Scientific Explanations

An eclipse takes place when Earth or the moon passes through a shadow of another heavenly body.

Scientists are taking to the skies to chase the shadow of the moon and study the total solar eclipse on Aug. 21 from the unique vantage point of two retrofitted WB-57F jet planes.

Scientist to Discuss '2017 Total Solar Eclipse: Through the Eyes of NASA' at Library of Congress Lecture

The 2017 solar eclipse will be a show in the skies, as the US experiences its first total solar eclipse in 38 years. Find out how to see it.

How solar and lunar eclipses work.

We answer basic and burning questions about the total solar eclipse that will cut across the U.S. on August 21, 2017.

A total solar eclipse occurs when the new Moon passes between the Sun and the Earth, and totally blocks out the Sun. Animations of Solar and Lunar Eclipses worldwide.

On Aug. 21, a total solar eclipse will be visible from coast to coast. But what, exactly, is this phenomenon?

What is an eclipse of the Sun? What causes eclipses and why? How often do eclipses happen and when is the next eclipse of the Sun? You'll learn the answers to these questions and more in MrEclipse's primer on solar eclipses. Before we learn more about the eclipses of the Sun, we need to first talk about the Moon.

All solar eclipses involve the Moon passing between the Earth and the Sun, and casting a shadow on the Earth. However, the type of eclipse which can be seen from a given location depends on whether the Moon passes directly, or only partly, between the Earth and Sun; but also on where on Earth you stand to observe it, and on a number of other factors.

Everything you need to know about the August 21 eclipse.

As seen from the Earth, a solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks ("occults") the Sun. This can happen only at new moon when the Sun and the Moon are in conjunction as seen from Earth in an alignment referred to as syzygy. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured.