History Channel
Season. 1 Episode. 5
http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
http://www.youtube.com/watch?v=x-EZ5iJgw20
EXCERPTS:
"At last count, over 150 moons populate our solar system.
Neptune 13
Saturn 48
Jupiter 62
Earth on the other hand have just one,
but it is a special one.
Our moon, Luna, as the Romans named it, is remarkable in its size.
It is by no means the larges moon in the solar system.
Several others are bigger.
One of Saturn's moons, Titan for instance, is twice the size.
But our moon is the largest in relation to its host planet."
It's a quarter the size of the Earth.
"The relative sizes of the two bodies are close enough
that some astronomers goes so far as to refer to the "Earth-Moon system"
as a Double Planet."
"
DISTANCE FROM EARTH: 234,000 MILES
TRAVEL TIME: 3 DAYS
DIAMETER: 2160 MILES (ROUGHLY ONE QUARTER. EARTH 8000 MILES)
SINGLE DAY: 27.3 EARTH DAYS
ONE SIDE PERMANENTLY FACES EARTH.
"
"Today, we call these dark regions Maria, the latin word for seas."
"Moon has absolutely no atmosphere at all"
(two persons cannot talk, as no medium to carry sound waves)
Temp:
"From 270 degrees above zero at midday,
to 240 degrees below zero at night."
"On the moon, there are no continental plate tectonics,
The surface is static."
"The Moon stabilizes Earth's climate.
The gravitational effect of the Moon
keeps the degrees of tilt in the Earth's rotational axis constant.
This tilt is what maintains the repeatable cycle of season,
as the Earth orbits the Sun."
"if we didn't have the Moon, or if we had a much smaller Moon, for example,
then you can mathematically show,
that the tilt of our north pole would vary widely,
with the angle going, from, say 0 to 90 degrees, currently it's 23.5 degrees,
and it would actually vary chaotically.
And so the Moon has played an important role in the stability
of our axis of rotation, of our planet and therefore in our climate."
Galileo Galilie, 1609 looked moon first time through telescope and detailed drawing.
"1873 first science based theory regarding the origin of the Moon publicly emerge.
French astronomer named Edouard Roche.
Roche advocated for what's called the co-accretion theory,
Earth and Moon grew up at the same time, out of the same materials.
But this idea had a fundamental weakness.
The Moon has a much lower iron content that the Earth.
It's much less dense."
"... and through extensive analysis of the tide-moon relationship
George Darwin (son of Charles Darwin) came to the realization
that the Moon is gradually moving farther and farther away from the Earth."
Mirror on the Moon
It wasn't proved until 95 years later.
when astronauts landed on the moon,
they put little mirrors on the moon.
And you can shine a laser at the moon
and the laser will bounce off the mirror, come back
and you can actually measure the exact distance between the Earth and the Moon.
And the rate at which this distance is increasing is 3.8 cm/year.
3.8 cm is about an inch and a half.
Darwin began to consider what would happen if you reversed the process,
As we move backwards in time, and the Moon moves closer,
both the Moon's orbit and the rotation of the Earth
get faster and faster.
And so what happens is that eventually the Moon must coalesce with the Earth,
it must hit the Earth.
CAPTURE THEORY
1909 Thomas Jefferson Jackson See
"Essentially See theorized that the Moon had actually formed
in a different part of the solar system form the Earth,
that it orbited the Sun just like the other planets.
But that at some point it had moved too close to Earth
and was captured by Earth's gravity."
[there is no resisting medium to slow down such a big moon like object]
"All three theories had significant weaknesses."
"The origin of the moon remained mystery."
Departed 16th July, Step 20th July 1969.
"They had landed their lunar module on the hardened lava plain
known as the Sea of Tranquility."
THE GIANT IMPACT THEORY, 1974, Bill Hartman
"The basic idea is that about 4.5 billion years ago
Earth collided with an object roughly the size of the current planet Mars.
It's a very large cllision.
And it started the Earth sinning.
It's what gave us our current 24 hour day we believe.
And this collision was so massive
that it lanunced material into orbit around the Earth.
And it's from that material that we believe the Moon later coalesced.
...
There is no sign of this impact on the Earth today
because at the time, our planet had only developed
to about 90% of its current size.
The remaining 10% would acuumulate from later much smaller impacts.
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