Complete List of Terms and Definitions for Astronomy 104

Terms Definitions
helocentric sun-centred
heliocentric model Sun-centered
latitude up and down
earth average density: 5500kg/m
pulsar a degenerate neutron star
has global dust storms mars
CFC's ChlorophlorocarbonsOnce used in fridges and aerosol cans.These chemicals deplete the ozone layer and changes chemical balance.Created a hole in the ozone layer, especially near South Pole.20-30 yr damage takes 100 yrs to regenerate.S. America and Australia recieve a lot of UV light as a result.
Photon A particle of electromagnetic radiation with no mass that carries a quantum of energy
Maxwell Montes is found on Venus
waves produced by stars all waves
gravity attractive force created by mass
absolute zero the temperature of −273.16°C (−459.69°F), the hypothetical point at which all molecular activity ceases.
Saturn a planet with very complex rings
photosphere the visible surface of the sun
Sunspot Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are darker because they are cooler regions on the Sun.
white dwarfs very small, very dense stars
copernicus rejected an earth cenetered universe, said it was centered around the sun
red the coolest color of a star
quasars very bright centers of distant galaxies.
Aries the Ram, a zodiacal constellation between Pisces and Taurus
Meteorite a meteoroid that does not completely burn up in the atmosphere and strikes the surface of a moon or planet
Which planet has the largest magnetic field in the solar system? Jupiter
hydrostatic equilibrium star's gravity pushes in, thermal pressures pushing out
protoplanetary disks disk of material encircling a protostar or a newborn start
Aristotle Most associated with the ancient Greek world view
Angular Separation the angle between lines originating from the eye of the observer toward two objects
Open Clusters Irregular clusters containing from a few ten to a
few thousands of stars. They typically contain many bright blue stars,indicating that they formed relatively recently. Open clusters contain stars in all parts of the main sequence of the HR diagram.
Weins Law (Def) dominant wavelength of radiation emitted by a blackbody is inversely proportional to its temperature.
Time Zones There are different time zones
the rotation pf the earth causes different places to get light at different times.
Time zones go up and down across the world
Places in the world can be at a different time, day, month or even year!
Maxwell showed that light is: an electromagnetic wave.
Universe the totality of all matter, energy, and space
Cold Dark Matter heavy particles
such as exotic supersymmetric particles best explains the observed universe
revolution the movement of an object around another object
axis the imaginary line that passes through a planet, about which it rotates
frequency Hz-beats per sec: describes the rate at which peaks of a wave pass by a point; measured in units of 1/s, often called cycles per second of hertz
proton particles found in atomic nuclei with positive electrical charge
Quasar A galaxy whose center is so bright that it obscures the outer regions
Ecliptic the apparent path of the sun against the background of stars over the course of a year
celestial sphere An imaginary sphere of very large radius surrounding Earth to which the plants, stars, sun, and moon seem to be attached
Spectrum a prism split light into the rainbow of light
what telescope can use infrared, ultraviolet measurments, and optical hubble space telescope
constellation A pattern of stars formed in the sky
sunrise the daily event of the sun rising above the horizon
inertia the tendency of a moving object to continue in a straight line or a stationary object to remain in place (p53)
Radial Velocity velocity along the line of sight toward or away from the observer.
circumpolar - stars remain above the h___ and move c____ clockwise in the sky horizon, counter
focus one of the two points inside an ellipse, the sum of whose distances from any point in the ellipse is constant
Prograde motion normal direction of motion for most objects in solar system. when viewed from above it is the counterclockwise motion of planets around sun and counterclockwise spin of a planet on its axis
Seyfert galaxy galaxy with a large bright center (maybe from a black hole)
Asteroid A piece of rock similar to the material of planets and is located in the Asteroid belt between Mars and Jupiter. Orbits the sun.
dark energy causes the expansion of the universe to accelerate
waxing crescent the Moon's crescent phase that occurs just after the new Moon
The radiation released by the Big Bang can still be seen today as CMBR
venus the planet second in order from the sun, having an equatorial diameter of 7521 miles (12,104 km), a mean distance from the sun of 67.2 million miles (108.2 million km), a period of revolution of 224.68 days, and no moons. It is the most brilliant planet i
Geostationary Orbit orbit that allows a satellite to be always located above the same location on the earth
Oort Cloud Is a sphere and is believed that comit's come from this cloud.
steady state theory theory that suggests that the universe always has been the same it is now. the universe always existed and always will
light year a distance that life travels in one year, 9.5 million kilometers
Penumbral Eclipse When the moon passes through only the earth's penumbra.
neap a ------ tide occurs when the sun is at right angles to the line between earth and the moon
radio telescope a device used to detect radio waves from objects in space
Spring Equinox When the Sun is directly above the Equator; 12 hours of daylight, 12 hours night at the Equator; occurs on 3/21.
Stefan-Boltzman Law F = σT^4
F = Energy Flow
σ = SB constant (sigma)
T = Temperature
The higher the temperature = More intense Light is
Tycho Brahe said moon and sun orbit the earth, planets orbit the sun, contributed an extensive set of position measurements of planets, comets, supernovas
Unbound Orbit an orbit in which the velocity is greater than the escape velocity
asteroid belt a region between the orbits of Mars and Jupiter where many asteroids occur
- Hottest Planet
-1 year is 243
- 1 day is 225
reflecting telescope a telescope that uses one or more mirrors to gather light
radial velocity (Vr) a component of an object's velocity directed away from or toward Earth
solar (star) system a star and all the material which orbits it, including its planets and moons
continuous spectrum a spectrum of light over a range of wavelengths without any spectral lines
Antipodal Point A point that is on the direct opposite side of a planet
What is the Red Giant instability? Pulsations (rapid expansion and contraction) of growing amplitude results in ejection of an envelope of stellar material.
impact basin a hollow left on the surface of the Moon caused by an object striking its surface
what kind of pressure supports a white dwarf electron degeneracy pressure
revolves this is the path around the sun that a planet travels
stile a series of steps or rungs by means of which a person may pass over a wall or fence that remains a barrier to sheep or cattle.
Zodiac Constellations Rise in east, set in west. (as seen in south)
Virgo - Spica
Scorpio - Antares
Taurus - Aldebaran
Gemini - Pollux
Leo - Regulus
When do eclipses occur? When the moons shadow hits the Earth or the Earths shadow hits the moon.
leap year Used to account for 1/4 of a day each year. Every 4 years add 1 day (February 29).
Change in energy across electromatic spectrum Low frequency = longer wavelength, radio waves etc into high energy=shorter wavelength, xrays, gamma rays
Radio waves and all other electromagnetic waves travel at the
speed of light.
What speed do Radio Waves travel at?
Newton's First Law of Motion This states that an object at rest will always stay at rest and an object in motion will stay in constant motion with speed and direction unless acted on by an outer force.
Mass of Main Sequence Star Low mass is defined as <10.0 Solar masses Low mass (Sun-Like) then Planetary Nebula then white dwarf High mass(>10 solar masses) then supernova type II then neutron star or black hole
What does the Big Bang Theory state? Galaxies were created by a BIG explosion
Which of the following is NOT a
reason for the difference in appearance
between Jupiter and Saturn (belts and zones)?
Saturn has a weaker magnetic field
How does matter store energy? (Electromagnetic energy in particular)
First, by virtue of their mass, the possess mass-energy in the amount mc^2. Second, the posses kinetic energ by virtue of their motion. Third, and most important to reading the messages encoded in light, atoms contain electrical potential energy that depends on the arrangement of their electrons around their nuclei.
–The energies of electrons in atoms correspond to particular energy levels.
–Atoms gain and lose energy only in amount corresponding to particular changes in energy levels.
For a star to remain at constant size and temperature, what must be true? The star generates As much energy as it radiates
The presence of a Mercurian magnetic field is somewhat surprising because C. theory predicted that Mercury was spinning too slowly for one
The presence of a Mercurian magnetic field is somewhat surprising because A. Mercury is low in iron
B. Mercury is too close to the Sun
C. theory predicted that Mercury was spinning too slowly for one
D. Mercury has no satellites
E. Mercury is too hot for its interior to have differentiated
Venus is never seen at midnight because it is closer to the Sun than is Earth
A star near the lower right of the H-R diagram is likely to be C. red with low luminosity
A star near the lower right of the H-R diagram is likely to be A. red, with high luminosity
B. blue, with high luminosity
C. red, with low luminosity
D. hot, bright and very large
e. yellow, with luminosity similar to our Sun's