Astronomy
Phys 181
Readings: ASTRONOMY TODAY
Ch 23.1, 23.2
Ch 24.1, 24.2, 24.5
Ch 26
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There was no "before" the beginning of our universe, because once
upon a time there was no time.
* John D. Barrow
Quotes
I don't pretend to understand the Universe--it's a great deal bigger
than I am.
* Thomas Carlyle
A universe that came from nothing in the big bang will disappear into
nothing at the big crunch. Its glorious few zillion years of existence
not even a memory.
* Paul Davies
Anyone informed that the universe is expanding and contracting in
pulsations of eighty billion years has a right to ask, "What's in it for
me?"
* Peter De Vries
Nothing puzzles me more than the time and space; and yet nothing
troubles me less.
* Charles Lamb
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EXAM REVIEW
The final exam will consist of a choice of TWO (2) essays, selected
by the student, from a list of FIVE (5) essay topics chosen by the
professor.
Essays should be a minimum of FOUR (4) bluebook pages in length.
ESSAY TOPICS
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•Key discoveries in the history of Astronomy.
•The role of Kepler’s laws in understanding the motions of the
planets.
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•A comparison of the evolution of high and low mass stars.
•A description of General Relativistic effects and their predictions
regarding Black Holes.
Essays will be scored on the following criterion:
•Coherence
•Accuracy of information
•Presence of four supporting arguments or evidence from the
lecture or readings.
•Presence of one referenced supporting argument or evidence
from another source.
•Conventional development: Thesis – Support – Conclusion
•Reasonable grammar
Milky Way Galaxy
The Milky Way Galaxy: Vital Statistics
•Diameter - 100,000 light years
•Thickness (Nucleus) - 20,000 light years
•Thickness (Disc) - 2,000 light years
•Number of Stars - 200,000,000,000
•Age - 15,000,000,000 years
Horizon
Horizon
N
Corona Borealis
Serpens
Draco
Hercules
Libra
Centaurus
SW
Horizon Cepheus
Ophiuchus
Lyra
Cygnus
Lupus
Crux
Scorpius
Vulpecula
Norma
Scutum
Sagitta
Cassiopeia
Horizon
Circinus
Aquila
Lacerta
Sagittarius
Delphinus
Telescopium
Corona Australis
Musca
Ara
Triangulum Australe
Pegasus
Capricornus
Apus
Equuleus
NE
Pavo
Microscopium
Aquarius
S
Indus
Octans
Tucana
Pisces
Viewed fr o m:
Equator
75° 09' 21" W
0° 00' 00" N
L o cal tim e:
01:22:31
2007/06/23
JD 2454274.73
Horizon
F ield o f view :
Mag n itu d es: 5.5 4.5 3.5 2.5 1.5 0.5
180° 00' 00"
Single star
Galactic Lon: 029.2226°
Multiple star
Galactic Lat: +00.7212°
Variable star
Piscis Austrinus
Horizon
Viewed fr o m:
Equator
75° 09' 21" W
0° 00' 00" N
L o cal tim e:
01:22:31
2007/06/23
JD 2454274.73
F ield o f view :
180° 00' 00"
Galactic Lon: 029.2226°
Galactic Lat: +00.7212°
Mag n itu d es: 5.5 4.5 3.5 2.5 1.5 0.5
Single star
Multiple star
Variable star
Viewed fr o m:
Equator
75° 09' 21" W
0° 00' 00" N
L o cal tim e:
01:22:31
2007/06/23
JD 2454274.73
F ield o f view :
180° 00' 00"
Galactic Lon: 029.2226°
Galactic Lat: +00.7212°
Mag n itu d es: 9.5 8.5 7.5 6.5 5.5 4.5
Single star
Multiple star
Variable star
The Halo
The Disk
The Core
Elliptical Galaxies
•1/3 of all galaxies
•Giant Ellipticals are the size of our galaxy but are rare
•Dwarf Ellipticals are more common (6000 light yrs across)
Riesen-E
Spiral Galaxies
Largest fraction of galaxies
Andromeda
Barred Spiral Galaxy
NGC-1365
Irregulars
Large Magellanic Cloud
Galaxies form groups or Clusters
Coma Cluster
Olber’s Paradox
The universe is expanding!
Hubbles Law