Transcript astronomy_SaturndayMPhysics09

Astronomy in the new Millenium
Volker Crede
Grigory Rogachev
Formation of the Solar System
Nebular contraction:
Cloud of gas and dust contracts due to gravity;
conservation of angular momentum means it spins faster and
faster as it contracts
Conservation of angular momentum
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Angular momentum – the tendency of a body to keep
spinning.
Formation of the Solar System
Condensation theory:
Interstellar dust grains
help cool cloud, and act as
condensation nuclei
Lets name them (in correct order).
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Mercury. (0.38 AU from the Sun)
Venus. (0.72 AU)
Earth. (1.0 AU ≈ 100,000,000 miles)
Mars. (1.52 AU)
Jupiter. (5.2 AU)
Saturn. (9.52 AU)
Uranus. (20 AU)
Neptune (30 AU)
Planets
Venus
Venus’s surface
“Cool” Venus features. (HOT actually)
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Venus is the hottest planet in the Solar system!
(900 oF – twice as hot as your oven can do).
Venus’s atmosphere is 90 time thicker then
Earth’s atmosphere!
HOT, Crashing and Orange/Red…
And, eh, it is also very sloooooooooow. One
Venus’s day = 243 Earth’s days and it rotates
the wrong way!
Any pictures?
A photograph of the surface, from the Venera
lander, which did not survive for long though…
Mars
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We learned SO much
about Mars during the last
decade!
Mars rovers, Spirit and
Opportunity, and Mars
orbiter Odyssey are
diamonds in our scientific
portfolio.
Mars
Mars
Mars’s “cool” facts. (wet actually)
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A long, long time ago…
In a galaxy far, far away…
Mars’s “cool” facts. (wet actually)
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1 or 2 billion years ago Mars was covered
with liquid WATER!
“Cool” facts. (cont.)
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Mars is home of the
largest mountain in the
Solar system –
Olympus mons. 25 km
high!
Mars has the largest
and the deepest
canyon in the Solar
system – Valles
Marineris. It is as big as
the entire USA and
7 km deep.
Gas Giants
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Gas Giants are …
Well, gas giant.
They consist almost exclusively of gas,
hydrogen and helium.
Lots of gas! 
Jupiter
“Cool” fact about Jupiter
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Jupiter is the Largest
and the most massive
planet in the Solar
system.
If it would be just 80 time
heavier it would become
a star!
Jupiter has storm which
is at least 300 years old!
(Great Red Spot).
It looks like a zebra. 
Jupiter moons
Saturn
Origin of Saturn rings
Saturn rings
Uranus
Neptune
What else is out there?
Asteroids
Asteroids
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Impact of a large asteroid can be VERY unpleasant.
Giant impact
65 millions years ago
asteroid impact caused
the Cretaceous extinction
Meteoroid
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Small rocky object
in space.
If burn in the
atmosphere –
meteor.
If survived the
atmosphere and
hits the ground –
meteorite.
Grand design
The Sun
The Heart of the Sun
Nuclear fusion requires that
like-charged nuclei get
close enough to each other
to fuse.
This can happen only if the
temperature is extremely
high – over 10 million K.
The Sun
The Sun
The Sun