Astronomy Picture of the Day

🌌Zeta Oph: Runaway Star Like a ship plowing through cosmic seas, runaway star Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the left at 24 kilometers per second. Its strong stellar wind precedes ...

🌌Apollo 14 Heads for Home When leaving lunar orbit in February 1971, the crew of Apollo 14 watched this Earthrise from their command module Kittyhawk. With Earth's sunlit crescent just peaking over the lunar horizon, the cratered terrain in the foreground is along the lunar farside. Of course, while orbiting the Moon, the crew could watch Earth rise and set, but the Earth hung stationary in the ...

🌌Goldilocks Zones and Stars The Goldilocks zone is the habitable zone around a star where it's not too hot and not too cold for liquid water to exist on the surface of orbiting planets. This intriguing infographic includes relative sizes of those zones for yellow G stars like the Sun, along with orange K dwarf stars and red M dwarf stars, both cooler and fainter than the Sun. M stars (top) have ...

🌌Two Clusters and a Comet This lovely starfield spans some four full moons (about 2 degrees) across the heroic northern constellation of Perseus. In telescopic exposures made during the nights of January 24, 26, and 28 it holds the famous pair of open or galactic star clusters h and Chi Persei with comet PanSTARRS (C/2017 T2) captured each night as it swept left to right across the field of view ...

🌌Milky Way over Yellowstone The Milky Way was not created by an evaporating lake. The pool of vivid blue water, about 10 meters across, is known as Silex Spring and is located in Yellowstone National Park in Wyoming, USA. Steam rises off the spring, heated by a magma chamber deep underneath known as the Yellowstone hotspot. The steam blurs the image of Venus, making it seem unusually large. Unre ...

© Francesco Antonucci

🌌Star Formation in the Tadpole Nebula What's all of the commotion in the Tadpole Nebula? Star formation. Dusty emission in the Tadpole Nebula, IC 410, lies about 12,000 light-years away in the northern constellation of the Charioteer (Auriga). The cloud of glowing gas is over 100 light-years across, sculpted by stellar winds and radiation from embedded open star cluster NGC 1893. Formed in the ...

🌌Comet CG Evaporates Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets is shown in the featured picture, taken in 2015 by ESA's robotic Rosetta spacecraft that orbited Comet 67P/Churyumov-Gerasimenko (Comet CG) from 2014 to 2016. The picture shows plumes of gas and du ...

🌌Hills, Ridges, and Tracks on Mars Sometimes, even rovers on Mars stop to admire the scenery. Just late last November the Curiosity rover on Mars paused to photograph its impressive surroundings. One thing to admire, straight ahead, was Central Butte, an unusual flat hill studied by Curiosity just a few days before this image was taken. To its right was distant Mount Sharp, the five-kilometer ce ...

🌌Rubin's Galaxy In this Hubble Space Telescope image the bright, spiky stars lie in the foreground toward the heroic northern constellation Perseus and well within our own Milky Way galaxy. In sharp focus beyond is UGC 2885, a giant spiral galaxy about 232 million light-years distant. Some 800,000 light-years across compared to the Milky Way's diameter of 100,000 light-years or so, it has around ...

© Laszlo Francsics

🌌Into the Shadow On January 21, 2019 moonwatchers on planet Earth saw a total lunar eclipse. In 35 frames this composite image follows the Moon that night as it crossed into Earth's dark umbral shadow. Taken 3 minutes apart, they almost melt together in a continuous screen that captures the dark colors within the shadow itself and the northern curve of the shadow's edge. Sunlight scattered by t ...

© Jose Joaquin Perez

🌌Globular Star Cluster NGC 6752 Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri and 47 Tucanae as the third brightest globular in planet Earth's night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter ...

© Jose Mtanous

🌌The Hyades Star Cluster It is the closest cluster of stars to the Sun. The Hyades open cluster is bright enough to have been remarked on even thousands of years ago, yet is not as bright or compact as the nearby Pleiades (M45) star cluster. Pictured here is a particularly deep image of the Hyades which has brings out vivid star colors and faint coincidental nebulas. The brightest star in the f ...

🌌Parker: Sounds of the Solar Wind What does the solar wind sound like? A wind of fast moving particles blows out from our Sun, and although space transmits sound poorly, particle impact and variable-field data from NASA's near-Sun Parker Solar Probe is being translated into sound. The disarming audio track of the featured video recounts several of these reverberations, including spooky-sounding ...

© Petr Horálek

🌌Quadrantid Meteors through Orion Why are these meteor trails nearly parallel? Because they were all shed by the same space rock and so can be traced back to the same direction on the sky: the radiant of the Quadrantid Meteor Shower. This direction used to be toward the old constellation of Quadrans Muralis, hence the name Quadrantids, but when the International Astronomical Union formulated it ...

🌌M1: The Incredible Expanding Crab Nebula Are your eyes good enough to see the Crab Nebula expand? The Crab Nebula is cataloged as M1, the first on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, an expanding cloud of debris from the explosion of a massive star. The violent birth of the Crab was witnessed by astronomers in ...

© Gyorgy Soponyai

🌌An Almost Eclipse of the Moon This composited series of images follows the Moon on January 10, the first Full Moon of 2020, in Hungarian skies. The lunar disk is in mid-eclipse at the center of the sequence though. It looks only slightly darker there as it passes through the light outer shadow or penumbra of planet Earth. In fact during this penumbral lunar eclipse the Moon almost crossed into ...

🌌Apollo 17: A Stereo View from Lunar Orbit Get out your red/blue glasses and check out this awesome stereo view of another world. The scene was recorded by Apollo 17 mission commander Eugene Cernan on December 11, 1972, one orbit before descending to land on the Moon. The stereo anaglyph was assembled from two photographs (AS17-147-22465, AS17-147-22466) captured from his vantage point on board ...

© Eric Benson

🌌NGC 247 and Friends About 70,000 light-years across, NGC 247 is a spiral galaxy smaller than our Milky Way. Measured to be only 11 million light-years distant it is nearby though. Tilted nearly edge-on as seen from our perspective, it dominates this telescopic field of view toward the southern constellation Cetus. The pronounced void on one side of the galaxy's disk recalls for some its popular ...

© Goran Strand

🌌Iridescent Clouds over Sweden Why would these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly or even a whole spectrum of colors simultaneously. These polar stratospheric clouds clouds, also known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size. When the Sun is in the right ...

🌌Evidence of an Active Volcano on Venus Are volcanoes still active on Venus? More volcanoes are known on Venus than Earth, but when Venusian volcanoes last erupted is not directly known. Evidence bolstering very recent volcanism on Venus has recently been uncovered, though, right here on Earth. Lab results showed that images of surface lava would become dim in the infrared in only months in the ...

© Maxime Daviron

🌌A Desert Eclipse A good place to see a ring-of-fire eclipse, it seemed, would be from a desert. In a desert, there should be relatively few obscuring clouds and trees. Therefore late last December a group of photographers traveled to the United Arab Emirates and Rub al-Khali, the largest continuous sand desert in world, to capture clear images of an unusual eclipse that would be passing over. ...

© CHART32 Team

🌌Stars and Dust in Corona Australis Cosmic dust clouds and young, energetic stars inhabit this telescopic vista, less than 500 light-years away toward the northern boundary of Corona Australis, the Southern Crown. The dust clouds effectively block light from more distant background stars in the Milky Way. But the striking complex of reflection nebulae cataloged as NGC 6726, 6727, and IC 4812 pro ...

🌌NGC 602 and Beyond Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region, augmented by images in the X-ray by Chandra, and in the infrared by Spitzer. Fantastic ridges and swept back shapes strong ...

© Clear Skies

🌌Nacreous Clouds over Sweden Vivid and lustrous, wafting iridescent waves of color filled this mountain and skyscape near Tanndalen, Sweden on January 3. Known as nacreous clouds or mother-of-pearl clouds, they are rare. This northern winter season they have been making unforgettable appearances at high latitudes, though. A type of polar stratospheric cloud, they form when unusually cold tempera ...

© Ian Griffin

🌌Perihelion to Aphelion Perihelion for 2020, the point in Earth's elliptical orbit when it is closest to the Sun, occurred on January 5th. The distance from the Sun doesn't determine the seasons, though. Those are governed by the tilt of Earth's axis of rotation, so January is still winter in the north and summer in southern hemisphere. But it does mean that on January 5 the Sun was at its large ...

© Star Shadows Remote Observatory

🌌Galaxies in the River Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Locat ...