NASA Astronomy Picture of the Day:

Named for a forgotten constellation, the Quadrantid Meteor Shower is an annual event for planet Earth's northern hemisphere skygazers The shower's radiant on the sky lies within the old, astronomically obsolete constellation Quadrans Muralis. That location is not far from the Big Dipper, at the boundaries of the modern constellations Bootes and Draco. With the radiant out of the frame at the upper right, Quadrantid meteors streak through this night skyscape composed of digital frames recorded in the hours around the shower's peak on January 4, 2013. The last quarter moon illuminates rugged terrain and a section of the Great Wall in Hebei Province, China. A likely source of the dust stream that produces Quadrantid meteors was identified in 2003 as an asteroid. As usual, in 2020 the shower is expected to peak briefly on the night of January 3/4. Meteor fans in North America can anticpate a good show to celebrate the new year in moonless skies before tomorrow's dawn. Free Presentation: APOD Editor to show best astronomy images of 2019 -- and the decade -->tonight in NYC.

Photo by Cheng Luo

NASA Astronomy Picture of the Day:

Begirt with many a blazing star, Orion the Hunter is one of the most recognizable constellations. In this night skyscape the Hunter's stars rise in the northern hemisphere's winter sky on December 30, 2019, tangled in bare trees near Newnan, Georgia, USA. Red super giant star Betelgeuse stands out in yellowish hues at Orion's shoulder left of center, but it no longer so strongly rivals the blue supergiant star Rigel at the Hunter's foot. In fact, skygazers around planet Earth can see a strikingly fainter Betelgeuse now, its brightness fading by more than half in the final months of 2019. Betelgeuse has long been known to be a variable star, changing its brightness in multiple cycles with approximate short and long term periods of hundreds of days to many years. The star is now close to its faintest since photometric measurements in 1926/27, likely due in part to a near coincidence in the minimum of short and long term cycles. Betelgeuse is also recognized as a nearby red supergiant star that will end its life in a core collapse supernova explosion sometime in the next 1,000 years, though that cosmic cataclysm will take place a safe 700 light-years or so from our fair planet.

Photo by Jimmy Westlake

NASA Astronomy Picture of the Day:

Why is Betelgeuse fading? No one knows. Betelgeuse, one of the brightest and most recognized stars in the night sky, is only half as bright as it used to be only five months ago. Such variability is likely just normal behavior for this famously variable supergiant, but the recent dimming has rekindled discussion on how long it may be before Betelgeuse does go supernova. Known for its red color, Betelgeuse is one of the few stars to be resolved by modern telescopes, although only barely. The featured artist's illustration imagines how Betelgeuse might look up close. Betelgeuse is thought to have a complex and tumultuous surface that frequently throws impressive flares. Were it to replace the Sun (not recommended), its surface would extend out near the orbit of Jupiter, while gas plumes would bubble out past Neptune. Since Betelgeuse is about 700 light years away, its eventual supernova will not endanger life on Earth even though its brightness may rival that of a full Moon. Astronomers -- both amateur and professional -- will surely continue to monitor Betelgeuse as this new decade unfolds. Free Presentation: APOD Editor to show best astronomy images of 2019 -- and the decade -- in NYC on January 3

NASA Astronomy Picture of the Day:

The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this sharp image shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 7 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe.

Photo by Rui Liao

NASA Astronomy Picture of the Day:

The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide field with open star cluster Messier 21 (top left). Trisected by dust lanes the Trifid itself is about 40 light-years across and a mere 300,000 years old. That makes it one of the youngest star forming regions in our sky, with newborn and embryonic stars embedded in its natal dust and gas clouds. Estimates of the distance to open star cluster M21 are similar to M20's, but though they share this gorgeous telescopic skyscape there is no apparent connection between the two. In fact, M21's stars are much older, about 8 million years old.

Photo by Stanislav Volskiy

NASA Astronomy Picture of the Day:

If this is Saturn, where are the rings? When Saturn's "appendages" disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn's unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear. This is because Saturn's rings are confined to a plane many times thinner, in proportion, than a razor blade. In modern times, the robot Cassini spacecraft orbiting Saturn frequently crossed Saturn's ring plane during its mission to Saturn, from 2004 to 2017. A series of plane crossing images from 2005 February was dug out of the vast online Cassini raw image archive by interested Spanish amateur Fernando Garcia Navarro. Pictured here, digitally cropped and set in representative colors, is the striking result. Saturn's thin ring plane appears in blue, bands and clouds in Saturn's upper atmosphere appear in gold. Details of Saturn's rings can be seen in the high dark shadows across the top of this image, taken back in 2005. The moons Dione and Enceladus appear as bumps in the rings. Free Presentation: APOD Editor to show best astronomy images of 2019 -- and the decade -- in NYC on January 3

NASA Astronomy Picture of the Day:

Yes, but have you ever seen a sunrise like this? Here, after initial cloudiness, the Sun appeared to rise in two pieces and during partial eclipse, causing the photographer to describe it as the most stunning sunrise of his life. The dark circle near the top of the atmospherically-reddened Sun is the Moon -- but so is the dark peak just below it. This is because along the way, the Earth's atmosphere had an inversion layer of unusually warm air which acted like a gigantic lens and created a second image. For a normal sunrise or sunset, this rare phenomenon of atmospheric optics is known as the Etrucan vase effect. The featured picture was captured two mornings ago from Al Wakrah, Qatar. Some observers in a narrow band of Earth to the east were able to see a full annular solar eclipse -- where the Moon appears completely surrounded by the background Sun in a ring of fire. The next solar eclipse, also an annular eclipse, will occur in 2020 June. Notable Images Submitted to APOD: The Partial Solar Eclipse of 2019 December

Photo by Elias Chasiotis

NASA Astronomy Picture of the Day:

What's happened to the Sun? Yesterday, if you were in the right place at the right time, you could see the Sun rise partially eclipsed by the Moon. The unusual sight was captured in dramatic fashion in the featured image not only directly, in a sequence of six images, but also in reflection from Soltan Salt Lake in Iran. The almost-white Sun appears dimmer and redder near the horizon primarily because Earth's atmosphere preferentially scatters away more blue light. Yesterday's partial solar eclipse appeared in the sky over much of Asia and Australia, but those with a clear enough sky in a thin band across the Earth's surface were treated to a more complete annular solar eclipse -- where the Moon appears completely surrounded by the Sun in what is known as a ring of fire. The next annular solar eclipse will occur in 2020 June. Notable Images Submitted to APOD: The Partial Solar Eclipse of 2019 December

Photo by Majid Ghohroodi

NASA Astronomy Picture of the Day:

December's New Moon brought a solar eclipse to some for the holiday season. It also gave beautiful dark night skies to skygazers around the globe, like this moonless northern winter night. In the scene, bright stars of the Winter Hexagon along the Milky Way are rising. Cosy mountain cabins in the snowy foreground are near the village of Oravska Lesna, Slovakia. The shining celestial beacons marking the well-known asterism are Aldebaran, Capella, Pollux (and Castor), Procyon, Rigel, and Sirius. This winter nightscape also reveals faint nebulae in Orion, and the lovely Pleiades star cluster. Slide your cursor over the image to trace the winter hexagon, or just follow this link.

Photo by Petr Horálek

NASA Astronomy Picture of the Day:

What is this person doing? In 2012 an annular eclipse of the Sun was visible over a narrow path that crossed the northern Pacific Ocean and several western US states. In an annular solar eclipse, the Moon is too far from the Earth to block out the entire Sun, leaving the Sun peeking out over the Moon's disk in a ring of fire. To capture this unusual solar event, an industrious photographer drove from Arizona to New Mexico to find just the right vista. After setting up and just as the eclipsed Sun was setting over a ridge about 0.5 kilometers away, a person unknowingly walked right into the shot. Although grateful for the unexpected human element, the photographer never learned the identity of the silhouetted interloper. It appears likely, though, that the person is holding a circular device that would enable them to get their own view of the eclipse. The shot was taken at sunset on 2012 May 20 at 7:36 pm local time from a park near Albuquerque, New Mexico, USA. Tomorrow another annular solar eclipse will become visible, this time along a thin path starting in Saudi Arabia and going through southern India, Singapore, and Guam. However, almost all of Asia with a clear sky will be able to see, tomorrow, at the least, a partial solar eclipse. Free Download: 2020 APOD Calendar

Photo by Colleen Pinski

NASA Astronomy Picture of the Day:

What stars shine in Earth's northern hemisphere during winter? The featured image highlights a number of bright stars visible earlier this month. The image is a 360-degree horizontal-composite panorama of 66 vertical frames taken consecutively with the same camera and from the same location at about 2:30 am. Famous stars visible in the picture include Castor & Pollux toward the southeast on the left, Sirius just over the horizon toward the south, Capella just over the arch of the Milky Way Galaxy toward the west, and Polaris toward the north on the right. Captured by coincidence is a meteor on the far left. In the foreground is the Museum of the Orava Village in Zuberec, Slovakia. This village recreates rural life in the region hundreds of years ago, while the image captures a timeless sky surely familar to village residents, a sky also shared with northern residents around the world. Free Download: 2020 APOD Calendar

Photo by Tomas Slovinsky

NASA Astronomy Picture of the Day:

Where is the best place to collect a surface sample from asteroid Bennu? Launched in 2016, NASA sent the robotic Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) to investigate the 500-meter-across asteroid 101955 Bennu. After mapping the near-Earth asteroid's dark surface, OSIRIS-REx will next touch Bennu's surface in 2020 August to collect a surface sample. The featured 23-second time-lapse video shows four candidate locations for the touch, from which NASA chose just one earlier this month. NASA chose the Nightingale near Bennu's northern hemisphere as the primary touch-down spot because of its relative flatness, lack of boulders, and apparent abundance of fine-grained sand. Location Osprey is the backup. NASA plans to return soil samples from Bennu to Earth in 2023 for a detailed analysis. Free Presentation: APOD Editor to show best astronomy images of 2019 -- and the decade -- in NYC on January 3