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 withan 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 worldof scorching temp’s, rocky plains,& huge volcanoes.

• Data from 17 landing probes & 18 flybySpacecraft (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 Jupiterundisputed 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 setsthis 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 worldfour times the size of Earth and1.8 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 ofthe 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.

• 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, iceand 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