Astronomy and Cosmology

3685 topics in this forum

1. Cosmological Redshift and metric expansion 1 2 3 4

   By AbstractDreamer, May 23, 2023
   • 78 replies
   • 4.5k views
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   • KJW
   • December 20, 2023

2. Direction of ionized electric fields in star birth

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

3. Expansion

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

4. Hall Thrusters

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

5. 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
   • 8k views
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   • swansont
   • November 27, 2023

6. Lunar Corona or Halo?

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

7. What Is Space On?

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

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

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

9. The Speed of Light

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

10. 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

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

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

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

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

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

    By Boltzmannbrain, October 2, 2023
    • 27 replies
    • 1.4k views
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    • Genady
    • October 4, 2023

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

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

15. Life of the Sun

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

16. What Makes the E3 Comet Green?

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

17. Heat death before Big bang?

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

18. Is expansion an emergent property?

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

19. Best telescope

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

20. Space Expansion, wavelength and energy density

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

21. Spikes on Mars

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

22. The Universe and ATC

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

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

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

24. Ground speed of moon on earth

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

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

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