Science behind Eruption
Astrobiologists on Earth are raising questions on Jupiter’s icy moon Europa due to the powerful eruptions that may spew into space. The main question of concerns being that what will come out of the blast out from miles-high plumes or they hold signs of extraterrestrial life or what will be the location in Europa of origination. The expectations of origination are such that according to a new explanation pointing to a source closer to the frozen surface.
According to new evidence from researchers at Stanford University, the University of Arizona, the University of Texas, and NASA’s Jet Propulsion Laboratory stating that some eruptions may originate from water pockets embedded in the icy shell itself rather than originating from deep within Europa’s oceans.
The researchers developed a model using images collected by the NASA spacecraft Galileo that explains how a combination of freezing and pressurization could lead to a burst of water or cryovolcanic eruption. The results have implications for the habitability of Europa’s underlying ocean which were published Nov. 10 in Geophysical Research Letters and it is expected that it may explain eruptions on other icy bodies in the solar system.
LIFE: Present or Not?
Elements necessary to support life could be hidden in the vast ocean beneath Europa’s icy crust according to the speculations of scientists but short of sending a submersible to the moon to reconnoiter, it’s hard to know for sure. This has become a hot topic as if the reason behind eruptions are from the subsurface ocean, then NASA’s upcoming Europa Clipper mission spacecraft could more easily detect elements.
They may somehow turn the tables if the plumes originate in the moon’s icy shell resulting in less hospitable to life because it is harder to sustain the chemical energy to facilitate life there. So still a diminishing chance of detecting habitability from space remains the same.
Gregor Steinbrügge, a postdoctoral researcher at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth), who is also the lead author said that recognizing where these water plumes are arising from is very principal for knowing whether future Europa explorers could have a venture to detect life from space without probing Europa’s ocean.
An 18-mile-wide crater on Europa, known as Manannán, was the prime focus of analysis which originated by an impact with another celestial object some tens of millions of years ago. They made a model out of this huge amount of heat that must have been generated out of the collisions that resulted in melting and subsequent freezing of a water pocket within the icy shell could have resulted in the water to flare up.
Don Blankenship who is the co-author, also a senior research scientist at the University of Texas Institute for Geophysics (UTIG) said that the asteroid or comet hitting the ice shell was a big experiment which we’re using to construct theory to test. The team of polar and planetary sciences is focused on evaluating the ability of this instrument to test those theories at UTIG.
Europa’s water transformed into ice during the later stages of the impact as per the model with pockets of water with increased salinity could be generated on the moon’s surface. These salty water pockets can become even saltier in the process of where they migrate sideways through Europa’s ice shell by melting adjoining regions of less brackish ice.
Steinbrügge said that the team developed an important way that a water pocket can move laterally and not only in the down direction as pulled by gravity moving from cold to warm along thermal gradients.
Water is Salty
When the center of Manannán crater is approached by a migrating brine pocket, the model predicted that it became stuck and began freezing, spawning pressure that eventually resulted in a plume that was reckoned up to a mile high. A spider-shaped feature on Europa’s surface was observed by Galileo imaging due to the eruption of this plume leaving a distinguishing mark that was incorporated in the researchers’ model.
Joana Voigt, a graduate research assistant at the University of Arizona, Tucson said that Europa’s ice shell itself is very dynamic as direct insight into Europa’s ocean could not be provided by plumes generated by brine pocket migration.
The impact craters could not explain the source of others as the size of the plume can’t be a deciding factor but the process modeled for the Manannán eruption could occur on other icy bodies and even without an impact event. Voigt said that brine pocket migration is not distinctively applicable to Europa’s craters instead the mechanism might supply clarifications on other icy bodies where thermal gradients exist.
The saltiness of Europa’s frozen surface and ocean estimates is also provided in the study which in turn could influence the transparency of its ice shell to radar waves. The oceans of Europa could be one-fifth as salty as Earth’s ocean as per the calculations that will ameliorate the capacity for the Europa Clipper mission’s radar sounder to gather data from its interior.
The connection between the plumes and the Europa’s ocean is discouraging astrobiologists hoping Europa’s erupting plumes might contain clues about the internal ocean’s scope to support life. Europa’s complex surface features are entangled by the new model by offering insights toward hydrological processes, the pull of Jupiter’s gravity, and hidden tectonic forces within the icy moon.
Dustin Schroeder, an assistant professor of geophysics at Stanford thinks that the shallow subsurface, the ice shell itself, is an exciting place to explore the new way of thinking about its water near the surface.