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 June 20

Rock Fingers on Mars

Image Credit: NASA, JPL-Caltech, MSSS

Explanation: There, just right of center, what is that? The surface of Mars keeps revealing new surprises with the recent discovery of finger-like rock spires. The small nearly-vertical rock outcrops were imaged last month by the robotic Curiosity rover on Mars. Although similar in size and shape to small snakes, the leading explanation for their origin is as conglomerations of small minerals left by water flowing through rock crevices. After these relatively dense minerals filled the crevices, they were left behind when the surrounding rock eroded away. Famous rock outcrops on Earth with a similar origin are called hoodoos. NASA’s Curiosity Rover continues to search for new signs of ancient water in Gale Crater on Mars, while also providing a geologic background important for future human exploration.

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 June 19

Use this link to see Game: Super Planet Crash

Game Credit & License: Stefano Meschiari (U. Texas at Austin) & the SAVE/Point Team

Explanation: Can you create a planetary system that lasts for 1000 years? Super Planet Crash, the featured game, allows you to try. To create up to ten planets, just click anywhere near the central star. Planet types can be selected on the left in order of increasing mass: Earth, Super-Earth, Ice giant, Giant planet, Brown dwarf, or Dwarf star. Each planet is gravitationally attracted not only to the central Sun-like star, but to other planets. Points are awarded, with bonus factors applied for increasingly crowded and habitable systems. The game ends after 1000 years or when a planet is gravitationally expelled. Many exoplanetary systems are being discovered in recent years, and Super Planet Crash demonstrates why some remain stable. As you might suspect after playing Super Planet Crash a few times, there is reason to believe that our own Solar System has lost planets during its formation.

 

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 June 18

The Gamma Cygni Nebula

Image Credit & Copyright: Min Xie, Chen Wu, Yizhou Zhang, and Benchu Tang

Explanation: Supergiant star Gamma Cygni is at the center of the Northern Cross. Near the plane of our Milky Way galaxy, that famous asterism flies high in northern summer night skies in the constellation Cygnus the Swan. Known by the proper name Sadr, Gamma Cygni also lies just below center in this telescopic skyscape, with colors mapped from both broadband and narrowband image data. The field of view spans about 3 degrees (six Full Moons) on the sky and includes emission nebula IC 1318 and open star cluster NGC 6910. Filling the upper part of the frame and shaped like two glowing cosmic wings divided by a long dark dust lane, IC 1318’s popular name is understandably the Butterfly Nebula. Right of Gamma Cygni, are the young, still tightly grouped stars of NGC 6910. The distance to Gamma Cygni is around 560 parsecs or 1,800 light-years. Estimates for IC 1318 and NGC 6910 range from 2,000 to 5,000 light-years.

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 June 17

Good Morning Planets from Chile

Image Credit & Copyright: Elke Schulz (Daniel Verschatse Observatory)

Explanation: On June 15, innermost planet Mercury had wandered about as far from the Sun as it ever gets in planet Earth’s sky. Near the eastern horizon just before sunrise it stands over distant Andes mountain peaks in this predawn snapshot from the valley of Rio Hurtado in Chile. June’s other morning planets are arrayed above it, as all the naked-eye planets of the Solar System stretch in a line along the ecliptic in the single wide-field view. Tilted toward the north, the Solar System’s ecliptic plane arcs steeply through southern hemisphere skies. Northern hemisphere early morning risers will see the lineup of planets along the ecliptic at a shallower angle tilting toward the south. From both hemispheres June’s beautiful morning planetary display finds the visible planets in order of their increasing distance from the Sun.

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 June 15

In the Heart of the Virgo Cluster

Image Credit & Copyright: Saulius Adomaitis

Explanation: The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky – about 10 times the angle made by a full Moon. With its heart lying about 70 million light years distant, the Virgo Cluster is the nearest cluster of galaxies, contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The cluster contains not only galaxies filled with stars but also gas so hot it glows in X-rays. Motions of galaxies in and around clusters indicate that they contain more dark matter than any visible matter we can see. Pictured here, the heart of the Virgo Cluster includes bright Messier galaxies such as Markarian’s Eyes on the upper left, M86 just to the upper right of center, M84 on the far right, as well as spiral galaxy NGC 4388 at the bottom right.

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 June 14

Satellites Behind Pinnacles

Image Credit & Copyright: Joshua Rozells

Explanation: What are all those streaks across the background? Satellite trails. First, the foreground features picturesque rock mounds known as Pinnacles. Found in the Nambung National Park in Western Australia, these human-sized spires are made by unknown processes from ancient sea shells (limestone). Perhaps more eye-catching, though, is the sky behind. Created by low-Earth orbit satellites reflecting sunlight, all of these streaks were captured in less than two hours and digitally combined onto the single featured image, with the foreground taken consecutively by the same camera and from the same location. Most of the streaks were made by the developing Starlink constellation of communication satellites, but some are not. In general, the streaks are indicative of an increasing number of satellites nearly continuously visible above the Earth after dusk and before dawn. Understanding and removing the effects of satellite trails on images from Earth’s ground-based cameras and telescopes is now important not only for elegant astrophotography, but for humanity’s scientific understanding of the distant universe.

 

Astrophysicists: Browse 2,800+ codes in the Astrophysics Source Code Library

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 June 13

M51: The Whirlpool Galaxy from Hubble

Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Bernard Miller

Explanation: The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The featured image is a digital combination of images taken in different colors by the Earth-orbiting Hubble Space Telescope, highlighting many sharp features. Anyone with a good pair of binoculars, however, can see this Whirlpool toward the constellation of the Hunting Dogs (Canes Venatici). M51 is a spiral galaxy of type Sc and is the dominant member of a whole group of galaxies. Astronomers speculate that M51‘s spiral structure is primarily due to its gravitational interaction with the smaller galaxy on the image left.

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 June 12

Find the Man in the Moon

Image Credit & Copyright: Dani Caxete

Explanation: Have you ever seen the Man in the Moon? This common question plays on the ability of humans to see pareidolia — imagining familiar icons where they don’t actually exist. The textured surface of Earth’s full Moon is home to numerous identifications of iconic objects, not only in modern western culture but in world folklore throughout history. Examples, typically dependent on the Moon‘s perceived orientation, include the Woman in the Moon and the Rabbit in the Moon. One facial outline commonly identified as the Man in the Moon starts by imagining the two dark circular areas — lunar maria — here just above the Moon‘s center, to be the eyes. Surprisingly, there actually is a man in this Moon image — a close look will reveal a real person — with a telescope — silhouetted against the Moon. This featured well-planned image was taken in 2016 in Cadalso de los Vidrios in Madrid, Spain. Do you have a favorite object that you see in the 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 June 11

The Road and the Milky Way

Image Credit & Copyright: David Cruz

Explanation: At night you can follow this road as it passes through the Dark Sky Alqueva reserve not too far from Alentejo, Portugal. Or you could stop, look up, and follow the Milky Way through the sky. Both stretch from horizon to horizon in this 180 degree panorama recorded on June 3. Our galaxy’s name, the Milky Way, does refer to its appearance as a milky path in the sky. The word galaxy itself derives from the Greek for milk. From our fair planet the arc of the Milky Way is most easily visible on moonless nights from dark sky areas, though not quite so bright or colorful as in this image. The glowing celestial band is due to the collective light of myriad stars along the galactic plane too faint to be distinguished individually. The diffuse starlight is cut by dark swaths of the galaxy’s obscuring interstellar dust clouds. Standing above the Milky Way arc near the top of this panoramic nightscape is bright star Vega, with the galaxy’s central bulge near the horizon at the right.