Is there an ocean below Sputnik Planum on Pluto? The unusually smooth 1000-km wide golden expanse, visible in the featured image from New Horizons, appears segmented into convection cells. But how was this region created? One hypothesis now holds the answer to be a great impact that stirred up an underground ocean of salt water roughly 100-kilometers thick. The featured image of Sputnik Planum, part of the larger heart-shaped Tombaugh Regio, was taken last July and shows true details in exaggerated colors. Although the robotic New Horizons spacecraft is off on a new adventure, continued computer-modeling of this surprising surface feature on Pluto is likely to lead to more refined speculations about what lies beneath. via NASA

A nova in Sagittarius is bright enough to see with binoculars. Detected last month, the stellar explosion even approached the limit of naked-eye visibility last week. A classical nova results from a thermonuclear explosion on the surface of a white dwarf star — a dense star having the size of our Earth but the mass of our Sun. In the featured image, the nova was captured last week above ancient Wat Mahathat in Sukhothai, Thailand. To see Nova Sagittarius 2016 yourself, just go out just after sunset and locate near the western horizon the constellation of the Archer (Sagittarius), popularly identified with an iconic teapot. Also visible near the nova is the very bright planet Venus. Don’t delay, though, because not only is the nova fading, but that part of the sky is setting continually closer to sunset. via NASA

How much mass do flocculent spirals hide? The featured true color image of flocculent spiral galaxy NGC 4414 was taken with the Hubble Space Telescope to help answer this question. The featured image was augmented with data from the Sloan Digital Sky Survey (SDSS). Flocculent spirals — galaxies without well-defined spiral arms — are a quite common form of galaxy, and NGC 4414 is one of the closest. Stars and gas near the visible edge of spiral galaxies orbit the center so fast that the gravity from a large amount of unseen dark matter must be present to hold them together. Understanding the matter and dark matter distribution of NGC 4414 helps humanity calibrate the rest of the galaxy and, by deduction, flocculent spirals in general. Further, calibrating the distance to NGC 4414 helps humanity calibrate the cosmological distance scale of the entire visible universe. via NASA

Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the featured image on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible here in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focused on how massive stars form and how they affect their environment. via NASA

Why is it so warm in northern North America? Usually during this time of year — mid-November — temperatures average as much as 30 degrees colder. Europe is not seeing a similar warming. One factor appears to be an unusually large and stable high pressure region that has formed over Canada, keeping normally colder arctic air away. Although the fundamental cause of any weather pattern is typically complex, speculation holds that this persistent Canadian anticyclonic region is related to warmer than average sea surface temperatures in the mid-Pacific — an El Niño — operating last winter. North Americans should enjoy it while it lasts, though. In the next week or two, cooler-than-average temperatures now being recorded in the mid-Pacific — a La Niña — might well begin to affect North American wind and temperature patterns. via NASA

What is so super about tomorrow’s supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon’s fully illuminated phase occurs within a short time from perigee – when the Moon is its closest to the Earth in its elliptical orbit. Although the precise conditions that define a supermoon vary, tomorrow’s supermoon will undoubtedly qualify because it will be the closest, largest, and brightest full moon in over 65 years. One reason supermoons are popular is because they are so easy to see — just go outside at sunset and watch an impressive full moon rise! Since perigee actually occurs tomorrow morning, tonight’s full moon, visible starting at sunset, should also be impressive. Pictured here, a supermoon from 2012 is compared to a micromoon — when a full Moon occurs near the furthest part of the Moon’s orbit — so that it appears smaller and dimmer than usual. Given many definitions, at least one supermoon occurs each year, with another one coming next month (moon-th). However, a full moon will not come this close to Earth again until 2034. via NASA

How could that city be upside-down? The city, Chicago, was actually perfectly right-side up. The long shadows it projected onto nearby Lake Michigan near sunset, however, when seen in reflection, made the buildings appear inverted. This fascinating, puzzling, yet beautiful image was captured by a photographer in 2014 on an airplane on approach to Chicago’s O’Hare International Airport. The Sun can be seen both above and below the cloud deck, with the latter reflected in the calm lake. As a bonus, if you look really closely — and this is quite a challenge — you can find another airplane in the image, likely also on approach to the same airport. via NASA

A mere 20,000 light-years from the Sun lies NGC 3603, a resident of the nearby Carina spiral arm of our Milky Way Galaxy. NGC 3603 is well known to astronomers as one of the Milky Way’s largest star-forming regions. The central open star cluster contains thousands of stars more massive than our Sun, stars that likely formed only one or two million years ago in a single burst of star formation. In fact, nearby NGC 3603 is thought to contain a convenient example of the massive star clusters that populate much more distant starburst galaxies. Surrounding the cluster are natal clouds of glowing interstellar gas and obscuring dust, sculpted by energetic stellar radiation and winds. Recorded by the Hubble Space Telescope, the image spans about 17 light-years. via NASA

Look through the cosmic cloud cataloged as NGC 281 and you might miss the stars of open cluster IC 1590. Still, formed within the nebula that cluster’s young, massive stars ultimately power the pervasive nebular glow. The eye-catching shapes looming in this portrait of NGC 281 are sculpted columns and dense dust globules seen in silhouette, eroded by intense, energetic winds and radiation from the hot cluster stars. If they survive long enough, the dusty structures could also be sites of future star formation. Playfully called the Pacman Nebula because of its overall shape, NGC 281 is about 10,000 light-years away in the constellation Cassiopeia. This sharp composite image was made through narrow-band filters, combining emission from the nebula’s hydrogen, sulfur, and oxygen atoms in green, red, and blue hues. It spans over 80 light-years at the estimated distance of NGC 281. via NASA

Is only one black hole spewing high energy radiation — or two? To help find out, astronomers trained NASA’s Earth-orbiting NuSTAR and Chandra telescopes on Arp 299, the enigmatic colliding galaxies expelling the radiation. The two galaxies of Arp 299 have been locked in a gravitational combat for millions of years, while their central black holes will soon do battle themselves. Featured, the high-resolution visible-light image was taken by Hubble, while the superposed diffuse glow of X-ray light was imaged by NuSTAR and shown in false-color red, green, and blue. NuSTAR observations show that only one of the central black holes is seen fighting its way through a region of gas and dust — and so absorbing matter and emitting X-rays. The energetic radiation, coming only from the galaxy center on the right, is surely created nearby — but outside — the central black hole’s event horizon. In a billion years or so, only one composite galaxy will remain, and only one central supermassive black hole. Soon thereafter, though, another galaxy may enter the fray. via NASA