.........................................................................................
Interesting
Moon Facts
by John P. Millis, Ph.D
The
Moon is Earth's large natural satellite. It orbits our planet and has done
so since early in solar system history.
The
Moon is a rocky body that humans have visited and are continuing to explore
with remotely operated spacecraft.
It's also
the subject of much myth and lore.
Let's
learn more about our nearest neighbor in space.
Edited
and updated by Carolyn Collins Petersen.
The Moon Likely Formed
as a Result of a Collision Early in Solar System History.
There
have been many theories of how the Moon formed.
After
the Apollo moon landings and
the study of the rocks they returned, the most likely explanation of the Moon's
birth is that infant Earth collided with a Mars-sized planetesimal.
That
sprayed material out to space that eventually coalesced to form what we now
call our Moon.
Gravity
on the Moon is Much Less than on Earth.
A
person who weighs 180 pounds on Earth would weigh only 30 pounds on the Moon.
It is
for this reason that the astronauts could maneuver so easily on the lunar
surface, despite all the massive equipment (especially their space suites!)
that they toted along. By comparison everything was much lighter.
The
Moon Affects Tides on Earth.
The
gravitational force created by the Moon is significantly less than that of
Earth, but that doesn’t mean that it doesn’t have an affect.
As
the Earth rotates, the water bulge around the Earth is pulled along by the
orbiting Moon, creating a high and low tide each day.
We
Always See the Same Side of the Moon.
The
Most people are under the mistaken impression that the Moon doesn’t rotate at
all. It actually does rotate, but at the same rate it orbits our planet.
That
causes us to always see the same side of the Moon facing Earth. If it didn’t at
least rotate once, we would see every side of the Moon.
There
is No Permanent “Dark Side” of the Moon.
This
is really a confusion of terms. Many people describe the side of the Moon that
we never see as the dark
side.
It is
more appropriate to refer to that side of the Moon as the Far Side, since it is
always farther away from us than the side facing us.
But
the far side isn’t always dark. In fact it is lit up brilliantly when the Moon
is between us and the Sun.
The
Moon Experiences Extreme Temperature Shifts Every Couple Weeks.
Because
it has no atmosphere and rotates so slowly, any particular surface patch on the
Moon will experience wild temperature extremes, from a low of -272 degrees F
(-168 C) to highs approaching 243 degrees F (117.2 C).
As
the lunar terrain experiences changes in light and darkness about every two
weeks, there is no circulation of the heat as there is on Earth (thanks to wind
and other atmospheric effects).
So,
the Moon is at the complete mercy of whether the Sun is overhead or not.
The
Coldest Place Known in our Solar System is on the Moon.
When
discussing the coldest places in the solar system, one immediately thinks of
the farthest reaches of our Sun’s rays, like where Pluto inhabits.
According
to measurements taken by NASA space probes, the coldest place in our little
neck of the woods is on our very own Moon.
It
lies deep inside lunar
craters, in places that never experience
sunlight. The temperatures in these craters, which lie near the poles, approach
35 kelvin (about -238 C or -396 F).
The Moon has Water.
In
the last two decades NASA has crashed a series of probes into the lunar surface
to measure the amount of water in or beneath the rocks.
What
they found was surprising, there was much more H2O
present than anyone had previously thought.
In
addition, there's evidence of water ice at the poles, hidden in craters that
get no sunlight. In spite of these findings, the Moon’s surface is still dryer
than the driest desert on Earth.
The
Moon’s Surface Features Formed through Volcanism and Impacts.
The
Moon's surface has been changed by volcanic flows early in its history. As it
cooled, it was bombarded (and continues to be hit) by asteroids and meteoroids.
It also
turns out that the Moon (along with our own atmosphere) has played an important
role in protecting us from the same kinds of impacts that have scarred its
surface.
Dark
Spots on the Moon were Created as Lava Filled in Craters Left by Asteroids.
Early
in its formation, lava flowed on the Moon.
Asteroids and comets would come
crashing down and the craters they dug out penetrated down to molten rock
beneath the crust.
The
lava oozed up to the surface and fill in the craters, leaving behind an
even, smooth surface.
We
now see that cooled lava as relatively smooth spots on the moon, pockmarked
with smaller craters from later impacts.
BONUS: The Term Blue Moon Refers to a
Month that Sees Two Full Moons.
Poll a classroom of undergraduates and you’ll
get a variety of suggestions to what the term Blue Moon refers.
The simply fact of the matter is that it is
simply a reference to when the Moon appears full twice in the same month.
John P. Millis, Ph.D
Chairman, Department
of Physical Sciences and Engineering at Anderson University
Ph.D.
in Physics and Astronomy at Purdue University
Conducts
astronomical research at the VERITAS observatory
Experience
John
Millis is a former writer for ThoughtCo. He has taught physics and astronomy at
the collegiate level since 2001 and is currently the chair of the Department of
Physical Sciences and Engineering at Anderson University, in Anderson Indiana.
He teaches a wide variety of courses while maintaining an active research
program in high energy astrophysics.
John's
research focus is on pulsars, pulsar wind nebulae, and supernova remnants.
Using the VERITAS gamma-ray observatory in southern Arizona, he studies the
very high energy radiation from these dynamic sources to extract information
about their formation and emission mechanisms. In 2010, he co-founded a small
consulting business, Aurum Consulting, LLC, assisting with biological testing,
chemical formulations, and product development. John Millis wrote on Space and
Astronomy topics for the Dotdash/About.com networks for three years.
Education
Dr.
Millis received his bachelor of science in physics, with a mathematics minor
from Purdue University in West Lafayette, Indiana. He remained at Purdue for
the completion of his Doctor of Philosophy degree, where he focused on High
Energy Astrophysics.
John P.
Millis, Ph.D
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