Explanation: Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on Earth. Pictured above are the orbits of the over 1,000 known Potentially Hazardous Asteroids (PHAs). These documented tumbling boulders of rock and ice are over 140 meters across and will pass within 7.5 million kilometers of Earth -- about 20 times the distance to the Moon. Although none of them will strike the Earth in the next 100 years -- not all PHAs have been discovered, and past 100 years, many orbits become hard to predict. Were an asteroid of this size to impact the Earth, it could raise dangerous tsunamis, for example. Of course rocks and ice bits of much smaller size strike the Earth every day, usually pose no danger, and sometimes creating memorable fireball and meteor displays.
This is a closeup image of the Aerojet Rocketdyne RS-68A engine (center engine) and four (two on each side) Orbital ATK GEM-60 solid rocket motors that power United Launch Alliance's Delta IV Medium+ (5,4) rocket. This past Saturday, this Delta IV launched the 9th Wideband Global SATCOM satellite (WGS-9) for the USAF.I shoot for AmericaSpace as a launch photographer; before most launches from Cape Canaveral, other members of the media and I are escorted to the launchpads on Cape Canaveral Air Force Station to setup "remote" cameras. (I'm not credentialed for all of them--long story.)This image was taken with a Nikon D3300, Nikon 55-300mm f/4.5-5.6 lens (at 80mm) and was the shot was triggered by a Vela Pop sound trigger, as I watched the launch from ~2.5 miles away; the sound would kill anyone this close. The camera was about 300ft from the rocket, its tripod was staked down using tent stakes, and there was a plastic bag around the camera to protect it from weather and the rocket itself.Settings: 1/4000 f/13 ISO 100 - many other photographers have successfully executed these shots in the past, and I used their EXIF data as reference, but I opted to underexposed even further to properly expose the extremely bright exhaust. The D3300 has surprisingly good dynamic range and I was able to pull up the shadows in LR.I've been taking rocket launch images for about two years and have had up-close access for about a year, but this is probably my favorite shot I've ever taken.Thanks for viewing; feel free to ask anything about the setup or the launch!Personal stuff below Instagram: @johnkrausphotos - I'm doing the 365 day daily photo challenge after completing it last year. No missed days; feel free to follow for daily content WebsiteFlickr, which hosts solely my daily photo images from this year.
Explanation: This rock structure is not only surreal -- it's real. The reason it's not more famous is that it is, perhaps, smaller than one might guess: the capstone rock overhangs only a few meters. Even so, the King of Wings outcrop, located in New Mexico, USA, is a fascinating example of an unusual type of rock structure called a hoodoo. Hoodoos may form when a layer of hard rock overlays a layer of eroding softer rock. Figuring out the details of incorporating this hoodoo into a night-sky photoshoot took over a year. Besides waiting for a suitably picturesque night behind a sky with few clouds, the foreground had to be artificially lit just right relative to the natural glow of the background. After much planning and waiting, the final shot, featured here, was taken in May 2016. Mimicking the horizontal bar, the background sky features the band of our Milky Way Galaxy stretching overhead.
Explanation: Many details of Saturn appear clearly in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole. Each side of the dark hexagon spans roughly the width of our Earth. The hexagon's existence was not predicted, and its origin and likely stability remains a topic of research. Saturn's famous rings circle the planet and cast shadows below the equator. The featured image was taken by the robotic Cassini spacecraft in 2014 in several infrared colors -- but only processed recently. In September, Cassini's mission will be brought to a dramatic conclusion as the spacecraft will be directed to dive into ringed giant.
Explanation: Mt. Etna has been erupting for hundreds of thousands of years. Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high. Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, measuring over 50 kilometers at its base and rising nearly 3 kilometers high. Pictured in mid-March, a spectacular lava plume erupts upwards, dangerous molten volcanic bombs fly off to the sides, while hot lava flows down the volcano's exterior. The Earth's rotation is discernable on this carefully time, moon-lit, long duration image as star trails.
Explanation: What's happened to Comet Lovejoy? In the pictured image, a processed composite, the comet was captured early this month after brightening unexpectedly and sporting a long and intricate ion tail. Remarkably, the typically complex effect of the Sun's wind and magnetic field here caused the middle of Comet Lovejoy's ion tail to resemble the head of a needle. Comet C/2017 E4 (Lovejoy) was discovered only last month by noted comet discoverer Terry Lovejoy. The comet reached visual magnitude 7 earlier this month, making it a good target for binoculars and long duration exposure cameras. What's happened to Comet Lovejoy (E4) since this image was taken might be considered even more remarkable -- the comet's nucleus appeared to be disintegrating and fading as it neared its closest approach to the Sun two days ago.
Explanation: What glows in the night? This night, several unusual glows were evident -- some near, but some far. The foreground surf glimmers blue with the light of bioluminescent plankton. Next out, Earth's atmosphere dims the horizon and provides a few opaque clouds. Farther out, the planet Venus glows bright near the image center. If you slightly avert your eyes, a diagonal beam of light will stand out crossing behind Venus. This band is zodiacal light, sunlight scattered by dust in our Solar System. Much farther away are numerous single bright stars, most closer than 100 light years away. Farthest away, also rising diagonally and making a "V" with the zodiacal light, is the central band of our Milky Way Galaxy. Most of the billions of Milky Way stars and dark clouds are thousands of light years away. The featured image was taken last November on the Iranian coast of Gulf of Oman.
This is one of the most striking thunderstorm photos we've seen.Taken from a plane at the moment of a lightning flash, it illustrates both the ferocity of a turbulent atmosphere and the beauty of Mother Nature. A strong, roiling updraft; a smooth, flat anvil; and the overshooting top -- all features of intense developing thunderstorms.The photo was taken over the Pacific Ocean from the cockpit of an airplane. The photographer and pilot, Santiago Borja, says he was circling around it at 37,000 feet altitude en route to South America when he captured this spectacular view.Borja said it was difficult to get the shot in near-darkness and during a bumpy ride. "Storms are tricky because the lightning is so fast, there is no tripod and there is a lot of reflection from inside lights," Borja told The Washington Post in an email."I like this photo so much because you can feel the amazing size of the storm and its power," Borja said. "But at the same time it's wonderful how peacefully you can fly around it in still air without touching it."The photo was taken with his Nikon D750 camera south of Panama on a Boeing 767-300."I primarily enjoy nature, landscape and cityscape photography," Borja said. "Since I carry my camera everywhere, I started trying to capture storms and in-flight experiences some time ago combining my two greatest passions: flying and photography."
In a fitting farewell to the planet that had been its home for over 13 years, the Cassini spacecraft took one last, lingering look at Saturn and its splendid rings during the final leg of its journey and snapped a series of images that has been assembled into a new mosaic. Cassini's wide-angle camera acquired 42 red, green and blue images, covering the planet and its main rings from one end to the other, on Sept. 13, 2017. Imaging scientists stitched these frames together to make a natural color view. The scene also includes the moons Prometheus, Pandora, Janus, Epimetheus, Mimas and Enceladus.There is much to remember and celebrate in marking the end of the mission. Cassini's exploration of Saturn and its environs was deep, comprehensive and historic."Cassini's scientific bounty has been truly spectacular -- a vast array of new results leading to new insights and surprises, from the tiniest of ring particles to the opening of new landscapes on Titan and Enceladus, to the deep interior of Saturn itself," said Robert West, Cassini's deputy imaging team leader at NASA's Jet Propulsion Laboratory in Pasadena, California.The Cassini imaging team had been planning this special farewell view of Saturn for years. For some, when the end finally came, it was a difficult goodbye."It was all too easy to get used to receiving new images from the Saturn system on a daily basis, seeing new sights, watching things change," said Elizabeth Turtle, an imaging team associate at the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland. "It was hard to say goodbye, but how lucky we were to be able to see it all through Cassini's eyes!"For others, Cassini's farewell to Saturn is reminiscent of another parting from long ago."For 37 years, Voyager 1's last view of Saturn has been, for me, one of the most evocative images ever taken in the exploration of the solar system," said Carolyn Porco, former Voyager imaging team member and Cassini's imaging team leader at the Space Science Institute in Boulder, Colorado. "In a similar vein, this 'Farewell to Saturn' will forevermore serve as a reminder of the dramatic conclusion to that wondrous time humankind spent in intimate study of our Sun's most iconic planetary system."Launched in 1997, the Cassini spacecraft orbited Saturn from 2004 to 2017. The mission made numerous dramatic discoveries, including the surprising geologic activity on Saturn's moon Enceladus and liquid methane seas on Saturn's largest moon, Titan. Cassini ended its journey with a dramatic plunge into Saturn's atmosphere on Sept. 15, 2017, returning unique science data until it lost contact with Earth.The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the U.S., England, France, and Germany. The imaging operations center and team leader are based at the Space Science Institute in Boulder, Colorado.More information about Cassini:https://www.nasa.gov/cassinihttps://saturn.jpl.nasa.gov