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The Planetary Society Blog
By Emily Lakdawalla
Early science results from New Horizons at Jupiter
May. 1, 2007 | 14:09 PDT | 21:09 UTC
There was a press conference today at NASA Headquarters to put out some of the first science results from the New Horizons flyby of Jupiter -- an event that's still underway, as New Horizons is still taking new data on the long tail of Jupiter's magnetic field, which may stretch all the way to Saturn. Amir Alexander will be writing up and posting a detailed story on this, so I thought I'd just confine my comments to some of the way-cool pictures they released and point to him for the full story later. Before I do that, though, I just want to comment on what a great press conference the New Horizons team gave. On the panel were Alan Stern (Principal Investigator), Jeff Moore (Jupiter encounter science team leader), Hal Weaver (Project Scientist), and John Spencer (Jupiter encounter deputy science team leader). NASA press conferences can often be conducted in a lamentably stiff and flat manner, but this one was lively, with each of the panelists frequently interrupting each other to clarify and add points. On the whole they gave the impression that they were really enjoying themselves, and excited about all of the new science -- feelings shared, I think, by most scientists, but which somehow never seem to make it to press conferences. Well done, guys!
So, to the pictures. The biggest as-yet-unreported discovery was of clumps in Jupiter's rings, something that has been seen in other giant planet ring systems, but never before at Jupiter. Here's some pics: | Clumps following AdrasteaOne of the surprising discoveries from New Horizons' encounter with Jupiter was three clumps in the main rings following the tiny moon Adrastea (16 kilometers in diameter). The clumps most likely formed as a result of the impact of a Jupiter-family comet onto a large ring particle. The event must have happened shortly before New Horizons arrived in the Jupiter system. Such clumps are not stable and should disappear within a matter of months. The image shown here was taken from an animation of the clumps moving around the rings (Quicktime format, 4 MB). Credit: NASA / JHUAPL / SwRI / annotation by E. Lakdawalla |
John Spencer wanted to make sure I gave proper credit to Mark Showalter for the discovery of these ring clumps. Mark designed this imaging sequence in order to search for small, previously undiscovered moons among the rings. John reported at the press conference that no new moons have yet been identified in the images, but they yielded the discovery of these clumps, which was a complete surprise.
Here's another of my favorite images from the press conference: Io, from within Jupiter's shadow; all bright spots come from Io's volcanoes and from aurorae excited in Io's atmosphere by Jupiter's magnetic field. Io in eclipseAs New Horizons sailed past Jupiter on February 27, 2007, it watched Io pass in to Jupiter's shadow. Without the Sun illuminating the surface, New Horizons could keep its shutter open for a very long time, capturing the glow of hot spots and aurorae on Io's surface and atmosphere. The three brightest spots are from the incandescent glow of hot lava erupting from volcanoes: Pele and Reiden (south of the equator), and a previously unknown volcano near 22°N, 233°W. The disk is outlined by an auroral glow, produced by the interaction of Europa's thin atmosphere with the intense magnetic field of Jupiter. A spot at 2 o'clock is a cloud of atmosphere that is somehow levitating 330 kilometers above the surface. On the left side of the disk is a spotty region on the side of Io that faces Jupiter. Scientists are unsure what causes these glowing spots, but they hypothesize that the spots are related to electrical currents connecting Io to Jupiter's magnetosphere. Credit: NASA / JHUAPL / SwRI | Credit: NASA / JHUAPL / SwRI |
Here's a lovely image that shows you the benefit of having multiple kinds of remote sensing instruments on a spacecraft:Many eyes on IoLike most spacecraft, New Horizons has several different optical remote sensing instruments that are optimized for different types of science. Here, three of the instruments took simultaneous views of Jupiter's volcanic moon Io. On the left, the LORRI camera captured a highly detailed, black-and-white view of the sunlit crescent, showing surface structures as well as the gigantic plume of Tvashtar erupting near the north pole. At upper right, the MVIC near-infrared imaging spectrometer sees coloration due to compositional variations across the sunlit crescent, and also sees the incandescent glow of the throat of Tvashtar. At lower right, the LEISA spectrometer, which sees longer infrared wavelengths than MVIC, captured the glow of Tvashtar as well as a great many more volcanic centers on Io's night side. Further analysis of LEISA images will yield the temperatures of these volcanic centers. Credit: NASA / JHUAPL / SwRI |
I shot a question to Jason Perry at the Lunar and Planetary Laboratory in Arizona, who's currently on the Cassini imaging team but who has had a long fascination with everything Io, to ask if he could identify which volcanoes were active in this image. He sent me a list: Tvashtar, Amirani, Prometheus, Culann, Tupan, Malik, Shamash, an unnamed volcano at 42.5°S, 174.5°W, either Chaac or Sobo, Zamama, and possibly Thor or Savitr. From the eclipse image above he identified Pele, Reiden, a new "mystery volcano" discussed by John at the press conference, one in northern Lerna, Ra Patera, Amaterasu Patera, and a "cast of dozens" on the sub-Jovian hemisphere; and from one other image, he saw some of these as well as Isum, Donar, Mulungu, Pillan, Marduk, and an unnamed one at 10°S, 217.5°W. I knew that Io was volcanically active, but for some reason I had the impression that only a handful of its volcanoes were active at once. I had no idea that there so many going off at the same time. I remarked as much to Jason and he told me, "This is nothing....extrapolating from high-resolution NIMS data from the Galileo Io encounters, there may be as many as 400 active volcanoes on Io at any given time."
Finally, to the prettiest image from today's press conference:Europa risesIn this dramatic shot from the New Horizons flyby of Jupiter, it observed Europa, the smallest of the four Galilean moons of Jupiter, rising above the vast limb of Jupiter. This was one of seven observations made by New Horizons for primarily aesthetic rather than scientific reasons. Credit: NASA / JHUAPL / SwRI |
It's wonderful that the New Horizons took the time to take just a few pictures because of the wonderful views. Outer planet missions are justified by science, and science data can yield amazing photos -- all those Io pictures were taken for their science value, for instance. But we wouldn't be exploring space if we didn't find the sights wonderful -- I mean that literally, that they inspire a sense of wonder.
My congratulations to the New Horizons team for a job well done! And it gives us a taste of what we can expect from Pluto. In Jeff Moore's words: "We're going to do a killer Pluto encounter."
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