Image of the Day Archive
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Above: Great Basin National Park in Nevada is a great place for skywatching enthusiasts. The park's dark night skies are perfect for glimpsing stars, planets and other cosmic objects, including nebulas and galaxies.
This month, from Sept. 18-20, the park will host the Great Basin Astronomy Festival. Park rangers will lead talks about day and nighttime astronomy, and will teach people how to operate telescopes. A full schedule of events can be found on the Astronomy Festival's website. [Related: 6 Stellar Places for Skywatching in the US]
Stunning Shock Waves
This psychedelic photo is from a simulation showing shock waves traveling under the ocean as they pass Catalina Island, located off the coast of California. The photo represents an underground view looking south, according to researchers at the University of Southern California.
The red and yellow colors are regions of compression, and the blue and green colors show regions of dilation. Fainter hues add geographical context to the simulation — for instance, yellow for faults, red for roads and blue for the coastline. [Related Gallery: The World's Most Beautiful Equations]
Out of the Fog
The imposing silhouette of a moose can be seen through thick fog in the Seedskadee National Wildlife Refuge in southwestern Wyoming.
An official with the U.S. Fish and Wildlife Service snapped this photo of a bull moose snacking on Pacific willow leaves and branches in the river valley. [Related Gallery: 101 Animal Shots You'll Go Wild Over]
This illustration shows a blast wave expanding from the star Eta Carinae, which famously erupted in 1843. A fast shock wave propagates ahead of a slow-moving shell of gas and dust, known as the Homunculus Nebula.
Eventually, the fast shock wave will overtake and heat parts of the older shell, generating X-rays from the collision (shown in orange in this artist's conception). [Related: Top 10 Greatest Explosions Ever]
Yellowstone National Park
This breathtaking view of Yellowstone National Park shows part of Uncle Tom's Trail, which takes visitors on a picturesque tour to the base of the Lower Falls. The trail includes more than 300 steep stairs and paved inclines, and drops 500 feet (150 meters).
The trail was constructed in 1898 by "Uncle" Tom Richardson, who led visitors on tours into the canyon. [Related: 8 Amazing National Park Structures]
These incredible structures are so-called star dunes in Algeria. Star dunes form in areas with complex wind patterns, where winds blow from various directions over the course of a year to create interesting patterns in the sand, according to the National Park Service.
The Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA's Terra satellite snapped this photo on Oct. 27, 2012. The false-color image features tan-colored sand and shadows that are represented by black and gray patches. The blue streaks are likely mineral-rich sediments, according to NASA officials. [Related: 101 Stunning Images of Earth from Orbit]
This tiny creature is an albino wood frog that was found in Tamarac National Wildlife Refuge in northwestern Minnesota.
The refuge spans about 67 square miles (174 square kilometers), and includes more than 20 lakes. There are also three rivers and hundreds of marshes and ponds within the region. In addition to frogs, the Tamarac National Wildlife Refuge is home to bald eagles, grouse, deer, beavers, river otters, black bears and gray wolves. [Related Gallery: Cute and Colorful Frog Images]
Autumn in Alaska
Looking for an autumn escape? The colorful and incredibly lush Bering Land Bridge National Preserve in Alaska makes for an ideal fall destination.
The remote Bering Land Bridge National Preserve is located on the Seward Peninsula on the western coast of Alaska. The region protects part of the Bering Land Bridge that once connected North America and Asia, providing a pathway for plants, animals and people to migrate from the old world to the new, more than 20,000 years ago. [Related Gallery: A Rainbow of Fall Leaves]
President Obama Visits Stonehenge
Earlier this month, President Barack Obama took a guided tour of Stonehenge with Heather Sebire, property curator, and Matthew Barzun, the U.S. Ambassador to the United Kingdom. The president visited the famous stone megaliths on Sept. 5, on his way back to the United States from a NATO summit that was held in Wales. [Related Gallery: Hidden Monuments Discovered Beneath Stonehenge]
Magnificent Milky Way
A stunning view of the Milky Way over Arches National Park in eastern Utah.
These so-called noctilucent clouds are typically hard to see, since they form 50 to 60 miles (80 to 100 kilometers) above the ground — higher than where clouds typically form in the atmosphere.
Astronauts aboard the International Space Station snapped this photo of these mysterious clouds, known as polar mesospheric clouds, on Aug. 1, as the orbiting outpost flew over southern Ukraine. [Related Gallery: Photos of Mysterious Night-Shining Clouds]