Telescopes SatellitesSpacecraft

Earth’s days are _24 hours_ long. This is because . . . That’s how long it takes Earth to rotate once on its axis.

Picture of a day:Days on other planets:

Mercury = 58.65 Earth Days

Venus = 243 Earth Days

Mars = 1.03 Earth Days

Neptune = 19.1 Earth Days

Saturn 10.2 Earth Days

Earth’s months are _28-31 days_long. This is because . . . That’s how long it takes for the moon to revolve once around the Earth.

Picture of a month:

Earth’s years are _____365 1/4 days____ long.

This is because . . . That is how long it takes for the Earth to revolve around the sun once.

Picture of a year:

Years on other planets:

Mercury = 88 Earth days

Venus = 224.7 Earth Days

Mars = 687 Earth Days

Neptune = 164.8 Earth Years

Saturn = 29.46 Earth Years

Earth has seasons because . . .

Earth spins on its axis at a tilt of 23 degrees. When the Earth’s axis points toward the sun, it is summer in that hemisphere, when it points away from the sun, it is winter in that hemisphere.

Picture of why Earth has seasons:

Earth’s seasons depend on :

Your latitude (north or south of the equator) and what hemisphere you are in.

•Summer Solstice – first day of summer, longest daylight of year, June 21•Winter Solstice – first day of winter, shortest daylight of year, Dec. 21•Vernal Equinox – first day of Spring, March 20, beginning of tilt toward the sun.•Autumnal Equinox – first day of Autumn/Fall, Sept. 22, beginning of tilt away from the sun.

What causes them?

It depends on how much of the sunlit side of the moon we can see from Earth.

What does waxing mean?

Growing

What does waning mean?

Shrinking

How often do they occur?

Goes through all phases every 29.5 days (new phase every 3-4 days)

Miscellaneous info:

Moon cycle diagram:

What causes them:

The moon and sun’s gravitational pull.

What is happening at high tide?

The moon’s gravity pulls water toward the point on Earth’s surface closest to the moon and the water on the side of the Earth that is opposite of the moon does not get pulled so it bulges out too.

What is happening at low tide?

You have a low tide when you are at right angles to where the high tide is, the water is being pulled away from you and to the bulge.

What are neap tides?

The sun and moon are at right angles to the Earth and cause a high tide that is lower than usual.

What are spring tides?

The moon, Earth and sun are in a straight line and have a very high tide and a very low tide.

Tide facts:

There are 2 high tides and 2 low tides every day.

The first high tide tomorrow will be 50 mins. later than today.

Solar Eclipses: how they form, why they form, interesting information about them:

They form when the light from the sun is blocked by the NEW moon. Can only be seen by a small portion of people on Earth. (more rare than lunar eclipse)

Lunar Eclipses: how they form, why they form, interesting information about them:

They form when the light from the Sun can’t get to the moon because the Earth is in the way. Earth casts a shadow on the FULL moon.

A light year is 5.9 Trillion miles distance

away. • 1. Imagine a planet with intelligent beings on it that is 20

light years away from Earth. These beings have an extremely powerful telescope and can actually make out details of what is happening on Earth. If they aim their telescope at the White House in Washington, DC, who would they find living there as the president and first lady?

Ronald Reagan, Nancy Reagan 1993

• 2. Suppose that a child is born on Earth in the year 2000.You are on an imaginary planet that is 94.6 trillion miles away from Earth and looking through a very high-powered telescope and you witness this child's third birthday party. How old is that child on Earth at the time you are watching the child's third birthday party?

19 years old (94.6/5.9 = 16 + 3 years old)

• Distance light can travel through space in one year at a speed of 186,000 miles per second.

What is a light year?

Distance to other objects in space in light years . . .

Andromeda Galaxy 2,900,000 LY away

Moon – 1 ¼ light seconds away

Sun – 8 light minutes away

How does the Doppler Effect relate to astronomy? Light and sound waves bunch up when they are coming toward you and spread out when going away from you.

Red shift:

Object is moving away

Object is moving closer

Blue shift: Is the Universe expanding or getting smaller? How do we know?

Expanding because we see a red shift (red light on space objects)

What is The Big Bang Theory?

The theory that the universe began with a tremendous explosion. All the contents of the universe were compressed under extreme pressure, temperature, and density in a very tiny spot. Then, the universe rapidly expanded, and matter began to come together and form galaxies.

Proof:Red shift of galaxies show universe is expanding

How old is the universe?

13.7 billion years

What will happen if Universal Expansion continues to occur?

1.Expand forever

2.Slow down and stop expanding

3.Shrink again to one point

Define these terms:

Luminosity

Amount of energy a star puts out per second.

Apparent Magnitude

How bright the star looks as seen from Earth.

Absolute Magnitude

How bright the star actually is compared to all the other stars in the universe (If we lined them all up even)

Color Temperature Example

Blue Above 30,000 Lactarae

Blue-white

7,500 – 30,000 Rigel, Vega

Yellow-white

5,000-7,500 Sun, capella

Orange 3,000- 5000 Arcturus

Red Less than 3,000 Betelgeuse

What are binary stars? Give an example:

One star revolves around another or both revolve around each other

Example: Sirius A & B

Explain what’s happening at each of these stages:

Protostar: After nebula, dust and gas start to form YOUNG stars

Main Sequence Star: Any star that lines up on the diagonal line of the H-R diagram

Yellow Dwarf: Any small yellow star like the Sun

Red Dwarf: A small, dim star with relatively cool surface temperatures

Red Giant: Average stars will turn into this as they burn out

Blue Giant: Massive star, will become a red supergiant and explode in a supernova and become a neutron star or black hole

Super Giant: Biggest and brightest phase a star can go through

White Dwarf: Small and dense, final stage for average stars

Brown Dwarf: Stars who don’t have enough hydrogen to turn into helium, so can’t glow.

Neutron Star: Star composed almost entirely from neutrons and eventually collapses from gravity.

stars

•Protostar

•protostar

•Main sequence

Facts about our galaxy:

We live in the MILKY WAY. It has 200 billion stars and revolves at 40,000 miles per hour. It is 100,000 light years across.

Elliptical galaxies

Have bright centers and very little gas and dust – mostly old stars. Ex. M87

Spiral galaxies

Have a huge bulge in the center and spiral arms of gas, dust and new stars. Ex. Milky Way, Andromeda

Irregular galaxies

Don’t fit into either of the other 2 categories. Lots of gas and dust.

Ex. Large Magellanic Cloud galaxy.

There are _100 billion_ galaxies . . .

What are these? Label each of them.

Explain what they are made of and how they form.

• Horsehead nebula

• Eskimo galaxy

• Eye Galaxy

• Eagle nebula

Why doesn’t the moon come crashing down to Earth?

Because it is going at a high rate of speed so when pulled by gravity, it makes a curved path that orbits Earth.

Kepler’s 1st Law of Motion

Each planet orbits the sun in a path called an ellipse.

Kepler’s 2nd Law of Motion

The planets move faster when they are close to the sun and slower when they are farther away.

Kepler’s 3rd Law of Motion

Planets that are more distant from the sun take longer to orbit the sun.

Newton’s Law of Universal Gravitation

The larger the masses of two objects and the closer together the objects are, the greater the force of gravity between the objects.

Picture of Universal Law of Gravity

Comets are made of . .

Ice, dust, rocks and frozen gases.

Comets occur . . .

It varies from a few years to hundreds of thousands of years.

Comets . . .

Are left over parts from the formation of our solar system and can tell us about what happened 4.6 billion years ago. When they are close to the sun, they heat up and speed up and give out a tail of dust.

Orbits of comets compared to the orbit of Earth . .

Orbit is highly elliptical. Without the sun, we wouldn’t be able to see them. They do not glow, they only reflect light from the sun.

Famous comets . . .

Halebopp, Shoemaker-Levy9, Hyakutake, Haley’s comet

Asteroids are made of . .

rocky bodies – red or gray (rock or metal)

Asteroids occur . . .

Asteroid Belt, between Mars and Jupiter

Asteroid effect . . .

when they collide with planets, they can cause craters and mass extinctions.

Orbits of asteroids compared to the orbit of Earth .

Similar, they orbit the sun but farther out than Earth and Mars. Their path can interfere with ours.

Meteors, meteoroids, meteorites …

Meteor – bright streak of light when meteoroid is burning up in our atmosphere.

Meteoroid – small rocky bodies that revolve around the sun.

Meteorites – what actually hits the ground.

What are they?

An area of space having a gravitational field so strong that no matter or radiation (light) can escape.

How do they form?

When massive objects like giant stars collapse.

Why are they invisible?

Because in order to see them, light would have to reflect from it to our eye but light is pulled into it.

How do we know they exist?

When a black hole passes near a star , you can see the gas and dust being pulled into it. X-rays are given off by them.

What would happen if we fell in one?

The gravity on the part of the body closer to the hole would be slightly stronger than the part farthest from it so you would be stretched thinner and thinner until you would rip apart – they call this being spaghettified.

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