« on: 15/09/2019 19:26:01 »
What would moon have looked like from Earth on a clear evening, 4 billion years ago? Was that not shortly before life formed on Earth?Exact dates for both are not known, but it seems if life was barely there before the Theia event, that event would not have been kind to it. Maybe.. Life in general is impossibly resilient, and if such an impact should happen today, life would most likely survive it. Maybe life came from Theia itself. Think about it.
It would have been extremely close! Immediately after it's formation from the Thea collision it must have resolved to a closest orbit, and moved away over time due to tides over millions of years?The third of Kryptid's links gives distances, but oddly enough, not length of day or month. I've heard the day would have been around 10 hours (and will be again if the sun can be prevented from swallowing us before then). The calculations can be done with conservation of angular momentum laws.
At 4 billion years ago say 200 million years into it's life, the moon also had an atmosphere, coming from it's rocks and craters and internal sourced gases. What were those gases and what colours would they have been? And they would have been blowing in the solar wind, right? Under a dimmer colder sun?Solar wind might have blown that atmosphere away almost as fast as it was emitted from the rocks. Unclear if any appreciable pressure ever built up, but your subsequent link says yes, perhaps around 1% Earth's current pressure.
The Earth at this time along the equator, would not have had any land not swept over by the tide during the week?Oceans took a long time to form after the Theia event. Don't think tides ever swept clean over the continents.
I've heard of weather forecasts for back then: Hurricanes with mercury pressure down to about 15 cm, strong enough to polish the landscape down to smooth rock.
How many hours would a lunar orbit have taken back then?Right after the moon formed, less than a day. Several hundred million years later, maybe 4 days.
The point of centre of the two objects rotating would have been inside the Earth's diameter?It still is, about 75% of the way to the surface. Yes, it would have been deeper in back then.
Centrifugal forces would not have balanced out like with the Sun's gravity and the Earth's orbit? Or is there a solar tide?Don't know what you mean by centrifugal forces balancing out. I think the moon's acceleration on Earth might have been as strong that that of the sun at some point. It isn't close anymore. The Earth always accelerates towards the sun even when the moon is full, pulling hardest in the opposite direction. Yes, there have always been solar tides. You're very aware of them if you live at sea level.
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