Astronomy and Cosmology

3708 topics in this forum

1. Direction of ionized electric fields in star birth

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

2. Expansion

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

3. Hall Thrusters

   By Photon Guy, December 5, 2023
   • 3 replies
   • 503 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
   • 10.1k views
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   • swansont
   • November 27, 2023

5. Lunar Corona or Halo?

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

6. What Is Space On?

   By JoeyVimsanteThePoet, November 20, 2023
   • 1 reply
   • 345 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
   • 266 views
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   • Supercazzola
   • November 9, 2023

8. The Speed of Light

   By Chris Sawatsky, November 2, 2023
   • 2 replies
   • 473 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
   • 2.8k 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
    • 659 views
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    • md65536
    • November 1, 2023

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

    By tsmspace, October 11, 2023
    • 7 replies
    • 545 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
    • 1.6k 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
    • 647 views
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    • Genady
    • October 2, 2023

14. Life of the Sun

    By fwc67, September 9, 2023
    • 19 replies
    • 1.1k views
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    • mistermack
    • September 10, 2023

15. What Makes the E3 Comet Green?

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

16. Heat death before Big bang?

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

17. Is expansion an emergent property?

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

18. Best telescope

    By Gian, August 29, 2023
    • 11 replies
    • 1.1k views
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    • Genady
    • August 31, 2023

19. Spikes on Mars

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

20. The Universe and ATC

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

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

    By gib65, December 23, 2022
    • 6 replies
    • 1k views
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    • mistermack
    • July 19, 2023

22. Ground speed of moon on earth

    By Saber, June 14, 2023
    • 20 replies
    • 1.5k views
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    • Airbrush
    • July 18, 2023

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

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

24. Brown dwarf fusion

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

25. The 2nd biggest bang we know about, 3c186

    By Airbrush, April 3, 2023
    • 17 replies
    • 1.1k views
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    • Mordred
    • May 25, 2023