At first glance, Jupiter’s moon Europa doesn’t seem much like Earth. It’s a moon, not a planet, and it’s covered in ice. But it does have one important thing in common with Earth: a warm, salty ocean.
Now there’s even more evidence that Europa’s sub-surface ocean is habitable.
Scientists at NASA have developed a new model that supports Europa’s ability to support life. They presented their work at the 2020 Goldschmidt Conference, an annual conference on geochemistry and similar topics. It’s put on by the European Association of Geochemistry and the Geochemical Society.
The work is titled “Evolution of volatiles from Europa’s interior into its ocean.” The authors are M. Melwani Daswani and S. D. Vance, from the Jet Propulsion Laboratory. Their work hasn’t been peer-reviewed yet.
Europa is one of Jupiter’s Galilean moons, the smallest of the four. Its brethren Ganymede and Callisto may also host sub-surface oceans, while the fourth moon, Io, does not.
Europa’s ocean is buried beneath a frozen crust approximately 10–30 km (6–19 mi) thick, and liquid ocean underneath that may be 100 km (62 miles) thick. The likely source of heat for this liquid is tidal flexing due to Jupiter’s monstrous mass, and Europa’s orbital resonance with the other Galilean moons. The evidence for this ocean stretches back to the Voyager and Galileo spacecraft.
This new research presented at the Goldschmidt Conference suggests that this sub-surface ocean formed endogenously. That means that it formed by breakdown of water-containing minerals due to either tidal forces or radioactive decay. That’s opposed to an exogenous ocean like Earth’s, which was likely delivered to Earth by comets and/or asteroids.
This work is primarily based on data from the Galileo mission, which arrived at Jupiter in 1995. Galileo performed a series of orbits of Jupiter and some of its moons, and the mission ended when it was de-orbited into Jupiter in 2003. But images from the Hubble Space Telescope played a role, too.
“We were able to model the composition and physical properties of the core, silicate layer, and ocean,” said lead author Daswani in a press release. “We find that different minerals lose water and volatiles at different depths and temperatures. We added up these volatiles that are estimated to have been lost from the interior, and found that they are consistent with the current ocean’s predicted mass, meaning that they are probably present in the ocean.”
While many researchers think that tidal flexing is responsible for the heating, radioactive decay may play a role, too. But whatever the source, as the heat and pressure increased inside Europa, water-containing minerals broke down and released that water.
Some scientific thinking says that the water might be too acidic for life as we know it, due to higher concentrations of calcium, sulfate, and carbon dioxide. But this new modelling suggests that that was temporary, and the ocean became chloride rich over time.
“Indeed it was thought that this ocean could still be rather sulfuric” said Daswani, “but our simulations, coupled with data from the Hubble Space Telescope, showing chloride on Europa’s surface, suggests that the water most likely became chloride rich. In other words, its composition became more like oceans on Earth. We believe that this ocean could be quite habitable for life.”
Habitable is one thing, but inhabited is another. And that’s why there’s so much thinking about a mission to Europa to investigate further.
“Europa is one of our best chances of finding life in our solar system. NASA’s Europa Clipper mission will launch in the next few years, and so our work aims to prepare for the mission, which will investigate Europa’s habitability,” said Daswani. “Our models lead us to think that the oceans in other moons, such as Europa’s neighbor Ganymede, and Saturn’s moon Titan, may also have formed by similar processes. We still need to understand several points though, such as how fluids migrate through Europa’s rocky interior.”
The issue of habitability might boil down to one question. And it’s one that can only be answered by sending a spacecraft to the moon. In a press release, Steve Mojzsis, Professor of Geology at the University of Colorado, elaborated on that question as an independent commenter not involved in the research.
“A long-standing question over whether a “cloaked ocean” world like Europa could be habitable boils down to whether it can sustain a flow of electrons which might provide the energy to power life. What remains unclear is whether such icy moons could ever generate enough heat to melt rock; certainly interesting chemistry takes place within these bodies, but what reliable flow of electrons could be used by alien life to power itself in the cold, dark depths? A key aspect that makes a world “habitable” is an intrinsic ability to maintain these chemical disequilibria. Arguably, icy moons lack this ability, so this needs to be tested on any future mission to Europa.”
Europa’s surface is a frigid place. The temperature at the equator averages about 110 K (?160 °C; ?260 °F) and only about 50 K (?220 °C; ?370 °F) at the poles. That means its surface is as hard as rock. But while scientists know that the sub-surface ocean is warm, they don’t know its temperature.
Right now we only have a tantalizing taste of the nature of Europa’s ocean. There’ll be more studies and more modelling and simulating as time goes on, and that work is necessary. But only a mission to the moon can really answer our questions. (And it’ll probably pose a few more questions, too.)
While the Europa Clipper will be an orbiter only, other conceptual missions go further. One concept calls for a nuclear-powered tunneling robot to get through the ice and study the ocean itself. Another suggested boring through the ice with lasers to get to the ocean. But those ideas are fanciful, for now, and face many obstacles.
We’ll be relying on the Clipper to answer our questions about Europa and its ocean. And unfortunately, we’re going to have to wait a few years for that.
NASA injects $17M into four small companies with Artemis ambitions – TechCrunch
NASA awards millions of dollars a year to small businesses through the SBIR program, but generally it’s a lot of small awards to hundreds of companies. Breaking with precedent, today the agency announced a new multi-million-dollar funding track and its four first recipients, addressing urgent needs for the Artemis program.
The Small Business Innovation Research program has various forms throughout the federal government, but it generally provides non-dilutive funding on the order of a few hundred thousand dollars over a couple of years to nudge a nascent technology toward commercialization.
NASA has found, however, that there is a gap between the medium-size Phase II awards and Phase III, which is more like a full-on government contract; there are already “Extended” and “Pilot” programs that can provide up to an additional $1 million to promising companies. But the fact is space is expensive and time-consuming, and some need larger sums to complete the tech that NASA has already indicated confidence in or a need for.
Therefore the creation of this new tier of Phase II award: less than a full contract would amount to, but up to $5 million — nothing to sneeze at, and it comes with relatively few strings attached.
The first four companies to collect a check from this new, as yet unnamed program are all pursuing technologies that will be of particular use during the Artemis lunar missions:
- Fibertek: Optical communications for small spacecraft that would help relay large amounts of data from lunar landers to Earth
- Qualtech Systems: Autonomous monitoring, fault-prevention and health management systems for spacecraft like the proposed Lunar Gateway and possibly other vehicles and habitats
- Pioneer Astronautics: Hardware to produce oxygen and steel from lunar regolith — if achieved, an incredibly useful form of high-tech alchemy
- Protoinnovations: Traction control to improve handling of robotic and crewed rovers on lunar terrain
It’s important to note that these companies aren’t new to the game — they have a long and ongoing relationship with NASA, as SBIR grants take place over multiple years. “Each business has a track record of success with NASA, and we believe their technologies will have a direct impact on the Artemis program,” said NASA’s Jim Reuter in a news release.
The total awarded is $17 million, but NASA, citing ongoing negotiations, could not be more specific about the breakdown except that the amounts awarded fall between $2.5 million and $5 million per company.
I asked the agency for a bit more information on the new program and how companies already in the SBIR system can apply to it or otherwise take advantage of the opportunity, and will update this post if I hear back.
Watermelon snow shows up on Italian Alps – The Weather Network
Watermelon snow has appeared atop the Presena Glacier in the Italian Alps.
Researcher Biagio Di Mauro, of the Institute of Polar Sciences at Italy’s National Research Council, told CNN his team went to investigate the site over the weekend and encountered an “impressive bloom” — but that’s bad news for the glacier, as it can speed up melting.
Di Mauro says watermelon snow has been unusually common this year.
He plans to study it in greater detail with the help of satellite data.
File photo courtesy: USDA.
WHAT IS WATERMELON SNOW?
While it is a naturally-occurring phenomenon, watermelon snow is becoming increasingly common in the spring and summer because it requires light, higher temperatures, and water to grow.
“Watermelon snow is formed by an algal species (Chlamydomonas nivalis) containing a red pigment in addition to chlorophyll,” U.S. Geological Survey scientist Joe Giersch said in 2018 in an Instagram post of a photo of watermelon snow that he spotted at Glacier National Park.
This pigment protects the algal chloroplast from solar radiation and absorbs heat, providing the alga with liquid water as the snow melts around it. As snow melts throughout the summer, the algae are concentrated in depressions on the snow surface (which further accelerates melting), with small populations persisting in puddles through the fall.”
Watermelon snow is one of nature’s peculiarities. Scientists don’t fully understand it, or the long-term impact it could have on the environment.
Here’s one thing they do know: Watermelon may look neat but it’s not something conservationists want to see.
According to a study in Nature Communications, red algae can reduce a snow’s albedo — i.e., the ability to reflect light — by up to 13 per cent. That means the snow absorbs more of the sun’s energy and melts faster.
Couple that with a stint of above-seasonal temperatures and you’ve got a recipe for accelerated melting.
Oh, and one more thing: If you come across a patch of watermelon snow don’t eat it. You’ll make yourself sick.
Compounds Identified That Halt COVID-19 Virus Replication by Targeting Key Viral Enzyme – SciTechDaily
Four promising antiviral drug candidates identified and analyzed by a University of Arizona-University of South Florida team in the preclinical study.
As the death toll from the COVID-19 pandemic mounts, scientists worldwide continue their push to develop effective treatments and a vaccine for the highly contagious respiratory virus.
University of South Florida Health (USF Health) Morsani College of Medicine scientists recently worked with colleagues at the University of Arizona College of Pharmacy to identify several existing compounds that block replication of the COVID-19 virus (SARS-CoV-2) within human cells grown in the laboratory. The inhibitors all demonstrated potent chemical and structural interactions with a viral protein critical to the virus’s ability to proliferate.
The research team’s drug discovery study was published on June 15, 2020, in Cell Research, a high-impact Nature journal.
The most promising drug candidates – including the FDA-approved hepatitis C medication boceprevir and an investigational veterinary antiviral drug known as GC-376 – target the SARS-CoV-2 main protease (Mpro), an enzyme that cuts out proteins from a long strand that the virus produces when it invades a human cell. Without Mpro, the virus cannot replicate and infect new cells. This enzyme had already been validated as an antiviral drug target for the original SARS and MERS, both genetically similar to SARS-CoV-2.
“With a rapidly emerging infectious disease like COVID-19, we don’t have time to develop new antiviral drugs from scratch,” said Yu Chen, PhD, USF Health associate professor of molecular medicine and a coauthor of the Cell Research paper. “A lot of good drug candidates are already out there as a starting point. But, with new information from studies like ours and current technology, we can help design even better (repurposed) drugs much faster.”
Before the pandemic, Dr. Chen applied his expertise in structure-based drug design to help develop inhibitors (drug compounds) that target bacterial enzymes causing resistance to certain commonly prescribed antibiotics such as penicillin. Now his laboratory focuses its advanced techniques, including X-ray crystallography and molecular docking, on looking for ways to stop SARS-CoV-2.
Mpro represents an attractive target for drug development against COVID-19 because of the enzyme’s essential role in the life cycle of the coronavirus and the absence of a similar protease in humans, Dr. Chen said. Since people do not have the enzyme, drugs targeting this protein are less likely to cause side effects, he explained.
The four leading drug candidates identified by the University of Arizona-USF Health team as the best (most potent and specific) for fighting COVID-19 are described below. These inhibitors rose to the top after screening more than 50 existing protease compounds for potential repurposing:
- Boceprevir, a drug to treat Hepatitis C, is the only one of the four compounds already approved by the FDA. Its effective dose, safety profile, formulation and how the body processes the drug (pharmacokinetics) are already known, which would greatly speed up the steps needed to get boceprevir to clinical trials for COVID-19, Dr. Chen said.
- GC-376, an investigational veterinary drug for a deadly strain of coronavirus in cats, which causes feline infectious peritonitis. This agent was the most potent inhibitor of the Mpro enzyme in biochemical tests, Dr. Chen said, but before human trials could begin it would need to be tested in animal models of SARS-CoV-2. Dr. Chen and his doctoral student Michael Sacco determined the X-ray crystal structure of GC-376 bound by Mpro, and characterized molecular interactions between the compound and viral enzyme using 3D computer modeling.
- Calpain inhibitors II and XII, cysteine inhibitors investigated in the past for cancer, neurodegenerative diseases and other conditions, also showed strong antiviral activity. Their ability to dually inhibit both Mpro and calpain/cathepsin protease suggests these compounds may include the added benefit of suppressing drug resistance, the researchers report.
All four compounds were superior to other Mpro inhibitors previously identified as suitable to clinically evaluate for treating SARS-CoV-2, Dr. Chen said.
A promising drug candidate – one that kills or impairs the virus without destroying healthy cells — fits snugly, into the unique shape of viral protein receptor’s “binding pocket.” GC-376 worked particularly well at conforming to (complementing) the shape of targeted Mpro enzyme binding sites, Dr. Chen said. Using a lock (binding pocket, or receptor) and key (drug) analogy, “GC-376 was by far the key with the best, or tightest, fit,” he added. “Our modeling shows how the inhibitor can mimic the original peptide substrate when it binds to the active site on the surface of the SARS-CoV-2 main protease.”
Instead of promoting the activity of viral enzyme, like the substrate normally does, the inhibitor significantly decreases the activity of the enzyme that helps SARS-CoV-2 make copies of itself.
Visualizing 3-D interactions between the antiviral compounds and the viral protein provides a clearer understanding of how the Mpro complex works and, in the long-term, can lead to the design of new COVID-19 drugs, Dr. Chen said. In the meantime, he added, researchers focus on getting targeted antiviral treatments to the frontlines more quickly by tweaking existing coronavirus drug candidates to improve their stability and performance.
Reference: “Boceprevir, GC-376, and calpain inhibitors II, XII inhibit SARS-CoV-2 viral replication by targeting the viral main protease” by Chunlong Ma, Michael Dominic Sacco, Brett Hurst, Julia Alma Townsend, Yanmei Hu, Tommy Szeto, Xiujun Zhang, Bart Tarbet, Michael Thomas Marty, Yu Chen and Jun Wang, 15 June 2020, Cell Research.
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