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 July 8

Roots on a Rotating Planet

Image Credit & Copyright: Marcella Giulia Pace

Explanation: With roots on a rotating planet, an old tree is centered in this sequence of 137 exposures each 20 seconds long, recorded one night from northern Sicily. Digital camera and fisheye lens were fixed to a tripod to capture the dramatic timelapse, so the stars trailed through the region’s dark sky. Of course that makes it easy to spot the planet’s north celestial pole. The extension of Earth’s axis of rotation into space is toward the upper left, at the center of the concentric star trail arcs. The Milky Way is there too. The plane of our galaxy stretches across the wide field of view from north to east (left to right) creating a broader luminous band of diffuse starlight.

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 July 7

The NGC 6914 Complex

Image Credit & Copyright: Giorgio Ferrari

Explanation: A study in contrasts, this colorful skyscape features stars, dust, and glowing gas in the vicinity of NGC 6914. The interstellar complex of nebulae lies some 6,000 light-years away, toward the high-flying northern constellation Cygnus and the plane of our Milky Way Galaxy. Obscuring interstellar dust clouds appear in silhouette while reddish hydrogen emission nebulae, along with the dusty blue reflection nebulae, fill the cosmic canvas. Ultraviolet radiation from the massive, hot, young stars of the extensive Cygnus OB2 association ionize the region’s atomic hydrogen gas, producing the characteristic red glow as protons and electrons recombine. Embedded Cygnus OB2 stars also provide the blue starlight strongly reflected by the dust clouds. The over 1 degree wide telescopic field of view spans about 100 light-years at the estimated distance of NGC 6914.

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 July 5

A Molten Galaxy Einstein Ring

Image Credit: ESA/Hubble & NASA, S. Jha; Processing: Jonathan Lodge

Explanation: It is difficult to hide a galaxy behind a cluster of galaxies. The closer cluster’s gravity will act like a huge lens, pulling images of the distant galaxy around the sides and greatly distorting them. This is just the case observed in the featured image recently re-processed image from the Hubble Space Telescope. The cluster GAL-CLUS-022058c is composed of many galaxies and is lensing the image of a yellow-red background galaxy into arcs seen around the image center. Dubbed a molten Einstein ring for its unusual shape, four images of the same background galaxy have been identified. Typically, a foreground galaxy cluster can only create such smooth arcs if most of its mass is smoothly distributed — and therefore not concentrated in the cluster galaxies visible. Analyzing the positions of these gravitational arcs gives astronomers a method to estimate the dark matter distribution in galaxy clusters, as well as infer when the stars in these early galaxies began to form.

New APOD Social Mirrors in Arabic: On Facebook, Instagram, and Twitter

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 July 4

Strawberry Supermoon Over Devil’s Saddle

Image Credit & Copyright: Lorenzo Busilacchi

Explanation: Near the horizon the full moon often seems to loom large, swollen in appearance by the famous Moon illusion. But time-lapse image sequences demonstrate that the Moon’s angular size doesn’t really change as it rises or sets. Its color does, though. Recording a frame about every 60 seconds, this image also shows how red the Sun can look while low on the horizon. The featured montage was taken from Cagliari, Sardinia, Italy, the day after June’s Strawberry Moon, a full moon dubbed a supermoon due to its slightly larger-than-usual angular size. This Strawberry Supermoon is seen rising behind the Devil’s Saddle, a mountain named for the unusual moon-sized dip seen just to the right of the rising moon. A shrinking line-of-sight through planet Earth’s dense and dusty atmosphere shifted the moonlight from strawberry red through honey-colored and paler yellowish hues. That change seems appropriate for a northern June Full Moon also known as the Strawberry or Honey Moon. A Thunder Supermoon — the third of four supermoons in 2022 — will occur later this month.

Today’s Adventure Link: Click on “Cagliari”

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 July 3

Phobos: Doomed Moon of Mars

Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. These martian moons may well be captured asteroids originating in the main asteroid belt between Mars and Jupiter or perhaps from even more distant reaches of our Solar System. The larger moon, Phobos, is indeed seen to be a cratered, asteroid-like object in this stunning color image from the robotic Mars Reconnaissance Orbiter, with objects as small as 10 meters visible. But Phobos orbits so close to Mars – about 5,800 kilometers above the surface compared to 400,000 kilometers for our Moon – that gravitational tidal forces are dragging it down. In perhaps 50 million years, Phobos is expected to disintegrate into a ring of debris.