Scientists have found that the Moon is very slowly, but definitely,
drifting further away from Earth—a move that we mere humans can only dream
of making.
Ancient human societies have used the Moon as a clock for a very long time,
and we now understand that the Moon and Earth are gravitationally bound to
one another.
According to NASA, however, experts have now discovered that the Moon is
moving away from Earth at a rate of 3.8cm per year.
Reflective screens from the Apollo missions, which were placed on the Moon
in 1969 and allowed space agencies to calculate the distance between them
and the Earth, helped experts make the finding.
The new discovery may be intriguing, but it's also a "poor guide
for the past," according to Professor Joshua Davies at the Université du
Québec à Montréal, research associate Margriet Lantink from the University
of Wisconsin-Madison, as well as their colleagues from Utrecht University
and the University of Geneva.
This is due to the fact that the Moon, which is four and a half billion
years old, would have collided with Earth approximately 1.5 billion years
ago if it had been drifting at that pace throughout its entire life. Of
course that didn't happen because we're still here.
The "Milankovitch cycles" are thought to be the cause of the movement,
according to specialists. The cycles explain how minute variations in the
center and orbital shapes of the Earth have an effect on how much sunshine
we receive.
This in turn affects the type of environment we have and can determine when
it will rain or not. The Sahara desert once experienced a time of greening
due to Milankovitch cycles, and their effects have been observed to have an
effect on the size of lakes on Earth.
The Earth-Moon distance is also determined by Milankovitch cycles and their
rates. According to research, there would have been 17 hours of sunshine
each day 2.46 billion years ago when the Moon was 60,000 km closer to Earth
than it is today.
