Copyright © 2010 Pearson Education, Inc. Welcome to astronomy at ISM About me and astronomy About you and astronomy About this class: handout, website,

Copyright © 2010 Pearson Education, Inc.

Welcome to astronomy at ISM

• About me and astronomy • About you and astronomy• About this class: handout, website, text, me• Notes in class: write what I write• Our toolbox: eyes, Stellarium, physlets, models,

telescopes


Is astronomy class fun?

FUN

This class can be interesting, mindblowing, awesome, gratifying, and rewarding.

But you have to do your work in class and outside of class.


ISM Lab Safety Rules– No horseplay in the lab– No students may stand on chairs or tables– Students may not move chemicals from the lab– Eye goggles or safety glasses are required by all people in the

lab for the following conditions–Any heat source is in use–Anyone is using any material (liquid, dry, or gas) that would not be harmful if put directly into an eye–A pressure source (higher than a blown up balloon) is in use–Activities are in the lab that could result in chips, shards, or any flying objects, such as hammering, launching projectiles, etc.

– Food in the labs•Food is not allowed in the lab (except water in bottles)•Food can be allowed for planned special activities and with teacher permission, but all table tops must be disinfected and wiped down beforehand. •Food or water are not allowed if a lab activity is ongoing


25 Aug: Resources for the class• Ismscience.org

– Note assignment– See the points for this week

• Astronomy: A Beginner’s Guide to the Universe, 7th ed. Chaisson and McMillan

• Powerpoint slides• Stellarium software• Apps such as Solar Walk and Star Walk• “Yakko’s Universe” song from Animaniacs• Monty Python’s “Galaxy Song”


Neil Armstrong died this week, 2012Show when we left earth videohttps://www.youtube.com/watch?v=RMINSD7MmT4


Andromeda galaxy M31• Find on stellarium• 2.5 x 106 light years away from us• Nearly one trillion stars• Nearest spiral galaxy to the milky way• Overall is 6x as wide as the full moon!

the great thing about astronomy is how beautiful the subjects are.

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You are responsible to learn and use Stellarium

• Go to stellarium.org and download it• Find each and report magnitude

– Andromeda galaxy– Polaris– The moon

• You will demonstrate in two weeks that you know how to use it.


Preseason quiz

1. Define Astronomy.2. How many planets in our solar system?3. Name as many planets as you can.4. Arrange these in order of size, smallest first:

Saturn, Earth, galaxy, solar system, star, nebula5. What country was first to put a satellite in

space, a dog in space, a man in space, and a human to orbit the earth?

Copyright © 2010 Pearson Education, Inc.Copyright © 2010 Pearson Education, Inc.

Lecture Outline

Chapter 0Charting the

Heavens


Chapter 0Charting the Heavens


Units of Chapter 0

The “Obvious” View

Earth’s Orbital Motion

The Motion of the Moon

The Measurement of Distance

Science and the Scientific Method

Summary of Chapter 0


How to read/preview a chapter• FIRST, in 20 minutes

– Read learning goals and intro page carefully– Major titles and pictures– Highlighted words– Skip “discovery”, and Skip “more precisely”– Skip equations– Read summary

• Next, in 60-120 minutes– Now read (by skimming) all sections – Keep thinking about major points, skip equations


QUIZ FOR 26 Aug

• Write down 10 of the sources of information in each chapter of your text.

• Write down 10 additional resources in the book outside of the chapters.

• Work as a group, each contributing….


• Earth is average – we don’t occupy any special place in the universe• Universe: Totality of all space, time, matter, and energy• Astronomy: Study of the universe• Scales are very large, measured in light-years, the distance light travels in a year – about 10 trillion miles

2 sept. 0.1 The “Obvious” View


Part Opener 1.1


Part Opener 1.2


Part Opener 1.3


Part Opener 1.4


Part Opener 1.5


Part Opener 2.1


Part Opener 2.2


Part Opener 2.3


Part Opener 2.4


Part Opener 2.5


Part Opener 3.1


Part Opener 3.2


Part Opener 3.3


Part Opener 3.4


Part Opener 3.5


Part Opener 4.1


Part Opener 4.2


Part Opener 4.3


Part Opener 4.4


Part Opener 4.5


A blue moon can refer to either the third full moon in a season with four full moons, or the second full moon in a month.[1] Most years have twelve full moons that occur approximately monthly. In addition to those twelve full lunar cycles, each solar calendar year contains roughly eleven days more. The extra days accumulate, so every two or three years there is an extra full moon. The term "blue moon" comes from folklore. Different traditions and conventions place the extra "blue" full moon at different times in the year.

In calculating the dates for Lent and Easter, the Clergy identify the Lent Moon. It is thought that historically when the moon's timing was too early, they named an earlier moon as a "betrayer moon" (belewe moon), thus the Lent moon came at its expected time.[2]

Once in a blue moon (tonight)


Stars that appear close in the sky may not actually be close in space.

0.1 The “Obvious” View


The celestial sphere:

• Stars seem to be on the inner surface of a sphere surrounding the Earth.

• They aren’t, but we can use two-dimensional spherical coordinates (similar to latitude and longitude) to locate sky objects.

•What is the celestial equator?

**0.1 The “Obvious” View


• Full circle contains 360° (degrees).

• Each degree contains 60′ (arc-minutes).

• Each arc-minute contains 60″ (arc-seconds).

• Angular size of an object depends on actual size and distance away.

More Precisely 0-1: Angular Measure


• Declination: Degrees north or south of celestial equator• Right ascension: Measured in hours, minutes, and seconds eastward from position of the Sun at vernal equinox

*** 0.1 The “Obvious” View


•Daily cycle, noon to noon, is diurnal motion – solar day.

• Stars aren’t in quite the same place 24 hours later, though, due to Earth’s rotation around the Sun; when they are in the same place again, one sidereal day has passed.

•Show this on Stellarium

30 aug. 0.2 Earth’s Orbital Motion


A synodic day is the period of time it takes for a planet to rotate once in relation to the body it is orbiting (as opposed to a sidereal day which is one complete rotation in relation to the stars).Thus, a synodic day may be "sunrise to sunrise'" whereas a sidereal day may be "star-rise to star-rise".

Diurnal motion, meaning daily motion, describes the synodic day.


The 12 constellations the Sun moves through during the year are called the zodiac; the path is called the ecliptic. (see fig 0.9, find vernal equinox)

0.2 Earth’s Orbital Motion

See solar walk movie

What you see at night is opposite

to the sign’s season!


• Ecliptic is plane of Earth’s path around the Sun; at 23.5o to celestial equator.

• Northernmost point (above celestial equator) is summer solstice; southernmost is winter solstice; points where path crosses celestial equator are vernal and autumnal equinoxes.

• Combination of day length and sunlight angle gives seasons.

• Time from one vernal equinox to next is tropical year (“year”).

***0.2 Earth’s Orbital Motion

=Solar year. Is there a siderial year?


Quiz for Wednesday1. Out of 3000 stars in the visible sky, western civilization

created over 80 constellations. Why do we feature only 12 constellations in the zodiac? a: there are 12 months in the year b: there are 12 eggs in a dozen c: ancient people had 12 fingers d: 12 constellations fit along the ecliptic

2. If you look at the stars every night at midnight, they appear at slightly different positions. a: the earth spins on its axis b: the moon moves c: the earth moves around the sun d: the sun moves through the sky

3. a: diurnal b: declination c: ecliptic d: angle is the word used to describe position in the sky and is measured in degrees north or south of the Earth’s equator

4. Describe what the ecliptic is: _____________


A model of the earth-moon system

• Globe, diameter: 30cm (this sets the scale)• Moon, diameter: 8cm to scale• Earth-moon distance: 9.0 m to scale• Sun, diameter 33 m to scale! (we can’t do

this to scale)• Earth-sun distance: 3500 m to scale!

Sketch this in your notes


News you can use.

• http://www.nytimes.com/2014/09/03/science/space/the-v838-monocerotis-star-still-has-astronomers-heads-exploding.html?smprod=nytcore-iphone&smid=nytcore-iphone-share

• The eruption of a star 20,000 years ago made it a million times as luminous as the sun, and its violent beauty still echoes through space.


Precession: Rotation of Earth’s axis itself; makes one complete circle in about 26,000 years (demo with bike wheel or top)

*0.2 Earth’s Orbital Motion

The north star will shift slowly!


More about precession

• See for example problem 1.• Precission is the shift in our tilt during time.

– Takes 26000 years for one full rotation

• Recall that seasons (equinox, solstice) depend on that tilt, so seasons shift

• Therefore, the tropical year shifts during that 26000 years.

• Therefore, siderial and tropical year differ by 365 days/26000 = 20 minutes.


Precession • what exactly is precession?

– The shift in our tilt during time.– Takes 26000 years for one full rotation

• Recall that seasons (equinox, solstice) depend on that tilt• Therefore, the tropical year (solar year) shifts during that

26000 years.• Therefore, siderial and tropical year differ by 365

days/26000 = 20 minutes.• The zodiac year is where in the background stars the

vernal equinox points


Time for Earth to orbit once around the Sun, relative to fixed stars, is sidereal year. This is 20 minutes longer than a tropical year!

Tropical year follows seasons; sidereal year follows constellations – in 13,000 years July and August will still be summer, but Orion will be a summer constellation.

Did you know they just (2011) arranged the signs of the zodiac to account for this?

0.2 Earth’s Orbital Motion


September 1 was the date, in 1859, of a massive solar superstorm. It's sometimes called the "perfect space storm" or the Carrington Event, after British astronomer Richard Carrington. He reported witnessing a massive white-light solar flare: a bright spot suddenly appearing on the surface of the Sun. At the same time, the Sun produced a coronal mass ejection, or CME: a large eruption of magnetized plasma. CMEs usually take three to four days to reach Earth, but the magnetic burst from the superstorm of 1859 reached us in just under 18 hours.

While Earthlings of 1859 didn't have any cell phones, GPS units, or television signals to worry about, they were growing accustomed to rapid communication over the telegraph, which had been in use for 15 years. Within hours of the CME, telegraph wires began shorti ng out, starting fires and disrupting communication in North America and Europe. Compasses were useless because the Earth's magnetic field had gone haywire. The northern lights were seen as far south as Cuba and Hawaii, and the southern lights — aurora australis — were seen in Santiago, Chile. People in the northeastern United States could read the newspaper by the light of the aurora, and the Sun itself was twice as bright during the event.See http://www.youtube.com/watch?v=lT3J6a9p_o8 for good videoSee the SDO for our response…….


The Moon takes about 29.5 days to go through whole cycle of phases – synodic month.

Phases are due to different amounts of sunlit portion being visible from Earth.

Time to make full 360° around Earth, sidereal month, is about 2 days shorter than synodic month.

1 sep. 0.3 The Motion of the Moon



Play Movie: See next page for detail.


A NASA camera aboard the Deep Space Climate Observatory (DSCOVR) satellite captured on 16 July 2015 a unique view of the moon as it moved in front of the sunlit side of Earth last month. The series of images shows the fully illuminated “dark side” of the moon that is never visible from Earth.The images were captured by NASA’s Earth Polychromatic Imaging Camera (EPIC), a four megapixel CCD camera and telescope on the DSCOVR satellite orbiting 1 million miles from Earth. From its position between the sun and Earth, DSCOVR conducts its primary mission of real-time solar wind monitoring for the National Oceanic and Atmospheric Administration (NOAA).

NASA will post daily color images of Earth to a dedicated public website. These images, showing different views of the planet as it rotates through the day, will be available 12 to 36 hours after they are acquired.


Lunar eclipse: • Earth is between the Moon and Sun • Partial when only part of the Moon is in shadow• Total when all is in shadow

0.3 The Motion of the Moon


Umbra and Penumbra



Solar eclipse: the Moon is between Earth and Sun



6 sept: 0.3 The Motion of the Moon

Solar eclipse is partial when only part of the Sun is blocked, total when all is blocked, and annular when the Moon is too far from Earth for total.

What direction does the moon rotate as it orbits the earth?And the earth around the sun? ….


Do eclipses occur during the same months?

• eclipses can only occur when the Moon is close to a node and it is also either full or new.With no other forces acting, the line of nodes would therefore be in line with the Sun every six months.

• However, also like the Earth's axis, the gravitational force of the Sun on the Moon causes the line of nodes to precess.This precession is a much more noticeable effect than the Earth's precession, with one every 19 years.As a result, the time between alignments is decreased to about 5.4 months.

• Because of the finite size of the Earth, Moon, and their shadows, multiple eclipses can occur whenever the line of nodes points near the Sun.So, eclipses are actually very common!During a one-year period, there can be between two and five eclipses of each kind (solar and lunar), with a total of between four and seven.This includes partial and penumbral lunar eclipses, and partial and annular solar eclipses.

• Lunar eclipses are much more likely to be observed, since anyone on the night side of the Earth can see them.Solar eclipses, on the other hand, cover only a small fraction of the Earth, and often occur over unpopulated locations such as the polar regions or the oceans.


Solar Eclipses: 2011 - 2020

Calendar Date TD of Greatest Eclipse

Eclipse Type

Saros Series Eclipse Magnitude

Central Duration Geographic Region of Eclipse Visibility

(Link to Global Map)

(Link to Animation)

(Link to Google Map)

(Link to Saros)

(Link to Path Table)

2011 Jan 04 08:51:42 Partial 151 0.858 - Europe, Africa, c Asia

2011 Jun 01 21:17:18 Partial 118 0.601 - e Asia, n N. America, Iceland

2011 Jul 01 08:39:30 Partial 156 0.097 - s Indian Ocean

2011 Nov 25 06:21:24 Partial 123 0.905 - s Africa, Antarctica, Tasmania, N.Z.

2012 May 20 23:53:53 Annular

128 0.944 05m46s Asia, Pacific, N. America [Annular: China, Japan, Pacific, w U.S.]

2012 Nov 13 22:12:55 Total 133 1.050 04m02s Australia, N.Z., s Pacific, s S. America [Total: n Australia, s Pacific]

2013 May 10 00:26:20 Annular

138 0.954 06m03s Australia, N.Z., c Pacific [Annular: n Australia, Solomon Is., c Pacific]

2013 Nov 03 12:47:36 Hybrid 143 1.016 01m40s e Americas, s Europe, Africa [Hybrid: Atlantic, c Africa]

2014 Apr 29 06:04:32 Annular

148 0.987 - s Indian, Australia, Antarctica [Annular: Antarctica]

2014 Oct 23 21:45:39 Partial 153 0.811 - n Pacific, N. America

2015 Mar 20 09:46:47 Total 120 1.045 02m47s Iceland, Europe, n Africa, n Asia [Total: n Atlantic, Faeroe Is, Svalbard]

2015 Sep 13 06:55:19 Partial 125 0.788 - s Africa, s Indian, Antarctica

2016 Mar 09 01:58:19 Total 130 1.045 04m09s e Asia, Australia, Pacific [Total: Sumatra, Borneo, Sulawesi, Pacific]

2016 Sep 01 09:08:02 Annular

135 0.974 03m06s Africa, Indian Ocean [Annular: Atlantic, c Africa, Madagascar, Indian]

2017 Feb 26 14:54:32 Annular

140 0.992 00m44s s S. America, Atlantic, Africa, Antarctica [Annular: Pacific, Chile, Argentina, Atlantic, Africa]

2017 Aug 21 18:26:40 Total 145 1.031 02m40s N. America, n S. America [Total: n Pacific, U.S., s Atlantic]

Note that eclipses

come during all times of the year.



Eclipse tracks, 2010 - 2030

How long does an eclipse lastat any one point on earth?


Is the moon’s orbit circular?

• NO. No orbit is perfectly circular.• Check: how elliptical is it?• Know the phases of the moon

– Fig 0.13– Know days and names

• If the moon moved twice as fast, what would change above?

• Use SolarWalk to see moon movie.


Eclipses don’t occur every month because Earth’s and the Moon’s orbits are not in the same plane. Angle is 5.2o. Where did that arise?

*0.3 The Motion of the Moon

See solar walk on eclipses


Practice

• In groups of 3, show sun-earth-moon system for:– Lunar eclipse– Solar eclipse– First quarter moon– Waning gibbous moon– High-high tide


Triangulation: Measure baseline and angles, and you can calculate distance.

0.4 The Measurement of Distance


Parallax: Similar to triangulation, but looking at apparent motion of object against distant background from two vantage points

The measure of parallax allows us to measure the distance to remote objects in space.

(note, we can always find a further star for reference)

0.4 The Measurement of Distance

A good applet http://www.astro.ubc.ca/~scharein/applets/Sim/new-parallax/Parallax.html


Sizing up planet Earth

• Discovery 0.1• Please know

– The size of the earth: r = 6380km– That 2300 years ago, learned people knew the

earth was round• Was Columbus learned only 500 years ago?

– That 2200 years ago, the size of the earth was calculated within 1%.


Scientific theories:

• Must be testable

• Must be continually tested

• Should be simple

• Should be elegant

Scientific theories can be proven wrong, but they can never be proven right with 100% certainty.

0.5 Science and the Scientific Method


• Observation leads to theory explaining it.

• Theory leads to predictions consistent with previous observations.

• Predictions of new phenomena are observed. If the observations agree with the prediction, more predictions can be made. If not, a new theory can be made.

0.5 Science and the Scientific Method


Scientific method and the discovery of the first Galaxy

• http://scienceblogs.com/startswithabang/2013/09/02/messier-monday-andromeda-the-object-that-opened-up-the-universe-m31/

• Observe: Fuzzy nebula, thought to be a typical nebula (nova or dust cloud or cluster of stars nearby)

• Then, new data, astrophotography, plus variable star to give distance, meant it was far away and very large

• Much farther than any other star• Thus, a new “universe”, called a galaxy• All the subsequent data supported this


What is the practical value of astronomy to humans?

1. tides2. Energy from sun3. weather4. seasons5. navigation6. tourism 7. Asteroid avoidance8. minerals and materials in space9. solar storms affect us10. Sun affects earth’s weather and warming, solar storms dangerious, future of

humankind is out there, asteroid risk


• Astronomy: Study of the universe

• Stars can be imagined to be on inside of celestial sphere; useful for describing location.

• Plane of Earth’s orbit around Sun is ecliptic; at 23.5° to celestial equator.

• Angle of Earth’s axis causes seasons.

• Moon shines by reflected light, has phases.

• Solar day ≠ sidereal day, due to Earth’s rotation around Sun.

**Summary of Chapter 0


• Synodic month ≠ sidereal month, also due to Earth’s rotation around Sun

• Tropical year ≠ sidereal year, due to precession of Earth’s axis

• Distances can be measured through triangulation and parallax.

• Eclipses of Sun and Moon occur due to alignment; only occur occasionally as orbits are not in same plane.

• Scientific method: Observation, theory, prediction, observation …

Summary of Chapter 0, cont.


quiz

1. Describe precession in a sentence or two.2. Which is longer: solar day or siderial day?

1. By how many minutes?

3. During what phase of the moon does an eclipse occur? Why?


**I love space probes

• Voyager 1, good bye and good luck!– Wikipedia and pale blue dot photo


Super close Supernova

• http://latimesblogs.latimes.com/nationnow/2011/08/new-supernova-discovered-closest-exploding-star-to-earth-in-25-years.html

• Hard to see with small telescopes, but possible.

• Supernovae are key to 2011 Nobel Prize


What is this?


Astronomy lab #1: build solar system model in the school

• http://www.exploratorium.edu/ronh/solar_system/ is one tool, I did work on Excel.

• New challenge this year: scale distance AND size

• Start with earth of 1mm• Show limits of manned flight• Show limits of robotic flight


2014 Steps to build solar system1. Set the size of one object

Our choice: Earth = 1.0mm in diameter

2. Scale all other sizes from this3. Scale all distances from this4. Assign planets to students5. Find materials and construct, using black

backgrounds for visibility.6. Post in school, using Google Earth distances7. Admire and be amazed8. Use for rest of the year


2014

sol

ar s

yste

mObject Actual

diameter km

Actual distance from

sun 106 km

scale diameter in

mm

scale distance from sun in m assignment

scale factor 12.8*109 12756

Sun 1.40E+06 0 109.752 0.000 adamMercury 4880 57.9 0.383 4.539 kaminVenus 12104 108.2 0.949 8.482 luyuEarth 12756 149.6 1.000 11.728 emmaMars 6788 227.9 0.532 17.866 bradJupiter 142984 778.4 11.209 61.022 trahernSaturn 120537 1427 9.449 111.869 jamieUranus 51118 2871 4.007 225.071 xinzhuNeptune 49532 4498 3.883 352.618 ryanmoon 3475 0.384 0.272 0.030 dr. f

from moon to earth


Goo

gle

Eart

h di

stan

ces


2013 Steps to build solar system1. Calculate the correct distance and size scales2. Decide which of these we can model in the lab3. set final scale reference (sun)4. Assign planets5. Do research6. Find materials and construct durable object7. Hang where convenient and visible.8. Admire9. Use for rest of the year


Setting the scale 2013Object Actual

diameter km

Actual distance from sun 106 km

Scaled diameter for model cm

Scaled distance for model cm

assignment

Sun 14E5 0 1000 Fisher

Mercury 4880 57.9 0.35 0.14 Ashley

Venus 12104 108.2 0.86 0.26 Georgie

Earth 12756 149.6 0.91 0.37 Sophia

Mars 6788 227.9 0.48 0.56 Leo

Jupiter 142984 778.4 10.21 1.90 Ashley

Saturn 120537 1427 8.61 3.49 Georgie

Uranus 51118 2871 3.65 7.02 Lydia

Neptune 49532 4498 3.54 11.00 Kirsten

Documents

Copyright © 2010 Pearson Education, Inc. Welcome to astronomy at ISM About me and astronomy About you and astronomy About this class: handout, website,