Very Large Array (VLA)Soccoro, NM

Class 5: Astronomy 101

Celestial Motions

Class updates:

• Reading: 18.4, 22.1-22.5, 24.1• Extra credit: Geology Colloquium

- Wed./Thurs./Fri. this week (www.geo.utep.edu 2011

Colloquium link)

• Homework 2 & Midterm1 returnedToday’s topics:

• Where are we in the universe?

• Important people

• Tools of Astronomy

Class 5: Astronomy 101 & Celestial Motions

• Seasons

• Lunar phases

• Eclipses

Where are we in the universe?

Planet?

Star-orbiting system?

Galaxy?

Cluster Group?

Supercluster?

Universe?

Our Cosmic Address

A Universal Summary

ConstellationOrion

Stellar Nurseries

Hubble

Solar System Formation

solarnebula

Our Solar System

rocky planets(Terrestrial)

gas planets(Jovian)

STANDARD MODEL

1.5 AU

Mars

Jupiter

1 AU 2 AU 3 AU 4 AU 5 AUSUN

Venus

Mercury

1 AU 30 AU10 AU 20 AU 40 AU5 AU

Saturn, 9.5x Rearth

Uranus, 4.1x Rearth

Neptune, 4.0x Rearth

Jupiter, 11x Rearth

SUN

The Solar System

Pluto, 0.2x Re

Asteroid Belt

1 AU: distance from Sun to Earth = 150,000,00 km

words

The Solar System

MercuryVenusEarthMars

Asteroids JupiterSaturn UranusNeptune

Pluto

YOU SHOULD KNOW:

How do we know? Who is responsible?

Early Astronomers

• 500 BC Pythagoras - thought Earth was round from moon observations

• 350 BC Aristotle - first to suggest that all planets & stars orbited the Earth (wrong!)

- Earth-Centered model = Geocentric Model

PythagorasAristotle

AD500 250 0 250 1500 1600 1700 1800 1900

Ptoo bad for Ptolemey

Claudius Ptolemey (100 - 170 A.D.)

PythagorasAristotle Ptolemy

Ptolemy geocentric diagram(Earth at center)

AD500 250 0 250 1500 1600 1700 1800 1900

Nicholas Copernicus (1473-1543)

Crazy (but not really) Copernicus

Aristotle Ptolemy Copernicus

Copernicus heliocentric diagram(Sun at center)

Pythagoras

AD500 250 0 250 1500 1600 1700 1800 1900

Keeping up with Kepler

Johannes Kepler (1571 - 1630 A.D.)

Aristotle Ptolemy Copernicus Kepler

Kepler’s Laws (3)

AD500 250 0 250 1500 1600 1700 1800 1900

Pythagoras

Galileo the Great

Galileo Galilei (1564 - 1642 A.D.)

Aristotle Ptolemy CopernicusGalileo

Galileo’s moon phases

Kepler

500 250 0 250 1500 1600 1700 1800 1900

Pythagoras

AD

How do we know?

Light waves: traveling energy

infrared image

visible imagex-ray image

Tools of Astronomy: Telescopes

Main functions of optical telescopes

Optical Telescopes

(more common)

light in

eyepiece

mirror

eyepiece

light in

lense

Radio Telescopes light in

visible radio visible radio

Where should telescopes go?

US light pollution Mauna Kea, Hawaii

• Hubble Space Telescope

Telescopes and Observatories(you should visit)

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Clark: Lowell Obs., AZ

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Clark: Lowell Obs., AZ

• Shane: Lick Obs., CA

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Clark: Lowell Obs., AZ

• Shane: Lick Obs., CA

• Kitt Peak Obs., AZ

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Clark: Lowell Obs., AZ

• Shane: Lick Obs., CA

• Kitt Peak Obs., AZ

• Aricebo, Puerto Rico

• Hubble Space Telescope

• Keck: Mauna Kea, Hi

• Hale: Palomar Obs., CA

• Clark: Lowell Obs., AZ

• Shane: Lick Obs., CA

• Kitt Peak Obs., AZ

• Aricebo, Puerto Rico

• Very Large Array (VLA), NM

Rotation & Revolution

revolution

rotation

Reason for Seasons?

Equator

North Pole23.5°

Equator

Earth’sorbit Earth

Sun

Spin axis

Earth’sorbit

Sun

Reason for Seasons

Sun

NH

SH(Summer)

(Winter)

Earth’sorbit Earth

Sun

Spin axis

Earth’sorbit

Sun

Reason for Seasons

NH

SH(Winter)

(Summer)

Sun

Northern Hemisphere Seasons

Seasons, Tropics, & Circles

Seasons Review

Reason for Seasons Movie

• Why are days are longer in the summer, shorter in the winter?

Day/Night & the Seasons

Winter sunpath

Summer sunpath

The Phases of the Moon

Times of Moonrise and Moonset

Phase Moonrise MoonsetNew Dawn SunsetFirst Quarter Noon MidnightFull Sunset DawnThird Quarter Midnight Noon

Why We Always See the Same Side of the Moon

Day 1

Day 7

Day 14

Day 21

NP

Eclipses

lunar eclipse total solar eclipse partial solar eclipse

Lunar Eclipses

• Moon moves in between Sun and Earth, blocks sunlight

• Only from within the tiny area where the dark umbra touches the Earth will you see the Sun completely covered and witness a total eclipse.

• From anywhere in the grey penumbra, you will see some part of the sun shining from behind the moon. The penumbra is the area of partial eclipse.

Solar EclipsesHow do they happen?

The Moon is much smaller than the Sun so how can the

Moon block out the Sun?

Solar Eclipses

partialeclipse

totaleclipse

Solar Eclipse Movie

Movie of solar eclipse taken in India (NASA Goddard Space Flight Center)

Eclipses: Why so Infrequent?

Why isn’t there a solar eclipse & lunar eclipse once every month?

Earth’sorbit

Moon’sorbit

Sun

Earth Moon