Someone sent this rather bizarre segment of a Congressional hearing involving Rep. Louie Gohmert of Texas.
Rather than being clueless about science (he may be that too), I suspect he's echoing some baseless claims used to claim humans have no impact on global warming. While the orbits of the Earth and Moon are dynamic, they have no impact on current global warming. That said, the Moon's orbit is changing at a measurable rate and that's worth a short post.
The Moon and the Earth orbit a common center of mass called a barycenter that's about 1,700 kilometers beneath the Earth's surface. Seen from the Earth, the Moon's orbit is elliptical with a slight wobble. The gravitational interaction between the two bodies raises tides on the Earth, making our days longer and pushing the Moon out a bit less than four centimeters per year - roughly at the rate your fingernails grow.
So the Moon's orbit is changing, but slowly. Unchecked this process would continue for nearly fifty billion years when the Earth's day would have slowed to nearly fifty of our current days and the Moon would take the same amount of time to orbit the Earth. At that point we'd be permanently locked with the Moon.
Fifty billion years is a long time and something else will happen long before then. About five billion years from now the Sun will become a red giant. There are a few scenarios - here's my favorite.
The Sun's atmosphere, as it heats and expands, will create drag on the Moon's orbit bringing it closer to Earth. There's a limit called the Roche limit to how close a gravitationally formed body can hold together before tidal forces rip it apart. For the Earth-Moon system that's a bit under 19,000 kilometers (say 12,000 miles). The Moon is ripped apart and scattersinto a Saturn-like ring that might stay around for a few hundred thousand years.
If the Sun keeps growing the Earth will eventually be in or near enough to its photosphere that the Earth would spiral into the Sun and be no more. But that's a long time away. In the meantime we need to worry about the here and now of global warming - perhaps not as dramatic as the ending five billion years out, but deadly nonetheless.
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