Solar and Lunar EclipsesSolar and Lunar Eclipses

What is an eclipse?

• An eclipse occurs any time a celestial body passes in front of the Sun, blocking its light. – Examples:

1. Earth

2. The Moon

Celestial Bodies Line Up…• Syzygy- When the Moon, the Earth, and

the Sun line up perfectly for an eclipse.

What are the types of eclipses?• There are 2 types:

– Lunar Eclipses- When the Earth casts a shadow on the moon, causing the moon to go dark.

• Earth comes between the Sun and the Moon and casts a shadow on the Moon (Full Moon)

– Solar Eclipse- When the Moon casts a shadow on the Earth, causing the sun to go dark.

• The Moon comes between the Sun and Earth and casts a shadow on part of Earth (New Moon)

• Umbra – The dark inner portion of the shadow cone.– Think Direct Shadow

• Penumbral – the lighter outer portion of the shadow.– Think “Side” Shadow

Parts of the shadow:

Lunar Eclipse• The Earth moves between the Sun and the Moon

– Blocks the Sun’s light– Causes the moon to glow red.

• There are 3 types:– Total – Partial– Penumbral

Types of Lunar Eclipses• Total Lunar Eclipse – when the Moon passes

completely into the umbra, or total shadow, of the Earth.

• Partial Lunar Eclipse – Occur when the Moon does not fully move into the umbra, or total shadow, of the Earth.

• Penumbral Lunar Eclipse – When the moon passes only through the penumbra, or partial shadow. – These eclipses are barely visible.

Total Lunar Eclipse :when the Moon passes completely into the umbra, or total shadow, of the Earth:

So, Why is the Moon Red during an Eclipse?

• The Earth’s atmosphere filters some sunlight and allows it to reach the Moon’s surface

• The blue light is removed– This light is usually scattered down to make a blue

sky over the earth in daytime

• Remaining light is red or orange– Some of this remaining light is refracted, or bent, so

that a small part of it reaches the Moon

• Exact appearance depends on dust and clouds in the Earth’s atmosphere

https://www.youtube.com/watch?v=a6CXLf_74AE

Partial Lunar Eclipse: Occur when the Moon does not fully move into the

umbra, or total shadow, of Earth

Penumbral Lunar Eclipse:When the moon passes only through the penumbra, or partial shadow.

These eclipses are barely visible.

12

Solar Eclipses• When the Moon’s shadow covers part of

the Earth• Only happens at New Moon• Three types:

– Annular– Partial– Total

Types of Solar Eclipses

• Total Solar Eclipse – can only occur if you are at the exact spot within the moon’s umbra (which isn’t very big).

• Partial Solar Eclipse – Visible is you are in the penumbra of the shadow. – Only some of the moon will be shadowed.

• Annular Eclipse – occurs when the moon is farthest from the Earth in its orbit. – Moon look smaller, so during the eclipse you see an outer

ring of light from the Sun.

14

Total Solar Eclipse• Observers in the “umbra” shadow see a total eclipse

– (safe to view the Sun); can see the corona (Outside layer of sun)

• Those in “penumbra” see a partial eclipse– not safe to look directly at Sun

• Only lasts a few minutes• Path of Totality about 10,000 miles long, only 100 miles wide

Total Solar Eclipse: can only occur if you are at the exact spot within the

moon’s umbra (which isn’t very big).

16

Photo of a Total Eclipse

https://www.youtube.com/watch?v=xx3EwETgN38

Partial Solar Eclipse:Visible if you are in the penumbra of the shadow.

-Only some of the moon will be shadowed.

18

Annular Solar Eclipse• When the Moon is too far to completely cover the Sun—the umbra doesn’t

reach the Earth• Sun appears as a donut around the Moon

Annular Solar Eclipse:•Occurs when the moon is farthest from the Earth in its orbit.

•Moon look smaller, so during the eclipse you see an outer ring of light from the Sun.

20

Photos of an Annular Eclipse

http://sunearthday.nasa.gov/2006/multimedia/gal_010.php; photos taken by Fred Espenak

How often do Eclipses Happen?

• That depends!! – Lunar Eclipses happen more often than Solar Eclipses.

• Why?

– Well everyone who is experiencing nighttime during a lunar eclipse can see it.

• But you have to be at the exact spot on Earth to see a Solar Eclipse.

• The spot on Earth is so small, that the same place only sees a Solar Eclipse every 350 years!!

When will the next Eclipse happen?Date Type of

EclipseWhere What will the Eclipse Look

Like?

March 20, 2015

Total Solar Eclipse

-Europe-North/East Asia-North/West Africa-West in North America-Atlantic-Arctic

April 4, 2015

Partial Lunar Eclipse

-Much of Asia-Australia-Much of North America-Much of South America-Pacific, Atlantic, Indian Ocean-Arctic-Antarctica

September 13, 2015

Partial Solar Eclipse

-South in Africa-Atlantic- Indian Ocean- Antarctica

September 28, 2014

Total Lunar Eclipse

-Europe-South/East Asia-Africa-Much of North America-Much of South America-Pacific, Atlantic, Indian Ocean-Arctic-Antarctica