Tuesday, June 30, 2015
Astronomy Picture of the Day: July 1st of 2015
Venus, Jupiter, and Noctilucent Clouds
Image Credit & Copyright: Petr Horálek
Explanation: Have you seen the passing planets yet? Today the planets Jupiter and Venus pass within half a degree of each other as seen from Earth. This conjunction, visible all over the world, is quite easy to see -- just look to the west shortly after sunset. The brightest objects visible above the horizon will be Venus and Jupiter, with Venus being the brighter of the two. Featured above, the closing planets were captured two nights ago in a sunset sky graced also by high-level noctilucent clouds. In the foreground, the astrophotographer's sister takes in the vista from a bank of the Sec Reservoir in the Czech Republic. She reported this as the first time she has seen noctilucent clouds. Jupiter and Venus will appear even closer together tonight and will continue to be visible in the same part of the sky until mid-August.
National Geographic Photo of the Day: July 1st of 2015
July 1, 2015
The Best Seat in Yosemite
Photograph by Christian Fernandez, National Geographic Your Shot
Under a blanket of stars, a man takes in the landscape of Yosemite National Park from the edge of the Diving Board, a rock formation at Glacier Point.
Astronomy Picture of the Day: June 30th of 2015
An Unusual Mountain on Asteroid Ceres
Image Credit: NASA, JPL-Caltech, UCLA, MPS/DLR/IDA
Explanation: What created this large mountain on asteroid Ceres? No one is yet sure. As if in anticipation of today being Asteroid Day on Earth, the robotic spacecraft Dawn in orbit around Ceres took the best yet image of an unusually tall mountain on the Asteroid Belt's largest asteroid. Visible at the top of the featured image, the exceptional mountain rises about five kilometers up from an area that otherwise appears pretty level. The image was taken about two weeks ago from about 4,400 kilometers away. Although origin hypotheses for the mountain include volcanism, impacts, and plate tectonics, clear evidence backing any of these is currently lacking. Also visible across Ceres' surface are some enigmatic light areas: bright spots whose origin and composition that also remain an active topic of investigation. Even though Dawn is expected to continue to orbit Ceres, officially dubbed a dwarf planet, for millions of years, the hydrazine fuel used to point Dawn's communications antenna toward Earth is expected to run out sometime next year.
National Geographic Photo of the Day: June 30th of 2015
June 30, 2015
Getting Their Shot
Photograph by Wim Uyttenbroeck, National Geographic Your Shot
“The Oslo Opera House is a very special place,” writes Wim Uyttenbroeck, who captured this picture in the Norwegian capital. “These three colorful photographers make a nice contrast against the white stone and plate glass of the building. The white clouds in the sky make the picture complete.”
Astronomy Picture of the Day: June 29th of 2015
Sunspot Group AR 2339 Crosses the Sun
Images Credit: NASA, SDO; Video compilation & Copyright: Stanislav Korotkiy (AstroAlert) & Mikhail Chubarets;
Music: Pas de Deux (Bird Creek)
Explanation: How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent a few weeks ago as the active region AR 2339 came around the limb of the Sun and was tracked for the next 12 days by NASA's Solar Dynamic Observatory. In the featured time lapse video, some sunspots drift apart, while others merge. All the while, the dark central umbral regions shift internally and their surrounding lighter penumbras shimmer and wave. The surrounding Sun appears to flicker as the carpet of yellow granules come and go on the time scale of hours. In general, sunspots are relatively cool regions where the local magnetic field pokes through the Sun's surface and inhibits heating. Over the past week, an even more active region -- AR 2371 -- has been crossing the Sun and releasing powerful flares that have resulted in impressive auroras here on Earth.
National Geographic Photo of the Day: June 29th of 2015
June 29, 2015
Put a Wing on It
Photograph by Mohd Khorshid, National Geographic Your Shot
In this picture by Mohd Khorshid, a willow warbler splashes in a pool of water in Al Ahmadi, Kuwait. Willow warblers pass through the country in large numbers during their long seasonal migrations.
Sunday, June 28, 2015
Astronomy Picture of the Day: June 28th of 2015
All the Colors of the Sun
Credit & Copyright: Nigel Sharp (NSF), FTS, NSO, KPNO, AURA, NSF
Explanation: It is still not known why the Sun's light is missing some colors. Here are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine what gasses compose the Sun. Helium, for example, was first discovered in 1870 on a solar spectrum and only later found here on Earth. Today, the majority of spectral absorption lines have been identified - but not all.
National Geographic Photo of the Day: June 28th of 2015
June 28, 2015
Peak of Dawn
Photograph by Katsuyoshi Nakahara, National Geographic Your Shot
Shirley poppies bloom in a field near Japan’s Mount Tsukuba, here silhouetted against an early morning sky. The mountain—which can be ascended via a hiking trail or cable car—has two peaks, each rising more than 2,800 feet.
Astronomy Picture of the Day: June 27th of 2015
Stars of a Summer's Triangle
Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)
Explanation: Rising at the start of a northern summer's night, these three bright stars form the familiar asterism known as the Summer Triangle. Altair, Deneb, and Vega are the alpha stars of their respective constellations, Aquila, Cygnus, and Lyra, nestled near the Milky Way. Close in apparent brightness the three do look similar in these telescopic portraits, but all have their own stellar stories. Their similar appearance hides the fact that the Summer Triangle stars actually span a large range in intrinsic luminosity and distance. A main sequence dwarf star, Altair is some 10 times brighter than the Sun and 17 light-years away, while Vega, also a hydrogen-fusing dwarf, is around 30 times brighter than the Sun and lies 25 light-years away. Supergiant Deneb, at about 54,000 times the solar luminosity, lies some 1,400 light-years distant. Of course, with a whitish blue hue, the stars of the Summer Triangle are all hotter than the Sun.
National Geographic Photo of the Day: June 27th of 2015
June 27, 2015
Tree Top
Photograph by Kat Lawrence, National Geographic Your Shot
A lone tree grows on a pillar of quartz and sandstone in China’s Zhangjiajie National Forest Park. There are more than 3,000 such peaks in the Hunan Province park, part of a UNESCO World Heritage site. Its diverse landscape—dense forest, gullies, cliffs, and valleys—shelter macaque and rhesus monkeys, pangolins, and Chinese giant salamanders, as well as rare birds and trees.
Friday, June 26, 2015
Astronomy Picture of the Day: June 26th of 2015
Planet Aurora
Image Credit: Scott Kelly, Expedition 44, NASA
Explanation: What bizarre alien planet is this ? It's planet Earth of course, seen through the shimmering glow of aurorae from the International Space Station. About 400 kilometers (250 miles) above, the orbiting station is itself within the upper realm of the auroral displays, also watched from the planet's surface on June 23rd. Aurorae have the signature colors of excited molecules and atoms at the low densities found at extreme altitudes. The eerie greenish glow of molecular oxygen dominates this view. But higher, just above the space station's horizon, is a rarer red band of aurora from atomic oxygen. The ongoing geomagnetic storm began after a coronal mass ejection's recent impact on Earth's magnetosphere.
National Geographic Photo of the Day: June 26th of 2015
June 26, 2015
Bay Breach
Photograph by David Howells, National Geographic Your Shot
“This image was captured as we were returning from a fruitless search for active humpback whales,” writes David Howells, who took this picture on Canada’s Witless Bay. “We had given up as the sun was setting and were returning to harbor when this young humpback started breaching right in front of us. Sometimes you just get lucky!”
Thursday, June 25, 2015
Astronomy Picture of the Day: June 25th of 2015
Star Trails above Table Mountain
Image Credit & Copyright: Eric Nathan
Explanation: Stars trail above and urban lights sprawl below in this moonlit nightscape from Cape Town, South Africa, planet Earth. The looming form of Table Mountain almost seems to hold terrestrial lights at bay while the stars circle the planet's South Celestial Pole. This modern perspective on the natural night sky was captured in June 2014, the scene composed of over nine hundred, stacked 30 second exposures. The stunning result was chosen as the winner in the Against the Lights category, a selection from over 800 entries in The World at Night's 2015 International Earth and Sky Photo Contest.
National Geographic Picture of the Day: June 25th of 2015
June 25, 2015
Morning Swim
Photograph by Massimo Rumi, National Geographic Your Shot
“Swimming is an early morning ritual for many people in Australia,” writes Massimo Rumi, who captured this sunrise shot on Sydney’s popular Bondi Beach.
Astronomy Picture of the Day: June 24th of 2015
Triple Conjunction Over Galician National Park
Image Credit & Copyright: Fernando Rey (LuzLux)
Explanation: What are those bright objects hovering over the horizon? Planets -- and the Moon. First out, the horizon featured is a shoreline of the Atlantic Ocean that occurs at the Galicia National Park in northern Spain. Next furthest out, on the left, is the Moon. Easily the brightest object on the night sky, the Moon here was in only a crescent phase. The next furthest out, on the right, is the planet Venus, while planet Jupiter is seen at the top of the triangle. The long exposure from our rapidly rotating Earth made all of celestial objects -- including the far distant stars -- appear as slight arcs. The featured image was taken last Sunday night. Although the Moon's orbit has now taken it away from this part of the sky, the planets Venus and Jupiter can be seen superposed just after sunset until mid-August. The closest apparent separation of Venus and Jupiter will occur in one week, when the two planets will appear separated by less than the angular diameter of the Moon.
National Geographic Photo of the Day: June 24th of 2015
June 24, 2015
Power Lines
Photograph by Nilton Quoirin, National Geographic Your Shot
In this entry to the Traveler Photo Contest, two power plant workers walk over a generator cover in Itaipu, a hydroelectric power plant on the border between Brazil and Paraguay.
Astronomy Picture of the Day: June 23rd of 2015
Sharpless 308: Star Bubble
Image Credit & Copyright: Kfir Simon
Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive star evolution. Fast winds from this Wolf-Rayet star create the bubble-shaped nebula as they sweep up slower moving material from an earlier phase of evolution. The windblown nebula has an age of about 70,000 years. Relatively faint emission captured in the expansive image is dominated by the glow of ionized oxygen atoms mapped to a blue hue.
National Geographic Photo of the Day: June 23rd of 2015
June 23, 2015
A Peek at Yoho
Photograph by Peter Essick, National Geographic
Once a whistle-stop on a wilderness railroad, Canada’s Yoho National Park is now a hot spot of science and scenery. Here, reed-fenced Emerald Lake reflects blue sky and snowy Michael Peak flanked by woodlands.
Monday, June 22, 2015
Astronomy Picture of the Day: June 22nd of 2015
New Horizons
Video Credit & Copyright: National Space Society
Explanation: In three weeks, the robotic New Horizons spacecraft will reach Pluto. As the featured video makes clear, though, humanity has been on an unprecedented epoch of robotic exploration of our Solar System's planets for the past half century. The video highlights artistic illustrations of Mariner 2 flying by Venus in 1962, Mariner 4 flying past Mars in 1965, Pioneer 10 flying past Jupiter in 1973, Mariner 10 flying past Mercury in 1974, Pioneer 11 flying past Saturn in 1979, and Voyager 2 flying past Uranus in 1986 and then Neptune in 1989. Next is a hypothetical sequence depicting New Horizons flying past Pluto next month. Assuming things work as planned, dwarf planet Pluto will then become the farthest world yet explored by humans. Of course, these Pluto illustrations are only a guess. How Pluto and its moons will really look may be a mixture of familiar things, such as craters, and unfamiliar things, such as …
National Geographic Photo of the Day: June 22nd of 2015
June 22, 2015
Energy Flow
Photograph by Sho Shibata, National Geographic Your Shot
The spring season comes slowly to the mountains of Aomori, Japan, writes photographer Sho Shibata, adding that the beech trees will begin to bud before the snow has even melted. Here, Shibata captures a Mount Hakkoda forest wreathed in morning mist.
Sunday, June 14, 2015
National Geographic Photo of the Day: June 15th of 2015
June 15, 2015
Bowl of Mountains
Photograph by Peter Essick, National Geographic
Lake O’Hara nestles in the Canadian Rockies at more than 6,600 feet “like an emerald in a bowl of mountains,” wrote paleontologist Charles Walcott in 1911. Generations of artists have put brush to canvas at this lookout, called All Souls Prospect, in British Columbia’s Yoho National Park.
National Geographic Photo of the Day: June 14th of 2015
June 14, 2015
Twilight in Bukhara
Photograph by Joel Koczwarski, National Geographic Your Shot
“As dusk settles in the ancient city of Bukhara, a lone woman passes by an incredible ancient mosque of epic proportions,” writes photographer Joel Koczwarski. Located in present-day Uzbekistan, Bukhara was once an important stop along the Silk Road.
Friday, June 5, 2015
Astronomy Picture of the Day: June 5th of 2015
Green Flash at Moonrise
Image Credit & Copyright: Daniel López (El Cielo de Canarias)
Explanation: Follow a sunset on a clear day against a distant horizon and you might glimpse a green flash just as the Sun disappears, the sunlight briefly refracted over a long sight-line through atmospheric layers. You can spot a green flash at sunrise too. Pinpointing the exact place and time to see the rising Sun peeking above the horizon is a little more difficult though, and it can be harder still to catch a green flash from the fainter rising Moon. But well-planned snapshots did record a green flash at the Full Moon's upper edge on June 2nd, from the Roque de los Muchachos Observatory on the Canary Island of La Palma. Looking a little south of due east, this long telephoto view finds the rising Moon above mountains and a sea of clouds. In sunlit profile are the mountaintop Teide Observatory telescope domes on the island of Tenerife some 143 kilometers away.
National Geographic Photo of the Day: June 5th of 2015
June 5, 2015
Hull-o
Photograph by Marc Henauer
A diver gazes at the Hilma Hooker, a cargo ship purposely sunk off the Caribbean island of Bonaire. The site is a popular destination for scuba divers.
Astronomy Picture of the Day: June 4th of 2015
NGC 2419: Intergalactic Wanderer
Image Credit & Copyright: Bob Franke
Explanation: Three objects stand out in this thoughtful telescopic image, a view toward the mostly stealthy constellation Lynx. The two brightest (the spiky ones) are nearby stars. The third is the remote globular star cluster NGC 2419, at distance of nearly 300,000 light-years. NGC 2419 is sometimes called "the Intergalactic Wanderer", an appropriate title considering that the distance to the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only about 160,000 light-years. Roughly similar to other large globular star clusters like Omega Centauri, NGC 2419 is itself intrinsically bright, but appears faint because it is so far away. NGC 2419 may really have an extragalactic origin as, for example, the remains of a small galaxy captured and disrupted by the Milky Way. But its extreme distance makes it difficult to study and compare its properties with other globular clusters that roam the halo of our Milky Way galaxy.
National Geographic Photo of the Day: June 4th of 2015
June 4, 2015
Residence Life
Photograph by Jing Wei, National Geographic Your Shot
Monastic dormitories crowd a mountain that’s home to the Seda Larung Wuming Tibetan Buddhist Institute in China’s Garzê Tibetan Autonomous Prefecture. The monastery is the world’s largest Tibetan Buddhist academy, with tens of thousands of male and female attendees. According to Your Shot member Jing Wei, the impressive site is worth visiting “to experience the peculiar landscapes and local life of the people there.”
Wednesday, June 3, 2015
Astronomy Picture of the Day: June 3rd of 2015
Flyby Image of Saturn's Sponge Moon Hyperion
Image Credit: NASA, JPL-Caltech, SSI
Explanation: Why does this moon look like a sponge? To better investigate, NASA and ESA sent the Saturn-orbiting robotic spacecraft Cassini zooming past Saturn's moon Hyperion, once again, earlier this week. One of the images beamed back to Earth is featured above, raw and unprocessed. Visible, as expected, are many unusually shaped craters with an unusual dark material at the bottom. Although Hyperion spans about 250 kilometers, its small gravitational tug on Cassini indicates that it is mostly empty space and so has very low surface gravity. Therefore, the odd shapes of many of Hyperion's craters are thought to result from impacts that primarily compress and eject surface material -- instead of the more typical round craters that appear after a circular shock wave that explosively redistributes surface material. Cassini is on track for another flyby of Saturn's Dione in about two weeks
National Geographic Photo of the Day: June 3rd of 2015
June 3, 2015
Dancing With the Moon
Photograph by Andrew George
The aurora borealis shares the sky with a bright moon in Iceland. Named for the Roman goddess of dawn, the vivid beams of light result from collisions between charged particles released from the sun’s atmosphere and gaseous particles in Earth’s atmosphere.
Monday, June 1, 2015
Astronomy Picture of the Day: June 1st of 2015
Pulsating Aurora over Iceland
Video Credit & Copyright: Stéphane Vetter (Nuits sacrées); Music: Eric Aron
Explanation: Why do some auroras pulsate? No one is sure. Although this unusual behavior has been known for a long time, the cause remains an active topic of research. Featured here is a dramatic video that captured some impressive pulsating auroras in mid-March over Svínafellsjökull Glacier in Iceland. The 48-second video shown is not time-lapse. The real-time pulsations are exemplified by sequences where the astrophotographer is visible moving about in the foreground. A close inspection of the enigmatic flickering sky colors reveals that some structures appear to repeat, while others do not. The quick rapidity of the pulsations seen here is somewhat unusual -- more common are aurora with pulsations that last several seconds. Recent research shows that pulsations are more common in electron-generated aurora, rather than proton aurora, and that the Earth's local magnetic field may fluctuate in unison.
National Geographic Photo of the Day: June 1st of 2015
June 1, 2015
What Feeds Beneath
Photograph by Alejandro Prieto
While on an expedition at Todos Santos in south Baja California, Mexico, Your Shot member Alejandro Prieto was searching for big predators—such as marlins, sharks, or tuna—feeding on sardine bait balls, but instead he found this Hawaiian petrel feeding on crustaceans. “Luckily I was able to capture the moment it submerged its head to feed on the tiny food source,” Prieto writes.
Astronomy Picture of the Day: June 2nd of 2015
Polaris and Comet Lovejoy
Image Credit & Copyright: Rogelio Bernal Andreo
Explanation: One of these two bright sky objects is moving. On the right is the famous star Polaris. Although only the 45th brightest star in the sky, Polaris is famous for appearing stationary. Once you find it, it will always appear in the same direction -- all night and all day -- for the rest of your life. This is because the northern spin pole of the Earth -- called the North Celestial Pole -- points near Polaris. On the left, about ten million times closer, is Comet Lovejoy, which noticeably changes its sky position by the hour. The featured image was taken last week. Officially designated C/2014 Q2 (Lovejoy), this disintegrating snowball is on a visit from the outer Solar System and will only appear near the North Star for a few more weeks. That should be long enough, however, for northerners with binoculars or a small telescope to see the greenish coma of this fleeting newcomer, perhaps with the help of a good star map.
National Gepgraphic Photo of the Day: June 2nd of 2015
June 2, 2015
Meeting of Shadows
Photograph by Denis Buchel, National Geographic Your Shot
Long shadows converge on a sunny day in Istanbul, Turkey, in this photo by Denis Buchel, a member of our Your Shot community.
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