Now that I’m more awake than I was last night, I recall better the material I had heard about the Theia idea - that the collision with Theia boiled off a considerable amount of the volatiles in the Earth (whether or not they were actually in an atmosphere at the time of the collision) reducing the amount of volatiles that were available later to become atmosphere or ocean. But as you say, this is so active an area of research that stuff I heard about in the mid 2010s might be out of date now.
Yeah, it’s really amazing how fast we are learning new things about the early history of the Earth-Moon system. One of the mysteries has been the volatile budget of the Moon, which we thought was pretty much a bone dry rock until very recently. Now it looks like the Moon was a lot wetter than we thought, and still is.
The Synestia theory of Moon formation is also interesting.
And what if the Moon falls into the Earth? Do you think it is possible?
Jason Barnes stated that the Moon could fall to Earth in 65 billion years. He explained his opinion by the fact that by that time the speed of rotation of the Earth’s axis would slow down very much.
According to various estimates, this could happen in about 50 billion years, when celestial bodies find themselves in mutual spin-orbital resonance. As a result, the Moon will not move away but will be attracted to our planet.
In about 5 billion years, Sun will run out of hydrogen, which is the source of energy for stars. It will move to a new stage in its evolution, turning into the so-called red giant. The luminosity of the star will increase, the pressure inside it will increase, and the outer shell will begin to expand. The most powerful emissions from the atmosphere of the red giant can quickly change the orbit of the Moon, forcing the latter to begin to slowly move towards the Earth.
Not impossible. If the Sun did not enter a red giant phase, the Moon would eventually migrate out of the Earth’s Hill Sphere, but it would still be a very nearby planet. In that case the Earth and Moon would periodically interact and either collide or move much further apart. So the odds are quite good that the Moon would fall into the Earth eventually anyway.
But since the Sun will turn into a red giant, our planet will be affected by friction with its outer envelope, and all sorts of nasty things would happen. probably including the destruction of both the Earth and Moon.
I suppose that, if both Earth and Luna were to fall into the core of the Sun, that could be construed as the two of them colliding.
Depending on the level of variation this constant flux brings it might not have dire consequences but could even turbocharge evolution.
Absent other factors, the moon will continue to move away from the Earth until the Earth is tidally locked to the moon, probably take somewhere in the order of 50 billion years or so.
But that doesn’t mean that the moon is no longer in orbit, once again absent any other factors, the system would more or less continue on that way for a very long time. I suppose gravitational radiation would dissipate some of the energy, and the moon would start moving back towards the Earth, but that’s the sort of thing that would be in many trillions of years.
When the sun goes red giant, a whole lot of things will change, and the moon’s orbit being affected would only be one of them.
Forget the moon! What about all that heat emanating from the stubbornly still-liquid core of Terra (vulgar name, Earth or “Rocky Primary”, is that what they’re calling it now?).
I expect there was some early benefit to having this virtual incubator handy for paleo-cave-bacteria to warm their fragile protoplasm by. It was after all the era of “Primordial Soup”, and everyone knows cold soup is just Vichyssoise! But that was long ago. Well over millions of years!
I don’t want to hijack this topic, but will instead refer everyone to my thread in the “MONDAY POINTLESS” (MPMPM) section, “Let’s Make Earth the #1 Planet”. It sparked a huge debate, maybe the greatest ever seen on this Message Board, and though it has lain fallow for a spell, I have by no means abandoned it and have much more to say on a topic that is not only urgent but also crucial at the same time!
But for now I’ll just drop this one name - ex-US Rep. Ted Yoho. (He has now retired from the House, which is good because he has more time than ever to devote to me - watch for an update and prepare for a shocking announcement, which we ignore at our peril!