AST Test a Flashcards

Black hole
Terms Definitions
violet
400nm
C
-273 0 100
Quasar spectra
are strongly redshifted
Venus
Runaway greenhouse effect makes scalding
Three laws of planetary motion:
Kepler.
parallax
d=1/p, Only works for nearby stars
precession
astological signs no longer correspond to the location of the sun on your b-day b/c of...
In some cases, astronomers have detected extrasolar planets as they pass in front of their stars.
True
kepler
described the shape of planetary orbits as well as their orbital speeds
In what general direction does the planet Mars set?
westerly
isotropic
Assumed property of the universe such that the universe looks the same in every direction.
Objects with the smallest diameters are:
white dwarfs
Short Period
comet: orbits LESS than 200 years
Red light burns _____ than blue light
Cooler
Unlike Jupiter and Saturn, at Uranus and Neptune the ________ rotates the slowest
equator
accretion
The process by which small objects gather together to make larger objects
Jupiter's diameter is about ___ times the Earth's.
10.
The satellite of Neptune that has active geysers is:
Triton.
How often is `earthrise' at a point near equator of the moon?
Never
astronomical unit (AU)
150 million km (measure of distance)
SN 1572
Tycho SN definitely a Type Ia, exploding white dwarf
Scientific Theory
an idea that proposes to explain observations
Charon's orbit is
highly inclined to Pluto's orbital plane
Atmospheric Drag
friction can cause lose of orbital energy
In a hypernova, a very energetic supernova creates a
black hole
Spectroscopic Binary Stars
figure out gravitational pull by observing doppler shifts in spectral lines. must have a tilted orbit (between face on and edge on binary) and be separted under 1 "arc. MUST BE VERY CLOSE TO EACH OTHER.
black hole
a bottomless pit in spacetime. Nothing can escape from within a black hole, and we can never again detect or observe an object that falls into a black hole
Rilles
lunar canyons, caused by lava flows or crustal cracking
Hubble constant
A number that expresses the current rate of expansion of the universe; designated H, it is usually stated in units of km/s/Mpc. The reciprocal of Hubble's constant is the age the universe would have if the expansion rate had never changed.
The most distant point of the orbit from the sun
Aphelion
Jupiter's mass is
larger than all the other planets' masses combined.
Poles
North can only see stars in the north; South can only see stars in the South
A meteor is
a streak of light in the atmosphere
earth shine
light from the sun reflecting off the earth, revealing the dark side of the moon
A radio-wavelength emission observed by aliens that comes from our solar system with a 24 hour periodic signal shape would come from
human made signals on earth
convection zone
the outer most layer of the sun's interior-hot gases rise and eventually cool as they approach the top
A typical comet nucleus is about ___ across.
10 km.
apparent magnitude
a measure of the brightness of light from a star or other object as seen from earth
Pop III:
First stars. H and He. Only form from)
What is it that is actually located at the event horizon of a black hole?
Nothing specific.
Kirchoff's Laws, Law 3
A low-density, cool gas produces an absorption line spectrum when viewed in front of a continuous source
(The) Disk Component
It consists of all matter confined to a PLANE of ROTATION
The Moon's near side always faces Earth due to
the earth's tidal force
Type of regions star form
cold, dense, interstellar clouds, dark nebula
2. What is the main element to be found in the core of massive stars (mass > 8M☉) at
the end of their life?
(b) Iron
After supporting the Copernicus theory, Galileo discovered what 3 things
Moon has mountains and valleysMily Way is made of countless starsJupiter was accompanied by 4 moons
What observation clinched the idea that the "spiral nebulae" were actually external galaxies rather than part of the Milky Way?
1) Curtis' observation that their spectra had lines from different elements than found in the Milky Way
2) The large red shift observed for M 31
Voyager I was unable to image Titan's surface because of
"smog" in Titan's atmosphere
The Cassini Division is a gap in Saturn's rings caused by
Gravitational interaction with Mimas
Interstellar dust consists mostly of _______.
microscopic particles of carbon and silicon.
These tiny, solid particles are very important, even though their total mass makes up less than 1% of the interstellar medium.
How far away from the sun is Pluto and the Kuiper Belt?
40 AU
A light year is defined as:
the distance that light travels in exactly one year.
Gravitational lensing leads to what?
It causes the light from distant stars to be bent or focused by unseen massive objects in its path.
1. What are the possible objects formed when a star with a mass greater than 8 times
the mass of the sun (mass > 8M☉) dies?
(a) Black Hole or Neutron Star
The magnetic fields of a pair of sunspots in the Sun's northern hemisphere were measured. The leading spot was found to be of north magnetic polarity. What would be the most probable magnetic polarities of a pair of sunspots in the southern hemisphere at
Leading spot south, trailing spot north.
Ch.19 Q#5: Summarize the star-gas-star cycle shown in figure 19.3
Looking at it yourself will help more, anyways it goes from atomic hydrogen clouds to molecular clouds then to star formation to nuclear fusion of stars then it starts to die and returns part of the gas back to hot bubbles and back again.
What is the law of conservation of angular momentum?
An objects angular momentum cannot change unless it transfers angular momentum to or from another object.
If the moon is rising at about 7 am, the phase of the Moon must be:
New (or nearly new)
What is Kepplers 3rd Law?
The cube of the semi major axis is related to the square of the period of a planets orbit.
What most closely describes a neutron star?
mass similar to the sun and diameter similar to San Antonio
In the Milky Way, the Sun is located
at about halfway out from the center
What are the two forces acting on a spinning molecular cloud? Which one has to win in order for a star to be born?
Gravity and pressure; gravity must win
Ch.23 Q#30: Which of the following does NOT provide strong evidence for the Big Bang theory? (a) observations of the cosmic microwave background (b) observations of the amount of hydrogen in the universe (c) observations of the ratio of helium to hydrogen
A and C greatly help the theory as shown in the previoius questions above so the only other choice is B as the amount of hydrogen alone does nothing as we can't really compare much.
A giant impact is thought to have caused the extinction of the dinosaurs:
At the end of the Cretaceous period about 65 million years ago; because a layer of clay enriched in iridium is found at the same geological time; a crater structure possibly dating to the same geological time has been found in Mexico.
What do we mean by the interstellar medium?
The gas and dust that lies in between the stars in the Milky Way galaxy.
Gases (mainly hydrogen and helium) and dust grains (silicates, carbon and iron) filling the space in between stars. The density of interstellar mass is very low. There is about one atom of gas in every cubic centimeter of space. The density of dust is a trillion times smaller. The temperature of the gas is about 100 K.
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