Chapter 29: Our Solar System Flashcards
Geocentric
The sun, planets, and stars, orbited a stationary Earth. “Earth Centered”
retrograde motion
When a planet appears to move in the opposite direction across the sky. This is apparent because it is just the inner planets moving quicker than the outer
heliocentric
“Sun centered” Nicolaus Copernicus. Earth and other planets orbit the sun
Kepler’s 1st Law
Each planet orbits the Sun in a shape called an ellipse rather than a circle (ellipse is an oval shape that is centered on two points instead of a single points likes a circle the two points are called foci)
Kepler’s 2nd Law
A planet sweeps an equal amount of area in equal amounts of time
perihelion
When a planet is closest to the sun in its orbit
aphelion
When a planet is farthest from the sin in its orbit
Kepler’s 3rd Law
Relationship between the size of a planets ellipse and its orbital period. The orbital period equals the cube of the semi-major axis of the orbital ellipse
Two categories of planets in our Solar System
Terrestrial (Inner)Earth,Venus, Mars, Mercury Gas Giants (outer) Jupiter, Saturn, Uranus, Neptune
What is a plantesimal
The beginning of a planet; grains of material condensing to form larger bodies as they solid bodies grow they eventually reach hundreds of km in diameter where they are considered plantesimals
What is an asteroid? Where are most found?
Leftovers from the formation of the universe, most are found in the orbits of Mars and Jupiter within the asteroid belt
what is the difference between between a meteor and meteorite and a meteoroid
meteoroid- interplanetary objects that falls toward Earth and enters Earth’s atmosphere
meteor- when a meteoroid falls into Earth’s atmosphere and produces a streak of light
meteorite- If the meteoroid does not completely burn up, part of it will collide with the ground
What is a comet? What is unique about a comet’s orbit around the sun?
comets are small, icy bodies that have eccentric orbits around the sun. The comets get disturbed by the gravity of the sun
Explain why the material surrounding a young star forms a disk
the cloud of material builds up and gets denser and if the cloud was spinning at all, it will pick up speed. and as the rotation slows the collapse in the equaltorial plane, the cloud becomes flattend
Why are the inner planets dense and the outer planets gassy
In the solar system, the first planets to form were the large gas planets. They came from merging icy planetesimals. They gravity of these planets then began to attract gas, dust, and other planetesimals. The inner planets formed from planetesimals formed from refractory elements so the inner planets are rocky and dense.
