Ocean, possibly habitable, on Jupiter's Europa? 90-year-old UCLA Prof Margaret Kivelson has evidence it's there.

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jserraglio
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Ocean, possibly habitable, on Jupiter's Europa? 90-year-old UCLA Prof Margaret Kivelson has evidence it's there.

Post by jserraglio » Sun Oct 28, 2018 7:54 am

PROFILES IN SCIENCE: How Do You Find an Alien Ocean? Margaret Kivelson Figured It Out
https://www.nytimes.com/2018/10/08/scie ... uropa.html

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Professor Emerita Margaret Kivelson in her office at the University of California, Los Angeles.

New Dive Into Old Data Finds Plumes Erupt From Jupiter’s Moon Europa
https://www.nytimes.com/2018/05/14/scie ... water.html

http://newsroom.ucla.edu/releases/ucla- ... oon-europa

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Jupiter (left) and its moon Europa. UCLA Professor Emerita Margaret Kivelson led the team that designed a key instrument on the Galileo spacecraft (right, foreground).

Abstract of Kivelson, et al. paper in Nature Astronomy: Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures
https://www.nature.com/articles/s41550-018-0450-z

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An image of Europa's surface. Scientists hope the Europa Clipper mission, which may launch in 2022, can be tweaked to allow one of its 40 planned flybys to pass through a plume. (ASU Space Photography Laboratory)

jbuck919
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Re: Ocean, possibly habitable, on Jupiter's Europa? 90-year-old UCLA Prof Margaret Kivelson has evidence it's there.

Post by jbuck919 » Tue Oct 30, 2018 2:38 pm

I know that jserraglio hates it when I am negative about something like this, but it does seem beyond improbable that there could be an ocean with liquid water that far out in the solar system, let alone one able to support life.

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jserraglio
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Re: Ocean, possibly habitable, on Jupiter's Europa? 90-year-old UCLA Prof Margaret Kivelson has evidence it's there.

Post by jserraglio » Tue Oct 30, 2018 5:33 pm

jbuck919 wrote:
Tue Oct 30, 2018 2:38 pm
beyond improbable that there could be an ocean with liquid water that far out in the solar system . . .
Beyond improbable, unless of course Europa has a heated core and a mineral-laden mantle below its icy crust for water to interact with. In fact, there is recent evidence of "hot spots" on Europa that vary over time (see the images below).

Additionally, the immense gravity of Jupiter could be creating tidal forces that (1) assist in keeping any subsurface water in a liquid state; (2) distend the crust; and (3) generate fissures thru which water could escape as vapor plumes (see the photo of Saturn's Enceladus below).

Scientists do not know for sure right now whether there is a subsurface ocean of liquid water on Europa but may be able to find out circa 2022 once NASA's Europa Clipper spacecraft orbits it. There is, however, indirect evidence that such an ocean exists (see Kivelson's 14 May 2018 abstract of her recent paper printed below). In the meantime, absence of definitive evidence is not evidence of absence.

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Thermal anomaly ("hot spot") variation on Europa imaged by the Atacama Large Millimeter Array (ALMA).

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ALMA's image of Europa's thermal anomalies superimposed on a Hubble ST image of Jupiter.
Margaret Kivelson in the journal 'Nature Astronomy' wrote:The icy surface of Jupiter’s moon, Europa, is thought to lie on top of a global ocean. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa’s surface, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo’s closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter’s corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa’s thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.
Image
Water vapor plumes on Saturn's Enceladus.

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