Saturn's moon Enceladus has a subsurface ocean covered by a layer of ice. Some liquid escapes into space through cracks in the ice, which is the source of one of Saturn's rings. In October 2015, the Cassini spacecraft flew directly through the plume of escaping material and sampled its chemical composition. Waite et al. found that the plume contains molecular hydrogen, H2, a sign that the water in Enceladus' ocean is reacting with rocks through hydrothermal processes (see the Perspective by Seewald). This drives the ocean out of chemical equilibrium, in a similar way to water around Earth's hydrothermal vents, potentially providing a source of chemical energy.
You may have seen celebs like Blake Lively, Ryan Reynolds, and Zac Efron drinking hydrogen water. Why is this the drink the latest craze in the trend of specialty waters? "Hydrogen water is just one of the newest fads, and there is much marketing hype around it," Sonya Angelone, MS, RDN, CLT, a spokeswoman for the Academy of Nutrition and Dietetics, told Fox News. Does the hype have strong scientific basis? Can hydrogen water really help your health?
Ever since'Oumuamua was discovered in 2017, the first interstellar object detected in our solar system has been a source of endless intrigue for astronomers. The giant hunk of space rock has an unusual cigar shape, is tumbling end over end, and isn't easily classified as a comet or an asteroid. The uncertainties about this interstellar interloper have resulted in a proliferation of theories about its provenance and composition. There's been speculation that it's a cosmic dust bunny, an alien spaceship, or the remnants of a small planet torn asunder by its host star. This week, two Yale astrophysicists put forth a new theory arguing that'Oumuamua has the makings of an interstellar iceberg.
Staphylococcus epidermidis and Staphylococcus aureus are pathogens that can form biofilms on implants and medical devices. Central to biofilm formation is a very tight interaction between microbial surface proteins called adhesins and components of the extracellular matrix of the host. Milles et al. used atomic force microscopy-based single-molecule force spectroscopy combined with steered molecular dynamics to explore how the bond between staphylococcal adhesin SdrG and its target fibrinogen peptide can withstand forces greater than 2 nanonewtons (see the Perspective by Herman-Bausier and Dufrêne). The peptide is confined in a coiled geometry in a deep and rigid pocket through hydrogen bonds between SdrG and the peptide backbone. If pulled, the load is distributed over all hydrogen bonds so that all bonds must be broken at once to break the interaction.
When the Cassini spacecraft flew through the plumes of Enceladus, it smelled, tasted and analyzed the chemical composition of the water, even pinpointing the probable temperature of the source of the plumes. "We've used the deep ocean as an analog for other ocean systems in our solar system," says Lim, "but many times the analogs that have been used have been mid oceanic ridge systems like black smokers and a lot of people have that come to mind when they think of deep ocean vents." But the catch with these black smokers--underwater chimneys that release iron sulfide--is that their temperatures linger around 700 degrees Fahrenheit and according to Cassini data the likely temperature for Enceladus plumes are around 300 degrees Fahrenheit. This is not an ideal match. Luckily, at Lō ihi there are white smokers (these release barium, calcium and silicon which make these particular vents white) whose temperatures stay around 392 degrees.