Meteors over Inner Mongolia
Did you ever get caught in a meteor shower? If yes, then every minute or so the sky sparked with fleeting flashes of light. This was the fate of the pictured astrophotographer during last year's Perseids meteor shower. During the featured three-hour image composite, about 90 Perseids rained down above Lake Duolun of Inner Mongolia, China. If you trace back the meteor streaks, you will find that most of them appear to radiate from a single constellation -- in this case Perseus. In fact, you can even tell which meteors are not Perseids because they track differently. Tonight promises to be another good night to get caught in a meteor shower because it is the peak for the Geminids. Gemini, the shower radiant, should rise shortly after sunset and be visible most of the night. Free APOD Lectures: January 5 in NYC & January 9 in DC
Highlights of the Winter Sky
What's up in the sky this winter? The featured graphic gives a few highlights for Earth's northern hemisphere. Viewed as a clock face centered at the bottom, early winter sky events fan out toward the left, while late winter events are projected toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center -- although almost everything pictured can be seen without a telescope. Highlights of this winter's sky include the Geminids meteor shower peaking this week, the constellation of Orion becoming notable in the evening sky, and many planets being visible before sunrise in February. As true in every season, the International Space Station (ISS) can be sometimes be found drifting across your sky if you know just when and where to look.
Mercury Visualized from MESSENGER
What would it be like to fly over the planet Mercury? Images and data taken from NASA's robotic MESSENGER spacecraft that orbited Mercury from 2011 to 2015 have been digitally combined to envision a virtual flight that highlights much of the hot planet's surface. In general, the Solar System's innermost world appears similar to Earth's Moon as it is covered by a heavily cratered gray terrain. MESSENGER discovered much about Mercury including that shadows near its poles likely host water ice. The featured video opens as Mercury is viewed from the Sun-facing side and concludes with the virtual spacecraft retreating into Mercury's night. Mercury actually rotates so slowly that it only completes three rotations for every two trips around the Sun. In 2018, Europe and Japan plan to launch BepiColombo to better map Mercury's surface and probe its magnetic field. Free Download: The 2018 APOD Calendar
In Green Company: Aurora over Norway
Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display. Arms went high in the air, patience and experience paid off, and the creative featured image was captured as a composite from three separate exposures. The setting is a summit of the Austnesfjorden fjord close to the town of Svolvear on the Lofoten islands in northern Norway. The time was early 2014. Although our Sun is nearing Solar Minimum and hence showing relatively little surface activity, holes in the upper corona have provided some nice auroral displays over the last few months. Follow APOD on: Facebook, Google Plus, Instagram, Twitter or Snapchat
Stardust in Aries
This composition in stardust covers over 8 degrees on the northern sky. The mosaicked field of view is west of the familiar Pleiades star cluster, toward the zodiacal constellation Aries and the plane of our Milky Way Galaxy. At right in the deep skyscape is bluish Epsilon Arietis, a star visible to the naked-eye and about 330 light-years away. Reflecting starlight in the region, dusty nebulae LBN762, LBN753, and LBN743 sprawl left to right across the field, but are likely some 1,000 light-years away. At that estimated distance, the cosmic canvas is over 140 light-years across. Near the edge of a large molecular cloud, their dark interiors can hide newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form around dense cores embedded in the molecular cloud.
Alpine Superga Moonset
December's Full Moon phase occurred near perigee, the closest point in its orbit around our fair planet. Big and bright, the fully illuminated lunar disk sets over rugged mountains in this early morningscape from Turin, Italy. Captured just before sunrise on the opposite horizon, scattered sunlight near the edge of Earth's shadow provides the beautiful reddish glow of the alpine peaks. Hills in the foreground are still in shadow. But the scattered sunlight just illuminates the dome and towers of Turin's historic Basilica of Superga on a hilltop near the lower right in the telephoto frame.
All the Eclipses of 2017
As seen from planet Earth, all the lunar and solar eclipses of 2017 are represented at the same scale in these four panels. The year's celestial shadow play was followed through four different countries by one adventurous eclipse chaser. To kick off the eclipse season, at top left February's Full Moon was captured from the Czech Republic. Its subtle shading, a penumbral lunar eclipse, is due to Earth's lighter outer shadow. Later that month the New Moon at top right was surrounded by a ring of fire, recorded on film from Argentina near the midpoint of striking annular solar eclipse. The August eclipse pairing below finds the Earth's dark umbral shadow in a partial eclipse from Germany at left, and the vibrant solar corona surrounding a totally eclipsed Sun from the western USA. If you're keeping score, the Saros numbers (eclipse cycles) for all the 2017 eclipses are at bottom left in each panel.
HH 666: Carina Dust Pillar with Jet
To some, it may look like a beehive harboring an evil bee. In reality, the featured Hubble image captures a cosmic pillar of dust, two-light years long, inside of which is Herbig-Haro 666 -- a young star emitting powerful jets. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's layered outline are shaped by the winds and radiation of Carina's young, hot, massive stars, some of which are still forming inside the nebula. A dust-penetrating view in infrared light better shows the two, narrow, energetic jets blasting outward from a still hidden infant star. Open Science: Browse 1,500+ codes in the Astrophysics Source Code Library
A Horizon with Blue and Red
What's happening on the horizon? The horizon itself, past a spinach field in Guatemala, shows not only trees but a large volcano: the Volcán de Fuego (Volcano of Fire). The red glow at the top of the volcano is hot lava. But your eye may also be drawn to the blue circle above the horizon on the left. This circle surrounds the Moon and, together with other colors, is called a corona. A corona is caused by diffraction of light -- here moonlight -- by small water droplets in the Earth's intervening atmosphere. A break in the clouds on the right shows stars and even the planet Saturn far beyond the volcano. Although Volcán de Fuego frequently undergoes low-level activity, the astrophotographer considered himself lucky to capture the scene just during an explosive eruption in late September. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter
Earth and Moon
On rare occasions, the Earth and Moon are photographed together. One of most spectacular times this occurred was 25 years ago this month when the Jupiter-bound Galileo spacecraft zoomed past our home planetary system. Then, robotic Galileo watched from about 15-times the Earth-Moon separation as our only natural satellite glided past our home world. The featured video combines 52 historic color-enhanced images. Although our Moon may appear small next to the Earth, no other planet in our Solar System has a satellite so comparable in size . The Sun, far off to the right, illuminated about half of each sphere, and shows the spinning Earth's white clouds, blue oceans, and tan continents. Tonight, a nearly full Oak supermoon will be visible from all of Earth from sunset to sunrise. Gallery: Supermoon 2017 Free APOD Lectures: January 5 in NYC & January 9 in DC