linking asteroids and meteorites through reflectance...
TRANSCRIPT
Course
• Course Website:– http://blogs.umass.edu/astron101-tburbine/
• Textbook:– Pathways to Astronomy (2nd Edition) by Stephen Schneider
and Thomas Arny.• You also will need a calculator.
Office Hours
• Mine• Tuesday, Thursday - 1:15-2:15pm• Lederle Graduate Research Tower C 632
• Neil• Tuesday, Thursday - 11 am-noon • Lederle Graduate Research Tower B 619-O
Homework
• We will use Spark• https://spark.oit.umass.edu/webct/logonDisplay.d
owebct• Homework will be due approximately twice a
week
Homework #1 (Due today)• Find an article concerning a topic concerning the
Solar System and write about why you found it interesting.
• Include the name of the article and where it was published.
• Submit using Spark
Homework #2 (due Tuesday)
• 10 questions• In Assessment on Spark
Why should we learn about the Solar System?
• http://www.thisistheend.com/2009/08/the-ihc-on-the-tv.php
Metric System
• 1 kilometer = 1,000 meters• 1 meter = 100 centimeters• 1 centimeter = 10 millimeters
Distances
• An Astronomical Unit (AU) is the average distance between the Sun and Earth
• 1 AU = 150 x 106 km = 150 x 109 m• 1 light-year is the distance light travels in a year• 1 light-year = 9.5 × 1015 meters
Scientific Notation
• 10000 = 104
• 100000000 = 108
• 10000000000 = 1010
• 100000000000000000000 = 1020
• 0.001 = 10-3
• 0.0000001 = 10-7
How do you write numbers?
• 31,700,000 = 3.17 x 107
• 2,770,000 = 2.77 x 106
• 0.00056 = 5.6 x 10-4
• 0.0000078 = 7.8 x 10-6
How do you do multiply?
• 106 x 108 = 10(6+8) = 1014
• 10-5 x 103 = 10(-5+3) = 10-2
• (3 x 104 ) x (4 x 105) = 12 x 10(4+5) = 12 x 109
= 1.2 x 1010
How do you divide?
• 108/106 = 10(8-6) = 102
• 10-6/10-4 = 10(-6-(-4)) = 10-2
• (3 x 108)/(4 x 103) = ¾ x 10(8-3) = 0.75 x 105
= 7.5 x 104
What is a galaxy?
What is a galaxy?• Is a massive, gravitationally bound system
consisting of stars, gas and dust, and dark matter. Galaxies can contain between ten million and a trillion stars
• Dark matter is matter that does not emit or reflect enough radiation to be seen, but whose gravitation effects can be felt
http://en.wikipedia.org/wiki/Image:NGC_4414_%28NASA-med%29.jpg
When we are looking at stars or galaxies• We are looking into the past
Light-year is the distance light travels in a year.
Milky Way Galaxy• Milky Way is 100,000 light-years in diameter• There are ~200 billion stars in the Milky Way (estimates
from 100-400 billions stars)
http://www.venusproject.com/ecs/images/photos/galaxy.jpg
What is the Universe?
What is the Universe?• Sum total of all matter and energy – all galaxies
and everything between them• Observable universe – portion of the universe that
can be seen from Earth, probably only tiny portion of the whole universe
~93 billion light-years
wide
How many stars in the Universe
• Say there are 100 billion galaxies• Each galaxy has 100 billion stars• So how many stars in the universe
Answer
• Number of stars in universe • = (100 x 109) x (100 x 109) = 10000 x 1018
= 1 x 1022 = 10,000,000,000,000,000,000,000• This is about the same number of grains of sand
in every beach in the world
Questions:
• How many of these 1022 stars have planets?• How many of these planets have life?
• My Very Eager Mother Just Served Us Nine Pizzas
• My - Mercury• Very - Venus• Eager - Earth• Mother - Mars• Just - Jupiter• Served - Saturn• Us -Uranus• Nine -Neptune• Pizzas - Pluto
Does anyone play basketball?
Assume
• That the sun is the same size as a basketball• Basketball diameter = 24.4 cm• Sun’s Diameter = 1.4 x 109 m = 1.4 x 1011 cm• Scale Factor = 1.74 x 10-10
• Multiply scale factor by actual diameters of planets to get their approximate size
Mercury
• Diameter = 4.88 x 106 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 8.5 x 10-4 m = 0.85 mm
Mariner 10 Messenger
Venus
• Diameter = 1.21 x 107 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 2.1 x 10-3 m = 2.1 mm
Mariner 10
Earth
• Diameter = 1.28 x 107 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 2.2 x 10-3 m = 2.2 mm
Apollo 17
Mars
• Diameter = 6.80 x 106 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 1.2 x 10-3 m = 1.2 mm
Hubble Space Telescope
Jupiter
• Diameter = 1.43 x 108 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 2.5 x 10-2 m = 25 mm = 2.5 cm
Voyager 1
Saturn
• Diameter = 1.21 x 108 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 2.1 x 10-2 m = 21 mm = 2.1 cm
http://en.wikipedia.org/wiki/File:Saturn_during_Equinox.jpg
Six moons are in the picture: Titan (5,150 kilometers across), Janus (179 kilometers across), Mimas (396 kilometers across), Pandora (81 kilometers across), Epimetheus (113 kilometers across) and Enceladus (504 kilometers across).
Cassini
Uranus
• Diameter = 5.18 x 107 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 9.0 x 10-3 m = 9 mm
Voyager 2
Neptune
• Diameter = 4.95 x 107 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 8.5 x 10-3 m = 8.5 mm
Voyager 2
Pluto
• Diameter = 2.30 x 106 m• Multiply by scale factor (1.74 x 10-10)• Relative Diameter = 4.0 x 10-4 m = 0.4 mm
Hubble Telescope
https://www.msu.edu/course/isb/202/snapshot.afs/tsao/images/scientific_method01.gif
Scientific method
What is a constellation?
Constellations
• People refer to constellations as a pattern of stars• Astronomers refer to constellations as specific
regions of the sky• In 1928, the IAU (International Astronomical
Union) decided there were 88 constellations• Many of the constellation names go back
thousands of years
Constellations
• The constellations are totally imaginary things that poets, farmers and astronomers have made up over the past 6,000 years (and probably even more!).
• The real purpose for the constellations is to help us tell which stars are which, nothing more.
What is thisconstellation?
Orion
Bigger the star, the brighter it is
Orion was the son of the god of the sea, Poseidon and a great hunter.One story is that he made an enemy of Hera who sent a scorpion to sting him.
Orion was restored to health by Ophiuchus, the first doctor of medicine.
Another story is that Artemis was tricked by by Apollo to shoot an arrow at Orion. When he died, Poseidon asked Zeus to put him among the stars.
Ursa Major
• Ursa Major, the Great Bear, was identified with a bear by native American Indians of the Northeastern United States and the ancient Greeks.
• The name common in Britain, the Plough,seems to have a medieval origin,
• Another common name among northern European cultures is the Wain, a shortened form of wagon
What are the constellations named after• 14 men and women• 9 birds • 2 insects• 19 land animals• 10 water creatures• 2 centaurs• one head of hair • a serpent• a dragon• a flying horse• a river• 29 inanimate objects
• Originally considered part of Leo’s tail
• Named after Queen Berenice II of Egypt, wife of Ptolemy III Euergetes (246 BC - 221 BC)
• Around 243 BC, the king undertook a dangerous expedition against the Syrians, who had murdered his sister.
• Berenice swore to the goddess Aphrodite to sacrifice her famous long hair if her husband returned safely.
• He did, she had her hair cut, and placed it in the goddess' temple.
• By the next morning, the hair had disappeared. • To appease the furious king and queen (and save the lives of
the temple priests), the court astronomer, Conon, announced that the offering had so pleased the goddess that she had placed it in the sky.
• He indicated a cluster of stars that at the time were identified as Leo's tail, but now have been called Berenice's Hair.
Zodiac
• The zodiac is an imaginary belt in the heavens extending approximately 8 degrees on either side of the Sun's apparent path (the ecliptic), that includes the apparent paths of the Moon and the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune.
Question:
• Why do all the planets seem to follow the same path?
Answer:• The planets, the Earth, and the Sun
all tend to fall in the same plane called the ecliptic
Why don’t all the constellations have ancient names?
• Ancient cultures such as the Greeks and Egyptians could not see the constellations in the Southern Hemisphere
Question:
• Why is the path of the constellations on the zodiac not on the celestial equator?
Answer:• The rotation axis of the Earth is
inclined with respect to the ecliptic
• Polaris is called the North Star• Brightest star in the constellation Ursa Minor.• 48th brightest star in the night sky• It is very close to the north celestial pole, making
it the current northern pole star.• Polaris' altitude, or height above the horizon, is
equal to an observer's latitude.
Question:
• How can do know that the sun is travelling along the zodiac since you can’t see stars during the day?
Answer:
• One can however figure out where the sun is on the zodiac by noting which is the last constellation of the zodiac to rise ahead of the Sun or the first to set after it.
Any Questions?