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The Conjunction of Comet R3 PanSTARRS and the Orion Nebula

Published: yesterday | Author: Jerry Bonnell (UMCP)

The bright blue Comet R3 PanSTARRS streaks across the right side of the image with the red cloud of the Orion Nebula in the background on the left.
Explanation: Today’s composite image features something old, something new, something borrowed, and something blue! Comet R3 PanSTARRS, streaking across the right of the image, likely originated from the Oort Cloud, meaning it is an old Solar System relic from billions of years ago. It’s bright extended ion tail glows blue as the gas escaping the comet’s core is ionized by sunlight. Astronomers are fascinated by comets for all sorts of reasons: comet compositions are untouched time capsules containing the building blocks of Solar System planets; comets may have delivered water to the young Earth; the behavior of cometary tails shed light on solar wind and radiation interactions. The background mosaic, featuring the Orion Nebula (M42), was taken over two nights of observation with the comet captured on the third night. The Orion Nebula is our nearest stellar nursery and, at about 2 million years old, is our something (relatively) new! Now at around 127.5 million kilometers from Earth, we wave goodbye to the borrowed Comet R3 PanSTARRS as it leaves the Solar System.
Enclosure

Moon Setting Behind Teide Volcano

Published: 2 days ago | Author: Jerry Bonnell (UMCP)


Explanation: These people are not in danger. What is coming down from the left is just the Moon, far in the distance. Luna appears so large here because she is being photographed through a telescopic lens. What is moving is mostly the Earth, whose spin causes the Moon to slowly disappear behind Mount Teide, a volcano in the Canary Islands of Spain off the northwest coast of Africa. The people pictured are 16 kilometers away and many are facing the camera because they are watching the Sun rise behind the photographer. It is not a coincidence that a full moon sets just when the Sun rises because the Sun is always on the opposite side of the sky from a full moon. The featured video was made in 2018 during a full Milk Moon. The video is not time-lapse -- this was really how fast the Moon was setting.
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Comet R3 PanSTARRS and Orion

Published: 3 days ago | Author: Jerry Bonnell (UMCP)

A starfield appears featuring a comet with a long tail
that extends from the lower right to the upper left. To the 
left of the comet is a bright star, and above the comet and
to the right is a red and white nebula. 
Please see the explanation for more detailed information.
Explanation: Orion never had a sword like this. As Comet C/2025 R3 (PanSTARRS) heads out of the inner Solar System, it is putting on quite a show for long exposure cameras. Currently seen toward the constellation of Orion the Hunter, the distant Orion Nebula is visible on the upper right. Comet R3 PanSTARRS is now showing two distinct tails: a short dust tail pointing toward the top of the image and a long and wavy ion tail trailing off toward the upper left. The ion tail points away from the Sun and glows blue from excited carbon monoxide. Large particles in the dust tail somewhat resist the radiation pressure that push them away from the Sun and so retain a bit of the comet's orbit. The dust tail shines by reflected sunlight. The featured image was taken a few days ago from France's Reunion Island in the southern Indian Ocean.
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Messier Craters in Stereo

Published: 4 days ago | Author: Jerry Bonnell (UMCP)

See Explanation.  Clicking on the picture will download
the highest resolution version available.
Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by the extremely shallow-angle trajectory followed by an impactor, moving left to right, that gouged out the craters. The shallow impact also resulted in two bright rays of material extending along the surface to the right, beyond the picture. Intended to be viewed with red/blue glasses (red for the left eye), this striking stereo picture of the crater pair was recently created from high resolution scans of two images (AS11-42-6304, AS11-42-6305) taken during the Apollo 11 mission to the Moon.
Enclosure

Comet R3 PanSTARRS Before Rigel

Published: 5 days ago | Author: Jerry Bonnell (UMCP)

A starfield appears with three large objects. Near the top is a 
bright star. Near the middle is a small light blue nebula. And 
near the bottom is a comet with its long tail extending to the 
upper left and passing in front of both the star and the blue 
nebula. 
Please see the explanation for more detailed information.
Explanation: Which way is Comet R3 PanSTARRS going? Not towards the star at the top of the image, because that is Rigel, which, being far in the background, is unrelated to the comet. Not through the nebula in the image middle, because that is the Witch Head Nebula and it, too, is far in the distance -- but not far from Rigel.  Not into northern skies because over the past week Comet C/2025 R3 (PanSTARRS) has moved into southern skies and is now best visible in Earth's Southern Hemisphere toward the west after sunset.  Angularly, Comet R3 PanSTARRS is slowly moving toward the upper right, night by night, and will soon be in the constellation Orion. Spatially, the comet is now headed out of our Solar System but should remain visible to cameras in southern skies for about a week. The featured image was captured last week near Cerro Paranal in Chile.
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The Retrograde Dance of Saturn and Neptune

Published: 1 week ago | Author: Jerry Bonnell (UMCP)

The image shows two parellel rings of bright dots in the night sky. This is a composite image of the positions Saturn and Neptune traced in the sky from May 2025 to January 2026. The brighter ring in the foreground is Saturn, while the dimmer ring in the background is Neptune. Please see the explanation for more detailed information.
Explanation: What does it mean for Saturn and Neptune to be in retrograde? Featured is a composite of images taken over 34 nights from May 2025 to February 2026 tracing Saturn (brighter, foreground) and Neptune (dimmer, background). Over that time, the two planets exhibited retrograde motion, meaning they appeared to move backward in the sky. This apparent backwards motion occurs when Earth overtakes the slower outer planets as they orbit the Sun. Imagine the Solar System is a running track. Earth "runs" faster along the inside of the track compared to the outer planets. As Earth approaches, aligns, and then "laps" the outer planets, they change position from ahead to behind from the Earth's perspective. This perspective shift is what causes the outer planets to change position in the night sky. An animation corresponding to today’s image shows Saturn and Neptune’s months-long dance across the northern night sky. Saturn stepped from the Pisces constellation into Aquarius and back again while Neptune remained in Pisces. This is the closest Saturn and Neptune have been in the sky since their last conjunction in 1989.
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Orion over Mount Teide

Published: 1 week ago | Author: Jerry Bonnell (UMCP)

A starry sky is seen above a snowy volcano peak. The sky is
bright with many stars and red nebula. In the foreground is dark
soil and green evergreen trees. 
Please see the explanation for more detailed information.
Explanation: Orion is rarely seen like this. To achieve this majestic vista, you need a camera capable of taking such long duration exposures that faint features in the night sky become revealed. Iconic nebulas that appear include the Orion Nebula, the Flame Nebula, and Barnard's Loop. For contrast, it also helps to have a volcano on the foreground, in this case the Teide volcano on Tenerife on the Canary Islands of Spain. But if you want your Teide volcano snow-covered, you also need good timing -- because that only happens, typically, for a few days each year. Good timing also includes waiting for Orion to appear just behind Teide, which occurred late last year after sunset. The featured image is the result of a series of images taken consecutively with the same camera from the same location.
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Trifid Pillars and Jets

Published: 1 week ago | Author: Jerry Bonnell (UMCP)

A field of stars on the left is mirred by a wall of
opaque brown dust on the right. Jutting out from the wall is
a long pillar with a rounded end that has a prominent light-
colored jet emanating toward the upper left. The stellar 
background toward the upper left is dark blue.
Please see the explanation for more detailed information.
Explanation: Dust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are slowly being eroded away by a hostile environment. Visible in the featured picture by the Hubble Space Telescope is the end of a huge gas and dust pillar in the Trifid Nebula (M20), punctuated by a smaller pillar pointing up and an unusual jet pointing to the upper left. Many of the bright dots are newly formed stars. A star near the small pillar's end is slowly being stripped of its accreting gas by radiation from a tremendously brighter star situated off the top of the image. The jet extends nearly a light-year and would not be visible without external illumination. As gas and dust evaporate from the pillars, the hidden stellar source of this jet will likely be uncovered, possibly over the next 20,000 years.
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Seeing Titan

Published: 1 week ago | Author: Jerry Bonnell (UMCP)

See Explanation.  Clicking on the picture will download
the highest resolution version available.
Explanation: Shrouded in a thick atmosphere, the surface of Saturn's largest moon, Titan, is really hard to see. Small particles suspended in Titan's upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding surface features from prying eyes. Still, Titan's surface is better imaged at infrared wavelengths, where scattering is weaker and atmospheric absorption is reduced. Arrayed around this visible light image (center) of Titan are some of the clearest global infrared views of the tantalizing moon so far. In false color, the six panels present a consistent processing of 13 years of infrared image data from the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft orbiting Saturn from 2004 to 2017. They offer a stunning comparison with Cassini's visible light view. NASA's revolutionary rotorcraft mission to Titan's surface is due to launch no earlier than July, 2028.
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Markarian's Chain

Published: 1 week ago | Author: Jerry Bonnell (UMCP)

See Explanation.  Clicking on the picture will download
the highest resolution version available.
Explanation: Near the heart of the Virgo Galaxy Cluster, a string of galaxies known as Markarian's Chain stretches across this telescopic field of view. Anchored in the frame at bottom right by prominent lenticular galaxies, M84 (bottom) and M86, you can follow the chain's gentle arc up and toward the left. Near center you'll spot the pair of interacting galaxies NGC 4438 and NGC 4435, known to some as Markarian's Eyes. An estimated 50 million light-years distant, the Virgo Cluster itself is the nearest galaxy cluster. With up to about 2,000 member galaxies, it has a noticeable gravitational influence on our own Local Group of Galaxies. Within the Virgo Cluster at least seven galaxies in Markarian's Chain appear to move coherently, while others may appear to be part of the chain by chance.
Enclosure