Transcript 0001 Views of Universe

0001 Scientific views of the universe: 1. demonstrate
knowledge of the development of theories about the
formation of the universe and the solar system
Milky Way Galaxy
Kinds of galaxies
• Spiral
• Elliptical
• Dwarf
“redshift”
• Hubble was first to notice that colors
emitted by different elements seemed to be
shifted toward the red (long-wavelength)
end of the spectrum.
• --pitch drops as moving source of sound
travels away from you
• --light shifts to red as it moves away from
you
Hubble’s Law tell us:
• the universe is expanding.
• The whole cosmos is blowing up like a
balloon
• The universe began at a specific point in
the past, and it has been expanding ever
since.
“morning stars”
& wanderers
Solar System
Figure 16-1
Most of the mass in the solar system is in the Sun, and most of
the rest is in the Jovian planets. (Distances in this figure are not
to scale.)
The Sun and its Planets
• Planets and moons tend to orbit about the
sun in a counterclockwise direction
• Orbits of planets and their moons are in the
same general plane
• Planets and moons tend to rotate on their
axis in counterclockwise direction
Solar System
The Nebular Hypothesis
• theory for origin of solar system
• rotating nebula had formed gaseous rings
which condensed into the planets and
moons, with the nebula’s nucleus forming
the sun p. 323
Figure 16-2
As the nebula that formed the solar system collapsed, it began to
rotate and flatten into a disk. The stages in solar system formation
include (a) a slowly rotating nebula, (b) a flattened disk with
massive center, (c) planets in the process of birth represented as
mass concentrations in the nebula, and (d) the solar system.
0001 Scientific views of the universe: 2. demonstrating
knowledge of characteristics and general locations of objects
in the solar system and universe
kidzone link
Small, rocky, airless world with
an extreme climate!
• Mariner 10, did 3 flybys 1974-75
• Years & Days: “fastest planet”
– Orbital period = 88 Earth days
– Rotation period = 59 Earth days
• Planet of Extremes
– Day temp’s exceed 800oF
– Night temp’s drop to –280oF
• Surface:
– Almost doubles as the moon. Mercury contains impact craters
ranging from ½ mile to one over 800 miles wide. Ridges and
basins filled with cooled lava fill the picture.
Venus (.72 au)
A forbidding yet fascinating world
of scorching temp’s, rocky plains,
& huge volcanoes.
• Data from 17 landing probes & 18 flyby
Spacecraft (Pioneer of ‘78 & Magellan of ’93)
• An Out-of-Control Greenhouse Effect
– 30-mile thick atmosphere of CO2 generates surface pressure
100X Earth’s and traps heat, sustaining temp’s > 800oF.
• Slow and Backward Planet
– Venus rotates very slowly, once every 243 Earth days
– Venus orbits the sun every 225 Earth days, so on Venus, a day is
longer than a year!
– Spins not from west to east, like the other planets, but from east
to west. Perhaps an asteroid collision set Venus on a backward
rotation.
Earth (1 au)
The very special “third rock.”
Hospitable Home Planet
• Vast oceans of liquid water and protective atmosphere
rich in oxygen.
• Orbits in stable, nearly circular path, so never too far or
too close to the Sun
• One Moon—large by solar system standards—acts to
stabilize Earth, preventing tilt from shifting wildly.
• Oceans of water absorb and transfer heat, regulating
global temperatures.
• Precious envelope of air serves as a breathable, protective
blanket.
Mars (1.52 au)
The red planet, our nearest neighbor.
• Observed by Mariner 9, ‘71, Viking ‘77,
And Pathfinder spacecraft of 1997
• An Unearthly World
– Thin atmosphere (like Earth’s at 140,000 ft) of 95% CO2
– Elliptical orbit accentuates seasonal differences—temp range
from –190oF to 62oF
– Dry, desolate surface, but tilted axis gives it polar ice caps
– 2 small moons: Deimos & Phobos—may be captured asteroids
– Olympus Mons – 13 mile high volcanoe the size of Arizona!
– Valles Marineris – system of canyons up to 4 miles deep forms
an immense gash 2500 miles across.
Tens of thousands of small rocky bodies
orbit the sun in a large area between Mars
and Jupiter. (asteroids, or better, planetoids)
• Thought to be
material that failed to
become a planet
during formation of
solar system.
Rocks in space through which the Earth
passes as it travels around the Sun.
• Meteors may be tiny
grains of sand or may
be very large.
• Billions enter Earth’s
atmosphere each year,
encounter friction
some 50 miles
overhead and burn
white hot.
• If lands = meteorite.
Enormous size and mass make Jupiter
undisputed giant of the solar system.
• Galileo in 1995 orbited Jupiter and
shot a probe into the atmosphere, radioed
back data for an hour before it was crushed.
• “Jovian” = giant Over 11X diameter and over 317X the
mass of Earth, Jupiter is twice as massive as all the other
planets combined!
• Colorful Clouds and a Whirlpool of Wind
– Light colored zones and dark colored bands created by jets of
wind circulating in alternating directions.
– 400 mph winds generated by convection currents, as Jupiter is
still cooling from its formation.
Spectacular ring system sets
this second largest planet apart.
• 2nd largest planet and 2nd largest mass.
• 96% H, 3% He, less dense than water.
• Rocky core is embedded in an outer core of water,
methane, and ammonia.
• Above the core is liquid hydrogen 21,000 km deep
• Rocks, dust, and ice orbiting the planet form several large
rings and thousands of narrow ringlets about 10 km thick
• Has at least 30 known satellites. Its largest moon, Titan,
is unique among moons for it has its own atmosphere.
• Voyager 2 flyby in 1981 gave us close-up of rings and
1990 Hubble Telescope recorded enormous storms.
Uranus
(19.18 au)
A puzzling blue-green world
four times the size of Earth and
1.8 billion miles away.
• Most of our knowledge of Uranus
is from Voyager 2 which sped by in 1986.
• A planet on its side: Since its rotation is nearly parallel
with orbit about the sun, each pole spends 42 years in
darkness and 42 years in light.
• Beneath the Blue-Green Clouds:
– A small rocky core is surrounded by thick layer of ice and rock
and an outer layer of H and He.
– Methane and ammonia condense into clouds at high altitudes.
Methane gives Uranus its blue-green color.
Smallest and most distant of
the gas giants, 30,800 miles away.
• Voyager 2 reached the 8th planet on
Aug 25, 1989 revealing a blue disk with
dark bands and white clouds.
• Early in the 19C, unexplained perturbations were
observed for Uranus. This led to the eventual finding of
Neptune by astronomers in Germany and England.
• Like Jupiter and Saturn, it emits twice as much heat as it
receives from Sun.
• Atmosphere mainly H and He; like Uranus, Neptune’s
bluish color caused by clouds of methane.
Pluto is a tiny, cold rocky world
with a tilted & very eccentric orbit.
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248 years per revolution about sun
2.8 billion mi away at closest approach
Only planet not visited by spacecraft
Smallest planet, (< 1,430 mi diameter) smaller than Moon
Rock-Ice composition similar to Triton
Pluto has close relationship to its single moon, Charon;
the two bodies spiral around a shared center of gravity.
• Both may be captured objects that wandered in from the
Kuiper Belt.
• Amateur astronomer Clyde Tombaugh discovered Pluto
in 1929.
“Dirty snowball” of water, ice
and dust orbits the sun
• Comets feature a head (coma)
at front, and a tail that faces away from the sun.
• Tail forms when ice is heated from sun, melts,
and spreads out as a dust-filled gas.
• Particles in tail may cause a meteor shower on
Earth if we pass through the tail.
• Famous comets include Hale-Bopp, Halley,
Hyakutake, and Shoemaker-Levy 9.
0001 Scientific views of the universe:
3. recognize the effects of gravity on the motion of objects
in the solar system
0001 Scientific views of the universe: 4. analyze the
motion of objects in the sky in terms of relative position
• Earth orbits the sun and rotates on its own axis.
• That’s why objects seem to move across the sky.
• While other bodies may be moving as well, the
Earth’s spin is continuous, making distant
objects appear to mov in a predictable manner.
For example, we can expect to see certain
planets or stars in specific locations at certain
times of the year and can chart their movements
across the sky.e
0001 Scientific views of the universe: 5. recognize the
effects of the orientations, positions, and movements of the
earth, moon, and sun
Phases of the Moon link
Eclipse
• When either the Sun or the Moon crosses
into the shadow cast by the other, an
eclipse occurs.
• Umbra: Inner core of total darkness
• Penumbra: Outer, partial shadow
Lunar Eclipse
• Moon passes through the
shadow of the Earth.
Types of Lunar Eclipses
Solar Eclipse
• Earth passes through the
shadow of the Moon.
Types of Solar Eclipses
0001 Scientific views of the universe:
6. identify the methods and types of technology used to
observe and collect data about the solar system and universe
Optical Telescopes:
Reflecting
Refracting
Large Reflecting Telescopes
• Keck telescopes,
Mauna Kea, Hawaii
• European Southern
Observatory, Chile
Radio Telescopes
Figure 14-4
Schematic diagrams of telescopes. In an optical telescope (a), light
strikes a curved mirror and is focused on a light-sensitive detector
such as the eye or a piece of film. In a radio telescope (b), radio
waves from space strike a curved metal dish that focuses the waves
onto an antenna. Signals are amplified and processed by computer.
Hubble Space Telescope
• launched in 1990 by
the space shuttle
Discovery
• Oops! Mis-shaped
mirror; repaired in
’93, ’97, ’98.
• Now it’s taking great
pictures of far away
galaxies
• Latest images!
Next Generation Space Telescope
• NGST and NASA’s
Origins Project
• Evolution of galaxies
• Production of
elements by stars
• Process of star and
planet formation