S EP ESP

Unit 5 – Astronomy: The Study of the Universe

http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide

I) Early Astronomers:

Ptolemy : (140 AD)

Greek Astronomer who theorized the model of the universe. The Ptolemaic theory suggested that the Earth was the center of the Universe. Ptolemy’s theory was popular for over 1,500 years in Europe.

Ptolemaic model:

Copernicus: (1543 AD)

A polish astronomer revolutionized astronomy with his new model of the universe. He theorized that the Sun was the center of the universe and all the planets, including Earth, orbited around it.

E S

P

S ^E

II) Electromagnetic Spectrum^:

The Electromagnetic spectrum is made up of all the wavelengths of electromagnetic energy.

(Ex: X-rays, radio waves, etc.)

Telescopes are instruments that are used to observe electromagnetic radiation from space.

Refraction – when light BENDS because it is passing through mediums of different densities.

III) Stars

Composition (make-up) of stars:

Stars are made up of different elements in the form of gases. (Ex. Hydrogen)

Scientists classify stars by:

 Color

 Temperature

 Brightness or Magnitude Star Color:

 Stars vary in the color that they glow

 A star’s color depends on the temperature at which it is burning and the elements that the star is composed of.

 Hotter temperatures – a star will glow blue

 Cooler temperatures – a star will glow yellow, orange and red

H-R Diagram

Types of Stars:

 Main Sequence Stars –

o Longest stage for a star. Most stars enter this phase of their life cycle.

 Giants and Supergiants –

o After the main sequence stage, a star can enter the next stage: Red Giant.

o Stars become red giants after burning up all their Hydrogen. This causes the star to shrink causing the outer gases of the star to expand and cool.

Red giants – 10 times larger than our sun.

Supergiants – 100 times larger than our sun.

 White Dwarfs –

o The final stage of a star’s life cycle.

o Similar mass to our sun

o Small, hot star that is leftover material from an older star

o No more hydrogen to burn

IV) The Life Cycle of Stars:

The Beginning:

 Stars begin as a ball of rotating gas and dust.

 Gravity pulls the gas and dust together to form a sphere.

 As sphere becomes denser, it gets hotter causing hydrogen to change into helium.

(Nuclear fusion).

 Nuclear fusion is what gives a star its energy (Heat and Light).

The End:

 As a star gets older, it loses some of its material.

 Star eventually runs out of gases to burn and dies or violently explodes into space.

 The material from old stars travels in space and can help form new stars.

 If an old star explodes it can form a variety of new objects:

o Black holes

 The center of a star collapses under its own gravity.

 The force of contraction crushes the center of the star forming a black hole

 Nothing can escape the gravitational pull of a black hole, not even light!

o Supernovas

 A massive star may explode in a bright flash called a supernova o Neutron stars

 Leftover material from a supernova can combine to form a new star

 The materials of the new star are neutron particles from old star.

Galaxies

Galaxies

 Large groups of stars, dust and gas

 Our Solar System is in a spiral galaxy called The Milky Way

The Big Bang Theory

 13.7 Billion years ago, all the matter in the universe was compressed into one small point

 The universe started with a huge explosion

 All the material from the explosion is still expanding outward

Evidence supporting The Big Bang Theory

 Cosmic background radiation

 Scientists found radiation spreading out to all parts of the universe

 The expanding universe (stars, planets)

V) The Solar System

 Consists of:

o 1 Star – The Sun o 8 Planets

 Mercury – Inner planet, rocky

 Venus – Inner planet, rocky

 Earth – Inner planet, rocky

 Mars – Inner planet, rocky

 Jupiter – Outer planet, gas giants

 Saturn - Outer planet, gas giants

 Uranus - Outer planet, gas giants

 Neptune - Outer planet, gas giants

My Very Excellent Mother Just Served Us Noodles

Our Solar System Inner Planets:

 Also called terrestrial planets (Earth-like planets)

 Very dense

 Composed mostly of rock

 Smaller than the gas giants

 Mercury, Venus, Earth and Mars

Outer Planets:

 Also called the Gas Giants

 Composed mostly of gases (Hydrogen, helium)

 Massive Atmospheres

 No solid surfaces

Gravitational Attraction

 Gravitational attraction is dependent upon the mass of the objects and the distance between them.

 The more massive (larger) the planets the stronger the gravitational pull it has

 The closer objects are, the stronger the gravitational pull

VI) Planetary Motion

Rotation vs. Revolution

 Rotation – the spin of an object on its axis. Ex:

Earth spins on its axis (Earth’s rotation is 24 hours)

 Revolution – the motion of a body that travels around another body in space. Example: Earth revolves (orbits) around the sun

(Earth’s revolution is 365 days)

VII) Moons Satellite:

 A natural or artificial body that revolves around a larger body (planet)

 Ex: Moons, television satellites, global positioning systems (GPS)

 All planets have moons except for Mercury and Venus

Our Moon: Luna

 4.6 billion years old (same as Earth and our Solar system)

 Same composition as Earth’s mantle

 Formed when a large object smashed into the molten Earth and caused a piece of the mantle to fly off in space.

 The piece spun around and gravity pulled it into its spherical shape

 No atmosphere

 Average distance between Earth and Luna:

240,000 miles

The moon revolves around Earth about every 30 days

(One “Moonth”)

Lunar Motions:

 Rotation – the moon rotates on its axis once every 27 1/3 days.

 Revolution – the moon makes one complete orbit around the earth every 27 1/3 days.

 The moon’s period of rotation and revolution are EQUAL. This means that the same side of the moon is always facing earth. (The far side can only be seen from space.

Phases of the Moon:

 The moon does not produce its own light;

moonlight is reflected light from the sun.

 As the moon revolves around the earth, the way it reflects light from the sun changes.

 Waxing: the illuminated part of the moon gets larger until you reach the FULL MOON (Wax ON – the right side is illuminated)

 Waning: the illuminated part of the moon gets smaller until you reach the NEW MOON.

(Wane OFF –the left side is illuminated)

Fun Moon facts:

1.We always see the same side of the moon because the Moon’s rotation rate equals its revolution rate

2.The moon is our closest neighbor (239,320 miles)

3.It takes 100 hours to get to the moon

4.A speed of 18,000 mph must be reached to orbit Earth

5.A speed of 25,000 mph is needed to escape Earth’s gravity

6.We weigh 1/6^th of our weight in the moon 7.1959-1^st flyby of moon by Soviet Union 8.1969-Neil Armstrong and Edwin Aldrin Jr.

were 1^st to walk on the moon

VIII) Solar Eclipse

 Can’t see the SUN (blocked by the moon’s

shadow as it moves between the earth and the sun. Only occurs during a NEW moon)

Lunar Eclipse

 Can’t see the MOON (blocked by Earth’s shadow when the earth is between the moon and the sun. Only occurs during a full moon

IX) Climate

Weather – day to day condition of the atmosphere

(includes temperature, humidity, precipitation, wind and visibility.

Climate – average weather condition in an area over a long period of time

Climate is affected by temperature and precipitation PLUS: Latitude , Wind Patterns, Mountains, Large Bodies of Water , Ocean Currents

1. Latitude: (the distance north or south of the equator) The higher the latitude the colder the climate -

10°HOT , 80°North Pole

2. Prevailing Winds: (Winds that blow mainly from one direction)

Affect area by amount of moisture that they carry 3. Mountains – Force air to rise

Usually wet and fertile on windward side, desert on far side

4. Large Bodies of Water – Oceans, Large Lakes, Bays Ex. Lake Effect Snow, Cool breezes on South Shore 5. Ocean Currents

Ex. Gulf Stream keeps climate of Ireland and England moderate

There are three main climate zones in the world Tropical - Near equator - HOT

Temperate – New York - Medium (with seasons) Polar - Near the poles – COLD

X) Seasons : New York has 4 seasons because of the TILT of the EARTH

Summer Solstice is June 21June 21^stst

•• The Northern Hemisphere has warm, long The Northern Hemisphere has warm, long daysdays

•• 15 hrs. daylight, 9 hrs. darkness in Northern 15 hrs. daylight, 9 hrs. darkness in Northern Hemisphere

Hemisphere

Winter Solstice - December 21^st

• The Northern Hemisphere has cold, short days

Equinoxes

• March 21^st (Vernal Equinox)

• September 21^st (Autumnal Equinox)

• On these 2 days all latitudes have 12 hrs.

daylight and 12 hrs.

darkness

XI) Tides

Tides are the daily changes in the level of the ocean water

 The tide ranges from a LOW

water level to a HIGH water level

 Every day high tide occurs twice and low tide occurs twice

Tides are influenced by the SUN and the MOON and occur in 4 Cycles

Pytheas- 0 AD- figured out that the phases of the moon are related to the tides

Tides are caused by:

the gravitational forces of the moon and the sun on the Earth’s oceans

 The moons gravity is the MAIN force behind the tides

 The position of the sun and moon relative to the position of the Earth causes tidal ranges

There are 4 types of tides

1. High Tide – happens at the part of the Earth CLOSEST to the moon – the

water bulges towards the moon

2. Low Tide – at the part of the Earth at a 90°Angle to the moon

3. Spring Tide – increased tidal range – occurs at Full and New Moon when the Sun and Moon are BOTH pulling the water in the same direction

4. Neap Tide – smallest tidal range – occurs at 1^st and 3^rd quarter when the moon and sun are pulling in opposite directions – (90 °Angle)