Complete List of Terms and Definitions for AST107 3

Terms Definitions
Discovered Uranus: Herschel
Meteorite Has hit the ground
Tranformation, veryshort range Weak force
heat transfer LOOK FOR BOOK INFO
Ultra-violet (UV) radiation the cause of sunburns
The larger terrestrials planets have surface features that tend to be more rocky
Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars behind the clouds appear redder
Culmination of the geocentric Solar System: Ptolemy
Can electron waves assume
just any form?



 null
The sidereal period of the Earth around the sun is measured as a(n): year
Quantum pressure Electrons cannot occupy the same region of space if they have the same energy. As matter is squeezed down, electrons develop more "uncertainty" energy depending only on the density and independent of temperature. With this pressure a star cannot regulate its temperature
Callisto the Jupiter moon that is NUMEROUS impact craters and has no sign of geological activity
terminator the line that seperates day from night
Uranus and ________ are very similar in size, mass, and color. Neptune
mass-luminosity relation the direct relationship between the masses and luminosities of main-sequence stars on the H-R diagram
Earth's magnetic field interacts with the solar wind to create: The aurora.
molecular cloud Cool, dense interstellar clouds in which the low temperatures allow hydrogen atoms to pair up into hydrogen molecules (H).
Longest day and shortest night. Sunrise/set is farthest northHighest position of the sun at noon. Summer Solstice
The planet with the length of solar day most different from Earth's is Venus.
Olber's paradox If the universe is homogeneous and isotropic, it must be uniformly populated with stars and galaxies. If you look at the night sky, any line of sight should eventually encounter a star. This implies that the entire night sky should be bright. Of course, this is not the case. This contradiction is known as Olber's paradox. In order to resolve Olber's paradox, we must look at the large-scale behavior of the universe.
The method of spectroscopic parallax is used to find the ____ of a star through knowledge of its _____. distance, spectral type
The chief gas in the martian atmosphere is carbon dioxide
flame test since the taste test was rather detramental, kirchoff and bunsen created the.....
Which of these moons has the densest atmosphere? Titan
photosphere the visible surface of the Sun, where the temperature averages just under 6000K
Fusion process hydrogen combines with helium in the sun
white dwarf a low-mass stellar remnant that has exhausted all its thermonuclear fuel and contracted to a size roughly equal to the size of the earth
Do the planets orbit around a similar plane? Yes
During which of the following days is the time of daylight the longest in the Southern Hemisphere? December 12
Secondary Craters formed by ROCKS EJECTED from the main impact area falling back to the surface
A long, thin cloud that stretches up from the horizon and ends directly overhead would have an angular size of ________. 90 degrees.
At which planet can the pole remain in darkness for 42 years, then have 42 years of constant daylight? Uranus
Perihelion When the a planet is closest to the sun in its orbit.
Spectral Classes Oh, Be, A, Fine, Guy, Kiss, Me (hottest ---> coolest)
O, B, A, F, G, K, M
B0-B9 (hottest ---> coolest)
apparent brightness energy per time per area detected by an object on earth
equinox the sun rises in exactly east and sets in exactly west in an...
What are these clouds made up of? Gas and dust
If the moon is past full and before third quarter, the phase is called waning gibbous
What type of object will a white dwarf eventually become? black dwarf
How hot is the Photosphere said to be? 6,000 degrees kelvin
• The light coming from a star has a dominant wavelength of 1000 nm. How hot is the star in degrees Kelvin? 2900k
eclipsing binary a binary star system in which the two stars happen to be orbiting in the plan of our line of sight, so that each star will periodically eclipse the other
What law explains why a collapsing cloud usually forms a protostellar disk around a protostar? conservation of angular momentum
Beyond red are ___ light, beyond ____ is ____ waves Infrared, infrared, radio
Neptune is so blue because methane in its atmosphere absorbs the more red part of the light that reaches it from the Sun.
On what day will the sun have a right ascension of 0 hours? Vernal Equinox.
The mass range for neutron stars is 1.4 to 3 solar masses
Mercury exhibits an extreme range of temperatures from day to night because: It has no substantial atmosphere.
What are the major gases that make up Uranus and Neptune? Hydrogen and helium.
Milky Way stars can group together as members of: open clusters and globular clusters
Kepler's third law equation p^2 = a^3 The square of each planet's orbital period is equal to the cube of its average distance (the semi-major axis) from the sun.
Provided following are various stages during the life of a high-mass star. Rank the stages based on when they occur, from first to last. 1. Contracting cloud of gas and dust
2. Protostar
3. Main-sequence Star
4. Red Supergiant
5. Supernova
6. Neutron Star
Remember also that high-mass stars progress through all these stages at a much faster rate than lower-mass stars. The highest-mass stars may be born, live, and die in only a few million years. Note also that while this particular high-mass star leaves behind a neutron star after its supernova, an even higher-mass star may instead leave behind a black hole.
Evidence for the Big Bang: (THIS IS IMPORTANT TO KNOW) 1. Expanding Universe: Galaxies uniformly moving & expanding.2. Nucleosynthesis: the Universe was hot & dense enough to be a nuclear furnace.3. Cosmic Microwave Background: The UV photons that escaped after 
recombination have been expanded down to microwave wavelengths (3K)4. Fluctuations in the CMB: 1 part in 100,000: need to be small, or the 
Universe would be too lumpy. Yet need to be there, or the Universe would
 be a smooth gas and could not form stars and such.
How does a main-sequence star's luminosity depend upon its mass? the more massive the star, the more luminous
The Kuiper Belt is found where in the solar system? beyond the orbit of Neptune
Supernova Explosions Type II once a red giant fuses to an Fe core, it can no longer support itself against gravitational pull because Fe doesn't release energy when fusing to push against gravitational pull. Gravity causes it to implode in a collapsive supernova
- lots of H in spectrum
- 1 star
The solar nebula hypothesis explains that: All planetary orbits are in the same direction; all planetary orbits lie nearly in the same plane; planets nearest the sun contain mainly high temperature condensates; all planets and the sun, to the extent that we know, are the same age.
The General Theory of Relativity was able to explain: the bending of light by gravity and slight changes in Mercury's orbit that weren't explained by Kepler's Laws
Which of the following statements is probably true about the very first stars in the universe? They were made only from hydrogen and helium.
Which of the following describes a star with a hydrogen-burning shell and an inert helium core? It is a subgiant that grows in luminosity until helium fusion begins in the central core.
Subgiants become more luminous until helium fusion ignites; their cores then expand and they become somewhat less luminous (though still brighter than they were as main-sequence stars).
Eclipsing binary systems allow us to determine: the masses of two stars and the radii of the two stars
In a fairly young star cluster, if the most massive stars are swelling up into giants, the least massive stars are continuing to shine as main sequence stars
What is the minimum mass for a star, and why can't objects with lower masses be true stars? An object must reach a large enough mass that pressure and heat inside its core is high enough to start the process of nuclear fusion. Only then is it considered a true star.
• What is the unit that we use to measure distances in the solar system? The astronomical unit or AU is very convenient.