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Module 1: Introduction to Astronomy

Stars & Constellations

Constellations: they are used as memory tools (ex. Seasons)

An example of Constellations is Orion's Belt

Motion in the Sky

this is an occurrence that happens as we rotate around the sun, or as the moon rotates around us.

How the Sun moves around in the sky is another example of this.

As the earth rotates we can see signs of this with the big dipper rotating through the night

The Celestrial Sphere is what we call the sky that we can see because all the stars seem to be the same distance away from us when really it is just how we view them.

Rotation - the earth rotates counter-clockwise (west to east) as do most planets we assume.

Day and Night and Systems of Measurement

We use

-longitude and latitude to measure around the globe

latitude =north to south

longitude = east to west

they give us cross sections for the earth

In astronomy we consider 1 degree to be 60 arcmin or 3600 arcseconds

60' = 3600''

latitude gives "declination" which is distance away from the equator

longitude gives "ascension" which is distance away from the equator

Local Coordinates in the sky are something that depend completely on where you are on the earth. The control what stars you see and when.

"altitude" = 0 degrees is horizon while 90 degrees is directly overhead

"Azimuth" = 0 degrees due north and 90 degrees is due east

Depending on our latitude at most we can see is half of the sky (this would be places close to the poles)

Angular Separation Units

Angle in Radians = theta = a/d where a = arc-length and d=distance

1 radian = 180 degrees/pie ~57.3 degrees

1 radian = 60 x 60 x 180/pie arc-seconds ~ 206265

a= d x theta-> where theta is in radians

The Moon

Throughout the month the moon goes through several phases depending on where it is in relationship with the Sun and Earth

For example when the Moon is in between the Sun and Earth it is called a New Moon While when the Earth is in between the Sun and the Moon it is called a Full Moon

The The Year

The Earth rotates once around the Sun and this is what we call a year.

This lines up with the 12 zodiac throughout the year as it appears in the calendar

The path that the Sun follows through the sky is called "Ecliptic" sometimes the other planets seem to follow this path through the sky.

The "Ecliptic" path the we see the Sun travel through the sky is actually a reflection of the opposite of what our Earth's motion around the Sun.

The Ecliptic line is on a 23.5 degree incline in the sky because of the Earth's rotation on its rotation.

FUN FACT: The planets that we can see in the sky with our naked eye are: Jupiter, Saturn, Mars, Mercury, and Venus.

Seasons - this is because the Earth's axis, depending on the time of year the axis is either pointing towards or away from the Sun.

Important dates to the Seasons are;

Winter Solstice: Dec. 22

Spring Equinox: Mar 22

Summer Solstice: Jun 22

Fall Equinox: Sept 22

The Calendar

This is time that is based on the Sun = Synodic (solar time)

Time based off the Stars = Sidereal

FUN FACTS: The day used to be defined from noon to noon and was counted in minutes 24X60X60 = 86,400 sec = 1 synodic day

1 second = "hyperfine transition of cesium"

You can measure the time of day by the stars = 23 hours 56 minutes and 4.091 seconds

Solar Time = Sun Time doesn't measure sunset to sunset

FUN FACT: Waterloo and Toronto have different points of the day that are it's noon.

Standard is what we live with now where the earth is divided into time zones. The earth is divided by 15 degree latitude

Lunar Calendar:

it would be more accurate to do from new moon to new moon but instead it is done every full moon to full moon

Synodic Month: 29.53 days (12X 29.53 = 354 days a year)

Sidereal Month: 27.32 days

Roman Calendar had 12 months and a 13th month every 3rd year

Julian Calendar: 12 months 30 or 31 days

- leap year ever four years

started in 45 BCE

added an extra extra three months to the years 46 BCE but lost a full year

in 1582 they got rid of 10 days from the year just that one year.

The calendar is messed up because things are not perfect

Eclipses

There are two types of Eclipses

1) Lunar eclipse: this happens when the moon passes through the earth's shadow (only happens on full moons)

2) Solar Eclipse: this happens when the Earth passes through the Moon's shadow

Eclipses do not happen often

Two pieces of the Earth's or Moon's Shadow are the Umbra & Penumbra.

Umbra - this is the smaller more dense part of the shadow

Penumbra - this is the more wide less condensed part of the shadow

There are three types of solar eclipses

1) Annular Eclipse this is when the you can still see the sun around the outside of the Moon

2) Partial Eclipse - this is when the Moon partially covers the Sun

3) Total Eclipse this is when for a short period of time the Moon completely overlaps the Sun

There is a specific eclipse season which happens twice a year and is about six months apart. Each year eclipse season happens earlier then the year before.

The eclipse circuit takes 18.6 years

Module 2: History of Astronomy

Early Astronomy

Astronomy has been used for many purposes. An example of this is for marking the seasons and different special times of the year.

Some example calendars from the olden days are

-Stonehenge

- pyramids

- mayans

- Sundials

-Crescent Moon

- predict seasons (wet seasons)

Ancient Astronomy

planet= "wanderer" (greek)

all the planets are Venus, Mercury, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune

Some important early discoveries

- the earth moved around a central fire (heat source)

-pythagoras -all spherical

Aristotle promoted the idea that we were at the centre of the universe

-the moon had phases and eclipses

- the sun is more distant then the moon

- earth is spherical

Aristarchus

(measured things)

- relative distance to the sun and moon

- relativie size of the earth moon, and sun

the calculation was made using this formula (1/2) (length of time/length of month) X360 = theta

Eratoshenes

-measured the circumference of the earth (guessing that the earth was around 42, 000km ~ actually the earth is 40, 000km)

Hpparchus

- invented trigonmetry

- measured the position of the stars and the brightness of stars

-invented a coordinate system and a magnitude system, and discovered a procession

estimated the size and distance of the Moon

- measured length of year

- explained eclipses

- worked on "retrograde motion" -tracking how planets move

- how planets loop around

- looking at the speed at which planets loop around in their orbit

-"Epicycle" everything is going around one central point which is going around the earth

Ptolemy (140 BCE)

-epicycle theory of the solar system - worked to justify that everything went around a central point that went around the earth

published an astronomy book

Paltrallax - this is a way to measure the distance from earth to moon

"Pre-Scientific" Astronomy

as used around the world

Hindus

-measured the moon

-systems of numbers

Islamic

-algebra

- planets related positions

-eclipse records

Babylonians

- time keeping

-surveying

Chinese

-most valuable

-error in the calendar (they found the mistake)

-recorded new stars (comets and meterites)

they also saw supernovae

Scientific Astronomy and Motion of Planets

What is Science?

when looking into astronomy there are many areas to study

-observe and record/keeping

- classification of properties

simple theories

communicate the results, ideas, and model

predictive powers

- try prediction and use the ones that work, and get rid of the ones that do not work

"scientists show only that models are wrong or flawed, not what's right"

Planetary Positions and Motion

You have the sun in the centre of our solar system. Then between the sun and earth you have inferior planets and then from the earth to the edges of our solar system you have superior planets.

Elongation - this is the angle between the sun and a planet from the earth

Conjunction this is when a planets a 0 degree elongation

-superior conjunction is behind the sun

inferior conjunction is in front of the sun

Opposition - this is when the planet has a 180 degree elongation

Quadrature - this is when the elongation is 90 degrees

(SEE PICTURE IN NOTES)

FUN FACT: The distance between the Earth and the Sun is one Astronomical Unit (1 AU) this is a universal measurement tool

European Developments in Astronomy

1) Nicholas Copernicus (1473 - 1543)

- worked on the idea that the Sun is the centre of our Solar System not earth

- worked on the idea that the planets rotate around the Sun and the closer they are to the Sun the faster they rotate

- the Earth rotates on an Axis

-orbits are cicular

-sidereal vs. synodic periods

- distances from earth to planets

When measure inferior planets orbital period the calculation is S + 1 = (S/P)

When measuring superior planets orbital periods

S = 1 + (S/P)

It all calculation work to put a triangle between the earth, planet and the sun.

Relative Distance for a Superior Planet

to find the distance of a superior planet we need to look at the sidereal period length and use measurement given from when the planet is at opposition and quadrature

cos (P'SE) = (SE'/SP')

angle P'SE' = ESE' - PSP'

SP' = (1.0 AU / cos (P'SE')

Note: notes has old and new calculations of the distances to the planets.

Tycho Brache (1546 - 1601)

- extremely detailed in his note and precise

-built large tools

Johannas Kepler (1571 - 1630)

-worked for Tycho

- worked on information just on Mars.

Kelper's Law

1) Orbits aren't circular

2) Equal are are swept out in equal times

3) Periods squared are "proportional to" a^3 = p^2 semi-major axis= a

distance from the centre of focus is = c

Eccentricity = e

e= (c/a)

Gallileo Galilei (1564 - 1642)

- used the telscope for astronomy

-discovered many things

- phases of Venus

- mountains on the moon

- sunspots

- moons of Jupiter

- Milky Way is made of Stars

- his ideas went against that of the pope this got hime into trouble in 1633

he was later "forgiven" in 1992

- looked at how the phases of Venus would differ depending on if it was between us and the Sun

Isaac Newton (1642 - 1727)

- invented the laws of Motion (F=ma)

- laws of gravity

- optics

- calculus

- "laws" which provide universal rules to how the planets motion is governed and thing on earth

F = (Gm1m2/r^2)

Albert Einstein (1879 - 1955)

- energy is stored in matter

- looked at mass energy - how objects would be converted into energy

E=mc^2

- Theory of relativity

- special relativity - that the speed of light is independent

- there is something called curved space

- mass simply curves space-time and objects move along the curvature

Development of Physics

Atomic theory of Matter

- atom is made up of the nucleus which contains protons and electrons

- structure of atoms

- lots of space in an atom

- common elements that are found in our universe are:

- hydrogen (element # 1 and makes up 90% of universe)

- helium (element #4 - makes up 9% of universe)

- carbon (element # 12 makes up the next largest amount of the universe

FUN FACT: Electrons lose or gain energy as they orbit the nucleus

low energy = ground state

higher than low state = excited state

enough energy to escape = ionized

electrons can only lose or gain a certain amount of energy

Temperature

Kelvin vs. Celsius

highest = 373.15 vs. 100

middle = 273.15 vs. 0

lowest = 0 vs. -273.15

when looking into astronomy we use Kelvin or Absolute Temperature Scale

Temperature vs. Heat

Temperature = average kinetic energy

Heat = total kinetic energy

Note: Notes has a scale showing how as gas heats up it ionizes

Module 3

Physics of Orbital Motion

- this looks at the properties of an ellipse

rmin = a(1 - e) ~> perihelion distance (closest to the Sun)

rmax = a (1 + e) ~> aphelion distance (farthest distance from the Sun)

rmin + rmax = 2a

a = semi-major axis

Note: There is a really good drawing of this in your notes look it over

e = (c /a)

Centre of MAss

an object's orbit is an ellipse

centre of mass depends on the planets masses

there are three ways that the centre of mass can work out between the planets

1) the planets share the same mass - if so the centre of mass in between the two

2) if one planets mass is double the others - the centre of mass is closer to the large planet

3) or you can have it that a planet has more mass while the other planet has a larger area

This is when you use

Kepler's Third Law:

p^2 (years) = a^3 is

(m1 + m2) P^2 = a^3 = (a1 + a2) ^3

this looks at the centre of mass of the two orbits and looks to find a common spot of focus

and this point completely depends on the size of the orbit and the centre of the orbit

Conservation of Energy

This is a principle (or law) is fundamental to physics. Basically looking at the fact that since stars shine they have to change over time

FUN FACT: Energy cannot be created nor can it be destroyed

Total orbital energy - is made up of gravitational potential energy + kinetic energy

- it is a constant that is not influenced by external forces.

Gravitational Energy - increases as distance increases

Kinetic Energy - energy increases as distance decreases

Angular = mass X speed X distance

L= mxv=r

The "spin" or angular momentum is conserved quantity

L in the equation is a constant (as long as there are no external forces from the outside)

if the distance r changes then the speed which is n will change as well

An example of angular momentum is with figure skaters who speed up as they bring their arms closer to their bodies and slow down when they do the opposite

Kepler's Law is derived from Celestrial Mechanics

P^2= [(4pie^2)/ (G (m1+ m2))]

you can also use conservation of energy and some other pieces of information to get the information that you want.

Three Version Kepler's Law

1. P^2 = a^3

2. (m1+m2)P^2=a^3=(a1+a2)^3

3. (m1+m2)P^2=4pie/G(a1+a2)^3

Example Calculations

This can be found in my notes and in the lecture (slides, videos, and audio). It will show some example problem working with the information that I have learned up to this point in the course. (which was not much)

Orbital Energy

The equations use for this are

v^2 = G (m1+m2) (2/r - 1/a)

vcirc = square root (GM/r)

Looking at orbital kinetic energy (1/2mv^2) it decreases with distance as it get further from the centre of mass

orbital speed works with distance

When looking at circular orbits you have two types:

1. Bound Orbit - this means that the orbit has a limit in regards to speed and mass

2. Unbound Orbit - this is an orbit which does not have the same limitations as a bound orbit

Tidal and Orbital Energy

Tides

- these are caused by different forces working across the water

equation:

Fg= G(m1m2/d^2)

Note: There is a drawing of this in my notes to look over and refer to while studying more

The difference in gravitational attraction is that it tries to pul apart, rising tidal bugles both towards and away from the Moon

Since we are in constant movement as a planet and our sun so does our high tides and where it is located on the planet

Ocean Tides on Earth

- the ties varying on the alignment of the Sun Moon, and Earth

Spring has the highest "high tides" and the lowest "low tides" on the full Moon

Reap Tides refer to when the tides are the most opposite of what they are suppose to be example "lowest" high tides and "highest" low tides they occur around the first and third quarter

Note: There is a drawing of this in the notes

Tidal Friction

- this is the fact that tides slow down the earth's rotation a little bit

-tidal forces are important

-planetary rings effect the planet tides

Galaxies: tidal streams from encounters

Orbits can be altered by an exchange of energy

galaxies colliding (merge) by an energy exchange

Module 4 Light

Properties of Light

what is light?

light is made up of colours and wavelengths. We use optics and telescopes to look light out in the universe

Astronomers don't do experience - rather they measure things out in space

-plus everything is too far away & takes to long to get to

astronomer observe through light

astronomers measure the brightness of an object

Brightness alpha = (1/d^2)

So what is light?

light is technically a wavelength that carries electromagnetic energy

when looking at light we distinguish it based off the wave "length" that is being given off and the colour that it is

When looking at light we look at the wavelength and the amplitude of the wavelength

Electromagnetic = velocity of light frequency v/f=wavelength

There is a relationship between wavelengths and frequency

speed of light = wavelength x frequency

c= weird symbol f

frequency is the number of wavelength given off each second

FUN FACT: Light travels 300, 000 km/per second

also light years is only used by amateur astronomers

Visible Spectrum - this looks at red light which gives off a longer wavelength at a lower frequency

Visible spectrum fall between 400nm - 700nm

Then it goes infrared ~> ultraviolet ~> X-rays ~> Gamma Rays

FUN FACT: Until the 1950's we only knew about the visible spectrum of light

frequency = energy of light (is dependent on frequency)

Blackbody Radiation

Definition: A blackbody is a theoretical construct, it is impossible to make a perfect one, some stars are close.

- with blackbodies the emission of light depends on the temperature

- blackbodies are called "perfect absorbers"

- they absorb and emit light at any wavelength though the amount of light is different depending on the wavelength.

Equations to do with Blackbodies

- wavelength the brightest = 1/T nm

- the higher the blackbody = brighter but for a shorter amount of time

- the colour order of stars

- blue hot > orange hot> wavelength red hot

- all the wavelengths added up for a blackbody is proportional to T^4

Note: In the notes there is a good drawing

Using Plank Law you can get a shape of how the emission looks and work (equation)

E = weird other symbol T^4

During lecture there were several example problems which I should look over for practice whether with lecture or audio or just the slides.

Spectra

Emission Line Spectrum

-this is a hot light bulb that produces light at all wavelengths

-with hot gas it would produce a "discrete" wavelength

- we can identify the elements present in a source from the spectral line signature (fingerprint)

- this way you can see the way what things are made up of. Depending on what colours come out through the spectra.

Photon Energy

E= hf = c(delta weird symbol thing/weird symbol thing)

There are three types of Spectrums

1) Continuous - this is when you see all the colours

2) Absorption - this is when you see most of the colours but not all

3) Emission - this is when you only see a few colours

FUN FACT: Look up the Solar Spectrum it's super cool

Doppler Shift

This is when you use wavelengths to see if another object in space is moving towards or away from Earth

-shorter wavelength, and higher frequency = moving towards Earth

-longer wavelength an lower frequency = moving away from Earth

The Doppler Shift is what we use to measure if stars are moving towards us or not

Equations:

(vrad/c)= (delta weird symbol/weird symbol)

this is used to see if things are moving towards or anyway from us.

We can use the Doppler Shift to measure how fast things are rotating and how fast things are moving.

Telescopes

- a telescope is something that uses a large collection of light (this is in the form of mirrors)

Equation:

A= (1/4)pie d^2 or A= pied

d= aperture diameter

Things that you look for in telescopes are

1) Resolution = how clear is it

2) What type of lens are you using

(the larger the lens is the better the resolution is)

Resolution of Telescopes

- this is something that does have it's limitations one of these can be the diffraction of light:

depending on the size and shape of the aperture compared to the wavelength.

- also if there are other images coming into the lens of the camera

- also does the light spread out after going into the telescope

Lenses

-made from glass

- bends the light to be seen better

The only problem is lenses like everything out there have their limitations.

Limitations of lenses

1) different wavelengths bend different light

2) hard to shift around

Telescopes cont.

Mirrors are the best way to look at stars

CCD inside the cameras used to look at stars comes from the military and astronomy field

Spectrograph

1) Brings the light in

2) Bounces from mirror to plate

3) Bounces from plate to mirror

4) Continues until it gets to the point where the image is being viewed by someone on a computer

FUN FACT: Our atmosphere blocks lots of wavelengths from coming in

Phenomena which are visible at other wavelengths require different kinds of telescopes and instruments to view

Radio and Infrared Telescopes have been invented and are used in this day in age

Interferometer

this gets better resolution because the telescope is made up of several smaller telescopes putting all their images together

Space Telescopes = HUBBLE TELESCOPE

- which will not be repaired when it breaks, they are working on it's replacement

Module 5

Overview of the Solar System

- our Solar System is full of many things

-a star

- planets

- meteors

- comets

- satellites

- asteroids

In the Appendix of the textbook there is the information on all the planets and dwarf planets

Appendix E more specifically

Orbit Properties

- most planets orbits are circular and have an axis tilt that varies

some properties:

-orbits are almost coplanar

- the moon of each planet is just above the equator

-planets closer to the sun have a rocky exterior and are more dense while planets further are less dense and more gaseous

Planetary Interiors and Surface

Using earthquake waves as a way to probe and investigate the centre of planets. They are how we gain understanding about what is underneath the surface of our planets

Earth has several layers

1) The rocky crust (medium density)

2) Rigid Lithosphere (mantle crust)

3) Mantle (medium density)

4) Metal Core (high density)

Now looking at the core of the Earth we ponder how are we heated as a planet?

1) Accretion -- this is when the heat leaves from the centre out towards the crust where it cools.

2) Differentiation - denser things are falling towards the centre while less dense things are leaving the centre

3) Radioactive Decay - rocks that are slightly radioactive bring heating

Whatever method a planet uses for heating it depends on the mass.

The other question is: How do planets cool down?

1) Conversion - hot rocks rise to the cool surface while, cool rocks fall to the warm core

2) Conduction (READ LECTURE FOR THIS)

3) Radiation (READ LECTURE FOR THIS)

One thing that is known is that all planets lose heat through the surface

- the bigger a planet is though the longer it stay hotter for

Planet Magnetic Field

On each planet since it is rotating and has a metallic core this works to create a magnetic field around the planet. The magnetic pole is the smallest by the poles

FUN FACT: Solar winds distort the magnetic fields and aurora = solar winds + magnetic fields (the solar winds are smashing into our atmosphere)

Planetary surfaces

-the surface of the planet is always moving

this is because there is stuff moving around under the surface and the plates are being moved around

Some of the movements that we see are:

- subduction

-collisions

- volvatism

- faut lines

- rift valley

-earthquakes

These things all take place across the tectonic plates boundaries

FUN FACT: Continental Drift is real!!!

Planetary Atmosphere

When looking at the Earth's Atmosphere we realize that it use to be really hot

The atmosphere haw come out by outgassing (mostly) in the form of CO2 and chemistry life

The Surface temperature is a combination of solar heating and IR radiation that is trapped by the cloud layer and a hot interior.

The Atmosphere circulation depends on the climate and heating during rotation

Layers of the Earth's Atmosphere and what they are heated by

1) Exosphere -this is heated by solar UV and x-rays, this is the region of the greatest escape (high temperature and altitude)

2) Thermosphere - heated by x-ray heat and ionized (in state)

3) Stratosphere - heated by UV light

4) Troposphere - the heat is kept in by the clouds. IR is trapped from the surface so it cannot escape. On this layer of the atmosphere radiation and convection is important

Heat trapping is done by a thick layer of clouds which is important also CO2 also helps to trap the heat in

The effect of the CO2 is called the "Greenhouse Effect"

-this is that CO2 works to trap heat which works to produce more CO2 which continues this cycle.

There is an equation works to estimate how quick/slow we are losing heat

: Peak Thermal Velocity

vthermal = sqrt (2kt/m)

originally the Solar System was a lot warmer then it is now

T Note: as M and m get larger so does T

Carbon Dioxide Cycle:

The carbon cycle is something that affect the atmosphere abundance

each year there is a CO2 increase by 3.4 pg/year

CO2 works in a negative way on the earth's thermostat.

While through the Carbon Dioxide Cycle we gain gas it has some negative impacts

Random Lecture Notes:

There is a theory that early comets were the cause of our oceans.

The Sun heats the equator and from there the warm air rises to the poles where it is slowly cool down leading to cool air which returns down to the equator to go through the same cycle again and again. This also works to move the clouds in a certain way through the sky.

The Coriolis Effect:

this is looking at the rising of heat as if it was to be first divided at the equator then from there the earth was divided into three section on the top half and three in the lower half. (larger planets have more then three of these divisions other smaller planets have less).

Terrestrial Planets

this is looking at all the planets between the Sun and Earth

Also note that earth is considered a terrestrial planet but it is the only one with a moon.

1) Mercury is the planet closest to the Sun. Mercury has not been investigated in great detail (the best image of the planet is from back in 1974).

- the planet is heavily cratered with a solid interior

- a surprising things about the planet is that it has a weak magnetic field

- the planet has lots of cliffs which are indication of shrinking and cooling

2) Venus is the second closest planet to the Sun

- has a very hot and dense atmosphere (730 K and 96.5% CO2)

- the planet is covered by sulphuric acid clouds

- it's atmospheric pressure is 90x that of the Earth

- it has been a struggle to observe the surface of this planet because of the strong atmosphere pressure destroying everything sent to observe it.

-the planet does not have a magnetic field because it has a slow rotation

- there might be several craters across it's surface, and there might be several volcanoes

- other then that there is little known about Venus

3) Earth - nuff said

4.20 our moon is the largest moon to planet ratio. The moon looks different from the other side the interior of the moon is different from the exterior but different from our interior.

The Moon has craters on it.

4) Mars

- it has two tiny moons

- Mar's atmosphere is very thin only 95.3% CO2 while the temperature sits at around 220K

FUN FACT: We could live on Mars it would be cold and a stretch but we could

- Mars has a weak magnetic field

-some superficial features of Mars are it's red colouring and craters on the surface, it contains the largest volcano and has a 24 hour rotation

Looking at cratering on a planet or moon you can see glimpses at the planets past and comparing planetology you can see how over time planets move to the places they are now in the sky and have changed in size and heating

Giant Planets

Giant planets have a faster rotation.

How giant planets differ from terrestrial planets?

-they have different cores from the Earth

- their cores are about 10 - 15x the size of the Earths

- in the cases of Jupiter and Saturn they have higher hydrogen percentages and H compounds then that of the terrestrial planets

1) Jupiter

- looking at the interior of Jupiter you have a planet with a core composed of rocky and metallic hydrogen components. This leads to a large magnetic field but the planet also has a low density.

- the atmosphere around Jupiter has water, ammonium hydrosulfide, and ammonia

- like the Earth the heat on Jupiter moves out from the centre and towards the poles

2) Saturn

-the atmosphere on Saturn is made up of water, ammonium hydrosulfide, and ammonia

- also on Saturn the bands are very prominent.

FUN FACT: Saturn has storms happening on it from time to time.

3) Uranus

FUN FACT: Uranus was discovered by accident.

-it is made up of hydrogen, helium, and methane

- it's axis is 98 degrees this causes extremes between the seasons.

4) Neptune

- has storms on it like Jupiter

- they predicted it's spot in the sky based off Uranus.

- it is similar to Uranus but has more methane, clouds and is warmer then Uranus

Moons for the Giant Planets

Like Earth the giant planets have Moons which orbit around them. The moon's of Jupiter are:

-Jovian

- Lo

-Europa

-Genymede

- Callisto

The moon's of Saturn:

- Titan

- there are many there and many to still be discovered

Moon's of Uranus:

- it has at least 20 different moons

-Miranda is one of the weirdest moon's it has

Moon's of Neptune:

-Triton is it's largest moon

- it has about five moons in total

Rings on Giant Planets

-Saturn is the most well known of all the planet's for it's prominent rings - they sent a "voyager" to look at the rings of Saturn it returned some time later after making several discoveries about the rings of Saturn

-Jupiter has rings around it, though they are very faint and not very well known

- Uranus' rings can only be seen in the IR

- Neptune's rings, they are narrow and bright and have large gaps between them.

Small Bodies and Scaling Astronomical Equations

when looking at the other smaller pieces of our Solar System we have things such as asteroids.

Here are some equation which are used to measure things in our solar system.

Planet Temperature: 6.00x10^9(1-A)(L/Lo) (1/D AU)^2

Vis-viva Equation v(km/s^2)^2 = 883 (M/Mo)(2/rAU - 1/aAU)

Gravitationally Unstable

Mjeans (Mo)= (2(C/0.2km/s)^3(n/10^3cm^-3) ^-1/2

Asteroids and their features

-these are small rocky bodies that do not have any atmosphere while they orbit the Sun

FUN FACT: the first asteroid discovered was called Ceres which has now been named a dwarf planet

-there are around 30, 000 asteroids that have been catalogued

-the "asteroid belt" is found at a = 2-3.30 AU

- very few asteroids have Earth crossing orbits

There are three types of asteroids

1) Carbonaceous (very dark 75% carbon)

2) Siliceous (15% silicates)

3) Metallic (made of iron and are the rarest type)

- when asteroids are seen in pictures they look like streak across the sky

- Asteroids are found anywhere between the Earth's orbit to out about 5.2 AU (Trojan)

-asteroids vary in size, density and mass

Meteors and Meteorites

- the difference between meteors and meteorites is that Meteors never fall to the Earth's surface, while Meteorites hit the Earth's surface

Meteorites are sometime called:

-shooting stars

-meteor shower

-meteor storm

FUN FACT: largest meteorite ever found was 2, 000kg

-meteorites are made up of organic material

- as they streak across the sky they become very bright

-meteor showers occur at the same time of year each year

-when looking for a meteor shower look at around 2 am the day before or the day after that is the best time to look

-craters on the Earth are a result of meteorites hitting the Earth

- it is believed that a giant Meteorite was the cause of dinosaur extinction

-depending on how often something happens the worst it will be (frequent=mild, while rare= could cause mass extinction)

-Jupiter protect us from a lot of Meteorite problems

Comets

there are two parts to a comet

1) Coma

2) Tail

Pretty self explanatory which part is which

Comets are not usually very bright and if the comet is bright then it is rare

There are two groups of Comets

1) Kuiper Belt - these comets have short lives

2) Oort Cloud - these are comets with longer lives

Dwarf Planets

Pluto has the most elliptical and inclined orbit of all the major planets

In Pluto's orbit it can sometime be closer to the Sun than Neptune, though it will never collide with Neptune

FUN FACT: Pluto was discovered by accident being found in 1978 along with Charon

Charon is another dwarf planet though it is less dense than Pluto.

Charon was formed by impact while Pluto is believed to have originated in the Kuiper Belt

Definition of Dwarf Planet:

it is a planet which orbits the Sun, has a spherical shape, and has not "cleared it's neighbourhood"

Several Dwarf Planets in our Solar System are:

-Pluto

- Charon

- Ceres

- Eris

Formation of the Solar System

There are 4 characteristics

1) large bodies have movement

2) rocky - small planets

3) large gassy planets

4) place where there are asteroids

Our solar system is a Nebular Model of a solar system

this mean that it was formed by a large swirling area of gas (this is what is going on when we see large gaseous nebulas in outer space)

Gravitational Collapse - this is when the gravity starts to bring everything in towards the middle of the gas collection

when the gas clouds collide they send shockwaves to one another.

This causes for a shrinking nebula and an increased gravity. As this is all happening the temperature begins to rise.

Like with the idea of a figure skater as everything starts to come in closer so the speed of the rotation of the nebula begins to speed up, and flatten.

Since it is the hottest in the centre that is where the Star is formed (in our case the Sun), the planet then are formed using the remaining dust.

Slowly everything in the nebula begins the same orbit around the centre.

Looking out into space we could see this happening in several Nebulas

Two Kinds of Planets?

What type of planet is formed depends on what temperature it is where the planet is being formed, also what material is in that part of the Nebula Cloud

For example rocky planets are found closer to the centre (generally) because most of the rocky material stays within 3.5 AU of the star.

In the process of making planets material gathers together and as it get big enough it is able to have a gravitational pull

With Large planets they pull in the gases and the smaller rocky planets too.

Moons are created from proptary disk. The solar system is finally done when the Star reaches final heat and send out a solar wave pushing all leftover material out of the solar system. Asteroids do not leave because they are not small enough to be pushed. This is a simple version of what happens when solar systems are formed

Planets and Other Stars

When looking out into space there is always the question about if there are other solar systems out there and how do they compare to our?

While we cannot observe them all directly we can use the Doppler Shift to observe them. This looks for when the star starts to wobble.

FUN FACT: First discovery of this was by a Canadian, Gamma Cephei in 1988.

Using the Doppler shift is a very complicated method to do this seeing as:

- planets are not bright

- they are too far away

When looking at the star they look for where it is red shifted vs. blue shifted (through Doppler Shift)

While there have been discoveries of solar system in space they generally contain planets with an average size around Jupiter, these planet are hotter and closer to their star, and contain a low density like that of Jupiter

-In 2009 they found the first planet that was Earth like

When looking at the Kepler 11 solar system the star is almost identical size to that of our Sun.

- Kepler - 10 is the planet that was found to be Earth like

being the first rocky exoplanet that was found, also like the Earth is mass and density

The Kepler Mission

- to find a habitable planet:

-liquid water

-good temperature range

- would be in the good zone which for us is 1 AU from the Sun

FUN FACT: in December 2011 they found Kepler 22b which is very Earth like

Another way to look for outside planets is using Infrared Emission which looks for the emission that a planet is letting out and then looks at the different phases of the planet. From there it can also discover the surface temperature, "day and night"

FUN FACT: 2014 has been great for confirming planets and in April 17, 2014 they found a new Kepler - Kepler 186f which is the first Earth sized planet to be found.

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