Moon Meets Jupiter
What's that below the Moon? Jupiter -- and its largest moons. Many skygazers across planet Earth enjoyed the close conjunction of Earth's Moon passing nearly in front of Jupiter in mid-June. The featured image is a single exposure of the event taken from Morón de la Frontera, Spain. The sunlit lunar crescent on the left is overexposed, while the Moon's night side, on the right, is only faintly illuminated by Earthshine. Lined up diagonally below the Moon, left to right, are Jupiter's bright Galilean satellites: Callisto, Ganymede, Io (hard to see as it is very near to Jupiter), and Europa. In fact, Callisto, Ganymede, and Io are larger than Earth's Moon, while Europa is only slightly smaller. NASA's robotic spacecraft Juno is currently orbiting Jupiter and made a close pass near Io only a week ago. If you look up in the night sky tonight, you will again see two of the brightest objects angularly close together -- because tonight is another Moon-Jupiter conjunction.
The Pelican Nebula in Gas, Dust, and Stars
The Pelican Nebula is slowly being transformed. IC 5070 (the official designation) is divided from the larger North America Nebula by a molecular cloud filled with dark dust. The Pelican, however, receives much study because it is a particularly active mix of star formation and evolving gas clouds. The featured picture was produced in three specific colors -- light emitted by sulfur, hydrogen, and oxygen -- that can help us to better understand these interactions. The light from young energetic stars is slowly transforming the cold gas to hot gas, with the advancing boundary between the two, known as an ionization front, visible in bright orange on the right. Particularly dense tentacles of cold gas remain. Millions of years from now, the Pelican nebula, bounded by dark nebula LDN 935, might no longer be known as the Pelican, as the balance and placement of stars and gas will surely leave something that appears completely different.
SN 1006: A Supernova Ribbon from Hubble
What created this unusual space ribbon? The answer: one of the most violent explosions ever witnessed by ancient humans. Back in the year 1006 AD, light reached Earth from a stellar explosion in the constellation of the Wolf (Lupus), creating a "guest star" in the sky that appeared brighter than Venus and lasted for over two years. The supernova, now cataloged at SN 1006, occurred about 7,000 light years away and has left a large remnant that continues to expand and fade today. Pictured here is a small part of that expanding supernova remnant dominated by a thin and outwardly moving shock front that heats and ionizes surrounding ambient gas. The supernova remnant SN 1006 now has a diameter of nearly 60 light years.
NGC 1360: The Robin's Egg Nebula
This pretty nebula lies some 1,500 light-years away, its shape and color in this telescopic view reminiscent of a robin's egg. The cosmic cloud spans about 3 light-years, nestled securely within the boundaries of the southern constellation Fornax. Recognized as a planetary nebula, egg-shaped NGC 1360 doesn't represent a beginning though. Instead it corresponds to a brief and final phase in the evolution of an aging star. In fact, visible at the center of the nebula, the central star of NGC 1360 is known to be a binary star system likely consisting of two evolved white dwarf stars, less massive but much hotter than the Sun. Their intense and otherwise invisible ultraviolet radiation has stripped away electrons from the atoms in their mutually surrounding gaseous shroud. The predominant blue-green hue of NGC 1360 seen here is the strong emission produced as electrons recombine with doubly ionized oxygen atoms.
The Falcon and the Redstone
In a photo from the early hours of July 29 (UTC), a Redstone rocket and Mercury capsule are on display at Cape Canaveral Launch Complex 5. Beyond the Redstone, the 8 minute long exposure has captured the arcing launch streak of a SpaceX Falcon Heavy rocket. The Falcon's heavy communications satellite payload, at a record setting 9 metric tons, is bound for geosynchronous orbit some 22,000 miles above planet Earth. The historic launch of a Redstone rocket carried astronaut Alan Shepard on a suborbital spaceflight in May 1961 to an altitude of about 116 miles. Near the top of the frame, this Falcon rocket's two reusable side boosters separate and execute brief entry burns. They returned to land side by side at Canaveral's Landing Zone 1 and 2 in the distance.
M82: Galaxy with a Supergalactic Wind
Why is the Cigar Galaxy billowing red smoke? M82, as this starburst galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas and dust, however. Evidence indicates that this gas and dust is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind. The dust particles are thought to originate in M82's interstellar medium and are actually similar in size to particles in cigar smoke. The featured photographic mosaic highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas and dust. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light and can be seen in visible light with a small telescope towards the constellation of the Great Bear (Ursa Major).
Monster Solar Prominence
The monsters that live on the Sun are not like us. They are larger than the Earth and made of gas hotter than in any teapot. They have no eyes, but at times, many tentacles. They float. Usually, they slowly change shape and just fade back onto the Sun over about a month. Sometimes, though, they suddenly explode and unleash energetic particles into the Solar System that can attack the Earth. Pictured is a huge solar prominence imaged almost two weeks ago in the light of hydrogen. Captured by a small telescope in Gilbert, Arizona, USA, the monsteresque plume of gas was held aloft by the ever-present but ever-changing magnetic field near the surface of the Sun. Our active Sun continues to show an unusually high number of prominences, filaments, sunspots, and large active regions as solar maximum approaches in 2025.
Phobos over Mars
Why is Phobos so dark? Phobos, the largest and innermost of the two Martian moons, is the darkest moon in the entire Solar System. Its unusual orbit and color indicate that it may be a captured asteroid composed of a mixture of ice and dark rock. The featured assigned-color picture of Phobos near the edge of Mars was captured in late 2021 by ESA's robot spacecraft Mars Express, currently orbiting Mars. Phobos is a heavily cratered and barren moon, with its largest crater located on the far side. From images like this, Phobos has been determined to be covered by perhaps a meter of loose dust. Phobos orbits so close to Mars that from some places it would appear to rise and set twice a day, while from other places it would not be visible at all. Phobos' orbit around Mars is continually decaying -- it will likely break up with pieces crashing to the Martian surface in about 50 million years.
Spiral Aurora over Icelandic Divide
Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of a great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization. In 1859, following notable auroras seen all across the globe, a pulse of charged particles from a coronal mass ejection (CME) associated with a solar flare impacted Earth's magnetosphere so forcefully that it created the Carrington Event. This assault from the Sun compressed the Earth's magnetic field so violently that it created high currents and sparks along telegraph wires, shocking many telegraph operators. Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced. The featured aurora was imaged in 2016 over Thingvallavatn Lake in Iceland, a lake that partly fills a fault that divides Earth's large Eurasian and North American tectonic plates.
Apollo 11: Catching Some Sun
Bright sunlight glints as long dark shadows mark this image of the surface of the Moon. It was taken fifty-four years ago, July 20, 1969, by Apollo 11 astronaut Neil Armstrong, the first to walk on the lunar surface. Pictured is the mission's lunar module, the Eagle, and spacesuited lunar module pilot Buzz Aldrin. Aldrin is unfurling a long sheet of foil also known as the Solar Wind Composition Experiment. Exposed facing the Sun, the foil trapped particles streaming outward in the solar wind, catching a sample of material from the Sun itself. Along with moon rocks and lunar soil samples, the solar wind collector was returned for analysis in earthbound laboratories.
Young Stars, Stellar Jets
High-speed outflows of molecular gas from a pair of actively forming young stars shine in infrared light, revealing themselves in this NIRcam image from the James Webb Space Telescope. Cataloged as HH (Herbig-Haro) 46/47, the young stars are lodged within a dark nebula that is largely opaque when viewed in visible light. The pair lie at the center of the prominent reddish diffraction spikes in the NIRcam image. Their energetic stellar jets extend for nearly a light-year, burrowing into the dark interstellar material. A tantalizing object to explore with Webb's infrared capabilities, this young star system is relatively nearby, located only some 1,140 light-years distant in the nautical constellation Vela.
IC 4628: The Prawn Nebula
South of Antares, in the tail of the nebula-rich constellation Scorpius, lies emission nebula IC 4628. Nearby hot, massive stars, millions of years young, irradiate the nebula with invisible ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the visible nebular glow, dominated by the red emission of hydrogen. At an estimated distance of 6,000 light-years, the region shown is about 250 light-years across, spanning over three full moons on the sky. The nebula is also cataloged as Gum 56 for Australian astronomer Colin Stanley Gum, but seafood-loving deep sky-enthusiasts might know this cosmic cloud as the Prawn Nebula. The graceful color image is a new astronomical composition taken over several nights in April from Rio Hurtado, Chile.
The Eagle Nebula with X-ray Hot Stars
What do the famous Eagle Nebula star pillars look like in X-ray light? To find out, NASA's orbiting Chandra X-ray Observatory peered in and through these interstellar mountains of star formation. It was found that in M16 the dust pillars themselves do not emit many X-rays, but a lot of small-but-bright X-ray sources became evident. These sources are shown as bright dots on the featured image which is a composite of exposures from Chandra (X-rays), XMM (X-rays), JWST (infrared), Spitzer (infrared), Hubble (visible), and the VLT (visible). What stars produce these X-rays remains a topic of research, but some are hypothesized to be hot, recently-formed, low-mass stars, while others are thought to be hot, older, high-mass stars. These X-ray hot stars are scattered around the frame -- the previously identified Evaporating Gaseous Globules (EGGS) seen in visible light are not currently hot enough to emit X-rays.
Chemicals Glow as a Meteor Disintegrates
Meteors can be colorful. While the human eye usually cannot discern many colors, cameras often can. Pictured here is a fireball, a disintegrating meteor that was not only one of the brightest the photographer has ever seen, but colorful. The meteor was captured by chance in mid-July with a camera set up on Hochkar Mountain in Austria to photograph the central band of our Milky Way galaxy. The radiant grit, likely cast off by a comet or asteroid long ago, had the misfortune to enter Earth's atmosphere. Colors in meteors usually originate from ionized chemical elements released as the meteor disintegrates, with blue-green typically originating from magnesium, calcium radiating violet, and nickel glowing green. Red, however, typically originates from energized nitrogen and oxygen in the Earth's atmosphere. This bright meteoric fireball was gone in a flash -- less than a second -- but it left a wind-blown ionization trail that remained visible for almost a minute.
The Antikythera Mechanism
It does what? No one knew that 2,000 years ago, the technology existed to build such a device. The Antikythera mechanism, pictured, is now widely regarded as the first computer. Found at the bottom of the sea aboard a decaying Greek ship, its complexity prompted decades of study, and even today some of its functions likely remain unknown. X-ray images of the device, however, have confirmed that a main function of its numerous clock-like wheels and gears is to create a portable, hand-cranked, Earth-centered, orrery of the sky, predicting future star and planet locations as well as lunar and solar eclipses. The corroded core of the Antikythera mechanism's largest gear is featured, spanning about 13 centimeters, while the entire mechanism was 33 centimeters high, making it similar in size to a large book. Recently, modern computer modeling of missing components is allowing for the creation of a more complete replica of this surprising ancient machine.
