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 May 30

Red Crepuscular Rays from an Eclipse

Image Credit & Copyright: Fefo Bouvier

Explanation: What’s happening behind that island? Things both expected and unexpected. Expected, perhaps, the pictured rays of light — called crepuscular rays — originate from the Sun. Unexpected, though, the Sun was being partially eclipsed by the Moon at the time — late last month. Expected, perhaps, the Sun’s rays are quite bright as they shine through gaps in below-horizon clouds. Unexpected, though, the crepuscular rays are quite red, likely the result an abundance of aerosols in Earth’s atmosphere scattering away much of the blue light. Expected, with hope, a memorable scene featuring both the Moon and the Sun, superposed. Unfortunately, from this location — in Uruguay looking toward Argentina — clouds obscured the eclipse — which wasn’t completely unexpected. However, after packing up to go home, the beauty of bright red crepuscular rays emerged — quite unexpectedly. Oh — and that island on the horizon — it’s really two islands.

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 May 27

Titan: Moon over Saturn

Image Credit: NASA, JPL-Caltech, Space Science Institute

Explanation: Like Earth’s moon, Saturn’s largest moon Titan is locked in synchronous rotation. This mosaic of images recorded by the Cassini spacecraft in May of 2012 shows its anti-Saturn side, the side always facing away from the ringed gas giant. The only moon in the solar system with a dense atmosphere, Titan is the only solar system world besides Earth known to have standing bodies of liquid on its surface and an earthlike cycle of liquid rain and evaporation. Its high altitude layer of atmospheric haze is evident in the Cassini view of the 5,000 kilometer diameter moon over Saturn’s rings and cloud tops. Near center is the dark dune-filled region known as Shangri-La. The Cassini-delivered Huygens probe rests below and left of center, after the most distant landing for a spacecraft from Earth.

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 May 26

NGC 4565: Galaxy on Edge

Image Credit & Copyright: Michael Sherick

Explanation: Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy’s boxy, bulging central core cut by obscuring dust lanes that lace NGC 4565’s thin galactic plane. NGC 4565 itself lies about 40 million light-years distant and spans some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

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 May 25

The Lively Center of the Lagoon Nebula

Image Credit: NASA, ESA, Hubble; Processing & Copyright: Mehmet Hakan Özsaraç

Explanation: The center of the Lagoon Nebula is a whirlwind of spectacular star formation. Visible near the image center, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight. A tremendously bright nearby star, Herschel 36, lights the area. Vast walls of dust hide and redden other hot young stars. As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnels. This picture, spanning about 10 light years, combines images taken in six colors by the orbiting Hubble Space Telescope. The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of the Archer (Sagittarius).

 

Almost hyperspace: 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 May 24

A Deep Sky Behind an Eclipsed Moon

Image Credit & Copyright: Andrei Ionut Dascalu

Explanation: The plan was to capture a picturesque part of the sky that was hosting an unusual guest. The result included a bonus — an additional and unexpected guest. The beautiful background features part of the central band of our Milky Way galaxy on the far left, and the colorful clouds of Rho Ophiuchi in the image center. The unusual guest, a dimmed and reddened Moon on the right, was expected because the image was taken during last week’s total lunar eclipse. The timing had to be right because the Moon — both before and after eclipse — would be so bright it would overwhelm the background. The unexpected guest was the bright meteor across the image center. The fleeting meteor streak was captured on only one of the 10 consecutively-captured deep-field images from La Palma in the Spanish Canary Islands, while the eclipsed Moon image was taken immediately afterwards with the same camera and from the same location. The next total lunar eclipse — also quite expected — will occur in early November.

 

Notable Submissions to APOD: Total Lunar Eclipse of 2022 May

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 May 22

A Large Tsunami Shock Wave on the Sun

Image Credit: NSO/AURA/NSF and USAF Research Laboratory

Explanation: Tsunamis this large don’t happen on Earth. During 2006, a large solar flare from an Earth-sized sunspot produced a tsunami-type shock wave that was spectacular even for the Sun. Pictured here, the tsunami wave was captured moving out from active region AR 10930 by the Optical Solar Patrol Network (OSPAN) telescope in New Mexico, USA. The resulting shock wave, known technically as a Moreton wave, compressed and heated up gasses including hydrogen in the photosphere of the Sun, causing a momentarily brighter glow. The featured image was taken in a very specific red color emitted exclusively by hydrogen gas. The rampaging tsunami took out some active filaments on the Sun, although many re-established themselves later. The solar tsunami spread at nearly one million kilometers per hour, and circled the entire Sun in a matter of minutes.

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 May 21

Planetary Nebula Abell 7

Image Credit & Copyright: Donald Waid, Ron Dilulio

Explanation: Very faint planetary nebula Abell 7 is some 1,800 light-years distant, just south of Orion in planet Earth’s skies in the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies, its generally simple spherical shape, about 8 light-years in diameter, is outlined in this deep telescopic image. Within its confines are beautiful, more complex details enhanced by the use of narrowband filters. Emission from hydrogen is shown in reddish hues with oxygen emission mapped to green and blue colors, giving Abell 7 a natural appearance that would otherwise be much too faint to be appreciated by eye. A planetary nebula represents a very brief final phase in stellar evolution that our own Sun will experience 5 billion years hence, as the nebula’s central, once sun-like star shrugs off its outer layers. Abell 7 itself is estimated to be 20,000 years old. Its central star is seen here as a fading white dwarf some 10 billion years old.

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 May 20

A View from Earth’s Shadow

Image Credit & Copyright: Maxime Oudoux

Explanation: This serene sand and skyscape finds the Dune of Pilat on the coast of France still in Earth’s shadow during the early morning hours of May 16. Extending into space, the planet’s dark umbral shadow covered the Moon on that date. From that location the total phase of a lunar eclipse had begun before moonset. Still in sunlight though, the International Space Station crossed from the western horizon and Earth’s largest artificial moon traced the bright flat arc through the sky over 400 km above. Simply constructed, the well-planned panoramic scene was captured over a 5 minutes in a series of consecutive images.

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 May 19

A Digital Lunar Eclipse

Image Credit & Copyright: Michael Cain

Explanation: Recorded on May 15/16 this sequence of exposures follows the Full Moon during a total lunar eclipse as it arcs above treetops in the clearing skies of central Florida. A frame taken every 5 minutes by a digital camera shows the progression of the eclipse over three hours. The bright lunar disk grows dark and red as it glides through planet Earth’s shadow. In fact, counting the central frames in the sequence measures the roughly 90 minute duration of the total phase of this eclipse. Around 270 BC, the Greek astronomer Aristarchus also measured the duration of total lunar eclipses, but probably without the benefit of digital watches and cameras. Still, using geometry he devised a simple and impressively accurate way to calculate the Moon’s distance in terms of the radius of planet Earth, from the eclipse duration.

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 May 18

A Jewel on the Flower Moon

Image Credit & Copyright: Tomas Slovinsky

Explanation: Cloudy skies plagued some sky watchers on Sunday as May’s Full Flower Moon slipped through Earth’s shadow in a total lunar eclipse. In skies above Chile’s Atacama desert this telephoto snapshot still captured an awesome spectacle though. Seen through thin high cirrus clouds just before totality began, a last sliver of sunlit crescent glistens like a hazy jewel atop the mostly shadowed lunar disk. This full moon was near perigee, the closest point in its elliptical orbit. It passed near the center of Earth’s dark umbral shadow during the 90 minute long total eclipse phase. Faintly suffused with sunlight scattered by the atmosphere, the umbral shadow itself gave the eclipsed moon a reddened appearance and the very dramatic popular moniker of a Blood Moon.

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 May 17

NGC 1316: After Galaxies Collide

Image Credit & Copyright: Capture: Greg Turgeon; Processing: Kiko Fairbairn

Explanation: Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Investigations indicate that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just on the upper right. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls and shells of stars and gas visible in this wide and deep image. One thing that >remains unexplained is the unusually small globular star clusters, seen as faint dots on the image. Most elliptical galaxies have more and brighter globular clusters than NGC 1316. Yet the observed globulars are too old to have been created by the recent spiral collision. One hypothesis is that these globulars survive from an even earlier galaxy that was subsumed into NGC 1316. Another surprising attribute of NGC 1316, also known as Fornax A, is its giant lobes of gas that glow brightly in radio waves.

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 May 16

Milky Way over French Alp Hoodoos

Image Credit & Copyright: Benjamin Barakat

Explanation: Real castles aren’t this old. And the background galaxy is even older. Looking a bit like an alien castle, the pictured rock spires are called hoodoos and are likely millions of years old. Rare, but found around the world, hoodoos form when dense rocks slow the erosion of softer rock underneath. The pictured hoodoos survive in the French Alps and are named Demoiselles Coiffées — which translates to English as “Ladies with Hairdos“. The background galaxy is part of the central disk of our own Milky Way galaxy and contains stars that are typically billions of years old. The photogenic Cygnus sky region — rich in dusty dark clouds and red glowing nebulas — appears just above and behind the hoodoos. The featured image was taken in two stages: the foreground was captured during the evening blue hour, while the background was acquired from the same location later that night.

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 May 15

Colors of the Moon

Image Credit & Copyright: Marcella Giulia Pace

Explanation: What color is the Moon? It depends on the night. Outside of the Earth’s atmosphere, the dark Moon, which shines by reflected sunlight, appears a magnificently brown-tinged gray. Viewed from inside the Earth’s atmosphere, though, the moon can appear quite different. The featured image highlights a collection of apparent colors of the full moon documented by one astrophotographer over 10 years from different locations across Italy. A red or yellow colored moon usually indicates a moon seen near the horizon. There, some of the blue light has been scattered away by a long path through the Earth’s atmosphere, sometimes laden with fine dust. A blue-colored moon is more rare and can indicate a moon seen through an atmosphere carrying larger dust particles. What created the purple moon is unclear — it may be a combination of several effects. The last image captures the total lunar eclipse of 2018 July — where the moon, in Earth’s shadow, appeared a faint red — due to light refracted through air around the Earth. Today there is not only another full moon but a total lunar eclipse visible to observers in North and South America — an occurrence that may lead to some unexpected lunar colorings.

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 May 13

The Milky Way’s Black Hole

Image Credit: X-ray – NASA/CXC/SAO, IR – NASA/HST/STScI; Inset: Radio – Event Horizon Telescope Collaboration

Explanation: There’s a black hole at the center of the Milky Way. Stars are observed to orbit a very massive and compact object there known as Sgr A* (say “sadge-ay-star”). But this just released radio image (inset) from planet Earth’s Event Horizon Telescope is the first direct evidence of the Milky Way’s central black hole. As predicted by Einstein’s Theory of General Relativity, the four million solar mass black hole’s strong gravity is bending light and creating a shadow-like dark central region surrounded by a bright ring-like structure. Supporting observations made by space-based telescopes and ground-based observatories provide a wider view of the galactic center’s dynamic environment and an important context for the Event Horizon Telescope’s black hole image. The main panel image shows the X-ray data from Chandra and infrared data from Hubble. While the main panel is about 7-light years across, the Event Horizon Telescope inset image itself spans a mere 10 light-minutes at the center of our galaxy, some 27,000 light-years away.

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 May 12

Young Stars of NGC 346

Image Credit: NASA, ESA – acknowledgement: Antonella Nota (ESA/STScI) et al.,

Explanation: The massive stars of NGC 346 are short lived, but very energetic. The star cluster is embedded in the largest star forming region in the Small Magellanic Cloud, some 210,000 light-years distant. Their winds and radiation sweep out an interstellar cavern in the gas and dust cloud about 200 light-years across, triggering star formation and sculpting the region’s dense inner edge. Cataloged as N66, the star forming region also appears to contain a large population of infant stars. A mere 3 to 5 million years old and not yet burning hydrogen in their cores, the infant stars are strewn about the embedded star cluster. In this false-color Hubble Space Telescope image, visible and near-infrared light are seen as blue and green, while light from atomic hydrogen emission is red.