“Come, behold the works of the LORD” (Psalm 46:8)
On September 11, 2013, an approximately 1 meter meteor hit
the Moon at close to 40,000 mph, creating a crater 50 meters wide. The glow from its impact explosion lasted 8
seconds and was the brightest flash of light ever recorded on the Moon. Humans looking in that direction could have
seen it with the naked eye. The event
was caught on camera, and can be seen at http://www.slate.com/blogs/ bad_ astronomy/ 2014/02/24/lunar_impact_video_of_an_asteroid_hitting_the_Moon.html.
The Earth is much larger than the Moon, and so its
gravitational pull is much stronger. For
that reason we get hit by several meter-sized meteors several times a year even
while no one ever notices a thing. The
major explosion over Chelyabinsk, Russia the same year, from which a thousand
people were injured, was, by contrast, caused by a meteor estimated to be 19
meters across (and therefore nearly 20 times the diameter of the “Moon-bomb”). So to the question why the Moon got hit on
September 11 (ironically), the short answer is as simple as the answer to why a
chicken might not in the end succeed in crossing the road. That meteor hit the Moon because the Moon was
right in the way of its journey to the other side of the solar system!
The longer answer to the question, however, is much more
interesting. To get there, I want to
share a recent discovery of mine as the result of a reading assignment for the
class, “Historical Perspectives in Science and Religion,” for my Science and Religion MA degree program. It was my delight to read Galileo’s account
of the first time he ever looked at the Moon through a telescope (which, of
course, was the very first time ever
that anyone in history had seen the Moon
magnified at all!). Portions of his 1610 pamphlet, “The Starry
Messenger,” can be read in the article, “Neither Known Nor Observed by Anyone
Before,” from Dennis Danielson, ed., The Book of the Cosmos, (Perseus,
2000), p.145f. The magnitude (no pun
intended) of his discoveries are better understood by first clarifying the
hindering role that Aristotle’s (384-322 BC) cosmology played in the apprehension of the heavens many centuries later
in Galileo’s time (1564-1642 AD).
Aristotle believed, and the Western world for 2,000 years largely accepted,
that the heavenly bodies above, including the Moon, belong to a realm
altogether separate from the natural laws and conditions on Earth. These bodies were characterized as
unchanging, perfectly smooth, and perfectly round spheres (corresponding to the
Greek notion of ideal shapes and forms).
Galileo, by contrast, wrote after his lunar observations, “[I
do not] perceive the surface of the Moon
to be perfectly smooth, free from inequalities and exactly spherical (as a
large school of philosophers believes concerning the Moon and other heavenly
bodies), but to the contrary to be full of inequalities, uneven, full of
hollows and protuberances. It is like
the surface of the Earth itself, which is everywhere varied with lofty
mountains and deep valleys…The grandeur, however, of such prominences and depress-ions
in the Moon seems to surpass both in
magnitude and extent the ruggedness of the Earth’s surface” (p.147,8, boldface mine).
to be continued...
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