Galactic cosmic rays are high energy particles from explosive events like supernovae, zinging through our solar system, constantly bombarding both Earth and Mars. A researcher suggests they supply enough energy to make subsurface life on Mars possible.
After the Soyuz MS-14's first automated approach to the ISS was aborted due to a malfunction, the spacecraft has now docked safely at the station's Zvezda module. It carries supplies for the crew and a humanoid robot.
The spacecraft is slowing down for its final orbit, with its next maneuver scheduled for August 28. It's due to land September 7. Details about the mission, plus Chandrayaan-2's first image of the moon, here.
Analysis of measurements via the Gaia space telescope - of star positions, brightnesses and distances - has let astronomers probe a merger 10 billion years ago between the primitive Milky Way and a dwarf galaxy called Gaia-Enceladus.
Sharmila Kuthunur is a Seattle-based science journalist. She found her love for astronomy in one of Carl Sagan's books - The Pale Blue Dot and has been hooked ever since. She earned her MA in Journalism from Northeastern University, and has been a contributing writer for Astronomy magazine since 2017.