astronomy 2 Flashcards
a pendulum swings in a constant path
the earth rotates beneath it
focaults pendulum
earth moves around the sun
takes approximately 365 days
almost circular orbit
we are slightly closer to the sun in January than we are in July
earths revolution
when is the earth closest to the sun
147million km
January 2nd
when is earth farthest from the sun
152 million km
July 4th
apparent shift in position of a nearby star in relation to distant stars
parallax
a day is added every4 years to February to catch up
leap year
when is the next leap year
2020
changing constellations
we see different ones because we revolve around the sun
we can on,y see the constellations that are opposite the sun
Revolution
what is earths axis tilted at
23.5 degrees
what season is it while the sun is tilted toward the sun
summer
which season is it when the earth is tilted away from the sun
winter
when the earth is tilted neither toward nor away from the sun it is…
either spring or fall
what causes seasons
earths Revolution
earths tilt
earths axis
the Suns height above the horizon changes during the year
suns position
when is the sun the highest in the sky for Erie and when is it the lowest
highest- summer solstice
lowest- winter solstice
when does the sun rise into he east and set in the west
during the equinoxes
where does the sun ride and set in fall and winter
rise-southeast
set- southwest
where does the sun rise and set during spring and summer
rise- northeast
set- northwest
projection of the earths equator into space
calculate by subtracting current latitude from 90°
celestial equator
where is the celestial equator at earths equator
directly overhead
where is the celestial equator at the North Pole
the horizon
what is Eric’s latitude
42° north
the path that the sun travels in the sky
the signs of the zodiac are located along this
ecliptic
revolving toward full
waxing
revolving toward new
waning
moon revolves around earth in about how many days
29
how often does the moon rotate
once in 27 days
formed from a collision with a Mars-sized object
approximately 4.6 billion years old
debris from collision
after the surface cooled and became solid the surface was bombarded by meteoroids
formation of the moon
diameter is 3476km Gravity is 1/6 of earths mass is about 1/80 of earths mass average density is less than earths rocks are igneous
moons properties
spins on its own axis
produces night and day
takes approximately 24 hours
1000 mph
earths rotation
3.1-3.8 billion years old
Maria basins of basalts
4.0-4.3 billion years old
lighter colored parts of the moon
lunar highlands
moon has no…
atmosphere
what causes erosion
micrometeorites
objects in orbit around the sun
solar system
what is included in a solar system
planets
moons
asteroids
comets
developed a system to explain the planets motions
did not account for all of the motions seen
Ptolemy
developed a sun-centered model
heliocentric
accounts forge motions of the planets much more accurately
Copernicus
elliptical orbits
planets move faster near the sun
planetary motions
cloud of gas and dust
pronto-planetary disc
pulls particles together
Gravity
forms fusion of hydrogen
sun forms
form from remaining material through accretion
planets
four planets nearest the sun contain heaviest elements terrestrial planets have solid surfaces dense cores Mercury, Venus, earth, and Mars
inner planets
four planets beyond the asteroid belt gas giants no solid surface made up of gases solid cores Jupiter, Saturn, Uranus, and Neptune
outer planets
when an object in space passes into the shadow created by another object in space
two parts
eclipse
total shadow
umbra
partial shadow
penumbra
moon passes into the earths umbra
total lunar eclipse
moon passes into earths penumbra
half of earth can see this
about 2 hours long
partial lunar eclipse
moons umbra falls on the earth
total solar eclipse
moons penumbra falls on the earth
partial solar
ring is visible
moon doesn’t quite cover the sun
annular eclipse
movement of the earths axis
axis wobbles slowly over time
26000 years for 1 cycle
axis points at the North Star
precession
no longer accurate due to precession
zodiac signs
occurs when the sun is at its highest point
does not occur at the same time for everyone
solar noon
every degree of longitude is ______ mins of solar time
4 mins
how much does earth rotate every hour
15°
used to deal with different solar time
time zones
USA times zones
Eastern
Central
Mountain
Pacific
eastern
our time
central
minus 1 hour
mountain
minus 2 hours
pacific
minus 3 hours
used to save energy
adjust clocks to deal with changes in sun rise and set because of the earths tilt
daylight savings time
move clocks 1 hour ahead
spring
move clocks back 1 hour
fall
180° meridian
date changes
if you move west you add a day
if you move east you lose a day
international dateline
