Magazine Posts

NASA Astronomy Picture of the Day:

This is a map of the universe. The Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory, Arizona, has finished its five-year survey. It observed more than 47 million galaxies and quasars and created a 3D map centered on the Earth. Today's featured image shows a thin slice of these data: the black gaps indicate where our Galaxy obscures distant objects. The feathery web in the inset shows the large scale structure of the universe. Light of the most distant galaxies shown here travelled for 11 billion years to reach the Earth. Galaxies cluster throughout cosmic history under the competing influences of gravity and dark energy, responsible for the accelerated expansion of the universe. Analysis of early DESI results hinted at the possibility that dark energy, described as a cosmological constant by Albert Einstein, may not be constant after all. But we still have to wait for the analysis of the now complete dataset. The nature of dark energy is the biggest mystery of cosmology.

Saint George; upper altarpiece of the main altar of the parish church St. Georg, built in 1750 - 1751 by Peter Thumb (1681–1767), Hüfingen-Mundelfingen, Baden-Württemberg, Germany. Today is Saint George's Day.

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

African Impact on Unsplash

"Giraffes and zebras are often found grazing together in the savannah grasslands in Africa. There is a particular reason for this. Giraffes have the advantage of spotting advancing predators from far away due to their long necks; on the other hand, zebras have incredible night vision. The pair are a formiddable force. Our photography volunteers in the Greater Kruger Area (South Africa) captured this relationship quite well on one of their daily game drives, during the infamous Golden Hour".

NASA Astronomy Picture of the Day:

What does it mean for the Earth to set? Artemis II Commander Reid Wiseman gave us another spectacular view of Earth from their historic flyby of the Moon. Commander Wiseman's video, taken with an iPhone at 8x zoom, shows our entire planet gradually blocked from view by the Moon. On the Earth, the 24-hour planetary rotation causes the Sun to set below your horizon every night. However, on Artemis II the Earthset was caused not by the Moon’s rotation but by the spacecraft moving behind the Moon (at about 55 seconds in this video). Once rare, views of Earth are now taken many times a day from many spacecraft, including NASA’s SWOT (Surface Water and Ocean Topography) satellite tracking freshwater resources and USGS Landsat 8 and 9 satellites supporting water management for farmers, for example. Space agencies around our home planet now work together to provide unique and ever-improving views of our Earth. Celebrate: Earth Day

Glaucidium cuculoides (Asian barred owlet) in Kaziranga National Park, Assam, India.

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

Willian Justen de Vasconcellos on Unsplash

NASA Astronomy Picture of the Day:

Why are there three arches across the sky instead of two? Last month, after being dropped off by a helicopter at a high mountain peak in the Alps near the Swiss Italian border, an adventurous astrophotographer expected two arches of our Milky Way galaxy to be visible during the night. These were the inner arch looking in toward the center of our galaxy on the left, visible just before sunrise, and the outer arch on the right visible just after sunset. But there were three arches. The surprised astrophotographer soon realized that the sky was so dark that an entire arc of faint zodiacal light was also noticeable -- sunlight scattered by inner Solar System dust. And it artfully connected the two Milky Way arches! The next morning a helicopter picked the astrophotographer back up, and after 40 hours of processing and combining that night's images, the featured triple-arch 360-degree panorama resulted. Jigsaw Vistas: Astronomy Puzzle of the Day

Photo by Angel Fux

The Capitoline Wolf is a bronze sculpture made by unknown Etruscan sculptors (5th century BC), with the twins Romulus and Remus added in the late 15th century AD, by sculptor Antonio del Pollaiuolo. The sculptural group depicts a scene from the legend of the founding of Rome, occurred on 21 April 753 BC.

CC0, via Wikimedia Commons. View source.

James Wainscoat on Unsplash

NASA Astronomy Picture of the Day:

The best way to see comet R3 PanSTARRS’s long tail is with a camera. This week, the recently brightened comet appears in northern skies to the east just before dawn, but is only barely visible to the unaided eye. The many-degree ion tail captured on long duration camera exposures is not unusual for a comet - it is primarily due to the Earth's nearly sideways view of the tail as it points away from the Sun. In the featured image taken last week, Comet C/2025 R3 (PanSTARRS) showed off its flowing tail through a valley between two peaks in the Himalayan mountains of India.   The comet passed its closest to the Sun yesterday. As it nears its closest approach to Earth next week, a bushy dust tail may become visible. The comet is slowly moving out of northern skies and by the end of the month will be visible after sunset in southern skies as it fades and leaves our Solar System.  Growing Gallery: Comet R3 PanSTARRS in 2026

Photo by Basudeb Chakrabarti & Samit Saha

A shepherd wearing a red turban, smiling and waving in the setting sun at Jawai Bandh in Rajasthan, India.

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