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When the Earth was young, shortly after the moon formed, our planet was spinning so fast that a day was approximately five hours long. During the intervening billions of years, the dragging effect of the moon’s gravity slowed the Earth’s spin to the 24-hour day we now observe. Approximately 50,000 years in the future, this continuing effect will slow the Earth sufficiently that a leap second will need to be added to the clock every day if we wish to maintain our current calendar.
The moon is also very slowly moving away from the Earth as part of this process—every year, the average gap between the two bodies widens by 3.78 centimeters, approximately the speed of fingernail growth. Scientists can measure this increase to within one centimeter using laser reflectors that were placed on the surface of the moon by Apollo astronauts. In 600 million years or so, the moon will be so distant from the Earth that solar eclipses will no longer obscure the entire sun.
The moon, however, will never escape. Before it has a chance to break orbit entirely, the sun will have expanded into a red giant—some 6 billion years from now—and the moon will begin to drag against the sun’s growing atmosphere. Luna’s orbit will then decay, and it will begin to fall back toward Earth. When it comes within 18,470 kilometers of Earth—a distance known as the Roche Limit—tidal forces will overwhelm the gravity holding the moon together, and the moon will crumble into a short-lived ring system around our planet. Most of the material in the rings will subsequently fall to the Earth.
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Printed from https://www.damninteresting.com/curio/the-anticipated-future-of-the-moon/
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Not second. Thanks for another interesting article.
First, it will be raining rocks for awhile then.
J.Goodlet Perth Australia
This assumes humans wont do something to stop and/or reverse these processes, which is quite plausible.
Your wonderful shorts stopped showing up in the podcast feed. Not sure if you have abandoned that medium or if there is a problem. Just wanted to let you know I miss them.
The science seems solid and the whole raining down of moon fragments is interesting, but the whole scenario is unlikely to happen given the human factor. I would expect that we will have destroyed and rebuilt the Moon, Sun, and Earth many times before the determined time is reached and even then we probably won’t let it happen. Intelligent life also seems to be massively chaotic and disruptive, so all bets are off in what happens in the very long term except to expect the spark of intelligent life to go on, along with all the chaos it causes. :-)
If humans survive 5 billion more years, that in itself will be a great triumph, so who am I to say that we won’t be able to stop the sun’s death throes, which would consume the 3 inner planets. The reason for this happening would be exhaustion of the sun’s current fuel, so we’d face the enormous task of replacing much of the sun’s mass to refuel the sun. This would be an astoundingly energy intensive effort, even for an advanced civiliation, which might worry that such immensely wasteful activites would shorten the time to the ultimate heat death of the universe by a few days or years (that math is beyond me).
Would humans be so godlike in their talents that they’d undertake this activity because they can, or would humans have long since migrated to outer planets or to other, younger stars?
I suppose it’s totally irrelevant to any of us reading this now, but I can’t help but root for humanity 5 – 6 billion years in the future.
It’s refreshing to read of other commenter’s optimism and confidence in humanity’s future abilities. I read somewhere that more people believe in Angels than believe in global warming – I hope you’re all right that we have an enlightened and powerful future ahead of us.
The first time that I read about the moon’s moving away from Earth was -believe it or not – in a Peanuts strip.
My thanks to you for filling in the rest.