Astronomy and Cosmology

3684 topics in this forum

1. Direction of ionized electric fields in star birth

   By StringJunky, December 17, 2023
   • 0 replies
   • 139 views
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   • StringJunky
   • December 17, 2023

2. Expansion

   By geordief, December 10, 2023
   • 9 replies
   • 406 views
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   • KJW
   • December 11, 2023

3. Hall Thrusters

   By Photon Guy, December 5, 2023
   • 3 replies
   • 311 views
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   • TheVat
   • December 5, 2023

4. Is the universe at least 136 billion years old, is the universe not expanding at all, did the universe begin its expansion when Hubble measured its redshift for the first time or was light twice as fast 13.5 billion years ago than it is today? 1 2 3 4 8

   By tmdarkmatter, August 7, 2023
   • 187 replies
   • 7.9k views
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   • swansont
   • November 27, 2023

5. Lunar Corona or Halo?

   By sethoflagos, November 23, 2023
   • 0 replies
   • 344 views
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   • sethoflagos
   • November 23, 2023

6. What Is Space On?

   By JoeyVimsanteThePoet, November 20, 2023
   • 1 reply
   • 171 views
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   • swansont
   • November 20, 2023

7. How could we measure the ratio of a planet's radius to a star?

   By Supercazzola, November 9, 2023
   • 0 replies
   • 159 views
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   • Supercazzola
   • November 9, 2023

8. The Speed of Light

   By Chris Sawatsky, November 2, 2023
   • 2 replies
   • 346 views
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   • Halc
   • November 5, 2023

9. Could A Space Shuttle Get To The Moon? 1 2

   By Photon Guy, October 10, 2023
   • 42 replies
   • 1.7k views
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   • Photon Guy
   • November 2, 2023

10. What ratio of time is the ISS in sunlight?

    By md65536, November 1, 2023
    • 2 replies
    • 374 views
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    • md65536
    • November 1, 2023

11. Is the Sun "lumpy" on the inside??

    By tsmspace, October 11, 2023
    • 7 replies
    • 350 views
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    • mistermack
    • October 11, 2023

12. Why does fine-tunning for life suggest a multiverse? 1 2

    By Boltzmannbrain, October 2, 2023
    • 27 replies
    • 1.3k views
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    • Genady
    • October 4, 2023

13. Measuring the distance to the Moon from a photo of a solar eclipse

    By RomanRodinskiy, October 2, 2023
    • 5 replies
    • 439 views
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    • Genady
    • October 2, 2023

14. Life of the Sun

    By fwc67, September 9, 2023
    • 19 replies
    • 764 views
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    • mistermack
    • September 10, 2023

15. What Makes the E3 Comet Green?

    By exchemist, February 4, 2023
    • 7 replies
    • 669 views
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    • TheVat
    • September 8, 2023

16. Heat death before Big bang?

    By ollybach, September 3, 2023
    • 1 reply
    • 327 views
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    • Genady
    • September 3, 2023

17. Is expansion an emergent property?

    By Genady, September 2, 2023
    • 17 replies
    • 539 views
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    • TheVat
    • September 2, 2023

18. Best telescope

    By Gian, August 29, 2023
    • 11 replies
    • 617 views
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    • Genady
    • August 31, 2023

19. Space Expansion, wavelength and energy density

    By AbstractDreamer, August 28, 2023
    • 6 replies
    • 498 views
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    • MJ kihara
    • August 29, 2023

20. Spikes on Mars

    By mistermack, July 25, 2023
    • 11 replies
    • 777 views
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    • Boltzmannbrain
    • August 24, 2023

21. The Universe and ATC

    By rmw, August 23, 2023
    • 3 replies
    • 301 views
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    • swansont
    • August 23, 2023

22. Can life survive in the a galaxy's bulge? Between galaxies?

    By gib65, December 23, 2022
    • 6 replies
    • 907 views
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    • mistermack
    • July 19, 2023

23. Ground speed of moon on earth

    By Saber, June 14, 2023
    • 20 replies
    • 1.1k views
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    • Airbrush
    • July 18, 2023

24. could the moon be the remains of a planet that collided with earth?

    By boo, May 18, 2023
    • 2 replies
    • 408 views
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    • Airbrush
    • June 29, 2023

25. Brown dwarf fusion

    By Moontanman, June 5, 2023
    • 2 replies
    • 263 views
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    • swansont
    • June 5, 2023