Astronomy and Cosmology

3685 topics in this forum

1. Why did the universe expand when it was small enough to be gravitationally bound?

   By Rolando, February 4, 2014
   • 6 replies
   • 2k views
   • 
   • Schneibster
   • February 18, 2014

2. why did we move faster than light?

   By philaj, March 28, 2013
   • 8 replies
   • 1.6k views
   • 
   • Chrispen Evan
   • March 30, 2013

3. Why didn't they catch Genenis in mid-air like planned? 1 2

   By Kedas, September 8, 2004
   • 32 replies
   • 3.3k views
   • 
   • 5614
   • September 19, 2004

4. Why do all cosmological models assume time flow is the same for everyone in the universe?

   By Aki Tendo, October 15, 2017
   • 6 replies
   • 908 views
   • 
   • Mordred
   • October 15, 2017

5. Why do bigger planets have shorter days?

   By dstebbins, August 26, 2011
   • 3 replies
   • 12.3k views
   • 
   • khaled
   • September 5, 2011

6. Why do planets form? 1 2

   By ensonik, March 3, 2005
   • 39 replies
   • 3.8k views
   • 
   • ensonik
   • March 10, 2005

7. Why do stars blink?

   By greg1917, May 15, 2003
   • 6 replies
   • 2.3k views
   • 
   • Radical Edward
   • May 17, 2003

8. Why do the 9 planets orbit around the Sun?

   By Robo, October 3, 2005
   • 11 replies
   • 4.3k views
   • 
   • swansont
   • October 26, 2005

9. Why do the earth spin araund the sun? 1 2

   By jonsson, September 28, 2009
   • 27 replies
   • 3.4k views
   • 
   • swansont
   • September 24, 2010

10. Why do the supernovas explode?

    By Nano, June 12, 2010
    • 17 replies
    • 3.2k views
    • 
    • Johanluus
    • June 23, 2010

11. Why do we alway say that there has to be water for there to be life?

    By amoda, January 15, 2004
    • 20 replies
    • 2.7k views
    • 
    • [Tycho?]
    • June 13, 2004

12. Why do we think there is dark matter and dark energy?

    By Anthony Morris, October 12, 2017
    • 24 replies
    • 2.8k views
    • 
    • Strange
    • November 2, 2017

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

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

14. Why does gravity create discs?

    By dimreepr, February 9, 2012
    • 2 replies
    • 1k views
    • 
    • Keenidiot
    • February 9, 2012

15. why does the daylight Moon appear to have a 'horizonal' shadow?

    By balladofserenity, May 8, 2016
    • 2 replies
    • 1.5k views
    • 
    • Delta1212
    • May 8, 2016

16. Why does the temperature of the core and sufrace of the sun differ so much?

    By yyh020635, January 26, 2014
    • 4 replies
    • 1k views
    • 
    • Enthalpy
    • January 29, 2014

17. Why doesn't a long journey hinder photons?

    By Baby Astronaut, February 5, 2009
    • 1 reply
    • 666 views
    • 
    • Klaynos
    • February 5, 2009

18. Why doesn't the resonance of the entire universe experience damping?

    By John Harmonic, September 26, 2018
    • 5 replies
    • 654 views
    • 
    • John Harmonic
    • September 26, 2018

19. Why doesn't the space curvature restore the path of a photon?

    By Lazarus, May 14, 2013
    • 17 replies
    • 1.8k views
    • 
    • Lazarus
    • May 19, 2013

20. Why Don't All Moons Orbit Retrograde?

    By Elen Sila, September 5, 2011
    • 11 replies
    • 2.3k views
    • 
    • matterdoc
    • October 18, 2011

21. Why don't we feel like we are hanging backwards on earth??

    By Iwonderaboutthings, August 2, 2013
    • 10 replies
    • 3.1k views
    • 
    • Iwonderaboutthings
    • August 7, 2013

22. Why don't we make our calendar more rational and simple?

    By Myuncle, April 12, 2014
    • 17 replies
    • 1.6k views
    • 
    • Phi for All
    • April 15, 2014

23. Why don't you see stars in NASA space pics. of Earth?

    By ulrichburke, September 29, 2016
    • 6 replies
    • 1.1k views
    • 
    • StringJunky
    • October 2, 2016

24. Why Gravity Exist??

    By Harshit Mishra, February 1, 2021
    • 3 replies
    • 794 views
    • 
    • Phi for All
    • February 1, 2021

25. Why is a fine-tuned universe a problem? 1 2 3 4

    By 34student, February 11, 2022
    • 83 replies
    • 8.5k views
    • 
    • Mordred
    • December 27, 2022