'Gardened Zones' on Europa Could Be the Key to Finding Life, Study Says (vice.com) 22
Jupiter's moon Europa contains a voluminous ocean of liquid water under its icy crust that could potentially host extraterrestrial organisms. "But as evidence builds that Europa could be habitable under its crust, a problem remains: the intense radiation that Jupiter emits likely annihilates any signs of life, known as biosignatures, that upwell onto the moon's surface, presenting a challenge to future missions that aim to detect life with Europa landers," reports Motherboard. "Now, a team of researchers led by Emily Costello, a postdoctoral researcher at the Hawaii Institute of Geophysics and Planetology, have shed new light on this obstacle by examining the role of "impact gardening" in the search for life on Europa." From the report: Impact gardening occurs when rocks collide with a planetary body without an atmosphere, causing a mechanical churn that continually exposes new layers of the surface, known as the "gardened zone," to all the erosive effects of space, according to a study published on Monday in Nature Astronomy. "Knowing the depth of the gardened zone is critical for the exploration of Europa as a potentially habitable world," the researchers added. "We will need to sample material below the gardened zone if we wish to discover biomolecules that have never been exposed to hazardous radiation at the surface."
Of course, that raises the question: just how deep is Europa's gardened zone? To provide an answer, the team produced the first comprehensive models of impact gardening on Europa, with the help of Moon rocks returned from the Apollo program that also show a distinct gardened zone. This approach yielded good news and bad news. The bad news is that the models suggest that impact gardening exposes the top 30 centimeters (12 inches) of Europa's global surface to radiation, on average. Contrary to previous studies that proposed the possible presence of juicy biosignatures only a few centimeters under the moon's surface, the new study finds that signs of life would be embedded much deeper in the ice.
That said, the good news is that pristine material from Europa's ocean could be sampled at shallower depths in rare circumstances, such as in the fallout of recent landslides or fresh meteorite impacts. These natural processes can excavate layers of ice from below the gardened zone and position them within centimeters of the surface. Looking for recent examples of such disturbances could reveal samples that have not experienced the damaging long-term effects of radiation yet. Fortunately, scientists will soon benefit from close-up observations of Europa from ESA's Jupiter Icy Worlds Explorer (JUICE) and NASA's Europa Clipper, both scheduled to launch in the 2020s. These spacecraft will conduct intimate flybys of Europa, and they may be able to spot regions with freshly excavated material on the surface that would be prime destinations for future lander missions.
Of course, that raises the question: just how deep is Europa's gardened zone? To provide an answer, the team produced the first comprehensive models of impact gardening on Europa, with the help of Moon rocks returned from the Apollo program that also show a distinct gardened zone. This approach yielded good news and bad news. The bad news is that the models suggest that impact gardening exposes the top 30 centimeters (12 inches) of Europa's global surface to radiation, on average. Contrary to previous studies that proposed the possible presence of juicy biosignatures only a few centimeters under the moon's surface, the new study finds that signs of life would be embedded much deeper in the ice.
That said, the good news is that pristine material from Europa's ocean could be sampled at shallower depths in rare circumstances, such as in the fallout of recent landslides or fresh meteorite impacts. These natural processes can excavate layers of ice from below the gardened zone and position them within centimeters of the surface. Looking for recent examples of such disturbances could reveal samples that have not experienced the damaging long-term effects of radiation yet. Fortunately, scientists will soon benefit from close-up observations of Europa from ESA's Jupiter Icy Worlds Explorer (JUICE) and NASA's Europa Clipper, both scheduled to launch in the 2020s. These spacecraft will conduct intimate flybys of Europa, and they may be able to spot regions with freshly excavated material on the surface that would be prime destinations for future lander missions.
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You forgot to tick the "Post Anonymously" box before submitting your racist hate-filled post. Thanks for highlighting yourself as someone to ignore.
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The current acceptable method of being a racist hate-monger isn't to be anonymous, but to first declare yourself to be anti-racist and inclusive.
Also not sure that accounts with bad karma can even post ac.
Please don't land on Europa (Score:2, Insightful)
At least until we found a reliable way to perfectly sterilize probes. The last thing I'd want to see is yet another case of indigenous life wiped out because we had to sneeze on it.
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Whilst sensible in idea, unfortunately not practical in reality - a 99.9999% kill still leaves critters.
That said, the conundrum pops out.
Of course the worry is that Earth introduced microbes will dominate. Why would that be?
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I'm not saying we shouldn't waste time and money sterilizing spacecraft, but we don't need to limit space exploration because something might exist there alrea
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Re:Please don't land on Europa (Score:4, Informative)
If you study ancient human migration patterns, you see a trail of indigenous species wiped out in our path. And we're talking all the way back to the times long before we were giving thought to long term possibilities when encountering new species. We had, as a big portion of us still do, an attitude that thought if we can't eat it, use its skin for something useful, or use them as beasts of burden, we should either ignore them and their needs, or wipe them out as nuisance species.
One of the more famous examples of a species wiped out by man to look into would be the giant ground sloth of the Americas. Though to be sure, there are plenty of other examples if you poke around a bit.
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Only 30cm? Make our own zone! (Score:5, Interesting)
If (just) the top 30cm of material (ice primarily?) is exposed and sterilized then it seems that it would be easy to create our own impact crater that would expose fresh material. Just have the rocket stage that brings the probe to Enceladus hit the landing zone a little before it arrives; a few thousand kg of material traveling at several km/sec. would make a nice big crater.
Such a strategy was used for LCROSS, the lunar probe that had its upper stage (Centaur) impact shortly before the probe in order to kick up (and vaporize) a lot of lunar material. It was successful, so much so that it proved the existence of water (ice) on the moon thus leading to the current rush of missions to explore the permanently shadowed craters of the lunar South Pole.
Of course the lander would need to get into the newly created crater quickly but that would also be true of looking for (fresh) landslides or meteoric impacts. The success of the Perseverance rover landing on Mars, where the lander located in real time a suitable landing place, indicates that an autonomous probe could be tasked to land at the crater secure in the knowledge that it would find a safe place to land there.
Still, wouldn't the easiest thing be to have the lander land near one of the geysers which would presumably be bringing up fresh material constantly? Or even just having a probe coast through the plume in a low slow flyby? Enceladus is TINY which means that you should be able to orbit it really closely and really slowly, it is much smaller than for example the asteroid Ceres which NASA very slowly orbited with a probe.
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Or maybe just drill down 60 cm? Or even (and I shudder to think of the difficulties) drill down one meter?!
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Don't know if drilling down will expose some material which is currently under high pressure.
I assume even a short lived geyser of material will be able to shove a lander.
Could be even solid CO2 sublimating.when the hole has been made.
I assume studies will be done about what is the best way to access material at a shallow depth.
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With advances in flying on other planets, that could be an option too I would assume and since there is minimal atmosphere, I assume the shockwave would be minimal enough not to flip the craft (which I assume is one of the largest risks). I assume this could potentially be a better choice because a probe would be single use and it's not really something a rover could do without high risk.
Either way I agree with your conclusions that an impact is a better mechanism to explore the potential of life under Euro
You've been warned (Score:1)
ATTEMPT NO LANDING THERE
Fermi paradox (Score:5, Insightful)
Re:Fermi paradox (Score:4, Funny)
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We have bacteria that eats nuclear waste [sciencedaily.com]. We know chemosynthesis is possible in tandem with symbiosis that allows more complex organisms to thrive [si.edu] in the dark, high pressure, and high temperature environment of the deep sea volcanic vents.
The innate ability for life to develop where it can would seem to precede panspermia, but I see no reason why there can't be both.
The Fermi 'paradox' is overrated. We've only just started looking.
What radiation does Jupiter emit? (Score:2)
"But as evidence builds that Europa could be habitable under its crust, a problem remains: the intense radiation that Jupiter emits likely annihilates any signs of life, known as biosignatures, that upwell onto the moon's surface, presenting a challenge to future missions that aim to detect life with Europa landers,"
I thought it just had a very strong magnetic field that focused the solar radiation.
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Half correct. Jupiter's magnetic field is quite intense, and that does do impressive things with incoming solar radiation. The magnetic field extends something like But the magnetic field also collects and accelerates a lot of local material - principally material from Io, its inner-most moon - to create a local environment with a lot of radiation [astronomy.com]. The stream of ions and electrons between Io and Jupiter is on the order o
Re: What radiation does Jupiter emit? (Score:2)
10 million dental x-rays? How many transatlantic flights is that?
The JUICE... (Score:1)