Newtonian focus - look into telescope from the side, light reflects on big mirror in the
back, and bounces to smaller mirror near eyepiece. Most popular telescope.
A telescope has 30cm arduous mirror, Come to your eyes 0.3cm pupil radius, how
Sometimes as a result of collision electrons can be kicked so third they become
separated from the atom.
As a result we are left with a positively charged atom (ion) and a free electron
Less electrons than protons = ionized. Also called plasma
EM waves can travel through a vacuum.
Red light has the longest wavelength of visible light.
Heat is a form of potential energy.
Radio waves and infrared waves travel at the same speed.
A star the same size as ours, but twice a
Visible light measures in nano meters 400-700 nanometers
We feel infrared as heat
Atmosphere is opaque, however we have a radio wave window and optical window
All travel at speed of light, 300,000km/sec
Doppler effect - detected wavelength or fr
Ancient astronomy was mostly about constellations, names of stars, and motion of
Built Solar System Model
Never explained many questions:
Why do the planets move in a certain way?
Why are stars different brightness etc.
Ptolemy's Model - quite complicated with many different smaller circles to explain the
motion and Earth in the middle
With Sun in the middle, the model became much less complicated. Newton's laws came
in handy as well
Gravity - acts as an invisible string
Speed of Light
300,000 km per sec, 195,000 miles per second
1 light second - 300,000 km
1 light minute - 180,000 km
1 light hour= 1080000000 1.08x10^9
Astronomy comes from the Greek words meaning "law of the stars"
They divided sky into co
Wednesday is Test 3 - Ch. 22-26
Two pages what you learned/personal experience - any time this week - extra credit
Fate of the universe depends on how much matter there is
If gravity was the only force working on the universe, it could be recollapsing, cr
Dark Matter indications: Galaxy rotation, collisions, and formations. Gravitational lensing
- light bends around galaxies
Total mass of the dark matter is about 7-8x more than all mass of stars and gas clouds
Does not interact with other matter except gra
Initial step in galaxy formation
Like stellar evolution, hydrogen and helium begin to assemble into large structures,
eventually turns into a web-like structure
The first stars were quite massive, eventually turning into supernovae type-2
Much different even in optical light. it is very bright. The bright spot is relatively
large. The object is very compact, but it is small. The radiation makes it much bigger
than the source itself.
Most of the radiation is coming from the ce
Normal spirals -active stellar creation in the arms
Barred spirals - experience extensive structural changes
elliptical - made mostly from old stars
Irregulars - usually under a gravitational influence from more massive partner
The more red shifted the ga
The Milky Way Galaxy - a big assembly of stars. 100,000ly across and 200,000ly wide
Has central bulge where density of the stars is much larger and where we believe the
supermassive black hole sits
Spiral arms - blue because they have stars that are massi
Time dilation - twin paradox. Jill leaves earthand moves off at a very high speed to visit
a distant planet. Her clock during the trip runs slower, and when she comes back Jack
has aged more than she has.
But wait, from Jill's point of view, it is Jack wh
Neutron Star - Made out of neutrons only, very compact - 10km in radius, very hi
density, fast rotation, pulsars, have a very high temperature right after an explosions,
slowly cools off and spins down
Gamma Ray Bursts - Collapse of iron core is for usual
Gamma Ray Bursts - GRB
Cosmic gamma-ray bursts were discovered in the late 1960s by the US lea nuclear test
The Velas were built to detect secret nuclear tests in space by the USSR
If you have a nuclear explosion, you would see gamma
Neutron Stars and Black Holes - Chapter 22
Core Collapse supernovae
Fire ball moves away, and the core remains.
Matter is made out of atoms, and atoms are small. They are mostly empty space.
If ow push all the electrons into a nucleus they can be fused wi
Test 2 - March 19
One page of notes - ok
Small Iron Core is stable
Because the Iron does not fuse, there is no outward radiation pressure
There is a temporary equilibrium between compressing force of gravity and stability of
iron atoms (hol
fCh. 21 with Brandon White
Novae would appear, sudden stars, which is contradictory to eh theory of stellar
creation - what we know now is a star changes its brightness quickly
Novae - 20 to 60 per year in the Milky Way
Presence of a ne
Summary for the Sun
Eight main stages
Starts as glucose in plants goes to Coal
Coal is pure carbon, if you take a piece of coal and compress it to a high density and
temperature, it becomes diamond
Evolution of stars more massive than the Su
A protostar may temporarily be hundreds of times more luminous than the Sun.
Most stars are usually formed singularly, not in clusters.
A star spends much more time on the main sequence than it spends forming initially.
Type M stars evolve
Stars on the main sequence maintain a state of hydrostatic equilibrium
Every star is full of gas, so when ball of gas is affected by gravity, the gas is
pushed towards the center. Pressure from the thermonuclear reaction
pushes back in perfect balance.
Brown Dwarf cooling time is billion years
With age they become more and more dim
Total number of brown dwarfs is about the same as normal stars
Stars in the main sequence are majority "middle age"
Why is the solar system flat? They are all in the same pla
1. Star A and Star B have he same apparent magnitude. Star A is twice as distant as
Star B. Therefore, Star A has twice the luminosity as Star B. False
2. Interstellar matter is distributed very evenly throughout the galaxy. False
3. Dark dust clou
Extra Credit (2 points each)
Day observation: Wed, thurs, 3:30pm
Night observation: M, Tues, Wed 8:30p.m.
Total mass of interstellar media is 8x the total mass of all the stars
Ch. 19 - Stellar Formation
How were stars born? How do we study this?
Ch. 18, the Interstellar Medium
What is in the space between stars?
In the solar system, it is solar wind, which quickly loses its density far from the Sun
Pioneer probe is 1 l.d. away
The interstellar medium
In any direction from the solar stsme between
Stellar distances - measured by Astronomical Parallax up to 100 parsecs or 320ly
Stellar motion - transverse velocity measured by apparent displacement of the star, and
the radial velocity measured by doppler shift
Total velocity = (transverse velocity^2
How do we know that 4 hydrogens create a helium through thermonuclear reaction? We
can recreate the reaction on Earth.
How do we know it is the only source of energy in the Sun?
Rate of this reaction depends on temperature and density
Neutrinos are produc
All solar energy is generated in the solar core via Thermonuclear reactionL fusion of
Hydrogen and Helium
Test on ch 1-ch 5 and then ch 16
multiple choice - a-d
one page of handwritten notes
Sun - huge ball of gas, it's not liquid or solid, everything is
1.Photon is a tiny wavelet of the EM wave
2. Molecular spectra are less complex than atomic spectra
3.Rotation can widen the emission lines of a star
4. A low density gas must also be sufficiently hot in order to produce an emission