Can someone ELI5 how it is one side of the moon is never seen on Earth? The moon orbits and also rotates, does it not?
Yes and its rotation is synchronized to earth. See the animation at https://en.wikipedia.org/wiki/Tidal_locking
Lunar Flyby
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Re: Lunar Flyby
#52Re: Lunar Flyby
#53Can someone ELI5 how it is one side of the moon is never seen on Earth? The moon orbits and also rotates, does it not?
I believe it's caused by even the slightest imbalance in mass. Because the moon is so close to Earth, the imbalance causes gravity to be slightly stronger on one side than the other side. Eventually, that leads to no rotation at all.
I imagine most bodies rotating around a second object will eventually lose their angular velocity.
Re: Lunar Flyby
#54Can someone ELI5 how it is one side of the moon is never seen on Earth? The moon orbits and also rotates, does it not?
The moon is tidally locked to earth, we only ever see one side.
To add: this happens because the parts of the Moon that are closer to the Earth are pulled in more by Earth's gravity, compared to the ones further away.
Re: Lunar Flyby
#55I have to admit, I've been an Artemis hater ($4 billion per launch lol) but the experience of watching people go back around the Moon has been incredibly inspiring, and it proves to me that maybe we can still do hard things
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Ok I realize you're making a point, but 10 launches a day comes out to about $15 trillion a year, that's like half of the US GDP
Re: Lunar Flyby
#56This is the best animation of the trajectory I've seen: https://apod.nasa.gov/apod/ap260406.html
Re: Lunar Flyby
#57Re: Lunar Flyby
#58This is the best animation of the trajectory I've seen: https://apod.nasa.gov/apod/ap260406.html
Someone did a nice animation on YouTube.
Re: Lunar Flyby
#59Re: Lunar Flyby
#60Earlier quoted context omitted.
The moon is tidally locked to earth, we only ever see one side.
Is it 2-way? I guess moon see all around earth, or no?
If you are on the near side of the moon[1], you will always see Earth see around Earth as it rotates and as the moon orbits it. You will also see it in different phases, like how we see lunar phases from Earth. If you are on the far side of the moon, you will not see Earth at all as you will always be facing away from it.
[1] The Earth does move in the moon's sky a bit. If you are on the near side but getting close to the far side, the Earth will be below the horizon sometimes.