Earth 101 Exam 1 Sean Kelly

Spectrograph

Picture of colors that come out of an Object

Wavelength

Distance between waves

Frequency

the number of complete wavelengths that pass a point in a given time

electromagnetic radiation

a kind of radiation including visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously.

Amplitude

Height of a wave

Refraction

The bending of a wave as it passes at an angle from one medium to another

Spectrum

All the different colors that would come out of an object

kinetic energy

the energy an object has due to its motion

gravitational potential energy

Potential energy that depends on the height of an object

Thermal Energy

The total energy of motion in the particles of a substance. Unseen energy. When you drop your Keys the energy does not stop existing

blackbody radiation

emission of light from hot objects

Photon

a particle of light

Wien's Law

Hotter objects emit photons with a higher average energy

Stefan-Boltzmann Law

Total power radiated P= σAT⁴. Larger has more area, if you double the size four times the amount of light will come out.

Nebula

A large cloud of dust and gas in space. Glowing gasses

quantum mechanics

Energy comes in small pieces. Little bits of energy

Nucleus

Control center of the cell

Proton

positively charged particle

Neutron

A small particle in the nucleus of the atom, with no electrical charge

Electron

A subatomic particle that has a negative charge

ground state

The lowest energy state of an atom

excited state

a state in which an atom has more energy than it does at its ground state

Absorption

An electron jumping to another level. Needs the exact amount of energy to jump.

Emission

an electron emits a photon and drops to a lower energy state, losing energy

Transition

The energy difference between levels

Doppler effect

A change in sound frequency caused by motion of the sound source, motion of the listener, or both.

inverse square law

the intensity of radiation is inversely proportional to the square of the distance from the source of radiation

Aperture

Opening the lets light into a telescope. Bigger telescope collects more light

angular resolution

The ability of a telescope to distinguish between adjacent objects in the sky.

refracting telescope

A telescope that uses convex lenses to gather and focus light

reflecting telescope

A telescope that uses a curved mirror to collect and focus light

eye piece

What you look through in a telescope

Magnification

Making things bigger

chromatic aberration

the focusing of different colors of light at different distances behind a lens

Atmosphere transmission

Atmosphere allows some colors to pass through and others not

Opacity

A measurement of the transparency of a color.

adaptive optics

A technique in which telescope mirrors flex rapidly to compensate for the bending of starlight caused by atmospheric turbulence.

Interferometry

process that links separate telescopes so they act as one telescope, producing more detailed images as the distance between them increases.

Kepler's First Law

The orbit of each planet around the Sun is an ellipse with the Sun at one focus.

Kepler's 2nd law

The speed of a planet increases as it comes closer to the sun, and decreases when it's farther away

Kepler's Third Law

The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit. P^2= a^3

Mass

the amount of matter in an object

Force

A push or a pull

Velocity

Speed in a given direction

Acceleration

rate of change of velocity

Vector

A quantity that has magnitude and direction. An arrow

Weight

A measure of the force of gravity on an object

escape velocity

The velocity an object must reach to fly beyond a planet's or moon's gravitational pull.

Earth rotation

Axis of earth= 23.5. 24 hours

Earth Revolution

365.25 days

Horizon

the line at which the sky and Earth appear to meet

altitude

Elevation above sea level

Longitude

Distance east or west of the prime meridian

Latitude

Distance north or south of the equator

celestrial sphere

Imaginary sphere mimics earth

Meridian

a line of longitude

Declenation

the angular distance of a point north or south of the celestial equator.

Zenith

the point directly overhead

Right Ascension

The angular distance eastward along the celestial equator from the vernal equinox to the intersection of the hour circle that passes through the body

Vernal Equinox

the day of the year that marks the beginning of spring in the northern hemisphere

Summer Solstice

Day with the most hours of sunlight and the fewest hours of darkness

Vernal Equinox

the day of the year that marks the beginning of spring in the northern hemisphere

Precession of Earth's Axis

Axis wobbles like a top

-wobble or motion

-determines relations between timing of seasons and position of earth

constellation

A group of stars that form a pattern in the sky

eclipse

The partial or total blocking of one object in space by another

order of magnitude

the order of magnitude of a quantity is the number rounded to the nearest power of 10

planet

A large body in space that orbits a star and does not produce light of its own

star

A ball of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion.

planetary system

a star with orbiting planets

galaxy

A huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity

galaxy cluster

a system of galaxies containing from several to thousands of member galaxies

Galaxy Supercluster

groupings of galaxy clusters

Universe

All of space and everything in it

astronomical unit

A unit of length used for distances within the solar system (AU)

Light year

the distance light travels in one year

Parsec

3.26 light years

Size of the earth

Radius 6400 km = 4000mi. Diamater 12800km = 8000mi

How much bigger is the sun than the earth?

About 100 times as large

angular size

the angle an object appears to span in your field of view

Polaris (North Star)

star at the zenith of the North Pole

sidereal day

the time needed between successive risings of a given star. It represents the time taken by the earth to rotate on its axis relative to the stars, and is almost four minutes shorter than the solar day because of the earth's orbital motion.

solar day

From noontime to the next noontime; for Earth it is 24 hours.

small angle formula

a mathematical relation between the angular size of an object as measured on the sky and the object's distance and physical size

Autumnal Equinox

The equinox that occurs on September 22 or 23 in the Northern Hemisphere and on March 21 or 22 in the Southern Hemisphere

Winter Solstice

December 22, when the sun is at its southernmost point

Ecliptic

path of the sun and the planets

Zodiac Constellations

Constellations that follow the elipticle

phases of the moon

new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, waning crescent

synodic month

The period of revolution of the Moon with respect to the Sun; the length of one cycle of lunar phases; 29 1/2 Earth days.

sidereal month

The average period of revolution of the Moon around the Earth in reference to a fixed star, equal to 27 days, 7 hours, 43 minutes in units of mean solar time.

solar eclipse

Occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth

Lunar Eclipse

the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon

Umbra

the very darkest part of the moon's shadow

Penumbra

the lighter part of a shadow where light is partially blocked

Totality

A total eclipse occurs when the dark silhouette of the Moon completely obscures the intensely bright light of the Sun, allowing the much fainter solar corona to be visible. During any one eclipse, totality occurs at best only in a narrow track on the surface of Earth. This narrow track is called the path of totality.

Partial Eclipse

an eclipse in which the eclipsed body is only partially obscured

annular eclipse

an eclipse of the sun in which the edge of the sun remains visible as a bright ring around the moon.

penumbral eclipse

a lunar eclipse in which the Moon passes only through Earth's penumbra

Apogee and Perigee

Apogee - Farthest away from the earth's center

Perigee - Closest to the earth's center

Perihelion

orbital point nearest the sun