Magazine Posts

Fresh water collecting in the valleys between sand dunes in the Lençóis Maranhenses National Park in Brazil. A layer of rock beneath the sand prevents the rain water from dissipating during the rainy season, resulting in a broad expanse of lagoons.

Julius Dadalti, CC BY-SA 4.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

This composite of images spaced a weather-permitting 5 to 9 days apart, from 2024 September 19 (top right) through 2025 May 18 (bottom left), faithfully traces ruddy-colored Mars as it makes a clockwise loop through the constellations Gemini and Cancer in planet Earth's night sky. You can connect the dots and dates with your cursor over the image, but be sure to check out this animation of the Red Planet's 2024/25 retrograde motion. Of course Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the orbital motion of Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. In this case Mars' apparent eastward motion began to reverse around December 8, when it seemed to linger near open star cluster M44 in Cancer. After wandering back to the west, under Gemini's bright stars Castor and Pollux, Mars returned to pose near M44 by early May. At its brightest near opposition on 2025 January 16, Mars was a mere 96 million kilometers away.

Photo by Tunc Tezel

This stained glass window (1880) located in the Cathédrale Saint-Louis (La Rochelle, France) depicts Joan of Arc. Today is St. Joan's feast day.

Selbymay, CC BY-SA 3.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

Grand spiral galaxies often seem to get all the attention, flaunting young, bright, blue star clusters and pinkish star forming regions along graceful, symmetric spiral arms. But small galaxies form stars too, like irregular dwarf galaxy Sextans A. Its young star clusters and star forming regions are gathered into a gumdrop-shaped region a mere 5,000 light-years across. Seen toward the navigational constellation Sextans, the small galaxy lies some 4.5 million light-years distant. That puts it near the outskirts of the local group of galaxies, that includes the large, massive spirals Andromeda and our own Milky Way. Brighter Milky Way foreground stars appear spiky and yellowish in this colorful telescopic view of Sextans A.

Photo by Franz Hofmann

Kishū Kumano iwatake tori by Hiroshige II, a Japanese woodblock print in the ukiyo-e style, depicting the harvesting of iwatake mushrooms (Umbilicaria esculenta) near Kumano in the Kishū Domain.

Hiroshige II (1826-1869), Public domain, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

This might look like a double-bladed lightsaber, but these two cosmic jets actually beam outward from a newborn star in a galaxy near you. Constructed from Hubble Space Telescope image data, the stunning scene spans about half a light-year across Herbig-Haro 24 (HH 24), some 1,300 light-years or 400 parsecs away in the stellar nurseries of the Orion B molecular cloud complex. Hidden from direct view, HH 24's central protostar is surrounded by cold dust and gas flattened into a rotating accretion disk. As material from the disk falls toward the young stellar object, it heats up. Opposing jets are blasted out along the system's rotation axis. Cutting through the region's interstellar matter, the narrow, energetic jets produce a series of glowing shock fronts along their path.

Bicycle parked in front of a graffitied building façade with doors, in a street near Kloveniersburgwal, in Amsterdam, the Netherlands.

Basile Morin, CC BY-SA 4.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

Behold one of the most photogenic regions of the night sky, captured impressively. Featured, the band of our Milky Way Galaxy runs diagonally along the bottom-left corner, while the colorful Rho Ophiuchi cloud complex is visible just right of center and the large red circular Zeta Ophiuchi Nebula appears near the top. In general, red emanates from nebulas glowing in the light of excited hydrogen gas, while blue marks interstellar dust preferentially reflecting the light of bright young stars. Thick dust usually appears dark brown. Many iconic objects of the night sky appear, including (can you find them?) the bright star Antares, the globular star cluster M4, and the Blue Horsehead nebula. This wide field composite, taken over 17 hours, was captured from South Africa last June. Explore Your Universe: Random APOD Generator

Photo by Ireneusz Nowak

The window in a cafe in San Gimignano opens on Valdelsa, in Tuscany (Italy).

Rhododendrites, CC BY-SA 4.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

What’s happening in the center of spiral galaxy NGC 2566? First, the eight rays that appear to be coming out of the center in the featured infrared image are not real — they are diffraction spikes caused by the mechanical structure of the Webb space telescope itself. The center of NGC 2566 is bright but not considered unusual, which means that it likely contains a supermassive black hole, although currently not very active. At only 76 million light years away, the light we see from NGC 2566 today left when dinosaurs roamed the Earth. The picturesque galaxy is close enough so that Earthly telescopes, including Webb and Hubble, can resolve the turbulent clouds of gas and dust where stars can form and so allows study of stellar evolution. NGC 2566, similar in size to our Milky Way Galaxy, is notable for its bright central bar and its prominent outer spiral arms.

Runners in tunnel. São Martinho do Porto, Portugal.

Alvesgaspar, CC BY-SA 3.0, via Wikimedia Commons. View source.

NASA Astronomy Picture of the Day:

Jupiter is stranger than we knew. NASA's Juno spacecraft has now completed over 70 swoops past Jupiter as it moves around its highly elliptical orbit. Pictured from 2017, Jupiter is seen from below where, surprisingly, the horizontal bands that cover most of the planet disappear into swirls and complex patterns. A line of white oval clouds is visible nearer to the equator. Impressive results from Juno show that Jupiter's weather phenomena can extend deep below its cloud tops, that Jupiter's center has a core that is unexpectedly large and soft, and that Jupiter's magnetic field varies greatly with location. Although Juno is scheduled to keep orbiting Jupiter further into 2025, at some time the robotic spacecraft will be maneuvered to plunge into the giant planet. Jigsaw Jumble: Astronomy Puzzle of the Day

Photo by NASA, Juno, SwRI, MSSS; Processing & License: Gerald Eichstädt & Seán Doran