Astronomy 107 Flashcards

Terms Definitions
Right Ascension
contain galaxies
-highest gravitationally bound objects
solar day
24 hours
Spin around an axis
physics of the normal
Harlow Shapley
discovered globular clusters
spherically symmetric clusters of 50,000-100,000 stars
most clusters in same half of sky
sun not center of galaxy
red dwarf
a low-mass main-sequence star.
the center of the sun
Dark colored, low silica contents
What is declination?
like latitude, horizontal
a zodiacal constellation between Gemini and Aries, containing the bright star Aldebaran also called the Bull
NOT a form of electromagnetic radiation
Large and rocky. Scientists believe Demios is an asteroid caught by Mars gravity.
the repetitive gravitational tug of one body on another when the orbital period of one is a multiple of orbital period of the other
-similar to latitude on earth
-parallel to celestial equator on earth
-increments of 15 degrees
0-90 degrees + (N) or 0-90 degrees - (N)
- zero pt of latitude = equator
mercury has how many moons?
no moons
one direct method of measuring distance
An instrument that separates light into colors and makes an image of the resulting spectrum
the study of interaction of electromagnetic radiation with matter
a male given name, form of
Earth rotates at a __._ degree angle
absolute zero
The temperature at which thermal motions cease. The lowest possible temperature. Zero on the Kelvin temperature scale.
doppler effect
change in wavelength due to motion
when saturn is not visible from earth
Two Moons: Phobos and Deimos; small irregular shapes, not like our moon, more like captured asteroids
Earth's interior
solid crust, semi-solid mantle, liquid core, solid core
Shepherd moon
-A satellite that, by its gravitational field, confines particles to a planetary ring
-Responsible for Encke gap in Saturn's rings
number of wave crests passing any given point per unit time
larger circle around which the planets orbit the earth/sun
large rocks orbiting between mars and jupiter
The glowing light display that results when a planet's magnetic field guides charged particles toward the north and south magnetic poles, where they strike the upper atmosphere and excite atoms to emit photons.
GUT Epoch
After 10-^43 seconds, temperature fell to 10^32 K
in the habitable zone, surface water must be at least partially ______ in phase.
distinctive patterns in the night sky formed by groups of stars
Neutron stars are made of...
Type II Supernovae
speed of light in a vacuum
c=3.00x10^5 km/s
objects that are too small and too numerous to be considered planets.
Using shadows he was able to determine a fairly accurate measurement for the size of the Earth
the point in the sky directly beneath your feet
the study of the moon, stars, and other objects in space
the hubble space telescope is a _
cassegrain focus
Lunar Eclipse
occur when the full moon coincides with a node, earth is exactly between the sun and moon, 29 lunar eclipses
Hertzsprung-Russell diagram
a graph relating the temperature and brightness of stars (p108)
where would a small asteroid do the most damage hitting if it didn't directly hit a populated area
These are caused by the Earth's orbit and its' tilt on its' axis.
The path of an object around another object
Doppler Shift
if source and receiver get close, frequency of received waves will rise; if moving away, this goes down
t/f an E7 galaxy is an elliptical galaxy which is stretched out like a cigar?
irregular galaxies
does not have regular shapes, are typically smaller than other types of galaxies, and hace lots of gas and dust and form new stars
the use of two or more telescopes connected together to operate as a single instrument
a unit of temperature on a specified scale
continuous spectra
-relatively smooth variation of I with [wavelength]
-almost always produced by hot solid objects or hot ionized gas.
-known as blackbody radiation
the brightness of a star in comparison with that of the sun: the luminosity of Sirius is expressed as 23 and indicates intrinsic brightness 23 times greater than the sun
The time for half the nuclei in a substance to decay.
The Planet's
Planet's do not make light on there own. They reflect light off the sun making them appear to have a steady light, they do not twinkle.
Asteroid Belt
The region of the solar system between the orbits of Mars and Jupiter, where many asteroids are found.
The two days of the year on which neither hemisphere is tilted toward or away from the sun.
synchronous rotation
Because of the Moon's ___ an observer on Earth can at most see about 50% of the Moon's surface.
the periodic rise and fall of the sea level under the gravitational pull of the moon
the bending of light as it passes from one material to another.
point or time at which the sun is farthest from the equator
big bang theory
states that approximately 12 to 15 billion years ago, the formation of the universe began with a fiery explosion
heaviest atomic nuclei found on earth were made in what
a planetary nebula
the rate and direction of change of an object's position with time. Units meter per second (m/s) or kilometers per hour (km/h)
a group of stars that forms a pattern resembling a familiar object,character,or animal, and that changes position throughout the year because Earth moves
North Celestial Pole
On the celestial sphere, the star Polaris is found very near the..
Apollo 11
name of the mission that first landed on the moon
What is gravitational equilibrium?
The natural balance balance between the two competing forces of gravity (pulling inward) and pressure (pushing outward).
space based observatory
any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects
law of inertia
the physical law that an object will stay at rest or move at a constant speed in a fixed direction unless acted upon by an outside force
New and Full
What phase of moon do spring tides occur?
Top Down view of NGC 2997 shows what?
Spiral arm structure.
irregular galaxy
A galaxy that does not have a regular shape.
Full moon
the entire bright side of the moon can be seen on earth
Hydrogen & protons
What provides fuel for a main sequence star?
Annular Eclipse
sun is directly behind the moon but a ring of sunlight can be seen around the blackened moon
planetary nebula
a nebula that was once thought to be a star with its planets but is now thought to be a very hot star surrounded by an expanding envelope of ionized gases that emit a fluorescent glow because of intense radiation from the star
• From Kepler's third law, a hypothetical planet that is twice as far from the Sun as Earth should have a period of -
more than 2 Earth years
Order of Phases
Ful, Wan Gib, 1st, Wan Cres, New, Wax Cres, Last, Wax gib
The existence of convection currents in a planet's atmosphere requires that
A. the temperature decrease with altitude.
The existence of convection currents in a planet's atmosphere requires that
A. the temperature decrease with altitude
B. the temperature be sufficiently elevated
C. the density decrease with altitude
D. The planet rotate sufficiently rapidly
E. The planet be geologically active
circumfrence of a circle =
2 pi x radius = 2 pi r
what determines the stregnth of gravity
mas of the objects and distance between them
Four proofs that the earth rotates
Coriolis Effect, Star Trails, Day & Night, Foucault's Pendulum.
Why does Venus not have many craters?
Due to thick atmosphere and active volcanism
What are the Stats of the Spiral Galaxies? 3
1.Luminous central bulge, spiral arm structure illuminated by young O and B stars, dust and gas in the disk.
2. Sites of on-going star formation
3. Sa --> Sc, smaller bulge; arms unwind; more gas and dust.
How are protostars traced as an evolutionary track using the HR diagram?
By the change in temperature and luminosity with time
what is the difference between a solar and lunar eclipse? explain what causes each and why more people see a lunar eclipse.
solar eclipses occur when the moon's shadow falls on earth. lunar eclipses occur when earth's shadow falls on the moon. because earth's shadow is large compared with that of the moon, everyone on the night side of earth can see a lunar eclipse. the moon's shadow on earth is relatively small, so only those people inside the shadow can see a solar eclipse.
Pluto has been demoted from the status of a major planet primarily because
A. it has characteristics similar to other discovered Kuiper Belt objects
Pluto has been demoted from the status of a major planet primarily because
A. it has characteristics similar to other discovered Kuiper Belt objects
B. it does not have a magnetic field
C. it does not have satellites
D. it does not have an atmosphere
E. its orbit around the Sun is retrograde
What conditions are required for a lunar eclipse?
The phase of the moon must be full, and the nodes of the moons orbit must be nearly aligned with earth and the sun
Lunar eclipses do not occur every new moon because
Because the path of the moon is tilted relative to the ecliptic
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