The Moon, Our Constant Companion

Remember that the Moon doesn’t just go around the Earth. The pair orbit the Sun…

Photo of Earth/Moon from MRO

perigee apogee

The Moon is noticeably larger when it is near perigee

This Full Moon will pass through the Earth’s

shadow!Total Lunar Eclipse

Dates and times are in Universal Time (UT)

You can think of UT as the same as

Greenwich Mean Time (GMT)

One thing we really want to understand – Why does the Moon go through phases?

Moon Phases Demonstration

Moon Phases

1. Half of the Moon is always lit by the Sun (we’re not talking about eclipses!)2. The phase is how much of the lit half we can see from Earth.

One full cycle – New Moon to New Moon – takes 29½ days

Note the names and order of the phases

Notice that we always see the same side of the Moon

Does the Moon rotate?

A. Yes

B. No

Which statement is true for an observer located on the Moon?

A. She would see the Earth rise in the east and set in the west.

B. She would see the Earth rise in the west and set in the east.

C. She would not see the earth rise or set.

Lunar eclipse Solar eclipse

The parts of a planet’s (or moon’s) shadow

The kinds of lunar eclipses

The kinds of lunar eclipses

The next total lunar eclipse:

September 277:07 – 10:27 p.m.

Totality:8:11 – 9:23

Greatest Eclipse: 8:48

The kinds of solar eclipses

antumbra

Aug 21, 2017

Visible from Wyoming, Nebraska

From the NASA Eclipse website

The Moon’s shadow on the Earth

Taken from the international space station

Taken by the GOES-7 weather satellite

Why we don’t see eclipses every month

The Moon’s orbit around the Earth is tilted 5º relative to the ecliptic.

The Moon passes through the ecliptic twice in every orbit “nodes”

“line of nodes”

Most of the times the Moon, Earth, and Sun line up, the Moon is above or below the Earth-Sun line.

This special arrangement is called an “eclipse season”

The line o

f nodes

goes through th

e Sun

BUT, the line of nodes precesses.Eclipse seasons occur slightly LESS than 6 months apart

That precession, combined with the 29½ days lunar cycle, leads to …

The saros cycle – 18 years, 11⅓ days

From any given location (Alamosa, for example), which will you see more frequently?

A. Total solar eclipses

B. Total lunar eclipses

Astro-Cash Cab!

Daniel Lovell

Kylee Sowards

Miranda Glowczewski

Nick Smith

Adrianna Cordova

1) What kind of eclipse is this?(There are TWO parts to this. The first is either “solar” or “lunar”.)

2) Starting with New Moon, put the following phases in the order in which they occur:

New Moon

Full Moon

Waxing Gibbous

Waning Crescent

Third Quarter

Waxing Crescent

3) True or False?

Eclipse seasons occur about 1 year apart.

4) Match the parts of the Earth’s shadow to their correct name.

A) Umbra B) Antumbra C) Penumbra

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