three lines of evidence for the big bang: 1) doppler shift of stars 2) background microwave...
TRANSCRIPT
Three lines of evidence for the Big Bang:
1) Doppler shift of stars
2) Background microwave radiation
3) Composition of the universe
Nucleosynthesis:
1) Stellar nucleosynthesis – makes elements up to iron during last stages of a star
2) Explosive nucleosynthesis – makes elements larger than iron (from free neutrons) during supernova for large stars
Nucleosynthesis:
H + H He
He + He Be
Be + He C
Be + Be O
Be + O Mg
O + C Si
(etc.)
Red Giant Betelgeuse
Hourglass Nebula - collapsed white dwarf - gas ejected after red giant phase
Death of a star:
Helix Nebula - collision of two gas ejections from a dying star
Eagle Nebula: - Star birth clouds. UV radiation from nearby hot stars is eroding and condensing clouds of cool hydrogen gas that is an incubator for new stars
Helix Nebula – cometary knots
Why are compositions of the planets different?
1) Different temperatures in the protoplanetary disk with distance from the sun
2) No solid ices closer than Jupiter
Why are compositions of the planets different?
Sources for heat of early Earth
1. Impacts of planetesimals
2. Gravitational collapse
3. Compression
4. Radioactive decay of short-lived isotopes
5. Collapse of iron core
6. Impact of proto-moon
Sun is 99.85% of mass of the Solar System
STRUCTURE OF MERCURY
VENUS
MARS
Mars Exploration Rover
3 cm width
Mars Rovers: Mars Rovers: SpiritSpirit and and OpportunityOpportunity
Cross Bedding Indicates Surface Water
Last Chance
MI
Crossbeds
Mars Once Had Flowing Water
Evidence of Weathering
Broken Towers
ASTEROIDS
JUPITER
Io (a moon of Jupiter)
Europa (a moon of Jupiter)
Saturn
Saturn as seen from Titan?
Titan (a moon of Saturn)
A 360-deg panoramic view of the terrain around Huygens' landing site. The white streaks might be a ground 'fog' of methane or ethane vapor.
The temperature of the landing site itself was minus 291 degrees F. The soil has the consistency of wet sand or clay and is covered by a thin crust ... of something.
From an altitude of 16 km, Huygens photographed these drainage channels leading to a shoreline.
URANUS
NEPTUNE
Neptune's moon Triton. The surface is so cold (minus -391F) that it is mainly nitrogen ice.
PLUTO
Kuiper Belt
