Transcript WK9Winter2004

Phys 181
Astronomy
GR Simulation
“Gravity as Newton and Einstein knew it does not exist. When the
United States launched the first space probe it kept going off course.
Well, it took them awhile to re-analyze all the evidence and what they
came up with is that gravity does not exist in space. This is how I was
able to detect what has since been called the "Quasars" or" QuasiStellar Sources".
Quotes
-Don Albert from Brain in a Box
“I've never earned a penny in my life, not
one single penny from any of the research
I've ever done, no matter what I've
discovered. And I've literally discovered
somewhere between five and ten thousand
new things, and they all seem to be totally
worthless.”
Readings: ASTRONOMY TODAY
Chapter 22 and 23
R
e
a
d
General Solar Properties
Neutron Star: Eta Carinae
Neutron stars are the
remanant of Type II
(rebound) Supernova events.
•Roughly the size of a
major city.
•300,000 times more
massive than the earth.
•Composed primarily of
neutrons.
•Escape velocity is c/2
•Strong emission of radio
waves.
Jocelyn Bell: 24 year old
Cambridge grad student.
Detection of periodic radio signals in the constellation
Cygnus.
Mysteriously regular at 1.33701 second intervals.
In 1974, her advisor,
Anthony Hewish, was
awarded the Nobel Prize
in Physics for the
discovery of the
PULSAR!
Hubble Image of the Crab Nebula Pulsar
Rotates once every 0.0016 s !!!!
Black Holes
Space-Time is Curved
Albert Einstein
General Theory of Relativity
•All massive objects distort space
and time in their vicinity.
The distortion is the cause of
•Gravity
•Time Effects
•Gravitational Red Shifting
•Gravitational Lensing
Black hole properties:
•Light cannot escape
•Event horizon
•Mass (5 times the mass of the
sun and greater)
•Angular momentum
•Charge (most are neutral)
How can we detect them if they are black?
Gravitational
Lensing
Accretion
Disk
Emissions
End
Vega
Altair
Deneb
Cygnus X-1
Astronomy
Phys 181
Readings: ASTRONOMY TODAY
Ch 23.1, 23.2
Ch 24.1, 24.2, 24.5
Ch 26
R
e
a
d
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
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