Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2001 March 20
See Explanation. Go online for the highest resolution available.

Discovery Spring
Credit: NASA

Explanation: Welcome to the equinox! Moving northward in Earth's sky, today the Sun crosses the celestial equator at 13:31 Universal Time bringing Spring to the north and Fall to the south. The change of season is known as an equinox as the Sun rises due east on the horizon and sets due west -- providing an equal night, 12 night and 12 daylight hours, for both northern and southern hemispheres. In this picture from March 8, the Sun peers over the eastern horizon at the space shuttle Discovery's dramatic morning launch on mission STS-102. Having delivered supplies and taxied crew to the International Space Station, Discovery will remain in orbit for this first day of northern hemisphere Spring. Discovery is scheduled to land at Kennedy Space Center in Florida early tomorrow.

View this page (with external links) online at
http://apod.gsfc.nasa.gov/apod/ap010320.html.


< | Archive | Index | Calendar | Education | About APOD | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Official: Phillip Newman. Specific rights apply.
A service of: ASD at NASA/GSFC
& Michigan Tech. U.

DVD Table of Contents
Educator's Index