Embed Size (px)
Citation preview
Chapter 4: The Solar System
Comets
Comets are described as “dirty” snowballs
They are fragile conglomeration of frozen ices and dust
When they get close to the sun the ices begin to melt and jets of gasses escape from the nucleus caring dust with it.
Comets shine by reflected solar light
Finally comets are divided into two large classes of short-term and long term
Chapter 4: The Solar System
While the nucleus of a comet may be only a few km in sizeThe coma can be over 100,000 km in sizeand the tail can be up to 1 AU in size
Chapter 4: The Solar System
Comets usually form two different tails: gas and dust
The gas tail points directly away from the Sun while the dust tail tends to follow along the orbit
Chapter 4: The Solar System
Halley’s comet was the first comet discovered to be periodic.
Chapter 4: The Solar System
While the Kuiper belt may be the source of short period comets, while the Oort cloud appears to be the source of long-period comets.
Chapter 4: The Solar System
MeteoroidsThere are two basic types of meteoroids: random, shower
The random kind which can be observed on any clear night(few per hour) are probably left over interplanetary debris.
Chapter 4: The Solar System
Comets leave a dusty trail behind them and if their orbits intercept the Earth’s then me get meteor showers (dozens per hour) when the Earth slams into them.
Meteors enter the Earth’s atmosphere at such high speeds that friction heats them to white-hot temperatures and they burn up.
Most meteors are the size of gravel and burn up in the atmosphere. It takes a first sized object to reach the ground.
Chapter 4: The Solar System
Chapter 4: The Solar System
Some do hit the ground
Chapter 4: The Solar System
Two basic types of meteorites a) stony, b) iron
Chapter 4: The Solar System
The formation process
The solar nebular began to contract.
Due to conservation of angular momentum the cloud begins to flatten.
The central condensation condenses faster than the rest and eventually reaches densities and temperatures high enough to form a star.
Chapter 4: The Solar System
We can see disks of material around other stars.
Chapter 4: The Solar System
As the nebula continues to contract smaller clumps begin to grow by accumulation and accretion to form the planets.
Chapter 4: The Solar System
Because the planets form at different distances from the sun (and thus different temperatures) the planets are made out of different materials. The hot temperatures of the inner solar system prevented planets from collecting lighter gasses. So the inner planets are made of denser materials (iron and rock) while the outer planets retained mostly hydrogen and helium gases and ices.
Chapter 4: The Solar System
Finally, when the star is “born” it develops a “wind” that blows away most of the remaining dust to give us a “clean” solar system.
