Astronomy Exam1 4 Flashcards

Terms Definitions
Waxing Gibbous
hecto (h)
10-2
Healthy Star
fusion reaction
pulsar
spinning neutron stars
Saturn interior
similar to jupiter
geocentric cosmology
earth is centter
nebulosity
nebulous or nebular matter.
Penumbra
lighter part of the shadow
Oddities
1. Venus' rotation (collision)
2. Earth's moon (impact theory?)
3. Uranus on its side (Collison)
4. Neptune's retrograde moon (capture)
5. Mercury's orbit (collison)
rotation
Earth's spinning on its axis
Conjunction
Sun between planet and Earth
Galaxies
gigantic collection of stars, star clusters, and nebula held together by gravity, contain trillions of stars
mass
The single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar is its
Trojans
asteroids ahead of and behind Jupiter
Europa
Has potential for oceans with water
Gamma rays
Region of the electromagnetic spectrum, far beyond the visible spectrum, corresponding to radiation of very high frequency and very short wavelength.
Center of Milky Way
Intense infrared radiation
supermassive black hole
in the direction of Sagittarius A from earth
how many moons does mars have?
2
Saturn
gas planet(hydrogen & helium), rings made of ice and rock, 20 moons (titan is largest)
orbit
Curved path a satellite around Earth
Sirius
the Dog Star, the brightest-appearing star in the heavens, located in the constellation Canis Major
compression
leads to extreme heating of the Earth's interior
nebula
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
telescope
a device built to observe distant objects by making them appear closer
Ice Giant Composition
Water, ammonia, methane. Probably covered in huge, salty oceans due to high pressure and large magnetic fields.
Planet
Any big round celestial body that orbits the sun
H-R diagram
Hertz sprung-Russell diagram, a graph that shows the relationship between magnitudes and temperature.
Net Force No
Elevator moving at constant speed
Active optics
a technique using computer controlled mirrors to sharpen images distorted by the atmosphere
AU
The mean distance between the earth and the sun.
comets
A celestial object consisting of a nucleus of ice and dust and, when near the sun, a "tail" of gas and dust particles pointing away from the sun
parallelism
axis always points in same direction when orbiting
Stars that are approx. within 16.5 light years from earth
30
Big Bang
most accepted theory, universe once was condensed->large explosion
supergiant
stars that burn their fuel quicker than average stars
Mercury's volume is only about _____ of Earth's.
5.5%
alpha
used to designate the brightest star in a constellation
Solar Flare
an explosive release of energy that comes from the sun and that is associated with magnetic disturbances on the sun's surface
Venus Rotation and revolution
rotation-247 days revolution -225 days, rotates slowly backward or the wrong way
Gravity
a force of attraction between any two masses that causes accretion
neutron star
a very compact, dense stellar remnant composed almost entirely of neutrons.
False
A day on Uranus at the equator (sunrise to sunrise) is the same throughout the year.
what is the nucleus of halleys comet
very dark
eclipse
when an object in space comes between te sun and a third object,it casts a shadow on that object
autumnal equinox
first day of autumn (fall) -- september 23
every point on earth will experience a total solar eclipse once every _____yrs
400
intertia
The tendancy of a moving object to continue in a straight line or a stationary object to remain in place.
how much stronger is the gravitational pull of the sun on earth, at 1 au, than it is on saturn at 10 au?
100 times
astronomical unit (AU)
The average distance (semimajor axis) of the Earth from the Sun, which is about 150 million km
Aphelion
The place in the Earth's orbit where Earth is farthest away from the sun.
1 minute after Big bang
temperature decreased lightest particles could not be createdthrough interactions, matter came to dominate anti-matter
Neutron Stars
are the remains of high-mass stars after a supernova
astronomical unit
The average distance between Earth and the sun, about 150 million kilometers
Intrinsic brightness of a star; the apparent visual magnitude the star would have if it were 10 pc away
Absolute magnitude
synodic
pertaining to a conjunction, or to two successive conjunctions of the same bodies.
Main sequence
the narrow band of stars going from upper left to lower right on a H-R diagram
apparent magnitude
the brightness of a star when viewed from Earth
winter
when it is summer in the U.S. south america has
roche limit
distance from a planet inside of which gravitational tidal forces tend to disrupt satellites
Refraction
The bending of light as it passes from one material to another; A way to gather and focus light
infrared light
used to penetrate dust to see galaxy's center
homogenous and isotropic
this means universe not infinite and unchanging
order of electromanetic radiation
radio, micro, infrared, visible light, ultra violet, X-ray, gamma
The Kuiper Belt is located
slightly outside Neptune's orbit,
near Pluto's orbit
new moon
appears as no moon, moon is blocking sun
frequency
the number of peaks or troughs of a wave that pass a fixed point each second. also, the number of complete vibrations or oscillations per second.
geocentric
having the earth as the center of the system of planets
radiation zone
the region inside a star where energy is carried outward as photons
Latitude
(N-S)The # of degrees of arc you are either N or S of Equator (0-90_
Celstial north and south poles
Poinbt celstial sphere rotates each day
How have we discovered planets that orbit other stars? What are they like?
•Extrasolar Planets or exoplanets.
•Very small and dim compared to stars. Both the planet and star move in elliptical orbits around a point called the center of mass.
large parallax
A near-by star is more likely to have ___.
absolute magnitude
a measure of the amount of light that a star actually emits
ELECTROMAGNETIC SPECTRUM
The range of all the waves that can travel through matter as well as empty space.
Red Giants
A star that has a surface temp of about 3000*F and has a diameter from 10 to 100 times bigger than the sun
white dwarf
The blue-white hot core of a star that is left behind after its outer layers have expanded and drifted out into space
The phases of the moon are causes by
the moon's reolution.
Thomas Wright (1750)
Proposed the Milky Way was due to a thin band of stars (like a shell).
o Thought Universe was spherical.
o God at the center of the Universe.
o Speculated that others stars were like the Sun with planetary systems.
o God directed orbits, center of universe.
A x f = c
Wavelength x frequency = speed of light
circumpolar stars
stars that are up all night and do not rise or set
celestial poles & equator
earths poles and equator extend to the sphere
Van Allen Radiation Belts
The Van Allen radiation belt is a torus of energetic charged particles (plasma) around Earth, which is held in place by Earth's magnetic field.
There are no auroras on Venus because it
lacks a strong magnetic field.
what is a solar wind
it pushes a tail away from the sun
You note that a particular star is directly overhead. It will be directly overhead again in
C. 23 hours 56 minutes
You note that a particular star is directly overhead. It will be directly overhead again in
A. 1 hour
B. 12 hours
C. 23 hours 56 minutes
D. 24 hours 4 minutes
E. 1 year
What is a standard candle?
An object for which we are likely to know the true luminosity
Astronomers collect data on the state of the universe at different ages by
Looking at objects that are different distances from the Milky Way Galaxy.
Light takes different times to travel different distances.
What do the inner planets have in common?
They all of solid, rocky surfaces
Life History of a High-Mass Star
-Same phases as for low mass star up to formation of inert
carbon core, but all these phases happen much faster
what is kepler's second law?
a line from the planet to the sun will sweep out equal are in equal time.
A G2V star shines with magnitude m=4.8. How far is it?
10 pc. The properties of ANY G2V star are (almost) the same as the sun's. So its absolute magnitude must also be M = 4.8, as the sun. m=M only at 10pc.
Why does it need to be dark for a planet to form?
-Keep light out so it won't heat
-Dust grains absorb photons of light
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