History Channel
Season. 5 Episode.7
http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
EXCERPTS:
TOTAL ECLIPSE
"Total eclipse of the Sun
can be seen somewhere on Earth
an average of once every 16 months.
PENUMBRA
UMBRA
Only planets without eclipses
are Mercury and Venus
because they have no moons.
Eclipse on here on Earth are no other.
Cosmic Proportions
The Sun is about 400 times bigger than moon
But the sun also happens to be about 400 times farther away
from the Earth than the moon.
What that means is that
both the Sun and the Moon appear to be
almost exactly the same size in the sky.
Their sizes in the sky is crucial for eclipses.
EINSTEIN G. RELATIVITY
CURVE IN SPACE
"In 1915, Einstein published his predictions
that gravity causes space to curve,
and the light from stars would bend following that curve.
So if there were a star close to the Sun in the sky,
Its light would be bent by the Sun's gravity (curve).
The only way to test Einstein's prediction
was during an eclipse,
when the sun was darkened.
and the nearby stars were visible.
Eddington knew the accurate position of a star
that should have been blocked by the Sun
But if the Sun's gravity bent the star's light,
as Einstein said,
It would be seen in a different position altogether.
SOLAR CORONA
Without the occurance of total solar eclipses
It's really questionable today whether we actually even know
that the Sun had a corona -
an outer, hot, tenous atmosphere.
CHRONOGRAPHS
for Artificial Eclipses
KEPLER spacecraft
"In the beginning
In January 2010
the Kepler team announced
the discovery of the mission's
first five planets.
Four are gas giants like Jupiter, (Kepler 5b, Kepler 6b, Kepler 7b, Kepler 8b,)
the fifth the size of Neptune, (Kepler 4b)
Kepler saw their transit many times in first week,
it means they orbit their stars in a matter of days,
eclipsing their stars each time.
It means they are 10 times closer than the Mercury to our Sun.
Kepler is going to determine (in next 6 years)
if Earth-like planets
are common or rare,
and the answer either way
is going to be very interesting.
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