Exploring the Universe

Earth and Moon

Our moon orbits usGravity between the moon and Earth keep it in orbitThe moon appears to change shape

– due to our view of the part of the moon that is lit by the sun changing

– See diagrams in text on page C85LUNAR ECLIPSE = darkening of the moon when

it passes through Earth’s shadowTIDES = rise and fall of water in the ocean and

seas caused by the gravitational pull of the moon on the Earth

Moon Phases

Phases = the changing appearances of the moon as seen from Earth

New Moon occurs when dark side of moon is facing the Earth

Waxing = lit side becomes visible– Waxing Crescent = 1st thin slice of lit side– 1st Quarter = ½ of lit side or ¼ of moon’s

surface– Waxing Gibbous = less than ½ but more than

¼ visible

Moon Phases

Full Moon = ½ of the surface facing the Earth is lit up

Waning = lit portion becomes smaller– Waning Gibbous = less than ½ but more than

¼ visible – 3rd (last) Quarter = ½ of lit side or ¼ of

moon’s surface– Waning Crescent = last thin slice of lit side

To Review

When it appears to us that the moon is getting bigger, we call it:

A. Waning

B. Waxing The 3rd or Last Quarter of the moon is when the:

A. Left side of the moon appears lit

B. Right side of the moon appears lit

C. Entire half of the moon we see is lit

The Earth’s Motion

We REVOLVE around the sun once every 365 days

We also ROTATE on our axis once every 24 hours

We tilt in a west-to-east directionWe rotate from west to east also½ of planet faces the sun during the

rotation

Earth’s Seasons

When North Pole leans to sun = long daysWhen North Pole leans from sun = short days= change in seasonsWhy don’t days change much at Equator?SUMMER SOLSTICE = daylight is the longest,

June 21 or 22 in N. HemisphereWINTER SOLSTICE = shortest amount of

daylight, Dec. 21 or 22 in N. HemisphereEQUINOX = sun is directly above the equator

and hours of daylight and night are =

To Review

The Earth does this around the sun:A. Rotate

B. Revolve

We do this on the Earth’s axis:A. Rotate

B. Revolve

To Review

When the North Pole leans toward the sun we experience:

A. Longer days

B. Shorter days

T/F We experience the longest day of the year on December 21 or 22.

The Sun

Our most important star!Gives us RADIANT ENERGY

– White light of sunlight

– Ultraviolet light (invisible)

– Stored in fossil fuels – coal and oil

• Used to power cars

• Used to heat homes

The Sun

Made of hot gases– Hydrogen and Helium

Core is 15,000,000°CHydrogen atoms move so quickly in the

core that they crash into one another and form helium = FUSION

This gives the sun energyEnergy comes to us as sunlight and radiant

energy

How does the energy transfer from the core to the surface of the sun?

A. Conduction

B. Convection

C. Radiation

How does the energy transfer to the Earth?

A. Conduction

B. Convection

C. Radiation

The Sun

CORONA is the thin layer of gases that lie above the suns surface

We usually don’t see this

Hotter than the sun’s surface

The Sun

SOLAR ECLIPSE is when the moon is directly between the Earth and the sun

Sun is completely covered and we can see the corona

NEVER LOOK AT THIS WITH YOUR OWN EYES!

SUNSPOTShttp://www.nasa.gov/mission_pages/themis/auroras/aurora_live.html

Sunspots are regions of the sun with a very high magnetic field

These spots are cooler than the rest of the surface

They would appear darker than surrounding areas

# varies over a 11 year cycle

http://www.nasa.gov/vision/universe/solarsystem/0723sunspots.html

SOLAR FLARES

Solar flares are explosions of hot gases from the sun

They occur when the sunspot cycle is at its peak

Gas particles and radiation reach our atmosphere

May result in blackout or power surge

SOLAR FLARES

Can cause AURORAS =A glow or display of lightsForm when gas given off by solar flares hit

oxygen and nitrogen over the North and South poles

To Review…

What is the layer of gases that surround the sun’s surface?

A. Corona

B. Flares

C. Sunspots

D. Auroras

To Review…

What type of eclipse occurs when the moon is between the Earth and sun?

A. Lunar

B. Full

C. Solar

To Review…

What are the displays of light at the North and South Poles called?

A. Lunars

B. Flares

C. Auroras

D. Sunspots

Stars and their Classification

We will visit the following website:http://www.kidsastronomy.com/stars.htmView from Hubble:

http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/05/image/

Apollo11 http://www.nasm.si.edu/collections/imagery/apollo/AS11/a11av.htm

Back to the life cycle

Black Dwarf

NovaMid-sized

http://hubblesite.org/explore_astronomy/black_holes/