Astronomy Picture Of the Day (APOD)Green Flashes: Sun, Moon, Venus, Mercury
Follow a sunset on a clear day against a distant horizon and you might glimpse green just as the Sun disappears from view. The green flash is caused by refraction of light rays traveling to the eye over a long path through the atmosphere.
Mercury Meets Crescent Venus
That's not a bright star and crescent Moon caught between branches of a eucalyptus tree. It's Venus in a crescent phase and Mercury. Near the western horizon after sunset, the two inner planets closely shared this telescopic field of view on May 22, seen from a balcony in Civitavecchia, Italy.
Reflecting the International Space Station
Still bathed in sunlight, the International Space Station arced through the evening sky over lake Wulfsahl-Gusborn in northern Germany, just after sunset on March 25. The familiar constellation of Orion can be seen left of the trail of the orbital station's bright passage.
Earth and Moon through Saturns Rings
What are those dots between Saturn's rings? Our Earth and Moon. Just over three years ago, because the Sun was temporarily blocked by the body of Saturn, the robotic Cassini spacecraft was able to look toward the inner Solar System.
The Milky Way over Snow Capped Himalayas
WhatБs higher than the Himalayas? Although the Himalayan Mountains are the tallest on planet Earth, they don't measure up to the Milky Way. Visible above the snow-capped mountains in the featured image is the arcing central band of our home galaxy.
Mystic Mountain Monster being Destroyed
Inside the head of this interstellar monster is a star that is slowly destroying it. The huge monster, actually an inanimate series of pillars of gas and dust, measures light years in length.
Valles Marineris: The Grand Canyon of Mars
The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep.
Ghost Fungus to Magellanic Cloud
Stars shine and satellites glint in this clear, dark, night sky over Wannon Falls Reserve, South West Victoria, Australia. In fact the fuzzy, faint apparition above the tree tops is the only cloud visible, also known as the Large Magellanic Cloud, satellite galaxy of our own Milky Way.
South of Carina
With natal dust clouds in silhouette against glowing atomic gas, this colorful and chaotic vista lies within one of the largest star forming regions in the Milky Way galaxy, the Great Carina Nebula.
Phases of Venus
Just as the Moon goes through phases, Venus' visible sunlit hemisphere waxes and wanes. This composite of backyard telescopic images illustrates the steady changes for Venus during its current stint as our evening star, as the inner planet grows larger but narrows to a thin crescent.