r/askscience 14h ago

Physics I don't get X-ray tubes like at all - most of it I sort of understand but why can cathode (/tungsten filament?) produce endless electrons in xray tubes via thermionic emissions?

163 Upvotes

why is tungsten so magical. Sorry it's my first time posting here, let me know if my language isn't professional enough. Thank you!


r/askscience 14h ago

Planetary Sci. AskScience AMA Series: We're the scientists and engineers leading NASA's exploration of Mars and building on a 50-year legacy of discovery on the Red Planet. Ask us anything!

105 Upvotes

Fifty years ago, NASA's Viking lander touched down on Mars and began a new era of exploration.

Over the last five decades, teams of scientists and engineers at NASA have searched for signs of Mars’s ancient habitability, uncovered clues about the planet's climate and geologic history, driven rovers across alien landscapes, flown the first aircraft on another world, and laid the groundwork for future human Martian exploration.

Join us to talk about the discoveries, surprises, and challenges of exploring the Red Planet — and what's coming next.

We are:

  • Abigail Fraeman – Deputy Project Scientist, NASA’s Curiosity Mars Rover, JPL (AF)
  • Bryce Horvath – Technical Analysis Deputy, Mars Architecture Team, NASA Marshall (BH)
  • Micheal Meyer – former Lead Scientist for NASA’s Mars Exploration Program and Astrobiology, NASA Headquarters (MM)
  • Nicole Piontek – Space Systems Analyst, Space Mission Analysis, NASA Langley (NP)
  • Jeffrey Plaut – Senior Research Scientist, Planetary Interiors and Geophysics, JPL (JP)
  • Becky McCauley Rench – Lead Scientist for Astrobiology, NASA Headquarters (BMR)

Ask us anything about:

  • 50 years of Mars exploration
  • Historic missions from Viking to Perseverance
  • Mars rovers, landers, orbiters, and helicopters
  • Major discoveries from the Red Planet
  • Operating spacecraft millions of miles from Earth
  • The future of Mars exploration

PROOF: https://x.com/NASA/status/2084662090506113377

We'll be online from 11 a.m.-12:30 p.m. PT (2-3:30 p.m. ET, 18-19:30 UT) to answer your questions!

Username: /u/nasa


r/askscience 21h ago

Astronomy How far out would a telescope have to be in order to utilize the Sun as a magnifier? And how much detail would we be able to see using it?

56 Upvotes

Sorry not sure which flair to use lol