Galaxy NGC 474: Shells and Star Streams
Image Credit & License: CFHT, Coelum, MegaCam, J.-C. Cuillandre (CFHT) & G. A. Anselmi (Coelum)

Explanation: What’s happening to galaxy NGC 474? The multiple layers of emission appear strangely complex given the relatively featureless appearance of the elliptical galaxy in less deep images. The cause of the shells is a topic of research, but they are possibly tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years. Alternatively, the shells may be like ripples in a pond, where the ongoing collision with the spiral galaxy just to the right of NGC 474 is causing density waves to ripple through the galactic giant. Regardless of the actual cause, the featured image dramatically highlights the increasing evidence that the halos of some elliptical galaxies are surprisingly complicated. Similarly, the halo of our own Milky Way Galaxy is one example of such unexpected intricacies. NGC 474 spans about 250,000 light years and lies about 100 million light years distant toward the constellation of the Fish (Pisces).

Tomorrow’s picture: aurora below

Messier 24: Sagittarius Star Cloud
Image Credit & Copyright: Chuck Ayoub

Explanation: Unlike most entries in Charles Messier’s famous catalog of deep sky objects, M24 is not a bright galaxy, star cluster, or nebula. It’s a gap in nearby, obscuring interstellar dust clouds that allows a view of the distant stars in the Sagittarius spiral arm of our Milky Way galaxy. Direct your gaze through this gap with binoculars or a small telescope and you are looking through a window over 300 light-years wide at stars some 10,000 light-years or more from Earth. Sometimes called the Small Sagittarius Star Cloud, M24’s luminous stars stretch across this gorgeous interstellar scene. Spanning over four full moons on the sky toward the constellation Sagittarius, the telescopic field of view includes dark markings B92 and B93 near the center of M24, along with other clouds of dust and glowing nebulae toward the center of the Milky Way.

Tomorrow’s picture: shells and streams

Western Moon, Eastern Sea
Image Credit & Copyright: Guy Bardon

Explanation: The Mare Orientale, Latin for Eastern Sea, is one of the most striking large scale lunar features. The youngest of the large lunar impact basins it’s very difficult to see from an earthbound perspective. Still, captured on July 7 during a period of favorable tilt, or libration of the lunar nearside, the Eastern Sea can be found at the upper right in this sharp telescopic view. In the image, the large lunar mare is extremely foreshortened and stretches along the Moon’s western edge. Formed by the impact of an asteroid over 3 billion years ago and nearly 1000 kilometers across, the impact basin’s concentric circular features are ripples in the lunar crust. But they are a little easier to spot in more direct images of the region taken from lunar orbit. So why is the Eastern Sea at the Moon’s western edge? The Mare Orientale lunar feature was named before 1961. That’s when the convention labeling east and west on lunar maps was reversed.

Tomorrow’s picture: light-weekend

The Red Glow of the Cosmic Bat Nebula
Image Credit & Copyright: Humbert Cédric
Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Explanation: This Cosmic Bat wishes you a happy Summerween! This mid-year celebration of Halloween transcends hemispheres, even though summer in the Northern hemisphere is winter in the South. Contrary to its eery aura, the Cosmic Bat Nebula (LDN 43), not to be confused with the Bat Nebula (NGC 6995), is a vibrant birthplace for stars. A bit of young starlight peeks through the dense clouds of gas and dust that make up the Cosmic Bat’s 12 lightyear wingspan. The ultraviolet light from the young stars energizes the nebula’s hydrogen gas, causing it to glow an ominous red. The jet of glowing hydrogen gas emerging from the bat’s head hints at the star formation hidden within.

Tomorrow’s picture: open space

Swift Boost Mission
Image Credit: Katalyst Space
Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

Explanation: Sometimes we can all use a little help from a friend. NASA‘s Neil Gehrels Swift Observatory needs a boost to stay in orbit after almost 22 years of service. This video shows an artist’s visualization of the Swift Boost Mission: The Katalyst‘s LINK spacecraft was launched aboard a Northrop Grumman Pegasus XL rocket on July 3 and it is now en route to rendezvous with Swift and boost it to a higher orbit over the course of the next several months. This type of maneuver has never been attempted before. If successful, it will be the technology demonstration of a new key capability to extended the lifetime of spacecraft in low Earth orbit, whose orbits decay over time. Swift has an array of instruments that observe the most energetic explosions in the Universe in gamma-rays, X-rays and ultraviolet, and the unique ability to repoint in their direction within tens of seconds. Astronomers around the world, and indeed all fans of cosmic explosions, are anxiously hoping for a successful mission!

Tomorrow’s picture: Cosmic bat

NGC 6188: Dragons of Ara
Image Credit & Copyright: Rod Prazeres

Explanation: Where can you find dragons fighting in the night sky? In the southern constellation of the Altar: Ara. The dragons are, of course, actually made of suggestively shaped gas and dust. The celestial home of the mythological battling beasts is cataloged as NGC 6188 and located about 4,000 light years away near the edge of a large molecular cloud. Massive, young stars of the embedded Ara OB1 association were formed there only a few million years ago, sculpting the dark shapes and powering the nebular glow with stellar winds and intense ultraviolet radiation. Joining NGC 6188 on this cosmic canvas, visible toward the lower right, is unusual emission nebula NGC 6164, also created by one of the region’s massive stars. This impressively wide field picture, captured from Queensland, Australia, spans over 2 degrees (four full Moons).

Tomorrow’s picture: open space

Saturn’s Iapetus: Painted Moon
Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

Explanation: What has happened to Saturn’s moon Iapetus? Vast sections of this strange world are dark as coal, while others are as bright as snow. To help better understand this unusually tinted moon, in 2007 NASA directed the robotic Cassini spacecraft then orbiting Saturn to swoop within 2,000 kilometers. Pictured here, from about 75,000 kilometers out, is the hemisphere of Iapetus that is always trailing. A large impact crater seen in the south spans 500 kilometers and appears superposed on an older crater of similar size. The dark material is seen increasingly coating the easternmost part of Iapetus, darkening craters and highlands alike. A leading hypothesis is that the dark material is mostly a form of carbon-rich soil leftover from when relatively warm but dirty ice sublimates. An initial coating of this dark material may have been effectively painted on by the accretion of meteor-liberated debris from other moons.

Tomorrow’s picture: dueling space bands

Three Galaxies in Pavo
Image Credit & Copyright: Mike Selby

Explanation: Some 190 million light-years away, far beyond the bright stars and nebulae of the Milky Way, these three galaxies are drawn together by gravity in a mesmerizing cosmic dance. Clearly distorted by galactic-scale gravitational interactions, large spiral galaxies NGC6769 and NGC6770 are seen face-on, with luminous galactic disks scarred by obscuring interstellar dust lanes. Their young blue star clusters along drawn out spiral arms are spawned in star forming regions that result from collisions of massive molecular clouds. Below, spiral NGC6771 presents a more edge-on perspective, its boxy central bulge due to tidal star streams. Of course, in the distant future a merger of the three galaxies is inevitable. At the estimated distance of this galaxy trio, known to some as the Devil’s Mask, the sharp telescopic frame spans over 300 thousand light-years within the boundaries of the far southern constellation Pavo.

Tomorrow’s picture: beach balls from Earth

The Cotton Candy Clouds of Rho Ophiuchi
Image Credit & Copyright: Ángel Molina
Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Explanation: Although they look like cotton candy, you cannot eat these clouds! Taken in Cádiz, Spain, today’s image features the Rho Ophiuchi complex, a rich tapestry of young and old astronomical phenomena. This colorful cloud complex is a nearby star-forming region containing hundreds of young stellar objects, including protostars and T Tauri stars. Light from the triple star system at its center reflects off of small dust grains to create the blue reflection nebula. Ultraviolet light from hot stars ionizes the surrounding hydrogen gas, creating the red emission nebula. Antares, a red supergiant big enough to engulf the Solar System’s asteroid belt, lights up the yellow region. Dark interstellar dust blocks some of the complex’s color. Recent JWST observations exhibit shadows cast by hidden circumstellar disks, the beginning stages of planet formation. Messier 4, a globular cluster almost as old as the universe, sits in the bottom right and witnesses yet another chaotic burst of youth in the Milky Way.

Tomorrow’s picture: pixels in space

Unusually Smooth Sections of Asteroid Itokawa
Image Credit: JAXA, ISAS

Explanation: Why are parts of this asteroid’s surface so smooth? The answer seems likely to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid Itokawa was visited by the Japanese spacecraft Hayabusa in 2005 which imaged and documented its unusual structure and mysterious lack of craters. Analyses of the border regions between smooth and rugged sections indicate that jostling of the asteroid might be creating segregation between large and small rocks near the surface, like the Brazil nut effect. The robotic Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples. These samples were returned to Earth and are not only giving clues to the ancient history of this unusual asteroid, but also about the early years of our entire Solar System. Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years.

Tomorrow’s picture: open space