Season 6
History Channel
http://www.history.com/shows/the-universe
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Excerpts:
1- CATASTROPHES THAT CHANGED THE PLANETS
S06E01
10. MERCURY MENTAL DISASTER
... there are some estimates
that upto 16 million billion tons of material
from Mercury landed on Earth.
NASA's Messenger spacecraft is currently orbiting Mercury.
9. SATURN'S SHATTERED MOON
8. THE ORBITAL MAELSTROM
500 million years after the planets formed,
Jupiter elbowed inwards toward the Sun,
While Saturn, Uranus and Neptune drifted outwards.
Jupiter eventually orbited around the Sun
exactly twice for every one time that Saturn did.
This pivotal moment is known as "the two-to-one resonance."
Two to One Resonance is very strong gravitation interaction,
when taken over millions of years,
and having Jupiter and Saturn in a two to one resonance
leads to profound consequences throughout the Solar System.
It shakes the orbits of the other objects up.
It leads to crossing orbits, and it can led to giant impacts.
Neptune and Uranus may have switched orbits,
not once, but several times.
7. THE LATE HEAVY BOMBARDMENT
6. THE MARS MEGA-METEORITE IMPACT
5. THE MARS MAGNETIC DISASTERS
By the time the late heavy bombardment
slowly came to an end
3.8 billion years ago,
every planet in the Solar System
had received some kind of makeover.
4. THE MARS SUPER ERUPTIONS
On Earth, there's plate tectonics.
So, for example, the volcanic islands of Hawaii
are in a chain.
Because the plate is moving north,
the hot spot is relatively fixed,
and new islands keep on poppin up.
But on Mars, its' the same island all the time,
and it just keeps getting bigger and bigger.
3. THE GREAT VENUS MELTDOWN
Our closest planetary neighbor, Venus,
may have begun quite Earth-like.
It was born at roughly the same time
and made with the same cosmic materials,
but something transformed Venus into Earht's evil twin.
But on Earth, primitive life formed
shortly after the end of the late heavy bombardment.
2. THE SHOEMAKER LEVY 9 IMPACTS
Shoemaker Levy 9, July 1994
Another comet hit Jupter July 2009
If Jupiter was not in our Solar System,
the Earth would be essentially a sitting duck
for all the debris, the comets and the asterouds
that were fallin in towards the Sun.
1. PLANETARY ARMAGEDDON
If Mercury's orbit ever gets to the situation
where it's crossing Venus' orbit,
then basically all hell can break loose.
Scientists have calculated
onf of four disastrous consequences.
Mercury might collide with the Sun.
Might be ejected from the Solar System.
Might smash into Venus.
Or in a worst case scenarion,
Mercury might collide with the Earth.
As faf as we can tell from computer simulations,
there's about a 1% chance
that Mercury's orbit will go haywire.
And withing that 1% chance there's a small probability
that things will unfold.
Mars also faces orbital chaos in the future.
And it, too may slam into the Earth.
And if, as most expect,
the Andromeda galaxy ultimately collides with the Milky Way.
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2- NEMESIS: THE SUN'S EVIL TWIN
S06E02
"Some scientists suspect that Nemesis is a dark,
still-undiscovered star orbiting our Sun.
And every 26 million years, it triggers a disaster.
The Nemesis theory postulates that there's a star orbiting the Sun
at a 26-million-year period.
-RICHARD MULLER
But in fact, the majority of stars come in pairs.
Probably something like 60, 70% of stars may indeed be
binary, or have even higher nubers of stars in the system.
Nemesis is an extemely dim red dwarf.
Since the birth of the Nemesis hypothesis,
astronomers have been on the lookouit for a
faint red star that periodically disturbs the gravitation of the
Oort Cloud comets.
This sends them on a catastrophic rendezvous with the inner Solar System,
including Earth, every 26 million years.
But as scientists study the Oort Cloud, they have uncovered
unsettling evidence that something disturbing comet orbits right now.
When we look out into the sky, and look at where the comets are coming from,
their directiong tend to concentrate in a certain region of the sky.
And one possible explanation for that is that that skew is being
directed by the gravitational perturbations from an unseen object that is out there.
IN ASTRONOMY, WE FREQUENTLY INFER THE EXISTENCE OF SOMETHING,
NOT BECAUSE WE CAN ACTUALLY SEE IT, BUT BECAUSE
WE CAN SEE THE INFLUENCE IT HAS ON OTHE OBJECTS AROUND IT.
-LAURA DANLY
... scientists have proposed a remarkable theory to explain the congestion in the Oort Cloud.
According to this theory, the culprit disturbing the Oort Cloud isn't Nemesis.
Instead, it's someting equally astounding-- a giant, undiscovered planet,
four times the mass of Jupiter.
In short, the largest planet in the Solar System.
Scientists have proposed naming it TYCHE.
(1 millon orbit)
In 2003, astronomer Mike Brown made an historic discovery when
he found something floating around the night sky ghe could'nt explain.
...
What he stumble upon turned out to be a planetoid just smaller than our moon,
now named SEDNA.
But Sedna presents a scientific quandary.
At it nearest point, Sedna lies about three times farther away from the Sun than Pluto,
in a region whwere astronomers never expected to find planetary bodies.
It's important to realise thise is not just an abstract discussion.
Clearly these objects colliding with Earth happen very rarely.
But on the other hand, when they do collide, they're extremely cataclysmic.
So what we need to be able to do is get better understanding of
our Solar System, and keep an eye on the sky, because it may be crucial for oure survival.
-CLIFFORD JOHNSON
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3- HOW THE SOLARY SYSTEM WAS MADE
S06E03
The first stages of our Solar System's creation
are hardly unique.
Today we witness the same thing happening in the Orion constellation.
As gravity draws in the cloud's gas,
the cloud not only spins faster, it invevitably flatens into a disc.
When you look at the Solar System today, the sun is 99.85% of the total mass.
Asteroid, and Kuiper Belts
... Now, they were never able to coalasce to form a planet
because there's just not enough of them close enough together.
50 million years after the Solar System was born
both the Kuiper and the Asteroid belts have 100 times more objects in then than they do today.
The innter planets take as much as 10 times longer
to form than the giant planets outside the snow-line.
THEIA, protoplanet, Earth's sister.
collide, moon formed
At 500 milion years old, all the Solary System's planets have been formed.
When a planet ejects a planetesimal, the planet itself
has to move in a little bit,
and that's simple conservation of energy.
It's giving a lot of energy to the planetesimal,
dumping it way out there.
That means it, the planet, has to move in.
It losses energy.
If an orbiting object loses energy, it's not moving as quickly.
That means it drops to a lower orbit.
METEORITE NWA2364
In early 2011, cosmochemists in a similar lab at Arizona State University
dated part of a north African meteorite to an incredibly accurate 4.5682
billion years old,
the oldest material ever found on earth, older than the planet itself.
DAWN will orbit Vesta (2nd largest asteroid in SS) for a year before going
on to spend another year orbiting the larged asteroid, Ceres.
Our Solar System, however, has its planets in near-circular orbits,
spread out in a stable arrangement that seems almost too ferfect.
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4- THE MOON
S06E04
Neptune claims 13 of them.
Saturn has 48.
Jupiter hosts an astounding 62.
The mean distance from Earth to the Moon is 234,000 miles.
3 day flight.
Diameter roughly 1 quarter to the size of earth, (2160 miles)
Single day on the moon equivalant to 27.3 Earth days
This is because one side of the moon permanently faces us.
Luna is phase-locked with our planet.
And so the Moon has played an imprtant role in the stability
of our axis of rotation, of our planet and therefore in our climate.
In 1873 Frec scientist, Edouard Roche
proposed that the Moon simply formed alongside the Earth
out of essentially the same nebular cloud of particles and gasses.
But this idea had a fundamenta weakness.
The Moon has a much lower iron content that the Earth.
It's much less dense.
In 1878,George Darwin announced his fission theory of lunar origin.
The logical conclusion for Darwin
was that a protion of the molten rapidly spinning Earth
must have separated from the main mass and spun off to become our Moon.
In 1909, Thomas Jefferson Jackson See
"THE CAPTURE THEORY"
Essentially See theorized that the Moon had actually formed
in a different part of the solar system from 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.
If the Moon formed elsewhere its composition could be very different.
On the other hand the notion that Earth's gravity could capture and retain
such a large object was unlikely,
since there is no obvious resisting medium
to slow down an object as big as the Moon.
All three theories had significant weaknesses.
The origin of the Moon remained a mystery.
THE GIANT IMPACT THEORY.
[Bill Harmann, 1974]
The basic idea is that about 4.5 billion years ago
Earth collided with an object roughly the size of the current planet Mars.
Its very large collision. And it s started the Earth spinning.
It's what gave us our current 24 hours day we believe.
And this collision was so massive
that it launched material into orbit around the Earth.
And it's from that material that we believe the Moon later coalesced.
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5- CRASH LANDING ON MARS
S06E05
But, in fact, Mars' atmosphere
is 95% Carbon Dioxide and as thin
as Earth's atmosphere at 100,000 feet.
Earth and Mars is between 35 million and 240 million miles.
So the time lag between "how are you?" and "I'm fine."can be
between about 6 and 44 minutes.
That's for a complete exchange.
So if there's an emergency,
it can't be dealt with in real time.
But Mars lost its magnetic field 4 billion years ago.
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6- The Seven
WORST DAYS ON PLANET EARTH
S06E06
7. THE THEIA IMPACT
4.5 billion years ago.
Mars-like planet collided with Earth...
Moon formed.
6. THE LATE HEAVY BOMBARDMENT
150 million years after Thiea Imapact.
[4.1 to 3.8 billion years ago.]
precius metals: silver, gold and platinium
5. SNOWBALL EARTH
1st: 2.4 billion years ago.
2nd: 600 million years ago.
Enormous Flowering...
4. THE ORDOVICIAN EXTIINCTION
"In the billions of years of life on Earth
99% of all species that ever lived
have ultimately vanished.
Mostly due to the five mass extinction events.
"The first was during the Ordovician period
450 million years ago.
Shockwave Bow
"Our Solar Sytem isloates the Milky Way
travelling above and below the main disk of galaxy.
every 64 million years.
Once outside the galaxy's protective magnetic field
our planet is vulnarabel to deadly cosmic rays,
generated by the galactic bow shot.
3. THE KT EXTINCTION
65 million years ago.
Shiva Crater
fortune day for mammels
2. THE GREAY DYING
250 million years ago.
Siberia, volcano
1. THE SOLAR APOCALYPSE
5 billion years Sun will go.
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S06E07:
GOD AND THE UNIVERSE
click here
http://miscethoughts.blogspot.com/2011/12/universe-god-and-universe.html
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