The Moon And Earth Are Slowly Drifting Apart
The moon feels like a beautiful constant for many of us,there every night,but Earth’s satellite is actually slowly moving away from us,albeit very slowly.
By NASA’s calculations the moon is drifting away from our planet by about 1.5 inches every year. That’s not just tortoise vs. hare slow,NASA says that’s about the rate at which fingernails grow.
That slow movement means our days are slowly getting longer – one study found that the length of an average day has increased by about one millisecond every century since the late 1600s.
So how did NASA scientists even clock this slow-motion drift? It all started with the Apollo missions more than 50 years ago,when astronauts left reflective panels on the moon’s surface.
Since then,scientists have been shooting laser beams at the panels and recording the amount of time it takes for the light to come back to Earth. That’s how they were able to measure with such accuracy how fast the moon is retreating.
The slowly widening gap is caused by the gravitational tug-of-war between the two bodies. The moon’s gravitational pull causes our oceans to bulge toward it.
As NASA explains it,“Because Earth rotates on its axis faster than the Moon orbits it,the higher gravity from Earth’s bulge tries to speed up the Moon’s rotation. Meanwhile,the Moon is pulling on Earth and slowing the planet’s rotation. The friction that ensues from this tug-of-war forces the Moon into a wider orbit.”
That wider orbit is what creates the slowly growing distance between the moon and us each year.
So could we eventually lose the moon? The short answer is no.
NASA says that about 50 billion years from now,the moon would be so far away and its orbit so large that the Earth would tidally lock to the moon. The two bodies would stop moving away from each other. That means only half of our world (and whomever is left on it) would ever see the moon.
However,the sun would likely intervene long before that could happen. Scientists believe that in about 5 billion years, the sun will die,becoming a giant red star that obliterates both the moon and the Earth.
Here’s hoping that our future civilizations will be watching that happen from another planet we’ve learned to inhabit.
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