Moon size comparison

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Moon size comparison

#1  Postby Macdoc » Jul 27, 2020 11:02 am



Thought this well done
Travel photos > https://500px.com/macdoc/galleries
EO Wilson in On Human Nature wrote:
We are not compelled to believe in biological uniformity in order to affirm human freedom and dignity.
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Re: Moon size comparison

#2  Postby I'm With Stupid » Jul 27, 2020 2:47 pm

I always thought Europa was bigger than that. Nice video. It's interesting to see the exact size at which gravity turns them into a sphere too.
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Re: Moon size comparison

#3  Postby Matt_B » Jul 28, 2020 4:21 am

I'm With Stupid wrote:I always thought Europa was bigger than that. Nice video. It's interesting to see the exact size at which gravity turns them into a sphere too.


There isn't really an exact size, as it's not only dependent upon a body's own gravity, but also its composition and external forces. Consequently there's more of a transitional zone rather than an exact cut-off.

For instance, Saturn's satellite Mimas (around 200km) is close to spherical but considerably smaller than the asteroid Vesta (around 500km) which obviously isn't. However, Vesta is rocky and rather isolated from other bodies, where Mimas is mostly made of ices and subject to strong tidal forces from Saturn and orbital resonances with other satellites including the rings; it's basically been massaged into shape.
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Re: Moon size comparison

#4  Postby I'm With Stupid » Jul 28, 2020 4:56 pm

Matt_B wrote:
I'm With Stupid wrote:I always thought Europa was bigger than that. Nice video. It's interesting to see the exact size at which gravity turns them into a sphere too.


There isn't really an exact size, as it's not only dependent upon a body's own gravity, but also its composition and external forces. Consequently there's more of a transitional zone rather than an exact cut-off.

For instance, Saturn's satellite Mimas (around 200km) is close to spherical but considerably smaller than the asteroid Vesta (around 500km) which obviously isn't. However, Vesta is rocky and rather isolated from other bodies, where Mimas is mostly made of ices and subject to strong tidal forces from Saturn and orbital resonances with other satellites including the rings; it's basically been massaged into shape.

Interesting.
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