Galaxy Formation in a Magnetic Universe
How did we get here? We know that we live on a planet orbiting a star orbiting a galaxy, but how did all of this form? To understand details better, astrophysicists upgraded the famous Illustris Simulation into IllustrisTNG -- now the most sophisticated computer model of how galaxies evolved in our universe. Specifically, this featured video tracks magnetic fields from the early universe (redshift 5) until today (redshift 0). Here blue represents relatively weak magnetic fields, while white depicts strong. These B fields are closely matched with galaxies and galaxy clusters. As the simulation begins, a virtual camera circles the virtual IllustrisTNG universe showing a young region -- 30-million light years across -- to be quite filamentary. Gravity causes galaxies to form and merge as the universe expands and evolves. At the end, the simulated IllustrisTNG universe is a good statistical match to our present real universe, although some interesting differences arise -- for example a discrepancy involving the power in radio waves emitted by rapidly moving charged particles. Open Science: Browse 1,600+ codes in the Astrophysics Source Code Library
LL Ori and the Orion Nebula
Stars can make waves in the Orion Nebula's sea of gas and dust. This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. This beautiful painting-like photograph is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.
City lights shine along the upper east side of Manahattan in this dramatic urban night skyscape from February 13. Composed from a series of digital exposures, the monochrome image is reminiscent of the time when sensitive black and white film was a popular choice for dimly lit night and astro-photography. Spanning 2 minutes and 40 seconds, the combined 22 frames look across the reservoir in New York City's Central Park. Stars trail in the time-lapse view while drifting clouds make patterns in the sky. Traced from top to bottom, the dashed line in the surreal scene is the International Space Station still in sunlight and heading for the southeast horizon. The short time intervals between the exposures leave gaps in the space station's bright trail.
Comet PanSTARRS is near the Edge
The comet PanSTARRS also known as the blue comet (C/2016 R2) really is near the lower left edge of this stunning, wide field view recorded on January 13. Spanning nearly 20 degrees on the sky, the cosmic landscape is explored by well-exposed and processed frames from a sensitive digital camera. It consists of colorful clouds and dusty dark nebulae otherwise too faint for your eye to see, though. At top right, the California Nebula (aka NGC 1499) does have a familiar shape. Its coastline is over 60 light-years long and lies some 1,500 light-years away. The nebula's pronounced reddish glow is from hydrogen atoms ionized by luminous blue star Xi Persei just below it. Near bottom center, the famous Pleiades star cluster is some 400 light-years distant and around 15 light-years across. Its spectacular blue color is due to the reflection of starlight by interstellar dust. In between are hot stars of the Perseus OB2 association and dusty, dark nebulae along the edge of the nearby, massive Taurus and Perseus molecular clouds. Emission from unusually abundant ionized carbon monoxide (CO+) molecules fluorescing in sunlight is largely responsible for the telltale blue tint of the remarkable comet's tail. The comet was about 17 light minutes from Earth.
Enceladus in Silhouette
One of our Solar System's most tantalizing worlds, Enceladus is backlit by the Sun in this Cassini spacecraft image from November 1, 2009. The dramatic illumination reveals the plumes that continuously spew into space from the south pole of Saturn's 500 kilometer diameter moon. Discovered by Cassini in 2005, the icy plumes are likely connected to an ocean beneath the ice shell of Enceladus. They supply material directly to Saturn's outer, tenuous E ring and make the surface of Enceladus as reflective as snow. Across the scene, Saturn's icy rings scatter sunlight toward Cassini's cameras. Beyond the rings, the night side of 80 kilometer diameter moon Pandora is faintly lit by Saturnlight.
In the Heart of the Heart Nebula
What's that inside the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. It's shape perhaps fitting of the Valentine's Day, this heart glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all created by a small group of stars near the nebula's center. In the heart of the Heart Nebula are young stars from the open star cluster Melotte 15 that are eroding away several picturesque dust pillars with their energetic light and winds. The open cluster of stars contains a few bright stars nearly 50 times the mass of our Sun, many dim stars only a fraction of the mass of our Sun, and an absent microquasar that was expelled millions of years ago. The Heart Nebula is located about 7,500 light years away toward the constellation of the mythological Queen of Aethiopia (Cassiopeia).
Car Orbiting Earth
Last week, a car orbited the Earth. The car, created by humans and robots on the Earth, was launched by the SpaceX Company to demonstrate the ability of its Falcon Heavy Rocket to place spacecraft out in the Solar System. Purposely fashioned to be whimsical, the iconic car was thought a better demonstration object than concrete blocks. A mannequin clad in a spacesuit -- dubbed the Starman -- sits in the driver's seat. The featured image is a frame from a video taken by one of three cameras mounted on the car. These cameras, connected to the car's battery, are now out of power. The car, attached to a second stage booster, soon left Earth orbit and will orbit the Sun between Earth and the asteroid belt indefinitely -- perhaps until billions of years from now when our Sun expands into a Red Giant. If ever recovered, what's left of the car may become a unique window into technologies developed on Earth in the 20th and early 21st centuries.
Blue Comet Meets Blue Stars
What's that heading for the Pleiades star cluster? It appears to be Comet C/2016 R2 (PanSTARRS), but here, appearances are deceiving. On the right and far in the background, the famous Pleiades star cluster is dominated by blue light from massive young stars. On the left and visiting the inner Solar System is Comet PanSTARRS, a tumbling block of ice from the outer Solar System that currently sports a long ion tail dominated by blue light from an unusually high abundance of ionized carbon monoxide. Comet PanSTARRS is actually moving toward the top of the image, and its ion tail points away from the Sun but is affected by a complex solar wind of particles streaming out from the Sun. Visible through a small telescope, the comet is fading as it recedes from the Earth, even though it reaches its closest point to the Sun in early May.
A Partial Eclipse Over Manila Bay
What's happened to the setting Sun? An eclipse! In early 2009, the Moon eclipsed part of the Sun as visible from parts of Africa, Australia, and Asia. In particular the featured image, taken from the Mall of Asia seawall, caught a partially eclipsed Sun setting over Manila Bay in the Philippines. Piers are visible in silhouette in the foreground. Eclipse chasers and well placed sky enthusiasts captured many other interesting and artistic images of the year's only annular solar eclipse, including movies, eclipse shadow arrays, and rings of fire. On Thursday parts of the Sun again will become briefly blocked by the Moon, again visible to some as a partial eclipse of the Sun. Thursday's eclipse, however, will only be visible from parts of southern South America and Antarctica.
Roadster, Starman, Planet Earth
Don't panic. It's just a spacesuited mannequin named Starman. As the sunlit crescent of planet Earth recedes in the background, Starman is comfortably seated at the wheel of a Tesla Roadster in this final image of the payload launched by a Falcon Heavy rocket on February 6. Internationally designated 2018-017A, roadster and Starman are headed for space beyond the orbit of Mars. The successful Falcon Heavy rocket has now become the most powerful rocket in operation and the roadster one of four electric cars launched from planet Earth. The other three were launched to the Moon by historically more powerful (but not reusable) Saturn V rockets. Still, Starman's roadster is probably the only one that would be considered street legal.