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Explanation: A long solar filament stretches across the relatively calm surface of the Sun in this telescopic snap shot from April 27. The negative or inverted narrowband image was made in the light of ionized hydrogen atoms. Seen at the upper left, the magnificent curtain of magnetized plasma towers above surface and actually reaches beyond the Sun's edge. How long is the solar filament? About as long as the distance from Earth to Moon, illustrated by the scale insert at the left. Tracking toward the right across the solar disk a day later the long filament erupted, lifting away from...

Explanation: What's happening to Comet 67P/Churyumov-Gerasimenko? As the 3-km wide comet moves closer to the Sun, heat causes the nucleus to expel gas and dust. The Rosetta spacecraft arrived at the comet's craggily double nucleus last July and now is co-orbiting the Sun with the giant dark iceberg. Recent analysis of data beamed back to Earth from the robotic Rosetta spacecraft has shown that water being expelled by 67P has a significant difference with water on Earth, indicating that Earth's water could not have originated from ancient collisions with comets like 67P. Additionally, neither Rosetta nor its Philae lander detected...

The EmDrive, an experimental propulsion device, may be producing a warp field. According to posts on the NASA Space Flight forum, when lasers were fired into the EmDrive resonance chamber, it was found that some of the beams were travelling faster than the speed of light. (VIDEO-AT-LINK)If this is true, then it would mean that the EmDrive is producing a warp field or bubble. A forum post says that "this signature (the interference pattern) on the EmDrive looks just like what a warp bubble looks like. And the math behind the warp bubble apparently matches the interference pattern found in...

Explanation: It is one of the more massive galaxies known. A mere 46 million light-years distant, spiral galaxy NGC 2841 can be found in the northern constellation of Ursa Major. This sharp view of the gorgeous island universe shows off a striking yellow nucleus and galactic disk. Dust lanes, small, pink star-forming regions, and young blue star clusters are embedded in the patchy, tightly wound spiral arms. In contrast, many other spirals exhibit grand, sweeping arms with large star-forming regions. NGC 2841 has a diameter of over 150,000 light-years, even larger than our own Milky Way and captured by this...

Explanation: What's that in front of the Moon? It's the International Space Station. Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit Moon last year. The featured image was taken from Madrid, Spain with an exposure time of only 1/1000 of a second. In contrast, the duration of the transit of the ISS across the entire Moon was about half a second. The sun-glinting station can be seen just to the dark side of the day / night line known as the terminator. Numerous circular craters are visible on the distant Moon, as well...

One of the great challenges in molecular biology is to determine the three-dimensional structure of large biomolecules such as proteins. But this is a famously difficult and time-consuming task. The standard technique is x-ray crystallography, which involves analyzing the x-ray diffraction pattern from a crystal of the molecule under investigation. That works well for molecules that form crystals easily. But many proteins, perhaps most, do not form crystals easily. And even when they do, they often take on unnatural configurations that do not resemble their natural shape. So finding another reliable way of determining the 3-D structure of large biomolecules...

Last month, we are told, the world enjoyed “its hottest March since records began in 1880”. This year, according to “US government scientists”, already bids to outrank 2014 as “the hottest ever”. The figures from the US National Oceanic and Atmospheric Administration (NOAA) were based, like all the other three official surface temperature records on which the world’s scientists and politicians rely, on data compiled from a network of weather stations by NOAA’s Global Historical Climate Network (GHCN). But here there is a puzzle. These temperature records are not the only ones with official status. The other two, Remote Sensing...

Explanation: Why isn't this ant a big sphere? Planetary nebula Mz3 is being cast off by a star similar to our Sun that is, surely, round. Why then would the gas that is streaming away create an ant-shaped nebula that is distinctly not round? Clues might include the high 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and the magnetism of the star visible above at the nebula's center. One possible answer is that Mz3 is hiding a second, dimmer star that orbits close in to the bright star. A competing hypothesis holds...

Explanation: Located 20,000 light-years away in the constellation Carina, the young cluster and starforming region Westerlund 2 fills this cosmic scene. Captured with Hubble's cameras in near-infrared and visible light, the stunning image is a celebration of the 25th anniversary of the launch of the Hubble Space Telescope on April 24, 1990. The cluster's dense concentration of luminous, massive stars is about 10 light-years across. Strong winds and radiation from those massive young stars have sculpted and shaped the region's gas and dust, into starforming pillars that point back to the central cluster. Red dots surrounding the bright stars are...

Explanation: Lapping at rocks along the shore of the Island of Nangan, Taiwan, planet Earth, waves are infused with a subtle blue light in this sea and night skyscape. Composed of a series of long exposures made on April 16 the image captures the faint glow from Noctiluca scintillans. Also known as sea sparkles or blue tears, the marine plankton's bioluminescence is stimulated by wave motion. City lights along the coast of mainland China shine beneath low clouds in the west but stars and the faint Milky Way still fill the night above. Over the horizon the galaxy's central bulge...

Explanation: Earth's April showers include the Lyrid Meteor Shower, observed for more than 2,000 years when the planet makes its annual passage through the dust stream of long-period Comet Thatcher. A grain of that comet's dust, moving 48 kilometers per second at an altitude of 100 kilometers or so, is swept up in this night sky view from the early hours of April 21. Flashing toward the southeastern horizon, the meteor's brilliant streak crosses the central region of the rising Milky Way. Its trail points back toward the shower's radiant in the constellation Lyra, high in the northern springtime sky...

Explanation: Stars can form in colorful surroundings. Featured here is a star forming region rich in glowing gas and dark dust toward the constellation of the Swan (Cygnus), near the bright star Sadr. This region, which spans about 50 light years, is part of the Gamma Cygni nebula which lies about 1,800 light years distant. Toward the right of the image is Barnard 344, a dark and twisted dust cloud rich in cool molecular gas. A dramatic wall of dust and red-glowing hydrogen gas forms a line down the picture center. While the glowing red gas is indicative of small...

Explanation: You can explore asteroid Vesta. Recently, NASA's robotic spaceship Dawn visited Vesta, the second largest object in our Solar System's main asteroid belt, which lies between Mars and Jupiter. During a year-long stopover, Dawn's cameras photographed Vesta's entire surface, documenting all of the minor planet's major mountains and craters. These images have now been combined into a digital model that allows anyone with a full-featured browser to fly all around Vesta, virtually, and even zoom in on interesting surface features, by just dragging and clicking. If desired, the initially flat 2D map can be wrapped into a nearly spherical...

Explanation: Going, going, gone. That was the feeling in Svalbard, Norway last month during a total eclipse of the Sun by the Moon. In the featured image, the eclipse was captured every three minutes and then digitally merged with a foreground frame taken from the same location. Visible in the foreground are numerous gawking eclipse seekers, some deploying pretty sophisticated cameras. As the Moon and Sun moved together across the sky -- nearly horizontally from this far north -- an increasing fraction of the Sun appears covered by the Moon. In the central frame, the Moon's complete blockage of the...

Explanation: How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured on the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741, is known as a ring galaxy and was caused by an immense galaxy collision. When galaxies collide, they pass through each other -- their individual stars rarely come into contact. The ring-like shape is the result of the gravitational disruption caused by an entire small intruder galaxy passing through a large one. When this happens, interstellar gas and...

How long will this country remain free? Probably only as long as the American people value their freedom enough to defend it. But how many people today can stop looking at their electronic devices long enough to even think about such things? Meanwhile, attempts to shut down people whose free speech interferes with other people's political agendas go on, with remarkably little notice, much less outrage. The Internal Revenue Service's targeting the tax-exempt status of conservative groups is just one of these attempts to fight political battles by shutting up the opposition, rather than answering them. Another insidious attempt to...

Explanation: One of the largest young craters on Mercury, 114 kilometer (71 mile) diameter Hokusai crater's bright rays are known to extend across much of the planet. But this mosaic of oblique views focuses on Hokusai close up, its sunlit central peaks, terraced crater walls, and frozen sea of impact melt on the crater's floor. The images were captured by the MESSENGER spacecraft. The first to orbit Mercury, since 2011 MESSENGER has conducted scientific explorations, including extensive imaging of the Solar System's innermost planet. Now running out of propellant and unable to counter orbital perturbations caused by the Sun's gravity,...

Explanation: Galactic or open star clusters are young. These swarms of stars are born together near the plane of the Milky Way, but their numbers steadily dwindle as cluster members are ejected by galactic tides and gravitational interactions. In fact, this bright open cluster, known as M46, is around 300 million years young. It still contains a few hundred stars within a span of 30 light-years or so. Located about 5,000 light-years away toward the constellation Puppis, M46 also seems to contain contradictions to its youthful status. In this pretty starscape, the colorful, circular patch above and right of the...

Dr. Danielle N. Lee, who writes for the Scientific American blog network and calls herself "the Urban Scientist," believes that the push to visit Mars and eventually inhabit it is "white colonialism." Dr. Lee expressed her concerns in both the Scientific American blog and on Twitter. Writing in Scientific American in an article titled, "When discussing Humanity’s next move to space, the language we use matters," Dr. Lee discusses Elon Musk's push to inhabit Mars some day. She is very critical of Musk, saying that his language is not inclusive enough to either women and minorities. "Diversity, Inclusion, Access and...

Explanation: While most spiral galaxies, including our own Milky Way, have two or more spiral arms, NGC 4725 has only one. In this sharp color composite image, the solo spira mirabilis seems to wind from a prominent ring of bluish, newborn star clusters and red tinted star forming regions. The odd galaxy also sports obscuring dust lanes a yellowish central bar structure composed of an older population of stars. NGC 4725 is over 100 thousand light-years across and lies 41 million light-years away in the well-groomed constellation Coma Berenices. Computer simulations of the formation of single spiral arms suggest that...