Astronomy 100 Final Exam
Terms in this set (127)
Cosmic Scale( distance)
Distance=speed of light*time
Age of the Universe
13.7 billion years
Rotation, Orbit of the Earth
one rotation per day, orbits sun once per year
how the sky looks from Earths viewpoint
the path of the sun across celestial sphere, it is tilted at 23.5 degrees
where sun crosses Celestial Equator going northbound bringing spring to Northern hemisphere
Tropic of Cancer location
23.5 degrees north
Tropic of Capricorn location
23.5 degrees south
66.5 degrees north
66.5 degrees south
when the Sun is directly overhead
sun and moon are never near each other, moon sets before or after sun
moon rises just after the Sun does
moon rises 6 hours before the Sun does
moon rises 6 hours after the Sun does
rise a little before the sun does majority of moon lit
darkest part of lunar eclipses very small
partially shadowed part of lunar eclipses
when the moon goes into the shadow of the Earth, doesnt always happen bc Moon is on a 5 degree tilt
when the sun goes into the shadow of the Moon, generally very short and in small areas
too much light from the Sun gets through essentially destroying the penumbra
is like longitude and is measured in hours
is like latitude and is measured in degrees
great circle going from South to North that goes through the Zenith
Keplers 1st Law
Orbit of Earth is not in a perfect circular orbit, it is an ellipse
Keplers 2nd Law
The radius vector sweeps out equal areas in equal times, closer to sun goes quicker so wider, farther out goes slower so longer
Keplers 3rd Law
square of the orbit period of planet is equal to the cube of the semi major axis( p^2=q^3)
Semi Major Axis
distance from Sun to planet
earth center of universe, stars are unchanging sets of lights that revolve around Earth, all objects not on the same plane, sun had to be out past the moon
geocentric, explained movement of sun, moon, and planets in epicycles, explained retrograde motion with epicycles
circle orbit around point that planet travels on when going in orbit
supported by Copernicus, explained retrograde with planet lapping
The apparent motion of the planets when they appear to move backwards (westward) with respect to the stars from the direction that they move ordinarily.
created the first telescope, discovered the 4 moons of Jupiter orbit Jupiter not Earth, discovered the different phases of Venus
saw first supernova, mapped precise orbit of planet
Newtons 1st Law of Motion
object at rest or in motion will continue in that state unless acted upon by outside force
Newtons 2nd Law of Motion
Acceleration= Force/ Mass
Newtons 3rd Law of Motion
Every action has an equal and opposite reaction
Law of Gravity
Body Mass 1
Body Mass 2)/Distance^2
is a measure of gravitational force on the body, changes with pressure
is a measure of amount of material in body, never changes
the minimum velocity needed to escape a gravitational field
when both the Sun and the Moon are pulling the tides in one direction
a less than average tide occurring at the first and third quarters of the moon, pulling at right angles to each other
Newtons version of Kepplers 3rd
M1 + M2 = A3 / P2
Range of EM frquencies including radio waves, microwaves, infrared, visible, UV, x-rays, and gamma rays.
when an object absorbs light instead of reflecting it back out
change in pitch or wave frequency due to a moving wave source, smaller in the front longer in the back, used in astronomy by seeing which way stars are moving and shows us that Andromeda Galaxy is moving towards us
small rocky planets, small diameter, high density, closer to sun, too hot for gasses to form around them, mostly carbon dioxide and nitrogen atmospheres
jupiter-like, jupiter-neptune, large, low density, gaseous, massive, thick atmosphere made of hydrogen, helium, methane, ammonia
Nebular Theory of Formation
A nearby super massive star exploded into a supernova.
The shock waves from the explosion caused the nebula to spin in a counterclockwise direction.
It spun faster and became very hot and fusion occurred to create the sun.
As particles collide they clump together to form planetesimals in the swirling disk.
Due to their gravitational force, the planetesimals collect dust and gas.
Smaller planetesimals collide with the larger ones and the planets begin to form.
the minimum distance at which it was cold enough for ice to condense
- lies between mars and jupiter
- only rocks & metals condensed on inside, Hydrogen compounds (ices) condensed beyond the frost line.
large clumps of ice, dust and frozen gases that travel around the Sun in long elliptical orbits
in same orbit as Jupiter, centered around gravitational areas
determined by convection in the interior of the planet, and the planets rotation
between Neptune and Pluto, much icier due to distance to Sun
A spherical region surrounds the solar system, that extends from just beyond Pluto's orbit to almost halfway to the nearest start, and that contains billions of comets
asteroids that cross Earth's orbit
Tiny, solid pieces of rock, ice and gas that eventually accumulate to form a planet.
Planets outside of our solar system
the warming of the surface and lower atmosphere of Earth that occurs when carbon dioxide, water vapor, and other gases in the air absorb and reradiate infrared radiation
Venus Runaway Greenhouse Effect
Venus was thought to once have oceans, but as Sun got hotter oceans evaporated went into atmosphere making it increasingly thicker
4 ways that surface of planets change
Weathering- involves having an atmopshere
Differentiation- the sinking of heavier elements into the core
Why are Mercury and the Moon geologically dead?
Their cores were too small to maintain having volcanic activity for long periods of time
Water on Mars?
large amounts of ice, looks like there is riverbeds and areas churned out by water flow
Composition of Jovian Planets
colder temperatures, more dense, higher mass, shorter days, slower orbital speed, mostly made up of hydrogen
Moon of Jupiter, icy smooth surface, may have a liquid interior,
Moon of Jupiter, surface may have plate tectonics, icy dusty surface
Moon of Jupiter, rocky moon with lots of volcanic activity
Moon of Jupiter, heavily cratered surface
made up of ice and dust, comes from small moons in the rings of Saturn
Moon of Saturn, 2nd largest moon, cold with an atmosphere
one of two tails seen when a comet passes near the sun. it is composed of ionized gas blown away from the sun by the solar wind
(astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet
a meteoroid that does not completely burn up in the atmosphere and strikes the surface of a moon or planet
Proton Proton Chain
The chain of fusion reactions, leading from hydrogen to helium, that powers main-sequence stars.
in high mass stars, after H fusion ends, C, N and O are used to catalyse the fusion of H into He
lowest layer of the Sun's atmosphere; gives off light and has temperatures of about 6,000K
regions of strong magnetic fields where the gas temp is lower, number of them constantly changing
releases of energy associated with magnetic field activity
Layer of the Sun's atmosphere above the photosphere and below the corona that is about 2500 km thick and has a temperature around 30 000 K at its top, can only be seen during eclipses
largest layer of the Sun's atmosphere from which charged particles continually escape into space
Core of the Sun
25% of the entire mass, most energy generated here b/c of temperatures
The middle zone of the model of the sun's interior where thermal energy moves outward from the core by radiation
region surrounding the radiative zone of the sun where gases circulate in convection currents, bringing energy to the surface (photosphere)
A state that occurs when compression due to gravity is balanced by a pressure gradient which creates a pressure gradient force in the opposite direction. Hydrostatic equillibrium is responsible for keeping stars from imploding and for giving planets their spherical shape.
no electric charge, very little masss, and are hard to find. decayed material. never interact with other particles they pass right through the earth. type of lepton.
the brightness of a star as seen from earth
how bright the star would appear at a standard distance, this is a fair way to compare stars
Energy output from the surface of a star per second; measured in watts.
Inverse Square Law for light
the law stating that an object's apparent brightness depends on it actual luminosity and the inverse square of its distance from the observer: apparent brightness = luminosity/4pi x (distance) ^2
x axis--> spectral type/temp
y axis-->absolute mag/luminosity
white dwarfs are below the main line
giants and red giants are seen above the main
Spectral Types OBAFGKM
O is the hottest M is the coolest
oh boy a fat girl kissed me
Main Sequence Turnoff
The location on the H-R diagram of a single-aged stellar population where stars have just evolved off the main sequence. The position of this is determined by the age of the stellar population.
a dense star whose radius is approximately the same as the Earth's but whose mass is compariable with the Sun's. Burn no nuclear fuel and shine by residual heat. They are the end stage of stellar evolution for stars like the Sun.
1. 10 times more massive than our Sun
2. core heats up causing heavy elements to form
3. core collapses due to gravitational pressures
4. explodes into supernova
two stars that orbit close together around the same point
1) Visual Binaries- the two stars are easily seen as two due to their distance and brightness
2) Spectroscopic Binaries- the only way to distinguish between the two is by the Doppler effect
3) Eclipsing Binaries- ones that block the light from each other producing different variances in light intensity
a contracting cloud of gas and dust with enough mass to form a star
a type of pressure unrelated to an object's temperature that arises when electrons or neutrons are packed so tightly that the exclusion/uncertainty principles come into play
Low Mass Life Stages
a flattened, rotating galaxy with pinwheel-like arms of interstellar material and young stars winding out from its nucleus
a galaxy shaped like a round or flattened ball, generally containing only old stars
has an undefined shape and contains lots of young stars, dust and gas
Electron Degeneracy Pressure
supports white dwarfs against pressure; prevents electrons from being squeezed into a smaller space
-material falling onto another object in space will form into a disk as it spirals in
-collisions between the gas particles heat up the disk and cause it to glow
White Dwarf Mass Limit
1.4x Mass of our Sun
White Dwarf Supernova
a supernova that occurs when an accreting white dwarf reaches the white-dwarf limit, ignites runaway carbon fusion, and explodes like a bomb; often called a type la supernova
very small high mass star, formed after a supernova from a massive star
a neutron star that emits radiation out into space
formed by the death of stars that have a mass of more than 40 Msun, such great gravitational pull not even light can escape
the location around a black hole where the escape velovity equals the speed of light; the boundary of a black hole
when in a binary system the accretion disk around a neutron star gets hot enough to produce xrays
a class of binary stars that are luminous in X-rays; a generally normal star donating matter that falls to a neutron star, white dwarf, or black hole
The distance from the center of a black hole to its event horizon. No light or anything else can escape from within this radius.
Gamma Ray Bursts
matter falling into black holes giving large explosions of gammas
Center of the Galaxy
a Supermassive black hole
groups of stars with high luminosity that changes in size and brightness
Velocity= Distance * Hubbles Constant(Ho)
entire universe is expanding
a hypothetical form of matter that is believed to make up 90 percent of the matter in the universe
hypothetical form of energy that is a form of antigravity that is allowing for the continuing expansion of universe
The magnification or distortion (into arcs, rings, or multiple images) of an image caused by light bending through a gravitational field, as predicted by Einstein's general theory of relativity.
Dark matter might be subatomic particles that don't interact strongly with anything.
Dark matter might be big objects like faint stars and brown dwarfs.
gravity stronger than dark energy, universe collapses when Omega is greater than one
the universe will be increasing at a linear rate, Omega is equal to the dark energy
dark energy is far too strong, will eventually rip the universe apart, Omega is smaller than 1