The Moon
February 3, 2006 on 8:49 pm | In Physics |How big do you think our moon is? Perhaps the size of France… does that sound right? Actually it turns out that it’s about a quarter of the diameter of Earth. This is actually pretty big for a moon, 3476 km accross to be exact. Compare this with Pluto which is 2274 km accross. That means our moon is bigger than a planet! I for one am glad we have it, because without it the earth would not be so steady. The almost perpetual dance our planet and moon engages in keeps us from who knows what weird things a planet with a moving magma core would get up to. It also gives us our tides. When I say ‘almost’ perpetual, it means that our moon is slowly loosing interest in the dance and is drifting off, currently at a rate of about 4 cm a year. The second question to ask is where did we get our moon? It must have always been there and was just one of the planetesimals that formed with the earth and all the other planets and moons at the beginning of the galaxy. That’s what I would have guessed. Another thing could have been that we locked orbits as the moon floated by from who knows where. Turns out that the current theory says that it was actually part of Earth and was blown out when something the size of Mars hit us. I find it ironic how something that sounds so devistating is one of the items in a long list of why we are here.
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think of it this way. if we didnt have the moon, it is highly possible that the earth could not facillitate life. the oceans would not circulate and if they did, it would be stickly density driven ciruclation and little bit of heat conduction, but since the ocean is an excellent buffer this would probably be negligiable. All movement would be mostly chemically dirven rather than physically driven. Tide.
We have much to thank that lifeless, piece of dusty relic earth. I like the moon, it reminds me of how the earth would look like without our lovely atmosphere and magnetic fields.
i never realized how big it was.
and on a side note about scale.
the distance it takes to travel from vancouver to st. johns NFLD, is approximatly the distanced to travel from edmonton to the centre of the earth.
Comment by vasyL — March 7, 2006 #