History Channel
Season. 3 Episode. 9
GLIEASE 581 D (Super Earth)
Libra Constellation
http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
EXCERPTS:
ANOTHER EARTH
(Super Earth, Super Venus, Super Jupiter)
"Astronomers have found over 300 exoplanets
that is, planets outside our solar system.
The vast majority is gas giants.
which are easier to find than
small terrestrial planets like our Earth.
Goldilocks Zone, Habitable Zone, Just Right
"Water is an amazing substance.
We are frankly fortunate that
the universe has something called water.
It's the great cosmic cocktail mixer.
How many stars are there?
How many of those stars have planets?
How many of those planets are close anough to have water...
and on and on.
Thats a problem that astronomers Carl Sagan
and Frank Drake took on decades ago.
Drake came up with equation that estimated that
upto a million civilizations may exist
in just our Milky Way alone.
N=N* x fp x ne x fe x fi x fc x L/Tg
BOOK:
RARE EARTH
by Peter D. Ward & Donald Brownlee
explains why they think complex life, animal life, like humans
may be rare in the universe.
PLATE TECTONICS
"Plate tectonics is continental drift
and one wonders why whould that have anything to do
with the frequency of life on the planet.
Plate tectonics also produces a recycling of elements
and that recycling does some very fundamental things.
The most fundamental thing it does,
it produces a temperature gauge.
It's like a thermostat on the planet.
If we get too warm, plate tectonic processes help us cool off.
Then there's the presence of metal on the planet.
Secondly, if you want to be an intelligent civilization
you better have metal.
Metal is hard to find on a planet like Mars or Venus.
Plate tectonics rotates everything, causes cracks.
Up come the heavy metals.
then we need a Good Jupiter.
(to protect us from asteroids/comets.)
First Position in the galaxy.
away from killer neturon stars, black holes, and deadly gamma-ray bursts.
Earth itself may have narrowly missed such an even in 1998.
(extinguishing life)
Then a high density star called a magnetar
burped out a flare of deadly gamma rays,
unleashing as much energy in two-tenths of a second.
as the Sun will put out in the next 100,000 years.
Luckily, the magnetar was located 20,000 light-years away from Earth.
(if magnetar were 10,000 light years away, then)
It could punch our atmosphere off-whoof-in one burst...
and you go, "I can't breathe."
Thats catastrophic, and that is totally possible.
The Drake Equation was a fantastic construct
but it was done in the 1960s
We know so much more now.
So we've added in stuff that wasn't known then.
And i think it makes it more accurate
But, ultimately, it also brings down the numbers.
Advanced Civilizations in our Milky Way
"More than one but way less than a million."
[another scientist say in another program, 10,000 in one galaxy]
How to See an exoPlanet.
"Suppose you have a firefly,
a very small firefly, a very weak light.
and suppose that firefly is orbiting around
a light house.
and suppose you're trying to look at this firefly
flying around this lighthouse from 3000 miles away.
TRANSIT METHOD
When a planet move in front of star, the star would get dimmer
and you would notice that.
It's called the transit method of discovering a planet.
...
The amount of light it blocks
tells how big the planet is.
RADIO VELOCITY METHOD
The tranist method works if the observer of the telescope
is in the same plane as the star and its planets.
But if you're above or below the system
another technique, called the radio velocity method
might be used.
That method depends on careful observations of a distant star
to watch if it's being gravitationally tugged.
back and forth by an unseen exoplanets.
[If Star has iron so its planets have iron]
Astronomers have found a relationship between the composition of a star
and the probability that it may have planets.
The stars that have heavier elements in them
the iron and the nickel and the silicon
have heavier elements for a good reason.
...
And in so doing left some placental material around them
that eventually coagulated into the planets.
RIGHT SIZE
"Astronomers calculated that the smallest a palnet can be is
one-third of Earth's mass
On the high side, a habitable palnet
cannot be greater than 10 times our Earth's mass."
LAST DECADE.
"A little over 10 years ago
we had no known extrasolar planets at all.
The only planets we knew of were those orbiting our Sun.
FIRST EXOPLANET
"In the Pegasus constellation, some 50 light years form Earth
the planet 51 Pegasi B can be found.
It was the first planet discovered outside our solar system,
a gas giant as big as Jupiter.
4 days orbit around its Sun.
The planet 70 Virgins B is even farther away than Pegasi
60 ligty years
It's 7.5 times as massive as our Jupiter.
Trace 4,
is over 1.5 time the diameter of our Jupiter
making it the largest planet found so far.
Its' 1400 light years from Earth.
3.5 days orbit its sun.
Astronomers haven't been able to find
true Earth-like planets outside our solar system
... relatively small such rocky planet.
GLIEE 581 C
20.5 light years from Earth
in the Libra constellation.
5 times mass of our Earth.
Super Venus
600 degrees
GLIEASE 581 D
SUUPER EARTH
HD 69830 D
"This is a big planet,
17 times the size of our Earth.
42 light years away.
in the constellation Puppis.
"HD 69830 D is a potential planet where life could form
because it has aprox. the right temp.
Venus, Earth, and Mars
Venus is in the wrong place.
Mars is the wrong size.
Earth is the right place and the right size.
"There's a number of reasons why Alpha Centauri
is the best star in the sky for hunting for Earths.
Alpha Centaury has higher metallicity than our own Sun does.
The first exoplanet-finding mission will be Kepler
which launches in 2009.
Planets are 10 billion times dimmer than its star.
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