Origin of the Solar System Flashcards
What is the SOLAR NEBULAR HYPOTHESIS?
- Our solar system came from a rotating cloud of gas
- It contracted, and flattened into a thin disk of gas and dust
- Disk clears, a sun and orbiting planets emerge
What implies ongoing planet formation?
dust disks around T Tauri stars
What are T TAURI STARS?
very young stars like our Sun
Through what can we photograph dust disks?
Hubble Space Telescope
What are all our planets in?
elliptical orbits around the Sun
What is a REVOLUTION?
how planets orbit the Sun
What is a ROTATION?
how planets turn on their axes
What are the senses of revolution and rotation for most of our planets?
counter-clockwise
What are the planets that rotate clockwise?
Venus and Uranus
What’s the usual inclination of orbits?
3.4 degrees
Which planet has an orbit inclined 7 degrees?
Mercury
What is the order of the planets?
mercury, venus, earth, mars, jupiter, saturn, uranus. neptune
What are the two types of planets?
terrestrial, jovian
What are the terrestrial planets?
mercury, venus, earth, mars
What are the jovian planets?
jupiter, saturn, uranus, neptune
What makes a planet TERRESTRIAL?
earth-like, solid and rocky surfaces, close to Sun, short revolution
What makes a planet JOVIAN?
gas giants, far from Sun, long revolution
What are the different types of SPACE DEBRIS?
asteroids, comets, meteoroids
What are ASTEROIDS?
Large chunks of metal/rock, minor planets
What are COMETS?
icy nucleus, highly elliptical orbits
What causes the streaks of light behind comets?
icy nucleus melts and evaporates into space by solar wind pressure
What are METEOROIDS?
dust grains of ice, metals, or rocks floating through space
What are METEORS?
meteoroids that have entered the atmosphere
What are METEORITES?
surviving chunks of meteor on Earth’s surface
What are PLANETESIMALS?
grains of solid matter clumped together
How do planetesimals grow?
gradual condensation and accretion
What could’ve helped the growth of planetesimals into PROTOPLANETS?
gravitational instabilities
What is the order of planet growth?
planetesimals, protoplanets, planets
Describe the JOVIAN PROBLEM.
- Jovian planets outside our solar system are common
2. Protoplanetary disks are evaporated quickly by the radiation of nearby stars
What is the solution to the Jovian problem?
simulations prove that Jovian planets can form through direct gas accretion, without rocky planetesimals
