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Explanation: On another Valentine's Day 25 years ago, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide angle camera frames sweep through the inner Solar System at the left, linking up with gas giant Neptune, the Solar System's outermost planet, at the far right. Positions for Venus, Earth, Jupiter, Saturn, Uranus, and Neptune are indicated by letters, while the Sun is...

Explanation: Not from a snowglobe, this expansive fisheye view of ice and sky was captured on February 1, from Jökulsárlón Beach, southeast Iceland, planet Earth. Chunks of glacial ice on the black sand beach glisten in the light of a nearly full moon surrounded by a shining halo. The 22 degree lunar halo itself is created by ice crystals in high, thin clouds refracting the moonlight. Despite the bright moonlight, curtains of aurora still dance through the surreal scene. In early February, their activity was triggered by Earth's restless magnetosphere and the energetic wind from a coronal hole near the...

Explanation: Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. The stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm, lasting hundreds of millions of years. But their large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning about 500 thousand light-years, this stunning composited view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkable collaborative...

This information comes from NHATS, which stands for the Near Earth Object Human Spaceflight Accessible Targets Study. Yes, it’s an acronym containing acronyms. NHATS is an automated system based out of Greenbelt, Maryland which monitors and periodically updates its list of potential target candidates for accessibility. The NHATS system data is readily accessible to the public online, and as of February 11th 2015, 1346 NHATS compliant asteroids are known. ... Relative delta-V and return velocity is crucial. Apollo astronauts were subject to a blistering 11 kilometre per second reentry velocity on their return from the Moon, and future asteroid missions...

Guest Post by Willis EschenbachWell, as often happens I started out in one direction and then I got sidetractored … I wanted to respond to Michele Casati’s claim in the comments of my last post. His claim was that if we include the Maunder Minimum in the 1600’s, it’s clear that volcanoes with a VEI greater or equal to 5 are affected by sunspots. Based on my previous analysis I figured “No way!”, but I thought I should take a look … and as is often the case, I ended up studying something entirely different.Now, the SIDC monthly sunspot record...

Explanation: Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. It is a large galaxy of over 100 billion stars with well-defined spiral arms that is similar to our own Milky Way Galaxy. One of the brightest members of the Virgo Cluster of galaxies, M100 (alias NGC 4321) is 56 million light-years distant toward the constellation of Berenice's Hair (Coma Berenices). This Hubble Space Telescope image of M100 was made in 2006 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Studies of...

(Image: NASA & ESA) This smiley face hovering in space looks like it was beamed into the heavens by a celestial keyboard. Captured by the Hubble Space Telescope, it was in fact created by a quirk of general relativity known as gravitational lensing. The glowing eyes are bright galaxies that are part of a galaxy cluster known as SDSS J1038+4849. The massive structure warps space-time, bending light like a lens to create a stretched image of distant galaxies, called an Einstein ring. The well-positioned circular shape creates the outline of the face and the wry grin. The happy face was...

We’ve all heard of the claim of “settled science” when it comes to global warming/climate change, and we’ve all heard of the “Big Bang Theory”, and I’m not just talking about the popular TV show. The scientific theory goes all the way back to 1927. This is an artist’s concept of the metric expansion of space, where space (including hypothetical non-observable portions of the universe) is represented at each time by the circular sections. Note on the left the dramatic expansion (not to scale) occurring in the inflationary epoch, and at the center the expansion acceleration. The scheme is decorated...

This smiley face hovering in space looks like it was beamed into the heavens by a celestial keyboard. Captured by the Hubble Space Telescope, it was in fact created by a quirk of general relativity known as gravitational lensing. The glowing eyes are bright galaxies that are part of a galaxy cluster known as SDSS J1038+4849. The massive structure warps space-time, bending light like a lens to create a stretched image of distant galaxies, called an Einstein ring. The well-positioned circular shape creates the outline of the face and the wry grin.

Hypervelocity stars have been observed traversing the Galaxy at extreme velocities (700 km/s), but the mechanisms that give rise to such phenomena are still debated. Astronomer Thomas M. Tauris argues that lopsided supernova explosions can eject lower-mass Solar stars from the Galaxy at speeds up to 1280 km/s. “[This mechanism] can account for the majority (if not all) of the detected G/K-dwarf hypervelocity candidates,” he said. Several mechanisms have been proposed as the source for hypervelocity stars, and the hypotheses can vary as a function of stellar type. A simplified summary of the hypothesis Tauris favors begins with a higher-mass...

Explanation: Yesterday, the Sun exhibited one of the longest filaments ever recorded. It may still be there today. Visible as the dark streak just below the center in the featured image, the enormous filament extended across the face of the Sun a distance even longer than the Sun's radius -- over 700,000 kilometers. A filament is actually hot gas held aloft by the Sun's magnetic field, so that viewed from the side it would appear as a raised prominence. The featured image shows the filament in light emitted by hydrogen and therefore highlights the Sun's chromosphere. Sun-following telescopes including NASA's...

Did you hear the one about last month’s ‘supermoon?’ Yeah, we know. The hype was actually for an event that was less than spectacular, as it revolved around the first New Moon of 2015 on January 20th. Said suspect Moon was touted as ‘super’ (we prefer the quixotic term proxigean) as it occurred 18 hours prior to perigee. Not that the first lunar perigee of 2015 was an especially close one in time or space at 359,642 kilometres distant. Is every New and Full Moon now destined to become branded ‘super’ in the never ending SEO quest to get eyeballs...

Among the mysteries of how ancient people created structures to mark the solstice and equinox with astonishing accuracy, this one is central: How did they determine the dates of those astronomical events? Houstonian Gordon Houston, who is pursuing a doctorate on this riddle, says he believes he has figured out the answer for centuries-old glyphs known as the Pictographs of Paint Rock, Texas. Found on a private ranch near San Angelo in northern Concho County, these approximately 1,500 pictographs on a limestone cliff include about a dozen that "had a solar interaction," Houston said. "Some were incredible." Houston will talk...

Explanation: What caused these Martian rocks to be layered? The leading hypothesis is an ancient Martian lake that kept evaporating and refilling over 10 million years -- but has now remained dry and empty of water for billions of years. The featured image, taken last November by the robotic Curiosity rover, shows one-meter wide Whale Rock which is part of the Pahrump Hills outcrop at the base of Mount Sharp. Also evident in the image is cross-bedding -- rock with angled layers -- which were likely facilitated by waves of sand. Curiosity continues to find many layered rocks like this...

Explanation: This cosmic pillar of gas and dust is nearly two light-years wide. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's convoluted outlines are shaped by the winds and radiation of Carina's young, hot, massive stars. But the interior of the cosmic pillar itself is home to stars in the process of formation. In fact, a penetrating infrared view shows the pillar is dominated by two, narrow, energetic jets blasting outward from a still hidden infant star. The above featured...

After Neil Armstrong's death, his widow, Carol, discovered a white cloth bag in a closet, containing what were obviously either flight or space related artifacts. She contacted Allan Needell, curator of the Apollo collection at the Smithsonian's National Air and Space Museum, and provided photographs of the items. Needell, who immediately realized that the bag—known to the astronauts as the Purse - and its contents could be hardware from the Apollo 11 mission, asked the authors for support in identifying and documenting the flight history and purpose of these artifacts. After some research it became apparent that the purse and...

Explanation: It looks like a fine collection of aggies. But this grid of embedded swirls and streaks actually follows the dramatic development of planet Earth's auroral substorms. The sequence of over 600 horizon-to-horizon fisheye images was taken over a 2 hour period near the artic circle in March of 2012 from Lapland, northern Sweden. It begins at upper left in evening twilight and ends at lower right, covering two activity peaks with bright coronae forming overhead. While exploring space between Earth and Moon, NASA's fleet of THEMIS spacecraft discovered that these explosions of auroral activity are driven by sudden releases...

NASA's Dawn spacecraft has acquired its latest and closest-yet snapshot of the mysterious dwarf planet world Ceres. These latest images, taken on Feb. 4, from a distance of about 90,000 miles (145,000 km) clearly show craters – including a couple with central peaks – and a clearer though still ambiguous view of that wild white spot that has so many of us scratching our heads as to its nature. Get ready to scratch some more. The mystery spot has plenty of company. Take a look at some still images I grabbed from the video which NASA made available today. In...

Explanation: Our solar system's ruling giant planet Jupiter and 3 of its 4 large Galilean moons are captured in this single Hubble snapshot from January 24. Crossing in front of Jupiter's banded cloud tops Europa, Callisto, and Io are framed from lower left to upper right in a rare triple-moon conjunction. Distinguishable by colors alone icy Europa is almost white, Callisto's ancient cratered surface looks dark brown, and volcanic Io appears yellowish. The transiting moons and moon shadows can be identified by sliding your cursor over the image, or following this link. Remarkably, two small, inner Jovian moons, Amalthea and...

Explanation: What do the following things have in common: a cone, the fur of a fox, and a Christmas tree? Answer: they all occur in the constellation of the unicorn (Monoceros). Pictured as a star forming region and cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars they also reflect starlight, forming blue reflection nebulae. The image spans about the diameter of...