Astronomy Exam 1

Celestial body that orbits a star

Celestial body large enough to sustain hydrogen fusion

Collection of stars and planets gravitationally bound

Solar system

Star size, which in turn determines color

White from space, yellow to us, emits mostly green

Collection of star systems

Milky Way

100,000 light years

Collection of galaxies

Local Group

Larger collection of galaxies

No—Local Group is not in one

Collection of groups and clusters

Virgo Supercluster, which is part of Laniakea

Filaments, threadlike features

73% Hydrogen 25% Helium 2% metals

Its age—the younger the star, the more metals

The average distance from the Earth to the Sun, or 150 million km

About 30 AU

The distance light travels in one year

Coal, natural gas, and oil

High energy density Infrastructure is already in place Easy to find and transport Reliability

Non-renewable Accidents are dangerous and harmful Prices and supply are susceptible to weather and world events (like politics) Release greenhouse gases and pollute Dangerous to extract from the Earth

Gamma rays (most pressed together, most energetic) X-rays Ultraviolet Visible light Infrared Microwaves Radio waves (least pressed together, least energetic)

Photons

True

False; they move at the constant speed of light, they just have different wavelengths

The layer of gas around a planet

Troposphere Stratosphere Thermosphere Exosphere

Lowest level of the atmosphere, where visible light makes it to the surface

Second level of atmosphere, where UV is absorbed, has ozone layer

Third level of atmosphere, where x-rays are absorbed

Outer layer of atmosphere

It gets colder until the stratosphere, then it gets warmer, then colder nearing the thermosphere, then rises exponentially closer to space

Stratosphere

It absorbs UV light. Light hits an O2 molecule, splitting it into individual atoms, which then bond with more O2 to make O3 (ozone).

78% Nitrogen 21% Oxygen 1% all other gases

50% to the surface 20% absorbed by the atmosphere 30% albedo

Amount of light reflected off of a body

.3 or 30%

Greenhouse gases absorb infrared light and re-emit it in all directions—some makes it back to the surface, reheating it

False; it is good in moderation, but too much is harmful

Carbon Dioxide Methane Nitrous Oxide Water Vapor Ozone Fluorinated Gases

Troposphere

The time it takes to remove a molecule from the atmosphere

Water vapor, making up 50% of the greenhouse effect

9 days

Gases that have flourine

Fluorinated gases (sulfur hexafluoride is the most effective of these)

Aerosols, fire extinguishers, refrigerators, and more

800-3000 years

Chlorofluorocarbons, which were banned in 1989 because they damage the ozone layer

They take the oxygen atom away from O3, allowing it to bond with chlorine, then the oxygen atom will bond with another oxygen atom, making O2

Whipped cream, laughing gas

120 years

300x more powerful

Farming

12 years

30x more powerful

Stratosphere, in the ozone layer

Troposphere, ground-level

Weeks

Carbon dioxide

Unknown, due to the carbon cycle

82%

Carbon dioxide

Solar Hydroelectric Tidal Geothermal Biomass Wind

Cheap fuel source No carbon emissions (with exceptions during manufacturing) Renewable Does not depend on world events or foreign governments Government subsidizes it

Low energy density High start-up costs Intermittent (it's not constantly windy) Storage issues Location Large footprint Missing infrastructure Carbon emissions during manufacturing

Sunlight is reflected from mirrors onto a source

Mirrors reflect onto a tower, melting salt, which mixes with water to make steam, turning a turbine

Uses lots of water Kills birds due to temperature Lots of moving parts to replace Large footprint

High thermal efficiency Easy maintenance (heliostats are easy to replace) Heliostats track sun's movement

A giant, curved mirror that reflects sunlight onto a single point

Does not track sun Curved mirrors are fragile/expensive It is a huge structure and complex to build

No moving parts More thermal efficiency Small footprint

A trough of curved mirrors reflecting sunlight onto a receiver tube

Curved mirrors are fragile/expensive Uses oil at focal point Only tracks sun up/down

More thermal efficiency Tracks sun

Solar panels

Light hits the semi conductors, knocking the electrons off, which then move to make a current

Maximizing/minimizing the sun with building design

The seasons cause differences in amount of sunlight Lines of latitude—sun does not go high enough in the sky to be most efficient

Diagram of the sun's position from the exact same position at the exact same time every day of the year. It makes a figure eight

When the sun is directly overhead, occurs between Lat ±24. It happens twice per year at the equator (on the equinoxes) and once per year at the Tropic of Cancer/Capricorn. On the December solstice, it is at the Tropic of Capricorn (-24), while on the June solstice, it is at the Tropic of Cancer (+24)

When the sun shines all night in the arctic circle

When the sun does not rise all day in the arctic circle

The point in orbit closest to the sun, in December

The point furthest from the sun in orbit, in June

Earth's axis, which affects which part of the planet is closest to the sun

Solar radiation and the amount of sunlight

When the sun is perpendicular to the panel

Wind turns a turbine

The sun heats the atmosphere unevenly, which creates pressure differences, in turn making wind

Expensive to start Location dependent Kills birds Large land area for wind farms (they must be spread out due to air turbulence) Moving parts can break Radar interference

Small footprint per turbine Versatile No carbon output

Texas

Yes, but maintenance is hard and they interrupt shipping lanes

Sweep area or blade length, as well as wind speed