Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 9

Hubble’s Jupiter and the Shrinking Great Red Spot

Image Credit: NASA, ESA, Hubble, OPAL Program, STScI; Processing: Karol Masztalerz

Explanation: What will become of Jupiter’s Great Red Spot? Gas giant Jupiter is the solar system’s largest world with about 320 times the mass of planet Earth. Jupiter is home to one of the largest and longest lasting storm systems known, the Great Red Spot (GRS), visible to the left. The GRS is so large it could swallow Earth, although it has been shrinking. Comparison with historical notes indicate that the storm spans only about one third of the exposed surface area it had 150 years ago. NASA’s Outer Planets Atmospheres Legacy (OPAL) program has been monitoring the storm more recently using the Hubble Space Telescope. The featured Hubble OPAL image shows Jupiter as it appeared in 2016, processed in a way that makes red hues appear quite vibrant. Modern GRS data indicate that the storm continues to constrict its surface area, but is also becoming slightly taller, vertically. No one knows the future of the GRS, including the possibility that if the shrinking trend continues, the GRS might one day even do what smaller spots on Jupiter have done — disappear completely.

 

Tuesday over Zoom: APOD editor to present the Best APOD Space Images of 2021

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 8

Quadrantids of the North

Image Credit & Copyright: Cheng Luo

Explanation: Named for a forgotten constellation, the Quadrantid Meteor Shower puts on an annual show 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. In fact north star Polaris is just below center in this frame and the Big Dipper asterism (known to some as the Plough) is above it, with the meteor shower radiant to the right. Pointing back toward the radiant, Quadrantid meteors streak through the night in the panoramic skyscape, a composite of images taken in the hours around the shower’s peak on January 4, 2022. Arrayed in the foreground are radio telescopes of the Chinese Spectral Radioheliograph, Mingantu Observing Station, Inner Mongolia, China. A likely source of the dust stream that produces Quadrantid meteors was identified in 2003 as an asteroid.

 

Status Updates: Deploying the James Webb Space Telescope

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 7

Ecstatic Solar Eclipse

Image Credit & Copyright: Annie Schmidt (Point Blue Conservation Science)

Explanation: A male Adelie penguin performed this Ecstatic Vocalization in silhouette during the December 4 solar eclipse, the final eclipse of 2021. Of course his Ecstatic Vocalization is a special display that male penguins use to claim their territory and advertise their condition. This penguin’s territory, at Cape Crozier Antarctica, is located in one of the largest Adelie penguin colonies. The colony has been studied by researchers for over 25 years. From there, last December’s eclipse was about 80 percent total when seen at its maximum phase as the Moon’s shadow crossed planet Earth’s southernmost continent.

 

Status Updates: Deploying the James Webb Space Telescope

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 6

The Last Days of Venus as the Evening Star

Image Credit & Copyright: Tamas Ladanyi (TWAN)

Explanation: That’s not a young crescent Moon posing behind cathedral towers after sunset. It’s Venus in a crescent phase. About 40 million kilometers away and about 2 percent illuminated by sunlight, it was captured with camera and telephoto lens in this series of exposures as it set in western skies on January 1 from Veszprem, Hungary. The bright celestial beacon was languishing in the evening twilight, its days as the Evening Star coming to a close as 2022 began. But it was also growing larger in apparent size and becoming an ever thinner crescent in telescopic views. Heading toward a (non-judgemental) inferior conjunction, the inner planet will be positioned between Earth and Sun on January 9 and generally lost from view in the solar glare. A crescent Venus will soon reappear though. Rising in the east by mid-month just before the Sun as the brilliant Morning Star.

 

Status Updates: Deploying the James Webb Space Telescope

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 5

A Year of Sunrises

Image Credit & Copyright: Luca Vanzella

Explanation: Does the Sun always rise in the same direction? No. As the months change, the direction toward the rising Sun changes, too. The featured image shows the direction of sunrise every month during 2021 as seen from the city of Edmonton, Alberta, Canada. The camera in the image is always facing due east, with north toward the left and south toward the right. As shown in an accompanying video, the top image was taken in 2020 December, while the bottom image was captured in 2021 December, making 13 images in total. Although the Sun always rises in the east in general, it rises furthest to the south of east on the December solstice, and furthest north of east on the June solstice. In many countries, the December Solstice is considered an official change in season: for example the first day of winter in the North. Solar heating and stored energy in the Earth’s surface and atmosphere are near their lowest during winter, making the winter season the coldest of the year.

 

Status Updates: Deploying the James Webb Space Telescope

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 4

Moons Beyond Rings at Saturn

Image Credit: NASA, ESA, JPL, Cassini Imaging Team

Explanation: What’s happened to that moon of Saturn? Nothing — Saturn’s moon Rhea is just partly hidden behind Saturn’s rings. In 2010, the robotic Cassini spacecraft then orbiting Saturn took this narrow-angle view looking across the Solar System‘s most famous rings. Rings visible in the foreground include the thin F ring on the outside and the much wider A and B rings just interior to it. Although it seems to be hovering over the rings, Saturn’s moon Janus is actually far behind them. Janus is one of Saturn’s smaller moons and measures only about 180 kilometers across. Farther out from the camera is the heavily cratered Rhea, a much larger moon measuring 1,500 kilometers across. The top of Rhea is visible only through gaps in the rings. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn’s atmosphere, where it surely melted.

 

Explore Your Universe: Random APOD Generator

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 3

Comet Leonard’s Long Tail

Image Credit & Copyright: Jan Hattenbach

Explanation: You couldn’t see Comet Leonard’s extremely long tail with a telescope — it was just too long. You also couldn’t see it with binoculars — still too long. Or with your eyes — it was too dim. Or from a city — the sky was too bright. But from a dark location with a low horizon — your camera could. And still might — if the comet survives today’s closest encounter with the Sun, which occurs between the orbits of Mercury and Venus. The featured picture was created from two deep and wide-angle camera images taken from La Palma in the Canary Islands of Spain late last month. Afterwards, if it survives, what is left of Comet Leonard‘s nucleus will head out of our Solar System, never to return.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 2

Quadruple Lunar Halo Over Winter Road

Image Credit & Copyright: Dani Caxete

Explanation: Sometimes falling ice crystals make the atmosphere into a giant lens causing arcs and halos to appear around the Sun or Moon. One Saturday night in 2012 was just such a time near Madrid, Spain, where a winter sky displayed not only a bright Moon but four rare lunar halos. The brightest object, near the top of the featured image, is the Moon. Light from the Moon refracts through tumbling hexagonal ice crystals into a somewhat rare 22-degree halo seen surrounding the Moon. Elongating the 22-degree arc horizontally is a more rare circumscribed halo caused by column ice crystals. Even more rare, some moonlight refracts through more distant tumbling ice crystals to form a (third) rainbow-like arc 46 degrees from the Moon and appearing here just above a picturesque winter landscape. Furthermore, part of a whole 46-degree circular halo is also visible, so that an extremely rare — especially for the Moon — quadruple halo was captured. Far in the background is a famous winter skyscape that includes Sirius, the belt of Orion, and Betelgeuse — visible between the inner and outer arcs. Halos and arcs typically last for minutes to hours, so if you do see one there should be time to invite family, friends or neighbors to share your unusual lensed vista of the sky.

(I did not post the wrong picture for today, January 1, 2022)

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 January 1

The Full Moon of 2021

Image Credit & Copyright: Soumyadeep Mukherjee

Explanation: Every Full Moon of 2021 shines in this year-spanning astrophoto project, a composite portrait of the familiar lunar nearside at each brightest lunar phase. Arranged by moonth, the year progresses in stripes beginning at the top. Taken with the same camera and lens the stripes are from Full Moon images all combined at the same pixel scale. The stripes still looked mismatched, but they show that the Full Moon’s angular size changes throughout the year depending on its distance from Kolkata, India, planet Earth. The calendar month, a full moon name, distance in kilometers, and angular size is indicated for each stripe. Angular size is given in minutes of arc corresponding to 1/60th of a degree. The largest Full Moon is near a perigee or closest approach in May. The smallest is near an apogee, the most distant Full Moon in December. Of course the full moons of May and November also slid into Earth’s shadow during 2021’s two lunar eclipses.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 31

JWST on the Road to L2

Image Credit & Copyright: Malcolm Park (North York Astronomical Association)

Explanation: This timelapse gif tracks the James Webb Space Telescope as it streaks across the stars of Orion on its journey to a destination beyond the Moon. Recorded on December 28, 12 consecutive exposures each 10 minutes long were aligned and combined with a subsequent color image of the background stars to create the animation. About 2.5 days after its December 25 launch, JWST cruised past the altitude of the Moon’s orbit as it climbed up the gravity ridge from Earth to reach a halo orbit around L2, an Earth-Sun Lagrange point. Lagrange points are convenient locations in space where the combined gravitational attraction of one massive body (Earth) orbiting another massive body (Sun) is in balance with the centripetal force needed to move along with them. So much smaller masses, like spacecraft, will tend to stay there. One of 5 Lagrange points, L2 is about 1.5 million kilometers from Earth directly along the Earth-Sun line. JWST will arrive at L2 on January 23, 29 days after launch. While relaxing in Earth’s surface gravity you can follow the James Webb Space Telescope’s progress and complicated deployment online.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 30

The Further Tail of Comet Leonard

Image Credit & Copyright: Daniele Gasparri

Explanation: Comet Leonard, brightest comet of 2021, is at the lower left of these two panels captured on December 29 in dark Atacama desert skies. Heading for its perihelion on January 3 Comet Leonard’s visible tail has grown. Stacked exposures with a wide angle lens (also displayed in a reversed B/W scheme for contrast), trace the complicated ion tail for an amazing 60 degrees, with bright Jupiter shining near the horizon at lower right. Material vaporizing from Comet Leonard’s nucleus, a mass of dust, rock, and ices about 1 kilometer across, has produced the long tail of ionized gas fluorescing in the sunlight. Likely flares on the comet’s nucleus and buffeting by magnetic fields and the solar wind in recent weeks have resulted in the tail’s irregular pinched and twisted appearance. Still days from its closest approach to the Sun, Comet Leonard’s activity should continue. The comet is south of the Solar System’s ecliptic plane as it sweeps through the southern constellation Microscopium.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 29

Giant Storms and High Clouds on Jupiter

Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill

Explanation: What and where are these large ovals? They are rotating storm clouds on Jupiter imaged last month by NASA’s Juno spacecraft. In general, higher clouds are lighter in color, and the lightest clouds visible are the relatively small clouds that dot the lower oval. At 50 kilometers across, however, even these light clouds are not small. They are so high up that they cast shadows on the swirling oval below. The featured image has been processed to enhance color and contrast. Large ovals are usually regions of high pressure that span over 1000 kilometers and can last for years. The largest oval on Jupiter is the Great Red Spot (not pictured), which has lasted for at least hundreds of years. Studying cloud dynamics on Jupiter with Juno images enables a better understanding of dangerous typhoons and hurricanes on Earth.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 28

Sun Halo over Sweden

Video Credit & Copyright: Håkan Hammar (Vemdalen Ski Resort, SkiStar)

Explanation: What’s happened to the Sun? Sometimes it looks like the Sun is being viewed through a giant lens. In the featured video, however, there are actually millions of tiny lenses: ice crystals. Water may freeze in the atmosphere into small, flat, six-sided, ice crystals. As these crystals flutter to the ground, much time is spent with their faces flat and parallel to the ground. An observer may find themselves in the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view and creating phenomena like parhelia, the technical term for sundogs. The featured video was taken in late 2017 on the side of a ski hill at the Vemdalen Ski Resort in central Sweden. Visible in the center is the most direct image of the Sun, while two bright sundogs glow prominently from both the left and the right. Also visible is the bright 22 degree halo — as well as the rarer and much fainter 46 degree halo — also created by sunlight refracting through atmospheric ice crystals.

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 27

Comet Leonard behind JWST Launch Plume

Image Credit & Copyright: Matipon Tangmatitham (NARIT)

 

Explanation: Which one of these two streaks is a comet? Although they both have comet-like features, the lower streak is the only real comet. This lower streak shows the coma and tail of Comet Leonard, a city-sized block of rocky ice that is passing through the inner Solar System as it continues its looping orbit around the Sun. Comet Leonard has recently passed its closest to both the Earth and Venus and will round the Sun next week. The comet, still visible to the unaided eye, has developed a long and changing tail in recent weeks. In contrast, the upper streak is the launch plume of the Ariane V rocket that lifted the James Webb Space Telescope (JWST) off the Earth two days ago. The featured single-exposure image was taken from Thailand, and the foreground spire is atop a pagoda in Doi Inthanon National Park. JWST, NASA’s largest and most powerful space telescope so far, will orbit the Sun near the Earth-Sun L2 point and is scheduled to start science observations in the summer of 2022.

 

Gallery: Comet Leonard 2021
Gallery: Webb Space Telescope Launch: 2021 December 25

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2021 December 26

James Webb Space Telescope over Earth

Image Credit: Arianespace, ESA, NASA, CSA, CNES

Explanation: There’s a big new telescope in space. This one, the James Webb Space Telescope (JWST), not only has a mirror over five times larger than Hubble‘s in area, but can see better in infrared light. The featured picture shows JWST high above the Earth just after being released by the upper stage of an Ariane V rocket, launched yesterday from French Guiana. Over the next month, JWST will move out near the Sun-Earth L2 point where it will co-orbit the Sun with the Earth. During this time and for the next five months, JWST will unravel its segmented mirror and an array of sophisticated scientific instruments — and test them. If all goes well, JWST will start examining galaxies across the universe and planets orbiting stars across our Milky Way Galaxy in the summer of 2022.

 

APOD Gallery: Webb Space Telescope Launch