Astronomy Chapter 7-10
What dominates interior heating now for earth
(1) heat from when the planet formed and accreted, which has not yet been lost; (2) frictional heating, caused by denser core material sinking to the center of the planet; and (3) heat from the decay of radioactive elements.
Why are the smaller worlds less geologically active
1. It could be older (has had more time to cool) 2. It could be smaller (more heat-radiating surface area per unit of volume) 3. It could have smaller amounts of radioactive elements (which generate heat when they decay) 4. It could be farther from other large bodies which generate tidal forces on it (causing frictional heating)
what is the age of the solar system
4.6 Billion Years Old
what is differentiation
Calculating the rate of change at a point
Characteristics of Terrestrial Planets
Made of solid material, small, closest to sun.
Order of the planets
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (Pluto)
how do the atmospheres of mars and Venus compare to earth
Neither body has a permanent atmosphere.
why is the sky blue
Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
Why are sunsets red
Sunsets are red because of Rayleigh Scattering. Shorter wavelengths of light (blue) are scattered away by the atmosphere, while longer wavelengths (red) reach the observer.
Characteristics of Jovian planets
The density of these planets is less than that of the earth, as they are mainly formed of hydrogen along with helium and compounds of hydrogen such as methane and ammonia. Uranus and Neptune are also called the 'ice-giants' because along with hydrogen and other gases, they are mostly made up of ice and water
What are Martian polar caps made of
Water Ice
Planetesimal growth
a minute planet; a body that could or did come together with many others under gravitation to form a planet.
Kuiper Belt
a region of the Solar System beyond the planets, extending from the orbit of Neptune to approximately 50 AU from the Sun.
Oort Cloud
a theoretical spherical cloud of predominantly icy planetesimals believed to surround the Sun at a distance of up to around 100,000 AU.
Frost line; why does this yield two types of planets
also known as the snow line or ice line, is the particular distance in the solar nebula from the central protostar where it is cold enough for volatile compounds such as water, ammonia, methane, carbon dioxide, carbon monoxide to condense into solid ice grains
Law of Gravitational attraction
any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
why is venus hotter than mercury
atmosphere on Venus is so thick and heavy that it traps the solar energy that penetrates its clouds
what are the lunar highlands
brighter areas on the moon, mountain ranges and craters on the moon
Why are planets round
gravity. a sphere is the shape that minimises the energy of the system
why is mercury so hot
it is so close to the sun.
weather vs climate
weather is short term condition and a climate is a long term condition
what causes the aurora
In polar regions the ions radiate energy as shimmering lights called the auroras.
What is a Maria
a dark smooth patch on the moon