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Explanation: What kind of cloud is this? A type of arcus cloud called a roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado. Unlike a similar shelf cloud, a...

Explanation: Named for the southern constellation toward which most of its galaxies can be found, the Fornax Cluster is one of the closest clusters of galaxies. About 62 million light-years away, it is almost 20 times more distant than our neighboring Andromeda Galaxy, and only about 10 percent farther than the better known and more populated Virgo Galaxy Cluster. Seen across this two degree wide field-of-view, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. A standout barred spiral galaxy NGC 1365 is visible on the lower right as a prominent Fornax cluster member....

Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This sharp telescopic portrait uses narrow band image data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. Visible within the nebula, NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000...

World Famous Scientist: God Created the Universe ‘The final resolution could be that God is a mathematician.’ Michio Kaku has made a name for himself as a world-leading theoretical physicist unafraid to speak his mind.Kaku, the Henry Semat Chair and Professorship in theoretical physics at the City College of New York, has published more than 70 articles in physics journals on topics such as supersymmetry, superstring theory, supergravity, and hadronic physics.His latest claim is likely to make waves in the world of science.“I have concluded that we are in a world made by rules created by an intelligence”, Kaku says...

Explanation: The night side of Pluto spans this shadowy scene. The spacebased view with the Sun behind the distant world was captured by New Horizons last July. The spacecraft was at a range of over 21,000 kilometers, about 19 minutes after its closest approach. A denizen of the Kuiper Belt in dramatic silhouette, the image also reveals Pluto's tenuous, surprisingly complex layers of hazy atmosphere. The crescent twilight landscape near the top of the frame includes southern areas of nitrogen ice plains informally known as Sputnik Planum and rugged mountains of water-ice in the Norgay Montes.

Explanation: While drifting through the cosmos, a magnificent interstellar dust cloud became sculpted by stellar winds and radiation to assume a recognizable shape. Fittingly named the Horsehead Nebula, it is embedded in the vast and complex Orion Nebula (M42). A potentially rewarding but difficult object to view personally with a small telescope, the above gorgeously detailed image was taken in 2013 in infrared light by the orbiting Hubble Space Telescope in honor of the 23rd anniversary of Hubble's launch. The dark molecular cloud, roughly 1,500 light years distant, is cataloged as Barnard 33 and is seen above primarily because it...

Explanation: Why is Venus so different from Earth? To help find out, Japan launched the robotic Akatsuki spacecraft which entered orbit around Venus late last year after an unplanned five-year adventure around the inner Solar System. Even though Akatsuki has passed its original planned lifetime, the spacecraft and its instruments are operating so well that much of its original mission has been reinstated. In the featured image taken by Akatsuki late last month, Venus was captured in infrared light showing a surprising amount of atmospheric structure on its night side. The vertical orange terminator stripe between night and day is...

Explanation: What can this galaxy tell us about the expansion rate of the universe? Perhaps a lot because UGC 9391, featured, not only contains Cepheid variable stars (red circles) but also a recent Type Ia supernova (blue X). Both types of objects have standard brightnesses, with Cepheids typically being seen relatively nearby, while supernovas are seen much further away. Therefore, this spiral is important because it allows a calibration between the near and distant parts of our universe. Unexpectedly, a recent analysis of new Hubble data from UGC 9391 and several similar galaxies has bolstered previous indications that Cepheids and...

Explanation: It's rare that such different objects are imaged so close together. Such an occasion is occurring now, though, and was captured two days ago in combined parallel exposures from the Canary Islands of Spain. On the lower right, surrounded by a green coma and emanating an unusually split blue ion tail diagonally across the frame, is Comet C/2013 X1 (PanSTARRS). This giant snowball has been falling toward our Sun and brightening since its discovery in 2013. Although Comet PannSTARRS is a picturesque target for long-duration exposures of astrophotography, it is expected to be only barely visible to the unaided...

Explanation: Fifty years ago, Surveyor 1 reached the Moon. Launched on May 30, 1966 and landed on June 2, 1966 with the Moon at full phase it became the first US spacecraft to make a soft landing on another world. The first of seven Surveyor missions intended to test the lunar terrain for the planned Apollo landings it sent back over 10,000 images before lunar nightfall on June 14. The total rose to over 11,000 images returned before its second lunar night began on July 13. Surveyor 1 continued to respond from the lunar surface until January 7, 1967. Captured...

Explanation: NGC 4631 is a big beautiful spiral galaxy. Seen edge-on, it lies only 25 million light-years away in the well-trained northern constellation Canes Venatici. The galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others its popular moniker, The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this sharp color image, the galaxy's yellowish core, dark dust clouds, bright blue star clusters, and red star forming regions are easy to spot. A companion galaxy, the small elliptical NGC 4627 is just above the Whale Galaxy. Faint star streams...

Explanation: Seen any planets lately? All three planets now shining brightly in the night sky are imaged in these panels, captured last week with the 1 meter telescope at Pic du Midi Observatory in the French Pyrenees. Near opposition and closest to Earth on May 30, Mars is presently offering the best ground-based photo-ops in the last decade. The sharp image finds clouds above the Red Planet's north pole (top) and towering volcanos near its right limb. Saturn reaches its own opposition tonight, its bright rings and gaps clearly revealed in the telescopic portrait. Jupiter is currently highest during the...

Explanation: What star created this huge expanding puffball? Featured here is the first expansion movie ever created for Tycho's supernova remnant, the result of a stellar explosion first recorded over 400 years ago by the famous astronomer Tycho Brahe. The 2-second video is a time-lapse composite of X-ray images taken by the orbiting Chandra X-ray Observatory between the years 2000 and 2015, added to a stock optical frame. The expanding gas cloud is extremely hot, while slightly different expansion speeds have given the cloud a puffy appearance. Although the star that created SN 1572, is likely completely gone, a star...

Explanation: To some, it looks like a giant chicken running across the sky. To others, it looks like a gaseous nebula where star formation takes place. Cataloged as IC 2944, the Running Chicken Nebula spans about 100 light years and lies about 6,000 light years away toward the constellation of the Centaur (Centaurus). The featured image, shown in scientifically assigned colors, was captured recently in an 11-hour exposure from a backyard near Melbourne, Australia. Two star clusters are visible: the Pearl Cluster seen on the far left, and Collinder 249 embedded in the nebula's glowing gas. Although difficult to discern...

Explanation: How did the universe evolve from such a smooth beginning? To help understand, computational cosmologists and NASA produced the featured time-lapse animated video depicting a computer simulation of part of the universe. The 100-million light-year simulation starts about 20 million years after the Big Bang and runs until the present. After a smooth beginning, gravity causes clumps of matter to form into galaxies which immediately begin falling toward each other. Soon, many of them condense into long filaments while others violently merge into a huge and hot cluster of galaxies. Investigating of potential universe attributes in simulations like this...

Explanation: Mars will look good in Earth's skies over the next few days -- but not this good. To get a view this amazing, a spacecraft had to actually visit the red planet. Running across the image center, though, is one the largest canyons in the Solar System. 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. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris...

If Martians exist, they'll be closer to Earth on Memorial Day than they have been in 11 years. This Monday, around 5:34 p.m. EDT, when many Americans may be enjoying a holiday barbecue, the Red Planet will be the closest it has been to Earth in more than a decade, coming within 46.8 million miles, according to NASA. The relatively close encounter with Earth comes a week after the Martian opposition, when Mars and the sun lined up on exact opposite sides of the Earth.

Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its more familiar outlines are seen in the brighter central region of the nebula in this impressive wide-angle view. But the composite image combines many short and long exposures to also reveal an extremely faint outer halo. At an estimated distance of 3,000 light-years, the faint outer halo is over 5 light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. More recently, some planetary nebulae are found to have halos like this...

Explanation: A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This gorgeous telescopic close-up reveals remarkable details of the region's central glowing filaments of interstellar gas and obscuring cosmic dust clouds. The field of view is over 50 light-years across. The Carina Nebula is home to young, extremely massive stars,...

Had you searched the sky with a telescope just a few hundred thousand years ago, you would have struggled to find a red planet. Instead, you would have seen a gleaming-white ice ball where Mars should be. A team of astronomers led by Isaac Smith, an astrophysicist at the Southwest Research Institute in Boulder, Colorado, has collected the first concrete evidence that Mars has just exited an extreme ice age, one so intense it would have put Earth's recent frosty foray to shame. Using cameras and a radar-pinging device on board NASA's Mars Reconnaissance Orbiter, Smith's team deduced this history...