week 9 review

galaxy

(astronomy) a collection of star systems

Core

(sun's interior) central region, produces enormous amounts of energy, in the process of nuclear fusion (hydrogen joining to form helium). High temperatures & pressure.

Radiation Zone

(sun's interior) next up from the core; middle layer; region of tightly packed gas; energy is transferred in form of electromagnetic radiation. Very dense region

Convection Zone

(sun's interior)top or outermost layer. Gases rise and cool; then sink, forming loops of gas that move energy towards sun's surface. Generates sun's magnetic field.

Hertzsprung-Russel Diagram

A graph relating the temperature and brightness of stars

constellation

A group of stars that form a pattern in the sky

craters

A large round pit caused by the impact of a meteoroid.

continuous spectrum

A spectrum of light in which there are no gaps, so that each region blends directly into the next

red giant

A star that expands and cools once it runs out of hydrogen fuel

cepheid variable

A variable star that brightens and dims regularly, or pulses, and whose distance can be determined from its period of pulsation

red dwarf

A very small star with low temperature, reddish in color

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

Scientific Method

Approach to researching questions and problems through objective and accurate observation, collection and analysis of data, direct experimentation, and replication of procedures.

Aristotle

Believed the Sun moved around the earth and a stationary Earth.

F-type star

Color: White Temp: 6900°C or 12500° F

O-type star

Color: blue Temp: 9400-205040°C or 17000-37000° F

G-type star

Color: light orange Temp: 5540°C or 10000° F

Isaac Newton

Deducing a law of gravity and three general laws of motion that apply to all objects.

H-R Diagram

Hertzsprung-Russell Diagram; used to classify stars and to understand how stars change over time. Shows brightness and temperature

galilean moons

Io, Europa, Callisto, Ganymede

Galilean satellites

Io, Europa, Callisto, and Ganymede the moons around Jupiter.

Neptune

Last planet in the solar system and the fourth gas giant. Windiest planet in the solar system.

Magnitudes

Levels of brightness of stars. Perceived as brightness ratios.

crescent moon

Moon phase in which less than half of the Moon appears to be illuminated

Polaris

North star, star that the stars roatate around

summer solstice

Occurs when the Sun is directly overhead at 23.5° north latitude, around June 21, and results in the maximum number of daylight hours for the northern hemisphere and the minimum number for the southern hemisphere.

winter solstice

Occurs when the Sun is directly overhead at 23.5° south latitude, around December 21, and results in the minimum number of daylight hours for the northern hemisphere and the maximum number for the southern hemisphere.

vernal equinox

Occurs when the Sun is directly overhead at the equator and results in day and night of equal length for both northern and southern hemispheres

celestial pole

One of two points of intersection of the Earth's axis and the celestial sphere

Copernicus

Postulated a heliocentric solar system.

Mars

Red planet with rust on the surface causing the red glow. Fourth planet from the Sun.

protoplanets

Regions of condensed matter that serve as a starting point for the formation of a planet.

protoplanetary nebula

Regions with dense elements collaps due to shockwaves from nearby supernovas. May form planets and stars.

Venus

Second planet from the Sun, but is the hottest because it has a thick atmosphere which traps heat.

Uranus

Seventh planet from the Sun third gas giant. Has strange rotation which is top to bottom.

Saturn

Sixth planet from the Sun. Second of the gas giants with seven large shining rings.

Red Giants

Small & medium-mass stars run out of fuel; their outer layer expands

wavelength

The distance between crests of waves, such as those of the electromagnetic spectrum

magnetic field

The energy field created by the spinning of the inner and outer cores.

Jupiter

The first of the gas giants and fifth planet from the Sun. Largest planet in the solar system. Has great red spot which is a storm.

weight

The force of gravity on an object

penumbra

The lighter outer portion of a shadow cast by a planet or moon, where an observer in the shadow would see a partial solar eclipse

milky way

The name of our galaxy, a spiral galaxy that contains about 400 billion stars

thermosphere

The outermost layer of Earth's atmosphere.

eclipse

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

law of universal gravitation

The scientific law that states that every object in the universe attracts every other object.

solstice

The two days of the year on which the sun reaches its greatest distance north or south of the equator

Earth

Third planet from the Sun. Has atmosphere which sustains life.

Law of Nature

Well-confirmed summery statement of how a natural phenomenon behaves. Subject to change.

spring tide

When the Moon and the Sun pull together and create a higher than usual tide; occurs during the full moon and new moon phases

main sequence

a band of stars that includes most stars of average color, size, magnitude, and temperature

solar flare

a brief burst of energy from the sun's photosphere

aurora

a bright display of ever-changing light caused by solar radiation interacting with the upper atmosphere in the region of the poles

meteoroids

a chunk of rock or dust in space

prominence

a concentration of gases above the solar surface that appears as a bright archlike structure

protostar

a contracting cloud of gas and dust with enough mass to form a star

sunspot

a dark area of gas on the sun that is cooler than surrounding gases

sunspot

a dark region on the surface of the sun. Cooler temperatures.

telescope

a device built to observe distant objects by making them appear closer

white dwarf

a faint star of enormous density

solar wind

a fast-moving stream of particles thrown into space by solar flares

nebula

a large cloud of dust and gas that can break apart into smaller pieces and form stars

solar nebula

a large cloud of gas and dust such as the one that formed our solar system

neap tide

a less than average tide occurring at the first and third quarters of the moon

absolute magnitude

a measure of the amount of light that a star actually emits

plasma tail

a narrow, ionized comet tail pointing directly away from the Sun

photon

a particle of electromagnetic radiation having zero mass and carrying a quantum of energy

photon

a particle of light

force

a push or pull exerted on an object

pulsar

a rapidly spinning neutron star that produces radio waves

kuiper belt

a region of the solar system that is just beyond the orbit of neptune and that contains small bodies made mostly of ice

Hubble Space Telescope

a space telescope and camera named for a famous astronaut (Edward Hubble) used to study space elements

oort cloud

a spherical region of comets that surrounds the solar system

nova

a star that ejects some of its material in the form of a cloud and become more luminous in the process

main-sequence star

a star that falls into the main sequence category on the H-R diagram

solar wind

a stream of electrically charged particles produced by the sun's corona

solar nebula theory

a swirling cloud of dust and gas formed. in the center, it was hot and had high pressures where the sun formed. As the outer part of the cloud cooled solid particles condensed forming planets moon, and other solid objects

calendar

a system of organizing time that defines the beginning and length and divisions of the year

binary star

a system of two stars that revolve around each other under their mutual gravitation

reflecting telescope

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

chromosphere

a thin red region of the sun's atmosphere between the corona and the photosphere; too faint to see unless there is a total solar eclipse

light gathering

ability to make faint objects appear brighter

magnifying

ability to make objects appear larger

resolving

ability to see fine detail

White Dwarf

after a star runs out of fuel, about size of Earth, but with the mass of the sun; still glows from left-over energy

supergiant

an extremely bright star of very large diameter and low density

axis

an imaginary line that passes through Earth's center and the north and south poles, about which Earth rotates

Constellations

an imaginary pattern of stars in the sky

nebula

an immense cloud of gas (mainly hydrogen) and dust in interstellar space

element

any substance that cannot be broken down into simpler substances

Parallax

apparent change in the position of an object resulting from the change in direction or position from which it is viewed.

Sunspots

areas of gas on the sun's surface; cooler than the gas around it; appear darker; helped prove sun rotates on its axis; 11 year cycle; most disappear in two weeks; form where magnetic field is strongest

radio telescope

astronomical telescope that picks up electromagnetic radiations in the radio-frequency range from extra-terrestrial sources

gravity

attractive force between two objects that depends on the masses of the objects and the distance between them

Hipparchus

began the systematic observational work with written records. Determined length of a year. Categorized stars.

heliocentric model

belief that center of solar system is a stationary sun.

geocentric model

belief that center of the solar system is a stationary earth.

astroid belt

belt of rock that orbits the sun usually between mars and jupiter

lunar eclipse

blocking of the moon that takes place when the Earth comes directly between the sun and full moon

Apparent Brightness

brightness as seen from Earth

doppler effect

change in the apparent frequency of a wave as observer and source move toward or away from each other

Characteristics

characteristics used to classify stars: color, temperature; size; composition (elements); and brightness

perihelion

closest approach of a planet to the sun

Mercury

closest planet to the Sun. Very hot rocky planet. tSmall quickly moving planet.

Nebula

cloud of gas and dust; where stars & planets are born

Color

color reveals surface temperature; from coolest: red, light orange, yellow, white and blue

M-type star

color: red Temp: 3038°C or 5500° F

interferometry

combination of multiple signals from smaller telescopes to simulate one image

velocity

constant speed and direction an object moves without external force

solar wind

continuous stream of high-energy particles released into space in all direction from the sun's corona

Sun's Interior

core, radiation zone, convection zone

Pythagoras

credited with summerizing the ideas of geometry, credited with proposing the idea of a spherical earth and moon, by studying eclipses

umbra

dark center of a typical sunspot

maria

dark, flat areas on the moon's surface formed from huge ancient lava flows

Metric System

decimal system of weights and measures in kilogram, meter and liters.

latitude

decrees north or south of the equator

right ascension

degrees east of the vernal equinox

longitude

degrees east or west of the prim meridian

declination

degrees north or south of the equator

Brightness

depends on both size and color; described in two ways: apparent brightness and absolute brightness

How long a star lives

depends on its mass

Life of stars

depends on its mass; the more mass the shorter the life span

Eratosthenes

determined the circumference of Earth from observations by noting the angle of the sun.

aperture

diameter of the lens or mirror used to gather light.

Light year

distance used to measure distance between stars; the distance light travels in one year = 9.5 million km (300,000 k/s)

Protostar

earliest stage in star's life

universe

everything that exists, including the sun, stars, all the planets, and outer space

Scientific Notation

exponential numbers used to express measurement

gas-giant planets

farthest from the sun, large, massive, not dense, mostly gaseous with solid cores, primarily hydrogen and helium chemical makeup, deep and thick atmosphere, cold exterior temperature, fast rotation, many satellites.

Sun Features

features on or just above the sun's surface include sunspots, prominences and solar flares

Angle

formation of two lines that have the same endpoint, measured in degrees.

Aphelion

greatest distance between a planet and the sun

rocky planets

group of four planets in our solar system formed when the Sun melted ice particles creating rocky dense planets.

Prominences

huge reddish loops of gas; often link sunspots; possibly due to the sun's magnetic field

2 main gases found in stars

hydrogen combining to make helium

celestial sphere

imaginary sphere drawn in space with the earth at its center

Photosphere

inner layer of sun's atmosphere; sphere that gives off visible light; gases here are thick; considered sun's surface layer (note: sun doesn't have a solid surface)

Theory

integrated set of statements that explain various phenomena.

When a star runs out of fuel

it becomes a white dwarf, a neutron star, or a black hole

outer planets

jupiter, saturn, neptune, uranus

galaxy

large group of stars, gas, and dust held together by gravity

Ptolemy

last Greek astronomer. Formulated an explanation of a geocentric model

chromosphere

layer immediately outside the photosphere, pinkish in color. The region seen during a solar eclipse where the photosphere is blocked from view.

light year

light distance travels in one year (9.5 trillion km)

light-year

light distance travels in one year (9.5 trillion km)

penumbra

lighter outer area of a typical sunspot

photosphere

lowest layer of the Sun's atmosphere and the layer that gives off light

nebulae

massive clouds of dust and gases where stars are born

Mass

measure of the quantity of material in an object

Tacho Brahe

measured accurately the positions of celestial objects

Right angle

measurement of 90 degrees

inner planets

mercury, venus, earth, mars

planets

mercury, venus, earth, mars, jupiter, saturn, uranus, neptune, pluto

Chromosphere

middle layer of sun's atmosphere; visible during a total solar eclipse; called the color sphere

new moon

moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth

Size

most stars are med-sized; from smallest: neutron, white dwarf, star (low and high mass); red giant; super giant

redshift

motion of light away from the observer are measured longer or redder.

blueshift

motion of light toward the observer when wavelengths are measured shorter or bluer

spicules

narrow jet like fountains rising out of the solar atmosphere

terrestrial planets

nearest to the sun, small size, non-massive, dense, structure solid with iron cores, chemical composition heavy elements, thin atmosphere, warm exterior temperature, slow rotation, few satellites

Aurora Borealis

northern lights; caused by solar wind

Eighty-eight

number of constellations

Six thousand

number os stars visible to unaided eye

astroid

object in orbit around the sun; in reference to size, between meteroids and planets

Black Hole

object with strong gravity that doesn't allow anything, including light, escape; a possible last stage in a high mass star

momentum

objects mass times its velocity

Solar Wind

occurs in the corona; solar flares increases this; responsible for increase in number of magnetic particles reaching Earth's atmosphere; create powerful electric currents that result in greenish, red or purple glow in Earth's sky (called auroras); can also cause magnetic storms

solar eclipse

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

phases

one of the different apparent shapes of the moon as seen from Earth

Galileo Galilei

one of the first people to use a telescope. Discovering craters on the moon, Jupiter's satellites, Milky Way stars.

refracting telescope

optical telescope that has a large convex lens that produces an image that is viewed through the eyepiece

Corona

outer layer of sun's atmosphere; visible during total solar eclipse; looks like a halo around the sun; extends into space for millions of km; gradually thins into think streams of electrically charged particles called solar wind.

Ellipse

path of a point that moves so that the some of its distances from two fixed points (foci) is constant.

Astronomers

people who study the universe including origins, evolution, composition, motions, positions and celestial bodies.

Sun's Atmosphere

photosphere, chromospheres, corona

Nebula into

planet, brown dwarf, low or intermediate mass star, or a massive star

gas giants

planets farther from the Sun's heat where ice particles combined with gas creating larger lighter planets.

zenith

point right above you

vernal equinox

position of the sun on the first day of spring.

background radiation

radiation left over from the beginning of the universe

Neutron Star

remains of high mass stars; smaller and denser than white dwarfs

black hole

remnant of a star that is so dense that nothing, not even light, can escape its gravity field

Pulsars

short for pulsating radio sources; spinning neutron stars

Lifecycle

shows the stages of birth and death of stars; two different paths according to original mass of star.

meteoroids

small, rocky objects that orbit the sun in both the outer and inner regions of the solar system

Aurora Australis

southern lights; caused by solar winds

comet

space object made of dust and rock particles mixed with frozen water, methane, and ammonia that forms a bright coma as it approaches the Sun

emission spectrum

spectrum of electromagnetic radiation emitted by a self-luminous source

circumpolar stars

stars that can be seen at all times of the year and all times of night.

Law of Inertia

states that an object continues moving at the same rate unless acted upon by external force.

meteorite

stony or metallic object that is the remains of a meteoroid that has reached the earth's surface

Astronomy

study of the stars involving the study of the universe and every object in the universe.

Solar Flares

sudden bursts of energy in the form of fire that erupts on the sun's surface; happens when sunspot loops connect and release huge amounts of magnetic energy

highlands

tall mountain ranges and appear as light areas on the moon

optical telescopes

telescopes used to view visible light

corona

tenuous, and hot, outer atmophere with temperatures 1-2,000,000 K. With bright light emissions

Hypothesis

testable prediction

mass

the amount of matter in an object

parallax

the apparent change in position of an object when seen from different places

solar eclipse

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

lunar eclipse

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

Absolute Brightness

the brightness a star would have if it were a standard distance from Earth

magnitude

the brightness of a star

apparent magnitude

the brightness of a star when viewed from Earth

supernova

the brilliant explosion of a dying supergiant star

blue shift

the decrease in wavelength of light due to an object toward the observer

Composition

the elements found in stars; most are hydrogen and helium and a small percentage of other elements (like sodium & calcium); astronomers use spectrographs to determine this.

Supernova

the explosion of a supergiant star; this material may become part of a nebula

projection effect

the fact that the stars of a constellation may be located or not located at different distances from us.

red shift

the increase in wavelength of light due to an object moving away from the observer

umbra

the inner, darker part of a shadow

troposphere

the layer closest to Earth, where almost all weather occurs; the thinnest layer

mesosphere

the layer of the atmosphere between the stratosphere and the thermosphere and in which temperature decreases as altitude increases

stratosphere

the layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases

meridian

the line from north from zenith to south

coma

the luminous cloud of particles surrounding the frozen nucleus of a comet

precession

the motion of a spinning body (as a top) in which it wobbles so that the axis of rotation sweeps out a cone

revolution

the movement of an object around another object

corona

the outer layer of the sun's atmosphere

corona

the outermost region of the sun's atmosphere

orbit

the path of an object as it revolves around another object in space

tide

the periodic rise and fall of the level of water in the ocean

waning moon

the phase of the Moon when a decreasing amount of the Moon's near side is sunlit

waxing moon

the phase of the Moon when an increasing amount of the Moon's near side is sunlit

quarter moon

the phase of the Moon when half of the Moon's near side is sunlit

horizon

the plane you stand on

nuclear fusion

the process by which hydrogen atoms join together to form helium, releasing energy occurs in the core of the sun

chromatic abberation

the rainbow effect when light is dispersed through lens

convective zone

the region of the sun's interior in which energy is circulated by density differences

Newton's first law of motion

the scientific law that states that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force

neutron star

the small, dense remains of a high-mass star after a supernova

absorption spectrum

the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths

rotation

the spinning motion of a planet on its axis

Archaeoastronomy

the study of the astronomy of ancient cultures. Including ancient structures, early calendars, navigation, and mathematics EX: stone henge at the summer solstice

astronomy

the study of the moon, stars, and other objects in space

spectroscopy

the study of the spectra of stars by analyzing the spectral properties of the light they give off

solar system

the sun with the celestial bodies that revolve around it in its gravitational field

inertia

the tendency of an object to resist any change in its motion

light-year

the time light travels in a year

full moon

the time when the moon is fully illuminated

equinox

the two days of the year on which neither hemisphere is tilted toward or away from the sun

photosphere

the visible surface of the sun

luminosity

total energy emission of the sun, 2x10 to the twenty-six watts.

Johannes Kepler

used Tycho's figures to perform an analysis of planetary orbits.

Aristarchus

used a few simple observation to develop the first valid idea of the scale of the universe.

objective lens

used in refactors to collect light

primary mirror

used in reflectors to collect light

angles

used to denote the positions and apparent sizes of objects in the sky

reflecting telescope

uses a concave mirror to gather light

refracting telescope

uses a lens to ben the light to produce an image

eyepiece lens

uses light to bring the image to a focus

Constellations

well defined regions on the sky, made up of the presence or absence of bright stars in that region

focus

when light waves are coming from the same direction to a single point

meteors

when meteoroids enter Earth's atmosphere. Shooting star

prominences

when seen near the solar limb

plages

when seen superimposed on the solar disk

A star is born

when the contracting gas and dust from a nebula become so dense and hot that nuclear fusion starts

gibbous moon

when the size of the illuminated portion of the moon is greater than half but not a full moon

solstice

when the sun's apparent position from the sky reaches its northernmost and southernmost extremes.

equinox

when the tilt of the earth axis is inclined neither away nor towards the sun.

Black Dwarf

when white dwarf stops glowing

local sky

your view of the celestial sphere depending on your location