See the Solar Eclipse

SCIENCE

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit, including NASA’s awesome visualization of the eclipse path.

Discussion Ideas

Parts of Southeast Asia will experience a total solar eclipse this week. What is a total solar eclipse? Read through our activity for some help.
- A total solar eclipse happens when the sun, the moon, and the Earth are perfectly aligned—when the moon is directly between the sun and the Earth, and blocks out the solar surface. Solar eclipses can only happen during new moons, the first phase of the lunar cycle when the moon is invisible from Earth.

If the moon totally blocks the solar surface, what are we looking at in photos like the one at the top of this page?
- We’re looking at the moon’s umbra and the sun’s corona.
  - The umbra is the moon’s shadow, which blocks the photosphere, or bright surface of the sun.
  - The sun’s corona is the outermost part of the sun’s atmosphere. The corona is usually only visible during a solar eclipse like this one.
- A new NASA experiment is actually going to be looking pretty closely at this week’s eclipse, tracking the gases in the corona, as well as the velocity of the solar wind. Watch this video for insight to this awesome experiment.

Are there other types of solar eclipses?
- Yes.
  - A partial eclipse occurs when the sun and moon aren’t quite in exact conjunction, and the dark new moon only covers part of the solar disc. Here’s a lovely sequence of a partial eclipse.
  - An annular eclipse occurs when the moon is at its apogee, or furthest point in its elliptical orbit from Earth. The moon appears smaller at apogee, and fails to eclipse the entire solar disc. The photo at the top of this entry is an annular eclipse, and here’s a complete sequence.
  - A hybrid eclipse is the rarest type of solar eclipse. During a hybrid eclipse, parts of the Earth view a total eclipse and some view an annular eclipse. Here’s a beautiful example.

Why is Earth the only planet in the solar system that experiences total solar eclipses?
- The moon is about 400 times smaller than the sun, but about 400 times closer to Earth. So, the sun and moon appear to be the same size in the sky. This creates a perfect situation for the moon to completely block out the solar surface.

This week’s solar eclipse will only be visible in parts of Southeast Asia and the South Pacific. Why are total solar eclipses only visible in some places? Watch this video from the infrared-friendly folks at the Spitzer Space Telescope to answer that question.
- The moon is a lot smaller than the Earth. Imagine the shadow of a golf ball passing in front of a basketball. Here’s a nice image of southeastern China and Taiwan in the dark shadow of a solar eclipse seen from an orbiting spacecraft.The areas surrounding them are still illuminated by the sun.

Take a look at NASA’s nice map of all solar eclipses of the first two decades of the 21st century. When is the next total solar eclipse visible in the Northern Hemisphere?
- The total eclipse of August 21, 2017 will cut right through the continental United States. NASA already has a page for it, so build your solar eclipse viewer now!