APOD: 2023 March 19 Б Equinox at the Pyramid of the Feathered Serpent
19.03.2023

To see the feathered serpent descend the Mayan pyramid requires exquisite timing. You must visit El Castillo -- in Mexico's Yucatцn Peninsula -- near an equinox. Then, during the late afternoon if the sky is clear, the pyramid's own shadows create triangles that merge into the famous illusion of a slithering viper.

To Fly Free in Space
9.02.2020

What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was living the dream -- floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured, was floating free in space.

September Sunrise Shadows
24.09.2022

The defining astronomical moment for this September's equinox was on Friday, September 23, 2022 at 01:03 UTC, when the Sun crossed the celestial equator moving south in its yearly journey through planet Earth's sky.

Equinox on a Spinning Earth
22.09.2021

When does the line between night and day become vertical? Today. Today is an equinox on planet Earth, a time of year when day and night are most nearly equal. At an equinox, the Earth's terminator -- the dividing line between day and night -- becomes vertical and connects the north and south poles.

Equinox in the Sky
22.09.2020

Does the Sun set in the same direction every day? No, the direction of sunset depends on the time of the year. Although the Sun always sets approximately toward the west, on an equinox like today the Sun sets directly toward the west.

Rocket Plume Shadow Points to the Moon
24.06.2018

Why would the shadow of a space shuttle launch plume point toward the Moon? In early 2001 during a launch of Atlantis, the Sun, Earth, Moon, and rocket were all properly aligned for this photogenic coincidence.

Rings and Seasons of Saturn
21.06.2015

On Saturn, the rings tell you the season. On Earth, today marks a solstice, the time when the Earth's spin axis tilts directly toward the Sun. On Earth's northern hemisphere, today is the Summer Solstice, the day of maximum daylight.

Perihelion and Aphelion
3.07.2009

This year Aphelion, the point in Earth's elliptical orbit when it is farthest from the Sun, occurs tomorrow, July 4th. Of course, that doesn't affect the seasons on our fair planet. Those...

September s Harvest Moon
16.09.2011

A Full Moon rising can be a dramatic celestial sight, and Full Moons can have many names. For example, Monday's Full Moon was the one nearest this year's autumnal equinox for the northern hemisphere, traditionally called the Harvest Moon.

Endeavour s Starry Night
2.06.2011

This luminous night view of the space shuttle orbiter Endeavour, docked with the International Space Station for a final time, was captured on May 28. Orbiting 350 kilometers above planet Earth, Endeavour's payload bay is lit up as it hurtles through Earth's shadow at 27,000 miles per hour.