Lifeboat Foundation

Figures 4 and 5 effectively demonstrate that local acceleration is capable of heating electrons to ~7 MeV as the phase space density profiles show signatures of local acceleration during both of the geomagnetic storms considered. The phase space density enhancements for higher energies followed the enhancements at lower energies. In Supplementary Note 8, additional analysis establishes that locally growing peaks are also observed for lower values of K, corresponding to radiation belt electrons confined closer to the equator. Furthermore, as the values of K and L* are dependent on the magnetic field model chosen, results using an additional two field models are also presented (see Supplementary Note 9) and, once again, growing peaks are observed in the radial phase space density profile. Our results demonstrate that local acceleration had a significant effect on radiation belt particles during both of the storms in October 2012, acting on electrons up to 7 MeV. In the radiation belt region, local acceleration introduces radial gradients in phase space density and so is always accompanied by both outwards and inwards radial diffusion. Locally heating electrons to ~7 MeV provides a very high energy “source population” for inwards radial diffusion and could therefore help explain the occurrence of ~10 MeV electrons in April–May 2017¹⁶.

A recent study by Zhao et al.¹⁵, considered the acceleration of ultra-relativistic electrons via a statistical analysis of events during the Van Allen Probe era. The results were consistent with a two-step acceleration process, where locally heated electrons at large L*, beyond the Van Allen Probes apogee, are radially diffused inwards to reach energies of 7 MeV in the outer radiation belt. While the combination of local acceleration and radial diffusion produces 7 MeV enhancements¹⁵, the Van Allen Probe observations for the two storms shown in this study demonstrate that local acceleration can also act directly up to 7 MeV energies. The local energization mechanism responsible for generating 7 MeV electrons in the heart of the outer radiation belt, be that acceleration by chorus waves or some other process, presents an interesting focus for future research. Longer term analysis and statistical studies can be used to better understand the conditions leading to acceleration. Datasets formed via data-assimilation techniques may be useful for this purpose. Long term observations of the ultra-relativistic component of Earth’s radiation belts demonstrate that ≥7 MeV electrons are a relatively rare phenomenon, occurring far less frequently than enhancements at 1 or 2 MeV¹. It therefore follows that the circumstances leading to multi-MeV enhancements could be unusual, requiring specific conditions. Our results highlight that wave-particle interactions can provide the primary acceleration mechanism for electrons up to ultra-relativistic energies, a finding applicable to magnetized plasmas throughout the solar system.

Chlorine isotopes are a sensitive tracer of degassing throughout planetary evolution that provide evidence for the universal depletion of volatiles in the Moon. We show that much of the chlorine in mare basalts is trapped in water-soluble phases from vapor deposition with low isotope values, with the remaining being isotopically heavy from degassing. We also use halogen concentrations and bulk-Cl isotope values to show that most lunar halogen loss and heavy Cl enrichment occurred during the Giant Impact—resulting in a 10× depletion of halogens relative to the Earth. Last, we conclude that lunar apatite has much higher δ³⁷ Cl values compared to the bulk rock, likely explained by localized degassing, making their use as direct probes of planetary-scale processes problematic.

Lunar mare basalts are depleted in F and Cl by approximately an order of magnitude relative to mid-ocean ridge basalts and contain two Cl-bearing components with elevated isotopic compositions relative to the bulk-Earth value of ∼0‰. The first is a water-soluble chloride constituting 65 ± 10% of total Cl with δ³⁷ Cl values averaging 3.0 ± 4.3‰. The second is structurally bound chloride with δ³⁷ Cl values averaging 7.3 ± 3.5‰. These high and distinctly different isotopic values are inconsistent with equilibrium fractionation processes and instead suggest early and extensive degassing of an isotopically light vapor. No relationship is observed between F/Cl ratios and δ³⁷ Cl values, which suggests that lunar halogen depletion largely resulted from the Moon-forming Giant Impact. The δ³⁷ Cl values of apatite are generally higher than the structurally bound Cl, and ubiquitously higher than the calculated bulk δ³⁷ Cl values of 4.1 ± 4.0‰.

Planets that come into close contact with white dwarfs are usually destroyed in the process. Why wasn’t this one?

Has science fiction shaped our thoughts about space? In a new episode of our #GravityAssist podcast, astrobiologist Susan Schneider shares her theories on what life might be like in the future.

🎧 Listen: https://go.nasa.gov/3mfxZE4

🌖 #Artemis partnerships to return lunar dust, and fly science & NASA Technology to the Moon.

🌎 Our NASA Earth missions provide data to aid in wildfire response.

🛰️ New discoveries at asteroid Bennu from NASA’s OSIRIS-REx Asteroid Sample Return Mission.

Like Concrete

In simpler terms: the resulting material “feels like concrete but much lighter,” Fernandez told CNN. “Very light rock.”

“We have a route to… manufacturing buildings to tools from 3D printing to mold casting with just one single material,” he added.

Is it possible to discover an asymmetry of a few thousandths of a millimeter on a neutron star 42 million billion km from Earth?

What’s it like to live in space? To get some insight on playing an astronaut going to Mars, Hilary Swank visited NASA’s Johnson Space Center, and spoke with astronaut Jessica Meir, who lived aboard the International Space Station for over 200 days. Bonus: Mission Control cartwheel.

In a statement, Roscosmos noted that the first missions to explore Venus were carried out by the Soviet Union.

“The enormous gap between the Soviet Union and its competitors in the investigation of Venus contributed to the fact that the United States called Venus a Soviet planet,” Roscosmos said.

The Russians claim to have extensive material that suggests that some objects on the Venusian surface have changed places or could be alive, although these are hypotheses that have yet to be confirmed.

Continue reading “‘Venus is a Russian planet,’ Russian space agency director says” »