Astronomy Review

The universe began as a ________ _______that was infinitely hot and dense, similar to a _______ _______.

small point, black hole

• The current estimate for the age of the universe is ________ years.

13.7 billion

After the Big Bang, there were two major stages in the evolution of the universe, known as the _______ and ________ eras.

Radiation, Matter

Epochs of Radiation Era

planck, GUT, Inflationary, Electroweak, Quark, Hadron, Lepton, Nuclear

Epochs of Matter Era

Atomic, Galactic, Stellar

The first era involved the creation of the four fundamental forces:

Gravity, Electromagnetic, Strong nuclear, Weak nuclear

The first era involved the creation of the first element:

He

The beginning of the next era is characterized by the cooling of the universe, allowing for the creation of the second element: _______.

H

The creation of this element allowed atomic clouds to form, and once their gravity was strong enough these clouds formed into ______, which created the rest of the elements on the periodic table.

stars

Evidence of the Big Bang

1. Galaxies are moving farther apart, therefore they were close together before

2. Element ashes observed are proportional to the predictions using the Big Bang model

3. CMB, heat and light detected from the first stages of the universe

Eratosthenes

• Measured Earth's Circumference

• Found earth-moon distance, earth-sun distance

Hipparchus

• Believed in pure observation

• Examined precise positions of the stars

• Unable to detect parallax

• Found procession of the equinoxes

• Modern Magnitude system (bright=1st dim=6th)

Ptolemy

• Last of great astronomers of Alexandria

• Hid in library of Serapeum

• Created Ptolemaic Model (explained retrograde using epicycle and different)

• Bad model (no universal rule, all planets were independant, too complicated)

Copernicus

• First heliocentric model of universe (explained retrograde motion)

• Orbits were circular :(

Kepler

• Tycho's assistant, inherited all positional data

• redefined copernicus's model (eliptical orbits)

• laws of planetary motion (planets move in elipse around sun)

Galileo

• Delivered final blow to geocentric model

• Trouble with catholic church (said objects fall at same rate)

• Built his own telescope (observed phases of venus, moon mountains, suspots, moons of jupiter, rings of saturn, etc.)

• Roman Catholic Church put him in house arrest

Newton

• began devellopement of physics and calculus

• Laws of motion

  • in motion = remain in motion, at rest=at rest

  • F=ma

  • every action has an equal and opposite reaction

• Laws of gravitation (attracting force is proportional to mass, inversely proportional to distance apart)

Main types of galaxies

eliptical, lenticular, spiral (spiral, barred spiral), irregular, peculiar

When classifying galaxies, ellipticals are classified based on_________

how circular it is (circular=0, elliptical=7)

spirals are classified by _____________

how tightly thier arms are wound (a=tight, c=loose), if they have a bar or not

Components of galaxies

bulge, disk, halo

Bulge

centre of galaxy, spheroid, smooth structure, little to no rotation, little to no gas, no star formation, old stars

Disk

flat, rotates, contains stars and gas and dust, ongoing star formation, young stars, high and low mass stars, blue and red stars

Halo

older stars, no gas or dust, globular clusters, low mass red stars, formed when few heavy elements existed, no ISM, no star formation

Elliptical galaxies

pure bulge, no disk, very large

Spiral galaxies

varying amounts of disk, arms from nucleus classified by how tightly arms are wound, nucleus brightness correlates to arm tightness

Mass of low mass stars

less than 10M

Life cycle of low mass stars

1. Nebula of gas and dust

2. Low-medium mass Protostar

3. Low-medium mass main cycle star

4. Red giant

5. Planetary nebula

6. White dwarf

7. Black dwarf

Mass of high mass star

between 10M and 40M

Life cycle of high mass star

1. Nebula of gas and dust

2. High mass Protostar

3. High mass main sequence star

4. Red super giant

5. Supernova

6. a) neutron star

   b) black hole (extra high mass)

Trends of the H-R diagram

• main sequence stars are more luminous when they are hotter

• Red giants are more luminous than main sequence, but cooler

• white dwarf stars are less luminous that main sequence, but they can be hotter

• blue/white = hot, red=cool

Current North Star and its location

Polaris, northern hemisphere, ursa minor/little dipper

Little dipper is located in

Northern hemisphere, always above the horizon

Big dipper

Ursa major, northern hemisphere, always above the horizon