Transcript
Atmosphere …
Gives us the air we breathe
Protects us from meteorites and harmful cosmic radiation
Blanket covering the Earth from heat at day and cold at night
Bye-bye, Earth!
4.6 billion years ago:Heavy Bombardment
Barringer crater, Arizona49,000 yr oldIron meteorite of size 50 m, mass 300,000 tonImpact velocity 11 km/sec
Our Earth is a target, too!
150 known impact sites on Earth
Diameters from 50-70 m to 200 km
65 million years ago a huge meteorite of 10 km size hit the Earth
• World-wide fires• 1-km-hign tsunamis• Acid rains and atmospheric pollution• Darkness and severe winter for many decades
¾ of all living species have been killed
Our Moon could have been formed in a giant collision4.5 billion years ago
The Peekskill meteorite
October 9, 199212 kg stony meteorite hit the Earth
Venus the Beautiful
The goddess of beauty
Fig. 17-3a, p.349Greenhouse for trapping heat
Runaway greenhouse effect
Atmosphere lets the visible sunlight in, but traps infrared radiation and prevents rapid cooling of the surface at nights
"It will be possible to see cities on Mars, to detect navies in [its] harbors, and the smoke of great manufacturing cities and towns... Is Mars inhabited? There can be little doubt of it ... conditions are all favorable for life, and life, too, of a high order. Is it possible to know this of a certainty? Certainly."
Samuel Leland 1895
Seasons on Mars?Channels for irrigation ???
Sorry, no channels – just dry canyons, lava flows and dusty deserts …
Dry riverbeds, traces of flooding
No water, just dry desert …
Salty rocks on Mars: former sea bottom
8 billion miles through space!
Jupiter – the biggest planet
The Red Spot
Io Europa Ganymede Callisto
Total 61 moons discovered so farMost are captured small asteroids
Galilean moons:
Europa – a giant skating rink
Io – giant volcanoes
Saturn – second largest planetSo fluffy – it could float in water
Enormous winds: 1800 km/hr !!
The Great White Spot: huge storm
Thickness: less than 1 km
Extend from 74,000 to137,000 km
Discovered by Huygens in 1659
Saturn rings
Flying through the rings
Titan, the mysterious moon of Saturn
Uranus
What happened to Miranda?
Neptune
Triton
Pluto and Charon
The Kuiper Belt – home for short-period comets??
Starting in 1992, astronomers have become aware of a vast population of small bodies orbiting the sun beyond Neptune. There are at least 70,000 "trans-Neptunians" with diameters larger than 100 km in the radial zone extending outwards from the orbit of Neptune (at 30 AU) to 50 AU.
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