stuff; we’ve found new things out there. The boundaries of the heliosphere—actually the Sun carves out a spherical bubble of interstellar gas and it has a certain size. Now Voyager going through that boundary. So we know that size for the first time, and we know the very beginning to actually understand that phenomenon.