Notices
Results 1 to 13 of 13
Like Tree4Likes
  • 1 Post By Dywyddyr
  • 1 Post By Janus
  • 1 Post By Janus
  • 1 Post By Janus

Thread: If the Moon were replaced with some of our planets

  1. #1 If the Moon were replaced with some of our planets 
    Forum Senior pineapples's Avatar
    Join Date
    Apr 2011
    Location
    Ireland someplace
    Posts
    363
    Here’s a less than 2 min YouTube clip on replacing our Moon with some of the planets of the solar system. Nice idea, as it gives an interesting perspective of their sizes in comparison.

    If the Moon were replaced with some of our planets - YouTube

    Maybe somebody can comment on the accuracy of the sizes though? Personally I was disappointed in the size of Jupiter. Was expecting something bigger!

    Was about to say I’d like to see how the Sun would look like, but we’d be swallowed, surly


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Cosmic Wizard
    Join Date
    Aug 2013
    Location
    San Diego
    Posts
    2,229
    Plus a lot more eclipses, and MUCH higher tides.

    Of course with most of those planets it would be more accuate to say that we'd replace one of those planet's moons with Earth. If we were the same distance to Jupiter as we were to our own Moon we would be the closest of Jupiter's major moons,


    Reply With Quote  
     

  4. #3  
    Forum Senior pineapples's Avatar
    Join Date
    Apr 2011
    Location
    Ireland someplace
    Posts
    363
    The special effect intentionally only caters for the visual distance.

    But yea, It would be interesting to see a well produced graphical interpretation of how the Earth’s environment would completely change if it were to suddenly find itself magically orbiting a planet the size of Jupiter, instead of our Moon, orbiting us.

    With the pull of Jupiters gravity, I guess giant waves would be the first on the list of bad news. Probably volcanoes propping up too, but I don’t know? Would we feel heavier as a result of Jupiter’s gravity pulling us or would there be some sort of equilibrium, if you know what I mean?
    Reply With Quote  
     

  5. #4  
    Genius Duck Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    12,030
    Quote Originally Posted by pineapples View Post
    Would we feel heavier as a result of Jupiter’s gravity pulling us
    Lighter, surely?
    Edit: or both - it would depend on where it was in the sky...

    What would worry me if Jupiter were orbiting us is that it would make it much easier for them to invade us.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  6. #5  
    Forum Senior pineapples's Avatar
    Join Date
    Apr 2011
    Location
    Ireland someplace
    Posts
    363
    Hmm, lighter you say, because we’d be getting pulled towards another planet with a greater mass than Earth? I guess that makes sense, if that what you’re saying?

    Ok, so let’s scrap Jupiter for now, but we also completely remove our Moon too, would we be feeling heavier, ever so slightly? This is looking a good way to understand gravity a bit better by playing god with the planets
    Reply With Quote  
     

  7. #6  
    Genius Duck Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    12,030
    Quote Originally Posted by pineapples View Post
    Hmm, lighter you say, because we’d be getting pulled towards another planet with a greater mass than Earth? I guess that makes sense, if that what you’re saying?
    Yes.
    When it's night and Jupiter would be in the sky then it would be pulling us up - therefore we'd feel lighter. In the day, when it's on the other side of the Earth then its pull would be added to the usual gravity and we'd feel heavier.
    Well... I just checked the numbers - Jupiter's gravity is "only" 15 times that of the Moon - so, using the comparison that you haven't read yet (given below) we'd wouldn't actually feel lighter, any more than we feel the sideways pull when we're stood next to a mountain.

    Ok, so let’s scrap Jupiter for now, but we also completely remove our Moon too, would we be feeling heavier, ever so slightly?
    We'd be heavier, but we wouldn't feel it - the gravity of the Moon is about the same as if you filled a small house with water and stood about a meter away!
    pineapples likes this.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  8. #7  
    Moderator Moderator Janus's Avatar
    Join Date
    Jun 2007
    Posts
    2,242
    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by pineapples View Post
    Hmm, lighter you say, because we’d be getting pulled towards another planet with a greater mass than Earth? I guess that makes sense, if that what you’re saying?
    Yes.
    When it's night and Jupiter would be in the sky then it would be pulling us up - therefore we'd feel lighter. In the day, when it's on the other side of the Earth then its pull would be added to the usual gravity and we'd feel heavier.
    Er, no. You'd be lighter on the nightside as well. We are talking about an orbital situation and any difference in weight would be due to tidal effects.
    Well... I just checked the numbers - Jupiter's gravity is "only" 15 times that of the Moon - so, using the comparison that you haven't read yet (given below) we'd wouldn't actually feel lighter, any more than we feel the sideways pull when we're stood next to a mountain.
    Again, no. You are comparing surface gravities. Since Jupiter has a much larger radius than the Moon, you are then comparing gravity at much greater distances from the centers. What you want to do is compare gravity at equal distances. For example, the Earth is 81 times more massive than the Moon, but because of its larger radius has only 6 times the surface gravity. At the same distance, the Earth gravity would be 81 times that of the Earth. Jupiter is some 333 times more massive than the Earth, which makes it some 27000 times more massive than the Moon. So at the same distance, the gravity of Jupiter would be 27,000 times stronger than the Moon's.

    In terms of tidal effects this would raise some really high tides, and the Earth most likely would be tidally locked to Jupiter, but it still wouldn't make a noticeable difference in our weights that we could feel.

    Ok, so let’s scrap Jupiter for now, but we also completely remove our Moon too, would we be feeling heavier, ever so slightly?
    We'd be heavier, but we wouldn't feel it - the gravity of the Moon is about the same as if you filled a small house with water and stood about a meter away!
    Dywyddyr likes this.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


    Edit/Delete Message
    Reply With Quote  
     

  9. #8  
    Suspended
    Join Date
    Nov 2012
    Location
    Apocalyptic Paradise
    Posts
    6,613
    When he said 15 times that of the Moon, I wondered if he was referring to as perceived in their current positions from an observer on Earth.
    Reply With Quote  
     

  10. #9  
    Genius Duck Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    12,030
    Quote Originally Posted by Janus View Post
    Er, no. You'd be lighter on the nightside as well. We are talking about an orbital situation and any difference in weight would be due to tidal effects.
    Ah, okay.
    Again, no. You are comparing surface gravities. Since Jupiter has a much larger radius than the Moon, you are then comparing gravity at much greater distances from the centers. What you want to do is compare gravity at equal distances. For example, the Earth is 81 times more massive than the Moon, but because of its larger radius has only 6 times the surface gravity. At the same distance, the Earth gravity would be 81 times that of the Earth. Jupiter is some 333 times more massive than the Earth, which makes it some 27000 times more massive than the Moon. So at the same distance, the gravity of Jupiter would be 27,000 times stronger than the Moon's.
    It did strike me as a weird "increase" that I'd got...

    Overall: that'll teach me to stay up posting instead of going bed and getting some sleep.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  11. #10  
    Moderator Moderator Janus's Avatar
    Join Date
    Jun 2007
    Posts
    2,242
    Quote Originally Posted by pineapples View Post
    Here’s a less than 2 min YouTube clip on replacing our Moon with some of the planets of the solar system. Nice idea, as it gives an interesting perspective of their sizes in comparison.

    If the Moon were replaced with some of our planets - YouTube

    Maybe somebody can comment on the accuracy of the sizes though? Personally I was disappointed in the size of Jupiter. Was expecting something bigger!

    Was about to say I’d like to see how the Sun would look like, but we’d be swallowed, surly
    Here's a way to compare the visual appearance. The Moon looks the same size as a quarter held ~9 feet from the eye. Jupiter is about 40 times larger in terms of diameter than the Moon. So, Jupiter would appear to be the same size as a quarter held at a distance of 2.7 in from the eye.
    pineapples likes this.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


    Edit/Delete Message
    Reply With Quote  
     

  12. #11  
    Forum Radioactive Isotope cosmictraveler's Avatar
    Join Date
    May 2005
    Location
    Key West, Florida, Earth
    Posts
    4,788
    We all know that those who live on Jupiter are Jovial and therefor wouldn't harm us.
    When the power of love overcomes the love of power the world will know peace.
    Jimi Hendrix
    Reply With Quote  
     

  13. #12  
    Moderator Moderator Janus's Avatar
    Join Date
    Jun 2007
    Posts
    2,242
    Quote Originally Posted by cosmictraveler View Post
    We all know that those who live on Jupiter are Jovial and therefor wouldn't harm us.
    Right, what we really need to worry about are those from Venus, with all their venereal diseases.
    cosmictraveler likes this.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


    Edit/Delete Message
    Reply With Quote  
     

  14. #13  
    Forum Cosmic Wizard
    Join Date
    Aug 2013
    Location
    San Diego
    Posts
    2,229
    Quote Originally Posted by Dywyddyr View Post
    When it's night and Jupiter would be in the sky then it would be pulling us up - therefore we'd feel lighter. In the day, when it's on the other side of the Earth then its pull would be added to the usual gravity and we'd feel heavier.
    As Janus noted you'd feel "lighter" on both the close and far sides.

    Although quite literally you would feel very, very light - the tides would become so strong that most dry land would be inundated by ocean at the closest and farthest points on the planet, so you'd be floating. The resulting stresses would also cause some massive earthquakes, and the Earth would likely become tidally locked fairly quickly to its primary.

    Well... I just checked the numbers - Jupiter's gravity is "only" 15 times that of the Moon - so, using the comparison that you haven't read yet (given below) we'd wouldn't actually feel lighter, any more than we feel the sideways pull when we're stood next to a mountain.
    You'd never feel any sideways pull in that situation, any more than you feel a sideways pull when you stand on an inclined surface and the Earth is pulling at you with its 1G. You'd just tilt yourself so you are still upright per local gravity. If you had a very massive mountain (i.e. one made of condensed matter or something) you wouldn't feel any "sideways pull" - but you would wonder why all the land around you seems to be on a slope.
    Reply With Quote  
     

Similar Threads

  1. Are Free-floating Planets 'Planets'?
    By Cogito Ergo Sum in forum Astronomy & Cosmology
    Replies: 38
    Last Post: January 13th, 2014, 11:47 PM
  2. Have we replaced our animal instincts?
    By coberst in forum Philosophy
    Replies: 10
    Last Post: October 18th, 2009, 05:34 PM
  3. Occultations of planets by the eclipsed Moon
    By ricci70 in forum Astronomy & Cosmology
    Replies: 2
    Last Post: July 19th, 2008, 05:03 PM
  4. Simultaneous occultations of 2 planets by the Moon
    By ricci70 in forum Astronomy & Cosmology
    Replies: 0
    Last Post: July 15th, 2008, 04:45 AM
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
  •