* Astronomy

Blobrana · L

RE: Europa

Blobrana · L

Where are the Best Windows Into Europa's Interior?

The surface of Jupiter's moon Europa exposes material churned up from inside the moon and also material resulting from matter and energy coming from above. If you want to learn about the deep sal****er ocean beneath this unusual world's icy shell -- as many people do who are interested in possible extraterrestrial life -- you might target your investigation of the surface somewhere that has more of the up-from-below stuff and less of the down-from-above stuff.
New analysis of observations made more than a decade ago by NASA's Galileo mission to Jupiter helps identify those places.
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Blobrana · L

Keck findings support notion of life on Jovian moon Europa

Clues are building toward the possibility of life on Jupiter's moon Europa, which has a liquid water ocean under its icy crust.
Observations from the Keck Observatory on Mauna Kea show that the moon's surface has diluted but abundant hydrogen peroxide, a common cleaning agent that could be an important energy supply for simple forms of life.
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Blobrana · L

Mapping the Chemistry Needed for Life at Europa

A new paper led by a NASA researcher shows that hydrogen peroxide is abundant across much of the surface of Jupiter's moon Europa. The authors argue that if the peroxide on the surface of Europa mixes into the ocean below, it could be an important energy supply for simple forms of life, if life were to exist there. The paper was published online recently in the Astrophysical Journal Letters.
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Title: Keck II Observations of Hemispherical Differences in H2O2 on Europa
Authors: Kevin P. Hand, Mike E. Brown

We present results from Keck II observations of Europa over four consecutive nights using the near-infrared spectrograph (NIRSPEC). Spectra were collected in the 3.14--4.0 micron range, allowing detection and monitoring of the 3.5 micron feature due to hydrogen peroxide. Galileo Near-Infrared Spectrometer (NIMS) results first revealed hydrogen peroxide on Europa in the anti-jovian region of the leading hemisphere at an abundance of 0.13±0.07% by number abundance relative to water. We find comparable results for the two nights over which we observed the leading hemisphere. Significantly, we observed a small amount of hydrogen peroxide (~0.04%) during observations of Europa's anti- and sub-Jovian hemispheres. Almost no hydrogen peroxide was detected during observations of just the trailing hemisphere. We conclude that the Galileo observations likely represent the maximum hydrogen peroxide concentration, the exception potentially being the cold water ice regions of the poles, which are not readily observable from the ground. Our mapping of the peroxide abundance across Europa requires revisions to previous estimates for Europa's global surface abundance of oxidants and leads to a reduction in the total oxidant delivery expected for the sub-surface ocean, if exchange of surface material with the ocean occurs.

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Blobrana · L

Salty water oozes up from Jupiter moon's hidden ocean

Glimpses of Europa from the passing Voyager spacecraft in the 1980s first hinted that it might harbour a liquid ocean. Later investigations by the Galileo spacecraft, which orbited Jupiter from 1995 to 2003, showed a world covered in cracks and littered with dark debris, strengthening the case that Europa has a briny ocean under a relatively thin icy crust.
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Blobrana · L

A Window into Europa's Ocean Right at the Surface

If you could lick the surface of Jupiter's icy moon Europa, you would actually be sampling a bit of the ocean beneath. A new paper by Mike Brown, an astronomer at the California Institute of Technology in Pasadena, Calif., and Kevin Hand from NASA's Jet Propulsion Laboratory, also in Pasadena, details the strongest evidence yet that salty water from the vast liquid ocean beneath Europa's frozen exterior actually makes its way to the surface.
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Blobrana · L

Title: Salts and radiation products on the surface of Europa
Authors: M.E. Brown, K.P. Hand

The surface of Europa could contain the compositional imprint of a underlying interior ocean, but competing hypotheses differ over whether spectral observations from the Galileo spacecraft show the signature of ocean evaporates or simply surface radiation products unrelated to the interior. Using adaptive optics at the W.M. Keck Observatory, we have obtained spatially resolved spectra of most of the disk of Europa at a spectral resolution ~40 times higher than seen by the Galileo spacecraft. These spectra show a previously undetected distinct signature of magnesium sulfate salts on Europa, but the magnesium sulfate is confined to the trailing hemisphere and spatially correlated with the presence of radiation products like sulfuric acid and SO2. On the leading, less irradiated, hemisphere, our observations rule out the presence of many of the proposed sulfate salts, but do show the presence of distorted water ice bands. Based on the association of the potential MgSO4, detection on the trailing side with other radiation products, we conclude that MgSO4 is also a radiation product, rather than a constituent of a Europa ocean brine. Based on ocean chemistry models, we hypothesize that, prior to irradiation, magnesium is primarily in the form of MgCl2, and we predict that NaCl and KCl are even more abundant, and, in fact, dominate the non-ice component of the leading hemisphere. We propose observational tests of this new hypothesis.

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Blobrana · L

Astronomers Open Window Into Europa's Ocean

With data collected from the mighty W. M. Keck Observatory, California Institute of Technology (Caltech) astronomer Mike Brown - known as the Pluto killer for discovering a Kuiper-belt object that led to the demotion of Pluto from planetary status - and Kevin Hand from the Jet Propulsion Laboratory (JPL) have found the strongest evidence yet that salty water from the vast liquid ocean beneath Europa's frozen exterior actually makes its way to the surface.
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Blobrana · L

Ocean on Jupiter's moon Europa 'may be deep underground'

Missions hoping to explore the huge subsurface ocean thought to exist on Jupiter's moon Europa may have to dig really deep, researchers say.
According to new research, water stays in a liquid state near Europa's surface for just a few tens of thousands of years or so, which is a blink of an eye in geological terms, since our solar system is more than 4.5 billion years old.
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