vocabulary and astronomy notes Flashcards
blackhole
a massive star that has collapsed to such a small volume that its gravity prevents the escape of everything, including light
comet
a small body made of rocky and metallic pieces held together by frozen gases; comets generally revolve about the sun in an elongated orbit
constellation
an apparent group of stars originally named for mythical characters; the sky is presently divided into 88 constellations
galaxy
a group of stars, dust, and gases held together
main-sequence star
a star that falls into the main sequence category on the H-R diagram
this category contains the majority of stars and runs diagonally from the upper left to the lower right on the H-R diagram
meteor
the luminous phenomenon observed when a meteoroid enters earth’s atmosphere and burns up, popularly called a shooting star
meteorite
any portion of a meteoroid that reaches earth’s surface
neap tide
lowest tidal range
occurring near the times of the first quarter and 3rd quarter phases of the moon
nebula
a cloud or gas and/or dust in space
spring tide
highest tidal range that occurs due to the alignment of the earth moon and sun
supergiant
a very large, very bright red giant star
tide
daily change in the elevation of the ocean surface
aphelion
the place in the orbit of a planet where the planet is farthest from the sun
astronomy
the scientific study of the universe; it includes the observation and interpretation of celestial bodies
big bang theory
the theory that proposes that the universe originated as a single mass which subsequently exploded
doppler effect
the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer
electromagnetic spectrum
the arrangement of electromagnetic radiation according to wavelength
ellipse
an oval
geocentric
describes the concept of an earth-centered universe
greeks believed this
heliocentric
describes the view that the sun is at the center of the solar system
aristarchus(greek) believed this
he found planets relative distance
light year
the distance light travels in a year, about 9.5 trillion kilometers
nuclear fusion
the way in which the sun produces energy; Nuclear Fusion occurs when less massive nuclei combine into more massive nuclei, releasing tremendous amounts of energy
perihelion
the point in the orbit of a planet where it’s closest to the sun
precession
a slow motion of Earth’s axis that traces out a cone over a period of 26,000 years
revolution
the motion of 1 body about another as Earth about the sun
rotation
the spinning of a body, such as Earth, about its axis
galileo galilei
described the behavior of moving objects
- there are four moons orbiting jupiter
- planets are circular
- venus has moon phases
- the moon isn’t smooth it has holes and its rough
- the sun has sun spots
universal gravitation
every body attracts every other body
gravitational force is stronger with a larger distance
mass is greater when there is less gravitational force
johannes kepler
found 3 laws of planetary motion
orbit is an ellipse
planets go faster when closer to the sun
orbital revolution period is in earth years
The big bang theory
universe started as something smaller than an Atom( singularity ) and expanded
not big and not loud it was 13.8 billion years ago it’s still expanding today and it created everything
star
celestial body that emits light which is generated by nuclear energy it’s made of gases and plasma held together by gravity
a body of gases that gives off a tremendous amount of radiant energy in the form of light and heat
planets
celestial body that orbits the sun and has a nearly round shape due to its gravitational force and has cleared it’s orbital path
Solar system
A star in all of the planets that orbit around it
Galaxy
A large collection of interstellar material solar systems and dark matter that’s held together by gravity
universe
all of time space and its contents
geocentric model
model of the solar systems that states that the earth is the center of the solar system
heliocentric model
model of the solar system that states that the sun is the center of the solar system and the planets revolve around it
copernicus then galileo
Kepler’s laws of planetary motion
first law is planets orbit the sun in a path called an ellipse
Second law planets move fastest when they’re closest to the sun in their orbits
third law the farther away a planet orbits the longer the planet takes to revolve around the sun
ellipsoid earth
The earths diameter is wider at the equator than at the polls it’s not a perfect sphere
this is caused by the rotation of the earth and the centrifugal force perpendicular to it
revolution
movement in a predictable orbit around another object
revolution of the earth facts
The earth revolves around the sun and it takes 365.24 days(1 year)
rotation
spinning around on internal axis
earths rotation facts
Earth rotates counterclockwise and it takes 24 hours ( one day)
axis of earth facts
The earth is tilted on a 23.5° angle on its axis and the tilt of earths is the reason day and night are 12 hours each and why we have seasons
differential heating of water versus land
water heats up more slowly than land and water cools down more slowly than land
precession
change in the direction of the access but there’s not change in the 23.5° tilt
nutation
A wobble around the earth’s axis 1/2° change / 18 year period
due to moons gravity
barycenter
The balance between the masses of the planets as they orbit
constellations
A group of stars that form a pattern in the sky there’s 88 different ones
light year
The distance like to travel in one year which is 9.5 trillion km
it takes eight minutes for the suns light to reach earth
visible light
A small part of the electromagnetic spectrum
spectroscope
separate light into different colors
hydrogen and helium are the most abundant elements in stars
Doppler effect
apparent shift in the wavelength of light admitted by a light source moving toward or away from the observer
Blue shift
light waves appear to have shorter wavelength as the star moves toward the earth the spectrum shifted toward blue end
red shift
light waves appear to have a longer wavelength as the star moves away from the earth the spectrum shifted toward red end
a star forms when
nuclear fusion begins
Fusion
The joining of two or more atomic nuclei
different from nuclear fission which splits atoms
main sequence star
longest stage of life cycle- nuclear fusion releases energy
Black hole
Hole in space with gravity so great that not even light escapes – form from collapsed supernova
galaxies
large scale groups of stars how together by gravity – there are at least 100 billion galaxies – we are in the Milky Way galaxy – within one of the special arms
spiral
right center of stars with arms spiraling out
comet
composed of dust rock frozen water and gas
astroid
solid rock like mass irregular in shape
meteoroid
Rock or icy fragment moving through space – can’t be large as a boulder or as small as sand
meteor
light made by meteoroid as it passes through earths atmosphere
meteorite
A meteoroid that land on earth – most to burn up before striking the surface
phases
various shapes of the moon lighted by reflected sunlight – cycle takes about 30 days
waxing
when the size of the visible portion of the moon is increasing
waning
when does size of the visible portion of the moon is decreasing
New moon
no lighted area of the moon is visible from the earth – the moon is always half lit by the sun
Full moon
tire half of the side of the moon facing earth is lit
Crescent
less than half of the side facing the earth is lit
gibbous
more than half of the side facing the earth is lit
tides
daily changes in the level of the oceans – caused by the moons gravitational pool – tide changes every six hours – most areas have two hide tides and 2 low tides each day
Spring tide
tied with maximum daily title range that occurs during new in full moons
neap tides
tides with minimum daily title range that occurs during first and third quarter moons
