SJAA

Ephemeris

Mainly Europa

Jane Houston

Dr. Jeff Moore of the NASA AMES Research Center Galileo Imaging Team and a planetary geologist spoke to the SJAA Saturday December 5th.

Dr. Moore shared some incredible images of the Jovian satellites from four successful passes of Europa.

His remarks were sprinkled with humor about the patience and endurance required to work on these cross generational NASA Projects (where the young gung ho scientists, wheeling their elderly leaders who were the forerunners, have now aged and are entering their own dotage.)

He recommended exercise and a good diet to live long enough to see the results of your own research.

The focus was on the evidence for plate tectonics and liquid sub-ice ocean on Europa.

(Well also on Ganymede, and he is ready to return for a talk about Callisto, once thought to be the most boring object in the shallow sky).

First of the three lines of evidence we learned about was minor crust extension versus total crust separation. Vigorous warm ice convection broke the surface, and tilted it into a matrix of fine material. 10 meter pixel images showed individual pieces of rotated plate!

Those images were incredible, and the wind and rain whipping around Hogue Park, shaking the ground and the trees made a nice orchestral accompaniment to the whole lotta shaking that went on within Europa, which we saw thru the eyes of Galileo, the spacecraft.

The Case of the bunny head is the second line of geologic evidence.

The bunny head is where an ice pond rose up and flooded the surface, which in turn froze. This ice layer could protect ocean life from the radiation of the Van Allen belt.

We all imagined along with Jeff as he described squid flopping themselves up for image capture on these Jovian moons.

After paying tribute to the late great planetary geologist Gene Shoemaker, we concluded the discussion of evidence by showing three distinct craters, Pwill, Callanish Macula and Tyre as flooded craters.

A lively discussion occurred afterwards.


Jane Houston; last updated: 1998 Dec 16
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