Category Astronomy/Space

Underwater Snow Gives Clues about Europa’s Icy Shell

Underwater photo of the underside of an ice shelf. The ice is greenish and rough, like heaps of snow.
Mounds of snow-like ice under an ice shelf. ©Helen Glazer 2015 from the project Walking in Antarctica

Below Europa’s thick icy crust is a massive, global ocean where the snow floats upwards onto inverted ice peaks and submerged ravines. The bizarre underwater snow is known to occur below ice shelves on Earth, but a new study shows that the same is likely true for Jupiter’s moon, where it may play a role in building its ice shell.

The underwater snow is much purer than other kinds of ice, which means Europa’s ice shell could be much less salty than previously thought. That’s important for mission scientists preparing NASA’s Europa Clipper spacecraft, which will use radar to peek beneath the ice shell to see if Europa’s ocean could be hospitable to life...

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Astronomers confirm Star Wreck as Source of Extreme Cosmic Particles

This sequence compares Fermi results in three energy ranges. Pulsar J2229+6114 is the brilliant source at the top, the northern tip of supernova remnant G106.3+2.7 (outlined in green). In each energy range, the sequence first shows the number of gamma rays and then the excess amounts compared with expectations from a model of the background. Brighter colors indicate greater numbers of gamma rays or excess amounts. At the highest energies, a new source of gamma rays emerges, produced when protons accelerated by the supernova’s shock wave strike a nearby gas cloud.
Credit: NASA/Fermi/Fang et al. 2022

Astronomers have long sought the launch sites for some of the highest-energy protons in our galaxy...

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Rocket Launch to Image Supernova Remnant

Cassiopeia A

A Northwestern University astrophysics team is aiming for the stars—well, a dead star, that is.

On Aug. 21, the NASA-funded team will launch its “Micro-X” rocket from White Sands Missile Range in southern New Mexico. The rocket will spend 15 minutes in space—just enough time to snap a quick image of supernova remnant Cassiopeia A, a star in the Cassiopeia constellation that exploded approximately 11,000 light-years away from Earth. Then, the rocket will parachute back to Earth, landing in the desert—about 45 miles from the launchpad—where the Northwestern team will recover its payload.

Short for “high-resolution microcalorimeter Xray imaging rocket,” the Micro-X rocket will carry a superconductor-based X-ray imaging spectrometer that is capable of measuring t...

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Stars Determine their Own Masses

Simulation of a star-forming region, where massive stars destroy their parent cloud.

Simulations show why stars formed in different environments form similar masses. Last year, a team of astrophysicists including key members from Northwestern University launched STARFORGE, a project that produces the most realistic, highest-resolution 3D simulations of star formation to date. Now, the scientists have used the highly detailed simulations to uncover what determines the masses of stars, a mystery that has captivated astrophysicists for decades.

In a new study, the team discovered that star formation is a self-regulatory process. In other words, stars themselves set their own masses. This helps explain why stars formed in disparate environments still have similar masses...

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