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Explanation: What's happened to the center of this galaxy? Dramatic dust lanes run across the center of unusual elliptical galaxy Centaurus A. These dust lanes are so thick they almost completely obscure the galaxy's center in visible light. This is particularly unusual as Cen A's older stars and oval shape are characteristic of a giant elliptical galaxy, a galaxy type typically low in dark dust. Pictured in this deep image is a complex network of foreground gas and dust, as well as shells of dim stars and a jet projecting to the upper right. Also known as NGC 5128, Cen...

Explanation: What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of an upgrade to the Arecibo Observatory - then the largest single radio telescope in the world - a string of 1's and 0's representing the diagram was sent. This attempt at extraterrestrial communication was mostly ceremonial - humanity regularly broadcasts radio and television signals out into space accidentally. Even were this message received, M13 is so far away we would have to wait almost 50,000 years to hear an answer. The featured...

Explanation: Robert H. Goddard, considered the father of modern rocketry, was born in Worcester Massachusetts in 1882. As a 16 year old, Goddard read H.G. Wells' science fiction classic "War Of The Worlds" and dreamed of space flight. By 1926 he had designed, built, and flown the world's first liquid fuel rocket. Launched 100 years ago on March 16, 1926 from his aunt Effie's farm in Auburn Massachusetts, the rocket, dubbed "Nell," rose to an altitude of 41 feet in a flight that lasted about 2 1/2 seconds. In this posed photo, Goddard stands next to the 10 foot tall...

Explanation: Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups. The four prominent galaxies seen in this intriguing telescopic skyscape are one such group, Hickson 44. The Hickson 44 galaxy group is about 100 million light-years distant, far beyond the foreground Milky Way stars, toward the northern springtime constellation Leo. The two spiral galaxies in the center of the image are edge-on NGC 3190 with distinctive, warped dust lanes, and S-shaped NGC 3187. Along with the bright elliptical, NGC 3193 (left) they are also known...

Explanation: In the words of today's astrophotographer, Rositsa Dimitrova, "What have these silent sentinels watched pass across the sky?" The volcanic mo'ai (meaning statue) of Ahu Tongariki stand guard over Rapa Nui (Isla de Pascua, Easter Island), a Polynesian island (annexed by Chile in 1888) located thousands of kilometers off the coast of South America in the Pacific Ocean. Due to the island's remoteness, the mo'ai, with their backs to the dark ocean, are able to gaze upon a clear and vibrant night sky. Pictured, these larger-than-life statues stare at the bright band of the Milky Way, partly obscured by...

Explanation: Is gravity the same over the surface of the Earth? No -- in some places you will feel slightly heavier than others. The featured Earth map video shows in colors and exaggerated highs and lows where the gravitational field of Earth is relatively strong and weak. A low spot, where you would feel slightly lighter, can be seen just off the coast of India, in blue, while a relative high occurs in the mountains of Chile in South America. The cause of these irregularities does not always follow present surface features. Scientists hypothesize that other important factors lie in...

Explanation: What's happening at the end of that street? Pictured here are not auroras but light pillars, a phenomenon typically much closer. In most places on Earth, a lucky viewer can see a Sun pillar, a column of light appearing to extend up from the Sun caused by flat fluttering ice-crystals reflecting sunlight from the upper atmosphere. Usually, these ice crystals evaporate before reaching the ground. During freezing temperatures, however, flat fluttering ice crystals may form near the ground and are sometimes known as a crystal fog. These small ice crystals may then reflect not the Sun but ground lights....

Explanation: What would it look like to leave planet Earth? Such an event was recorded visually in great detail by the MESSENGER spacecraft as it swung back past the Earth in 2005 on its way in toward the planet Mercury. Earth can be seen rotating in this time-lapse video, as it recedes into the distance. The sunlit half of Earth is so bright that background stars are not visible. The robotic MESSENGER spacecraft orbit around Mercury from 2011 to 2015 has conducted the first complete map of the surface. On occasion, MESSENGER peered back at its home world. MESSENGER is...

Explanation: Spiral NGC 1300 and elliptical NGC 1297 are galaxies that lie on the banks of the southern constellation Eridanus (The River). At 70 million light-years distant or more, both are members of the Eridanus Galaxy Cluster. About 100,000 light-years across, at lower left in this sharp, galaxy group photo NGC 1300 is seen face-on with a prominent central bar and grand, sweeping spiral arms. Like other spiral galaxies, including our own barred spiral Milky Way Galaxy, NGC 1300 is thought to have a supermassive central black hole. A contrast in appearance and slightly more distant, NGC 1297 is the...

Explanation: The defining astronomical moment of the equinox today is at 14:46 UTC (March 20). That's when the Sun crosses the celestial equator moving north in its yearly journey through planet Earth's sky, marking the beginning of spring for our fair planet in the northern hemisphere and fall in the southern hemisphere. Then, day and night are nearly equal around the globe. In fact, both day and nighttime exposures from a spring equinox at the Observatorio del Teide in Tenerife, Canary Islands, Spain, are used in this composited skyscape. Over 1,000 images were taken with a fisheye lens and merged...

Explanation: Even if you live with your head in the clouds, you won’t find a jellyfish like this one very often. The featured image shows a SpaceX Falcon 9 rocket launch from Cape Canaveral in Florida on March 4. The launch happened 52 minutes before sunrise, and the second stage rocket exhaust plume was high enough in the sky to catch the light of the rising sun, while the photographer was still in the dark. This combination of light and shadow, possible at dawn or dusk, makes the exhaust, mostly water vapor and carbon dioxide, appear as a glowing cloud....

Explanation: A lone tree stands in a quiet meadow in Guadalajara, Spain, silhouetted against the Cygnus region rising above like flames in the night sky. This deep night skyscape is a composite of exposures that reveals a range of brightness and color human eyes can't quite see on their own. Spanning over a thousand times the angular size of the full moon, Cygnus sets the sky afire with active star formation where clouds of gas and dust collapse under gravity until nuclear fusion ignites and new stars are born. These stars ionize the surrounding hydrogen gas, causing it to glow...

Explanation: This telescopic close-up shows off the central regions of otherwise faint emission nebula IC 410, captured under backyard skies. Presented in a Hubble color palette, the image combines visible broadband and narrowband data with data from the near-infrared. Below and right of center are two remarkable inhabitants of the interstellar pond of gas and dust. the Tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. But...

Explanation: If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe containing billions of stars and situated about 40 million light-years away toward the constellation of the Dolphinfish (Dorado), NGC 1566 presents a gorgeous face-on view. Classified as a grand design spiral, NGC 1566 shows two prominent and graceful spiral arms that are traced by bright blue star clusters, red emission nebulas, and dark cosmic dust lanes. Numerous Hubble Space Telescope images of NGC 1566 have been taken to study star formation, supernovas, and the spiral's unusually active center. NGC 1566's flaring...

Explanation: To see the feathered serpent descend the Mayan pyramid requires exquisite timing. You must visit El Castillo -- in Mexico's Yucatán Peninsula -- near an equinox. Then, during the late afternoon if the sky is clear, the pyramid's own shadows create triangles that merge into the famous illusion of a slithering viper. Also known as the Temple of Kukulkan, the impressive step-pyramid stands 30 meters tall and 55 meters wide at the base. Built up as a series of square terraces by the pre-Columbian civilization between the 9th and 12th century, the structure can be used as a calendar...

Explanation: Want to visit a planet that has 3.14 days in a year? Then plan a trip to K2-315b, an earth-sized planet orbiting around a cool, red, M dwarf star about once every 3.14 days. The exoplanet's discovery, based on publicly available data from the planet-hunting Kepler Space Telescope's extended K2 mission, was announced in 2020. K2-315b's measured orbital period in days is nearly equal to the extremely popular irrational number Pi. That puts the exoplanet so close to its parent star that its surface is likely very warm, baking-hot in fact. And this Pi planet is over 185 light-years...

Explanation: In this composited night skyscape, stacked exposures trace graceful star trails above Lake Toolondo, Victoria, Australia, planet Earth. Captured while the lunar eclipse of March 3 was in progress, the exposures used were made during the hour-long total eclipse phase. So faint star trails are easily visible along with the trail of the reddened Moon in the eclipse-darkened skies above the lake and trees. Of course, the apparent motion of Moon and stars revealed in the timelapse composite reflect the Earth's daily rotation around its axis. Dramatically punctuating the Moon's trail as totality ended, a single, separate telephoto image...

Explanation: For the first time we are witnessing outer planet Uranus take center stage and pirouette. Uranus is one of the Solar System’s strangest planets, lying on its side and spinning like a rotisserie chicken. The featured video is composed of over 1000 spectra taken over 15 hours of continuous viewing by JWST's NIRSpec instrument while Uranus rotates. The data captures the behavior of Uranus’s ionosphere: the ionized layer of a planet’s atmosphere that strongly interacts with the planet's magnetic field. The aurora’s rosy glow traces the complex interplay between Uranus's misaligned rotation and magnetic axes. Clouds can be seen...

Explanation: Is this a cosmic monster ready to devour an unsuspecting galaxy? Thankfully, that is not the case. The red “monster” shown in the featured image is Cometary Globule CG 4, 1,300 light-years away in the Constellation Puppis. CG 4 is a molecular cloud, where hydrogen becomes cold enough to form molecules that can be brought together by gravity to create stars. The shape of CG 4 resembles that of a comet, but its head is 1.5 light-year in diameter and its tail is 8 light-years long; for comparison, the distance from the Earth to the sun is only 8...

Explanation: Are lasers from giant telescopes being used to defend the Earth? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some directions, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but in other directions, no bright star exists. In these directions, astronomers can create an artificial star with a laser. Subsequent observations of the artificial laser guide star can reveal information so detailed about the changing blurring effects of the Earth's atmosphere that much of it can be removed by rapidly flexing...