Notices
Results 1 to 19 of 19

Thread: Our Planet

  1. #1 Our Planet 
    Forum Freshman
    Join Date
    Jan 2008
    Posts
    90
    I dont know if this is the right subject but hey its worth a try. i was wondering what would happen to our planet if the moon decided to disapear (hypotheoretically speaking).

    Could somebody give me a list of things what would be affected and how.

    I know this could be alot but some people will benefit including myself.
    thank you very much, Rhys.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Freshman
    Join Date
    Feb 2008
    Posts
    36
    if the moon were to just disapear the earth would start to topple back and forth and it would go into an ice age. where we probably all die. and the earth would turn into this spinning ice ball.


    Reply With Quote  
     

  4. #3  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Just to expand on unoscooter's point: the moon provides significant stability to the orientation of the Earth's axis. The axial tilt, currently 23 1/2 degrees, varies between - roughly - 22 deg and 26 deg. In contrast Mars, with no moon of significant size, has an axial tilt that can vary between 15 deg and 35 deg.

    However, even without the moon disappearing this stability will not last, as illustrated by the following abstract.

    Ward, W.R. Comments on the long-term stability of the Earth's obliquity Icarus 2002.

    Continued tidal evolution of the Earth-Moon system will lengthen the day and expand the lunar orbit. Both of these changes increase the present 26,000-year equinoctial precession period. In less than 2 billion years, this period will become comparable to the 49,000- and 69,000-year periods of important terms describing the precession of the Earth's orbit plane due to planetary perturbations. These events occur when the lunar orbital semimajor axis drifts past 66.5 and 68.0 Earth radii, respectively, and will be accompanied by large oscillations of the obliquity and severe climatic alterations. The current rate of lunar recession implies that these resonances should have been encountered already, had present conditions been the norm throughout geologic time.

    However, since other changes will have rendered the planet unihabitable by advanced life forms by then, it is somewhat academic.
    Reply With Quote  
     

  5. #4  
    Time Lord
    Join Date
    Apr 2008
    Posts
    5,328
    No tides.
    Reply With Quote  
     

  6. #5  
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Posts
    14,168
    Quote Originally Posted by Pong
    No tides.
    Incorrect. The sun would still generate tides, though these would be less than currently experienced. I think about 1/3 of the height.
    Reply With Quote  
     

  7. #6  
    Forum Freshman
    Join Date
    Jan 2008
    Posts
    90
    thank you
    and one more question...
    why does the moons gravity make waves in the oceans wouldnt it just make sense if the water was higher where the moon was closest?
    Cheers, Rhys.
    Reply With Quote  
     

  8. #7  
    Forum Freshman
    Join Date
    May 2008
    Location
    Instow, Devon, UK
    Posts
    99
    Actually if you go into a sheltered bay you will find there are very few waves. The waves (to the best of my understanding) are caused by the wind picking up over the 'fetch' (length from one shore to another). The longer the 'fetch' the stronger the winds and the higher the waves. Or something to this effect.
    Reply With Quote  
     

  9. #8  
    Suspended
    Join Date
    Feb 2008
    Location
    I live in Bertrand Russells teapot!
    Posts
    902
    Quote Originally Posted by unoscooter
    if the moon were to just disapear the earth would start to topple back and forth and it would go into an ice age. where we probably all die. and the earth would turn into this spinning ice ball.
    Yes

    Which is one of the reasons why they shouldn't start messing about with it and extracting stuff or blowing holes in it!!
    Reply With Quote  
     

  10. #9  
    Forum Masters Degree SuperNatendo's Avatar
    Join Date
    Dec 2007
    Location
    Nashville, TN USA
    Posts
    505
    we have blown large megaton nuclear bombs on our planet, and yet we still haven't knocked it out of orbit. How could lightly excavating the moon do worse damage than that!?
    "It's no wonder that truth is stranger than fiction. Fiction has to make sense." - Mark Twain
    Reply With Quote  
     

  11. #10  
    Suspended
    Join Date
    Feb 2008
    Location
    I live in Bertrand Russells teapot!
    Posts
    902
    Quote Originally Posted by SuperNatendo
    we have blown large megaton nuclear bombs on our planet, and yet we still haven't knocked it out of orbit. How could lightly excavating the moon do worse damage than that!?
    Err

    Our planet is slightly bigger?

    I don't think it's wise to mess about with any natural system no matter how lightly considering how everything seems to work in a natural harmony

    Except when stupid arrogant man comes along with his fat head and dumb brain
    Reply With Quote  
     

  12. #11  
    Time Lord
    Join Date
    Apr 2008
    Posts
    5,328
    Quote Originally Posted by rhysboi1991
    thank you
    and one more question...
    why does the moons gravity make waves in the oceans wouldnt it just make sense if the water was higher where the moon was closest?
    Cheers, Rhys.
    Most waves are caused by wind. A wave can begin in a windy place and roll on to a tranquil shore.

    But tides cause waves too. The shifting tidal water must negotiate shorelines and varying depths. For example I live by the Straight of Georgia, a respectably sized pocket of the Pacific, open narrowly at either end. Now, for water to rise in this basin, it must rush through mazes of islands. Some narrows, we get white water rapids. Or eddies (whirlpools). Or surges, I guess you could call a "tidal wave". It's all clockwork and great fun to scoot a canoe in. Actually, smart canoers here don't paddle much because they know each tide will draw them into or out of the Straight, depending on whether tide is flooding or ebbing. I understand the tide can resonate around this basin and build some great waves, but I've never seen them and don't believe anybody predicts them. Where the Fraser river and a rising tide collide, they sometimes form a (little) standing wave, which does look funny - I'll bet many have tried to whack it down.
    Reply With Quote  
     

  13. #12  
    Forum Freshman
    Join Date
    May 2008
    Posts
    5
    Thank you on that opinion pong. I was thinking of going on a canoe trip these past few days, what i've read in here is certainly going to make me enjoy more.
    Reply With Quote  
     

  14. #13  
    Forum Freshman
    Join Date
    May 2008
    Posts
    12
    how the wave come from?
    Reply With Quote  
     

  15. #14  
    Forum Sophomore GrowlingDog's Avatar
    Join Date
    Feb 2008
    Location
    At the gates of Sto-vo-kor
    Posts
    181
    Quote Originally Posted by Selene
    Quote Originally Posted by SuperNatendo
    we have blown large megaton nuclear bombs on our planet, and yet we still haven't knocked it out of orbit. How could lightly excavating the moon do worse damage than that!?
    Err

    Our planet is slightly bigger?

    I don't think it's wise to mess about with any natural system no matter how lightly considering how everything seems to work in a natural harmony

    Except when stupid arrogant man comes along with his fat head and dumb brain
    Wow Selene, feeling a bit testy at the moment? hehehe
    Life is 10% what happens to you and 90% how you react to it.
    Reply With Quote  
     

  16. #15  
    Time Lord
    Join Date
    Apr 2008
    Posts
    5,328
    *Marks day of month*
    Reply With Quote  
     

  17. #16  
    Suspended
    Join Date
    Feb 2008
    Location
    I live in Bertrand Russells teapot!
    Posts
    902
    Quote Originally Posted by GrowlingDog
    Quote Originally Posted by Selene
    Quote Originally Posted by SuperNatendo
    we have blown large megaton nuclear bombs on our planet, and yet we still haven't knocked it out of orbit. How could lightly excavating the moon do worse damage than that!?
    Err

    Our planet is slightly bigger?

    I don't think it's wise to mess about with any natural system no matter how lightly considering how everything seems to work in a natural harmony

    Except when stupid arrogant man comes along with his fat head and dumb brain
    Wow Selene, feeling a bit testy at the moment? hehehe
    Yes

    It's hormonal
    Reply With Quote  
     

  18. #17  
    Suspended
    Join Date
    Jan 2008
    Posts
    439
    No more eclipse solar, lunar eclipses gosh it's making me so sad I cannot even format a coherent sentence..

    But wait! to balance it out, no more werewolfs (or should that be werewolves?)
    Reply With Quote  
     

  19. #18  
    Forum Freshman
    Join Date
    Jan 2008
    Posts
    90
    thanks i was always told that the moon caused the waves but hey i know now. but i suppose the moon has a part in the making of waves on the large scale.
    Reply With Quote  
     

  20. #19  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Are you referring to the tides? Actually they are pretty small. But the strong tides that appear at many coasts are often amplified by resonances. The tidal forces of the moon on earth can be explained in two different although equivalent ways.

    1. The moon pulls gravitationally at the earth. The force depends on the distance from the moon, i.e. it is slightly stronger on the side facing the moon. Since the water in the oceans is deformable, the rigid earth in contrast is much less so, the water is piled up in the direction to the moon. The earth itself is only displaced slightly by the gravitational force, offsetting it and thereby producing a second water accumulation on the opposite side. The earth is rotating underneath producing the changing tides which could be called waves.

    2. The moon rotates around the earth. But in fact, both revolve around their mutual barycentre with an orbital period of about 28 days. Gravitational and centrifugal forces only cancel out exactly at the earth's centre, i.e. gravity is slightly stronger on the side facing the moon, the centrifugal force dominates on the opposite side. This produces the tides on both sides of the earth. Additional to the one month's period, the earth rotates below again producing the changing tides.
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •