Earth's Atmosphere Layers, Celestial Movements, and Planetary Facts

Troposphere

Densest layer, 90% of all the gasses in the atmosphere, weather.

Stratosphere

Below freezing temperatures.

Ozone

Layer which absorbs and scatters UV rays.

Ozone depletion

Caused by ozone-depleting substances such as CFCs.

Mesosphere

-100oC, meteoroid, meteor, meteorite, meteor shower.

Ionosphere/Thermosphere

Hottest layer, aurora.

Exosphere

Boundary between the atmosphere and outer space.

Orbit

Path taken by an object revolving around another body of space.

Aphelion and perihelion

Farthest and nearest points around the sun.

Apogee and perigee

Farthest and nearest points around the earth.

Spherical earth model

Backed up by Ferdinand Magellan and Sebastian Elcano.

Ptolemy

Geocentric model = Sun, stars and the planets circled the Earth.

Copernicus

Heliocentric theory = Earth and the other planets revolve in circles around the sun.

Kepler

Laws of Planetary Motion = Orbit of every planet is an ellipse with the sun at one of the two foci.

Time Zones

Each 15o longitude has its own hourly time zone.

Eclipses

Astronomical object is temporarily obscured by another object.

Solar Eclipse

Moon blocks the sun's light.

Tides

Constant rise and fall of surface waters due to the interplay of gravitational forces of the earth.

Spring tides

Sun is in line with the moon.

Neap tides

Refers to a period of moderate tides when the sun and moon are at right angles to each other.

Mercury

Smallest, closest to the sun, no atmosphere.

Venus

Earth's twin planet, hottest planet, brightest from earth.

Earth

Has a moon.

Mars

Red planet, 2 moons.

Jupiter

Largest planet, has a ring, 67 moons.

Saturn

Most prominent ring, 62 moons.

Uranus

Ice giant, axis is tilted sideways.

Neptune

Densest gas planet, twin of Uranus.

The inner planets

Closest to the Sun - Mercury, Venus, and Mars.

The outer planets

Jupiter, Saturn, Uranus, and Neptune.

Dwarf Planet

Eris, Pluto, Ceres.

Asteroid Belt

Found between Mars and Jupiter.

Kuiper Belt

Found beyond Neptune.

Comet

Icy objects.

Star's Life Cycle

Nebula collapses into a single mass.

Post main-sequence

Hydrogen fuel - heavier elements.

Brightness and Luminosity of a star

Younger = hotter, older = colder.

Constellation

Internationally defined area of the celestial sphere.

Asterism

A pattern of stars that may be part of a constellation.