Why does the moon have phases? The revolution of the Moon around the Earth causes the Moon to appear to have phases. NSF North Mississippi GK-8

NSF North Mississippi GK-8 8 Phases of the Moon New Moon Waxing Crescent First Quarter or Half Moon Waxing Gibbous Full Moon Waning Gibbous Last Quarter or Half Moon Waning Crescent NSF North Mississippi GK-8

NSF North Mississippi GK-8 New Moon The moon is not visible from Earth. The moon is between the Sun and the Earth. The dark side is facing us. This phase lasts one night. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Waxing Crescent Waxing means that the bright side is increasing. The right side is the bright side. Less than one half of the moon is illuminated. This phase includes any visible moon from a small sliver to almost half. NSF North Mississippi GK-8

First Quarter or Half Moon The entire right side of the moon is illuminated. The moon looks like a half circle. The illuminated side is increasing. This phase only lasts one night. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Waxing Gibbous Gibbous means that more than one half is visible, but it is not quite full. This phase includes the night after the first quarter to the night before the full moon. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Full Moon The moon is full and bright. It looks like a large circle. The illuminated side is facing us. Only happens one night per lunation. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Waning Gibbous The moon appears more than half but not quite full. Waning means that the illuminated side is decreasing. The left side is the bright side. NSF North Mississippi GK-8

Last Quarter or Half Moon Left Half of the moon is illuminated. The illuminated side is decreasing. This phase also only lasts for one night. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Waning Crescent Less than one half of the moon is illuminated. The moon will continue to become smaller and smaller. NSF North Mississippi GK-8

NSF North Mississippi GK-8

A walk through the Universe Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that's just peanuts to space. Douglas Adams, The Hitchhiker's Guide to the Galaxy English humorist & science fiction novelist (1952 - 2001)

Distance and Speed Facts 1 light-year = 9.5 x 1012 km 1 light-year = 9,500,000,000,000 km 1 AU = 1.5 x 108 km = 8 light-minutes 1 AU= 150,000,000 km 1 light second = 300,000 km Speed of Voyager Probe= 62,000km/h Distance to Alpha Centauri= 4.2 light years

Place Unit of Measurement Example Street Address Feet or Meters A room might be 10x14feet City Miles or Fractions of Miles You might drive ½ mile to the grocery store; a town might be about 10 miles wide. State Tens to hundreds of miles The distance from Austin to San Antonio is a little more than 50 miles; Texas is about 600 miles across. United States Hundreds to thousands of miles The distance from New York to Los Angeles is 3,000 miles. . Begin by discussing the vastness of the universe. For example, tell students that light travels at the unimaginably fast speed of 300 million meters per second, and yet light takes years to travel to us from the stars and takes thousands or even millions of years to travel the depths of space between galaxies. When we’re dealing with those kinds of distances, it’s no wonder that we often think of them as being beyond our grasp. One way to put these distances into perspective is to think of them as multiples of smaller-scale distances. By putting these quantities in the context of a well-understood frame of reference, they begin to have more meaning.

Place Unit of Measurement Example Earth Tens of thousands of miles Earth’s circumference is 25,000 miles. Solar System Millions to billions of miles, or astronomical units (AU). (An AU is the average distance from Earth to the sun, or 93 million miles.) Neptune is 30 AU, or 2.79 billion miles, from the sun. Milky Way Galaxy Hundreds of thousands of light-years. (A light-year is the distance that light travels in one year, or about 6 trillion miles.) The Milky Way is about 100,000 light-years across. Universe Billions of light-years The farthest known galaxy (the edge of the observable universe) is 13 billion light-years away.

The Earth We are here

Pluto and moon Charon

EARTH Mercury Venus Mars

Uranus Jupiter Neptune Earth Saturn Pluto (not a planet) and its moon Charon Saturn

The Sun is our nearest star

The Solar System

The Milky Way (Our Galaxy) A hundred, thousand, million stars!

the Milky Way as seen from the Enterprise Light would take 100 000 years to travel across the galaxy. A hundred thousand light years across

Distances It takes 8 minutes for light to reach us from the Sun. A light-year is the distance travelled by light in 1 year. The Sun is our nearest star. Our next nearest star, Alpha Centauri is 4 light years away. The Milky Way is 100 000 light years across.

The local group of galaxies Andromeda is the nearest big galaxy to the Milky Way Milky Way

Light from Andromeda takes 2 million years to reach us. Milky Way Andromeda

The Universe is mind-bogglingly big! The Sun is about 150 000 000 km away from Earth Bright stars in the night sky are about 1000 000 (1 million) times as far away as the Sun. The near galaxies are about 100 000 times as far away as the bright stars. 15 000 000 000 000 000 000 km

We have found out in this class that the Universe is large, very large We have found out in this class that the Universe is large, very large! Even traveling from planet to planet in our solar system takes a considerable amount of time. For example, a round trip to Mars will take a year or more with current technology. Going to the outer solar system and beyond requires new, higher speed, and highly efficient propulsion technology. For example, right now the highest speeds that we have achieved for any of our space probes is that by the Voyager probes of about 62,000 km/hr (done with an assist using the gravity of Jupiter). How long does it take to tour the solar system at that speed? Well, Jupiter is 598,400,000 km away at its closest approach to Earth. If we could manage to achieve a speed of 62,000 km/hr without using Jupiter's gravity, it still would take more than 9,000 hrs to get to Jupiter (1 year and a few weeks). Not too bad. How about Pluto? Pluto never gets much closer than 39 AU (5.8 billion km). It would take this probe more than 10 years to get to Pluto. The nearest star is Alpha Centauri at 4.2 ly (4 x 1013 km, note that it has a low mass companion, "Proxima", on this side of the triple star system). This space probe would require 76,000 years to get to Alpha Centauri! Here is a table in terms you can grasp:

NASA