Articles about Earth

September Equinox

The Sun shines directly at the Equator on the September equinox and the length of day and night is nearly equal, but not quite. more

December Solstice

The December solstice is also known as the summer solstice in the Southern Hemisphere and the winter solstice in the Northern Hemisphere. more

When is Spring Equinox?

The Vernal (Spring) Equinox in the Northern Hemisphere is in March. In the Southern Hemisphere it's in September. more

About Moon phases

There are 4 primary phases of the Moon - new, first quarter, full and third quarter, and 4 intermediate phases - waxing crescent and gibbous, and waning gibbous and crescent. more

March Equinox

The March equinox around March 20-21 is the spring (vernal) equinox in the Northern Hemisphere and fall (autumnal) in the south. Night and day are nearly the same length. more

What Is a Total Lunar Eclipse?

A Total Lunar Eclipse happens when the Earth's shadow blocks the direct light from the Sun reaching the Moon's surface. more

Total Solar Eclipses

Everything you need to know about total eclipses of the Sun. more

Solar and Lunar Eclipses

Solar and lunar eclipses, why they occur, when the next eclipse is, and from where you can see them. more

Solar Eclipses in History

Solar eclipses were historically viewed as omens that bring about death and destruction and people in many ancient civilizations tried their best to understand and predict them. more

Annular Solar Eclipse

An annular solar eclipse occurs when the Moon moves in front of the Sun but does not cover it completely. more

Partial Solar Eclipse

More common than a total solar eclipse, a partial solar eclipse happens when the Moon only partially covers the Sun. more

Never Look Directly at the Sun

Protect your eyes during a transit or solar eclipse. more

What is a Penumbral Lunar Eclipse?

A penumbral lunar eclipse occurs when the outer shadow of the Earth falls on the Moon's face. It is easy to miss this type of lunar eclipse. more

What is a Partial Lunar Eclipse?

A partial lunar eclipse happens when the Earth moves between the Sun and the Moon, but they are not precisely aligned. more

The Future of Leap Seconds

Organizations and individuals have for many years argued about abolishing leap seconds for good. more

Astronomical Terms

What do astronomers really mean when they use those technical terms? more

September Equinox Facts

10 things you may not know about the September Equinox. more

December Solstice Facts

10 things you may not know about the December Solstice. more

March Equinox Facts

10 things you may not know about the March Equinox. more

10 Facts: Total Solar Eclipse

The March 20, 2015 Total Solar Eclipse will be a grand and rare sight. Here are 10 facts not to be missed. more

What's a Blood Moon?

Blood Moon is sometimes used to describe 4 total lunar eclipses in a row. When the Earth casts its shadow on a full Moon and eclipses it, the Moon may get a red glow. more

11 Facts: Total Lunar Eclipse

The Sept 27/ 28, 2015 Total Lunar Eclipse is the final eclipse in a series of 4 total eclipses of the Moon called eclipses of the Blood Moon. more

Eclipse Magnitude

Eclipse magnitude is a number astronomers associate with solar or lunar eclipses. What does it mean? more

What's a Solar Eclipse?

Solar eclipses happen when the Moon moves between Sun and Earth, blocking the Sun's rays and casting a shadow on Earth. more

Solar Eclipse Myths

The solar eclipse has inspired many mythical stories and influenced human behavior. Even today, eclipses of the Sun are considered bad omens in many cultures. more