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 Thebe, along with their shadows, can also be found in the sharp Hubble view. The Galilean moons have diameters of 3,000 to 5,000 kilometers or so, comparable in size to Earth’s moon. But odd-shaped Amalthea and Thebe are only about 260 and 100 kilometers across respectively.

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The striking spiral galaxy M104 is famous for its nearly edge-on profile featuring a broad ring of obscuring dust lanes. Seen in silhouette against an extensive bulge of stars, the swath of cosmic dust lends a broad brimmed hat-like appearance to the galaxy suggesting the more popular moniker, The Sombrero Galaxy. Hubble Space Telescope and ground-based Subaru data have been reprocessed with amateur color image data to create this sharp view of the well-known galaxy. The processing results in a natural color appearance and preserves details often lost in overwhelming glare of M104’s bright central bulge when viewed with smaller ground-based instruments. Also known as NGC 4594, the Sombrero galaxy can be seen across the spectrum and is thought to host a central supermassive black hole. About 50,000 light-years across and 28 million light-years away, M104 is one of the largest galaxies at the southern edge of the Virgo Galaxy Cluster.

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What are those red streaks in the sky? While photographing unexpected auroras over a distant thunderstorm, something extraordinary happened: red sprites. This brief instance of rarely imaged high-altitude lightning flashed so bright that it was witnessed by several people independently. Pictured over Minnesota, USA in May 2013, these red sprites likely followed an extremely powerful low-altitude conventional lightning bolt. Captured in the featured frame are a house and electrical pole in the foreground, thick clouds in the lower atmosphere, a lightning storm on the horizon, distant red sprites and green aurora in the upper atmosphere, and distant stars from our local neighborhood of the Milky Way Galaxy. The spectacular image is thought to be only the second known case of sprites and auroras photographed together, and possibly the first in true color.

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Where do comet tails come from? Although it is common knowledge that comet tails and comas originate from comet nuclei, exactly how that happens is an active topic of research. One of the best images yet of emerging jets is shown in the featured image, taken last November by the robotic Rosetta spacecraft in orbit around the Comet 67P/Churyumov-Gerasimenko (Comet CG), and released last month. The overexposed picture shows plumes of gas and dust escaping numerous places from the Comet CG’s nucleus as it nears the Sun and heats up. Although Comet CG is currently further out from the Sun than Mars, its orbit will take it almost as close as the Earth this coming August, at which time its jet activity is expected to increase by a factor of about 100. You’ve likely seen some debris from comet nuclei before but in another form — when sand-sized bits end their journey through the Solar System by impacting the atmosphere of Earth as meteors.

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Why would the surface of Titan light up with a blinding flash? The reason: a sunglint from liquid seas. Saturn’s moon Titan has numerous smooth lakes of methane that, when the angle is right, reflect sunlight as if they were mirrors. Pictured here in false-color, the robotic Cassini spacecraft orbiting Saturn imaged the cloud-covered Titan last summer in different bands of cloud-piercing infrared light. This specular reflection was so bright it saturated one of Cassini’s infrared cameras. Although the sunglint was annoying — it was also useful. The reflecting regions confirm that northern Titan houses a wide and complex array of seas with a geometry that indicates periods of significant evaporation. During its numerous passes of our Solar System’s most mysterious moon, Cassini has revealed Titan to be a world with active weather — including times when it rains a liquefied version of natural gas.

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These two mighty galaxies are pulling each other apart. Known as the “Mice” because they have such long tails, each spiral galaxy has likely already passed through the other. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy. Because the distances are so large, the cosmic interaction takes place in slow motion — over hundreds of millions of years. NGC 4676 lies about 300 million light-years away toward the constellation of Bernice’s Hair (Coma Berenices) and are likely members of the Coma Cluster of Galaxies. The above picture was taken with the Hubble Space Telescope‘s Advanced Camera for Surveys in 2002. These galactic mice will probably collide again and again over the next billion years until they coalesce to form a single galaxy.

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Infrared wavelengths of 3.6, 8.0, and 24.0 microns observed by the Spitzer Space Telescope are mapped into visible colors red, green, and blue in this striking image. The cosmic cloud of gas and dust is W33, a massive starforming complex some 13,000 light-years distant, near the plane of our Milky Way Galaxy. So what are all those yellow balls? Citizen scientists of the web-based Milky Way Project found the features they called yellow balls as they scanned many Spitzer images and persistently asked that question of researchers. Now there is an answer. The yellow balls in Spitzer images are identified as an early stage of massive star formation. They appear yellow because they are overlapping regions of red and green, the assigned colors that correspond to dust and organic molecules known as PAHs at Spitzer wavelengths. Yellow balls represent the stage before newborn massive stars clear out cavities in their surrounding gas and dust and appear as green-rimmed bubbles with red centers in the Spitzer image. Of course, the astronomical crowdsourcing success story is only part of the Zooniverse. The Spitzer image spans 0.5 degrees or about 100 light-years at the estimated distance of W33.

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