Transcript A Solar System - Cloudfront.net

ASTRONOMY
TERMS
The Universe: Everything in existence. Created around 15 billion years ago
due to the Big Bang. Approximately 30 billion light years in diameter and
expanding at the speed of light. Contains possibly 200 billion galaxies.
A Light Year: The distance that light travels in one year; 5,878,625,373,183.61mi
Light Speed: approximately 300,000 km per second
A Cluster: A grouping of millions of galaxies
A Galaxy: A grouping of around 500 billion solar systems. Many galaxies
revolve around black holes.
TERMS CONTINUED
The Milky Way: Our galaxy
containing up to 400 billion
solar systems. Earth is
located on one spiral arm.
A Solar System: One star
and any planets, dwarf
planets, moons, asteroids,
meteors, and comets that
revolve around it.
CELESTIAL BODIES
Stars: A massive, luminous ball of plasma (ionized gas) that releases energy
due to thermonuclear fusion.
The Sun
CELESTIAL BODIES CONTINUED
Constellations: Man-made groupings of stars usually with mythological
associations, created to provide an explanation concerning how they got there;
used in the past for navigation and astrology.
Polaris: The North Star which can be found
by drawing a line through the 2 pointer stars
in the big dipper. (angle in the sky =
observer’s latitude)
CELESTIAL BODIES CONTINUED
Planets: A body that orbits the sun, is massive enough to be rounded by its
own gravity, and has cleared its neighboring region of planetesimals.
Moons: A celestial body that orbits a planet, or dwarf planet. 240 in solar
system.
THE PLANETS
Terrestrial Planets: Solid inner planets w/ high density: Mer., Ven., Ear., Mars.
Mercury: Closest to
sun, 2nd hottest,
smallest, looks like
moon, many caters, no
atmosphere, visible
from Earth.
TERRESTRIAL PLANETS CONTINUED
Venus: 2nd closest, hottest, extremely thick
atmosphere of carbon dioxide, volcanic activity,
lightning and acid rain possible, visible from Earth
TERRESTRIAL PLANETS CONTINUED
Earth: Life, water, atmosphere of Nitrogen and oxygen, volcanic activity 1
moon.
TERRESTRIAL PLANETS CONTINUED
Mars: 4th planet, red in color, thin atmosphere, 2 small irregular shaped moons,
possibly had/has water.
PLANETS CONTINUED
Jovian Planets: Outer, gas-giant planets; Jupiter Saturn, Uranus, Neptune
Jupiter: 5th planet, largest by far, mostly hydrogen some helium, huge storms at
least 63 moons, (ref. tables says 16), faint rings Jupiter storms Storms 2
JOVIAN PLANETS CONTINUED
Saturn: 2nd biggest, 93% hydrogen, less dense than water, visible rings of ice
rock and dust, around 60 moons, (tables say 18) small rocky core. Hexagonal
storm
JOVIAN PLANETS CONTINUED
Uranus: Hydrogen, helium and frozen ice,
methane and ammonia atmosphere, faint
rings, rotates on its side, small rocky core,
large icy mantle, 27 moons (tables say 21)
JOVIAN PLANETS CONTINUED
Neptune: Furthest
planet, hydrogen,
helium, and methane,
strongest winds at
1,300 mph, faint rings,
13 moons (tables say
8)
DARK SPOT
To Scale
CELESTIAL BODIES CONTINUED
Asteroids: Solar system bodies that are smaller than planets but larger than
meteoroids. (at least larger than 10 meters in diameter) Most can be found in a
belt between Mars and Jupiter.
Meteorites/ Meteoroids
Ceres
952 km
50 km across
+ Meteors: Small sand
to boulder sized debris in
the solar system. (ite=on
the surface, oid= in space,
or = coming through
atmosphere) (Shooting
stars)
253 Mathilde
CELESTIAL BODIES CONTINUED
Comets: Bodies that
orbit the sun with an
extremely elliptical
orbit and exhibit a mini
atmosphere or tail due
to effects of solar
radiation on its
nucleus. (rock, dust,
water, ice, frozen
gases) Comet
Hyakutake
West
Hale-Bopp
OTHER CELESTIAL BODIES
Neutron stars: The fast-rotating, collapsed remnant of a massive star after a
smaller super-nova. Extremely dense, yet very small (10km) with an incredible
gravitational force.
OTHER CELESTIAL BODIES
Pulsars: Highly magnetized, rotating, neutron stars which emit a beam of
detectable electromagnetic radiation in the form of radio waves that can only be
detected when it points toward Earth.
OTHER CELESTIAL BODIES
Quasars: An extremely bright and distant, active galactic nucleus or a compact
halo of matter surrounding the central super-massive black hole of a young
galaxy.
OTHER CELESTIAL BODIES
Black Hole: a region of space in which the gravitational field is so powerful that
nothing, not even light, can escape its pull after having fallen past its event
horizon. Only around
4 times the size of the sun. Black Hole
THE BEGINNING?
Steady State Theory and Cyclic Universe Theory: Postulate that the
universe always existed and never had a “beginning”; matter is created over
time.
Big Bang Theory: An explosion (expansion of space-time) occurred roughly
15 billion years ago from an infinitely dense point, the size of ½ an atom, which
expanded into (and is still expanding) today’s universe. Accepted by vast
majority of today’s scientists. Introduction to the Big Bang Theory
BIG BANG EVIDENCE
1) Doppler Effect: Light appears different depending on the motion of the
object that is projecting it. Doppler Effect Shifts Video Video 2
Red Shift: If a galaxy is moving away from Earth, the light
received from it will be shifted toward the right or red end of the
electromagnetic spectrum. (all galaxies show this shift)
Blue (Violet) Shift: If a galaxy is moving closer to us, the light
received will shift closer to the left or violet end of the spectrum.
(none of the galaxies show this shift)
2) Background Microwave Radiation: Remnants from the Big-Bang has
been found showing energy that was produced. microwaves
ELECTROMAGNETIC SPECTRUM
Electromagnetic Spectrum: Chart that shows the varying types of light
radiation broken down according to frequency. Only a very small portion is
visible with the naked eye.
ENERGY TRANSFER
Radiation: Energy transfer through open space.
Conduction: Energy transfer through solid objects.
Convection: Energy transfer through liquids and gases.
Insolation: Solar energy that is absorbed by the Earth’s surface. June 21st is
the date with the greatest potential insolation in the northern hemisphere since
the sun is out the longest. Noon is always the time of day when insolation is
the greatest since the sun is nearest to perpendicular to the surface. Dark and
dull objects will absorb the most solar energy.
SOLAR SYSTEM MODELS
Geocentric Model:
The earliest model of
the solar system which
put the Earth at the
center.
Heliocentric Model:
The 2nd model showing
the sun directly in the
center of the planets’
circular orbits.
SOLAR SYSTEM MODELS CONTINUED
The Variable Speed Model: The true model of the solar system which shows
the Sun at one focus and the planets orbiting the star in elliptical orbits.
ELLIPTICAL ORBITS
Ellipse: The shape of the
planets’ orbits which is an
elongated circle with 2 foci.
Focus: One of 2 central
points in an ellipse.
Perihelion: The closest
position between a planet
and the Sun. The Sun’s
gravitational pull is the
strongest and the planet’s
orbital velocity is the
greatest here.(sun looks big)
Aphelion: Where a planet
is furthest away from the
sun. Planet’s velocity is
slowest and Sun’s
gravitational force is the
least. (sun appears smaller)
(nothing to do with seasons)
(Apogee and Perogee refer to Earth/Moon points)
ELLIPTICAL ORBITS CONTINUED
Kepler’s 2nd Law: The line
joining the sun and Earth
sweep out equal areas in equal
times due to change in
gravitational attraction.
ECCENTRICITY
Eccentricity:
Measures the amount
that a planet’s orbit
deviates from a perfect
circle. The higher the
value, the more linear
the orbital path. (0=
circle, 1= line)
NO UNITS!!
E = Distance between the foci
Length of the Major Axis
Major Axis: The distance
between the Aphelion and
Perihelion.
CELESTIAL MOTIONS
Rotation: When an object spins on
its axis. It takes the Earth roughly
24 hours to make one complete
rotation on its tilted axis which we
call 1 day. (rotates counterclockwise from north-polar view at
15°/ hour. hence the time-zones)
Foucault Pendulum: The instrument that
assisted in proving that the Earth rotates.
Revolution: The length of time it takes for one object to make a complete trip
around another. Earth’s revolution takes 365.26 days around the sun which we
label as one year. (leap year occurs every 4 years to account for the extra .26)
SOLAR SYSTEM DATA pg. 15
THE SEASONS
Seasons: Man-made groupings of time within a year that vary in temperature
and are created due to the revolution of the Earth around the sun and the 23.5°
tilt of the Earth’s axis. Seasons Seasons 2
IMPORTANT DATES
June 20th-23rd: Summer Solstice; first day of summer, longest day of the year
for locations north of the Tropic of Cancer (approx. 15 hours of daylight for NY),
sun appears to be located directly overhead of the Tropic of Cancer at 23.5° N
latitude.
September 20th-23rd: Autumnal Equinox; first day of Fall, 12 hours of light and
dark, sun appears to be over the equator.
December 20th-23rd: Winter Solstice; first day of Winter, shortest day of the
year for locations north of the Tropic of Cancer ( approx. 9 hours of daylight for
NY), sun appears directly overhead of the Tropic of Capricorn at 23.5° S
latitude.
March 20th-23rd Vernal Equinox; first day of Spring, 12 hours of light and dark,
sun appears to be over the equator.
THE SUN’S APPARENT PATH
Arc: The apparent motion of the sun throughout a given day. It rises in the
east and sets in the west. (only due east and west during the equinoxes and
never at the zenith for NY)
Zenith: Position directly 90°
above an observer.
Altitude: The angle of an
object in the sky.
SHADOW LENGTH
Note: On a given day, shadows
will be longest at sunrise and
sunset and smallest at noon. In
NY, the noon-time shadow is
smallest on June 21st and
largest December 21st.
H + R DIAGRAM
Hertzsprung Russell Diagram: Shows the luminosity, color, temperature and
magnitude of star groups as compared to the Sun.
Luminosity: A star’s brightness as compared to the Sun, determined by its
magnitude
LIFE CYCLE OF A STAR
The stages in a star’s existence depends on its initial mass: Life Cycle of a
Star 4 min vid
THE MOON
Tides: The increase and decrease in sea level due to the gravitational pull of
the Moon and, to a lesser extent, the Sun. Tides will switch from high to low or
low to high gradually every 6 hours.
Spring Tides: The extremely high high-tides and low low-tides produced twice
a month during new and full moon phases due to the Sun, Moon, and Earth
being lined up.
Neap Tides: The tides with the least variation between high and low tides.
Occurs twice a month at first and last quarter moon phases when the Sun,
Moon, and Earth are at right angles.
TIDES CONTINUED
SPRING AND NEAP TIDES
MOON PHASES
Phases: At all times (other than lunar eclipse) ½ of the moon is lit. However,
due to the position of the moon in its orbit around the Earth, we will see different
portions of the lit moon. Each different fraction that we see is called a phase.
MOON INFO. CONTINUED
Sidereal Month: The amount it takes for the Moon to complete one full
revolution around the Earth. 27 1/3 days
Lunar Month: The amount of time it takes for the moon to go from full moon to
the next full moon. 29 ½ days This is over 2 days more than a Sidereal month
to account for Earth’s new position in its orbit around the sun.
Lunar Eclipse: The irregular occurrence of the moon revolving into the Earth’s
shadow. Occurs during a full-moon phase and complete darkness lasts for
approximately 30 minutes to 1 hour. (Earth is between Sun and Moon)
Lunar Eclipse Animation Lunar video
ECLIPSES CONTINUED
Solar Eclipse: The irregular occurrence of the moon revolving directly
between the Sun and Earth and thus blocking out the light for a very small
portion of the planet. Occurs during a New-moon phase and lasts for about
10 minutes. Solar Eclipse Animation Solar Video
Why don’t solar and lunar eclipses
Umbra: The total, dark shadow of an eclipse.
happen during every new and full
Penumbra: Partial, dim shadow of an eclipse. moon phase?: The moon’s orbital
plane is tilted at 5° relative to
Earth’s.
KUIPER BELT
Kuiper Belt: An asteroid belt beyond Neptune that contains the dwarf planet
Pluto and is 20 times as wide and 200 times as massive as the belt between
Mars and Jupiter. Objects are mostly frozen volatiles such as ammonia, water
and methane.
OORT CLOUD
Oort Cloud: A spherical collection of billions of comets roughly one light year
from the Sun, the extent of which defines the outer boundary of our solar
system.