Comet Hale Bopp Over Val Parola Pass

Comet Hale-Bopp, the Great Comet of 1997, became much brighter than any surrounding stars. It was seen even over bright city lights. Away from city lights, however, it put on quite a spectacular show. Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d’Ampezzo, Italy. Comet Hale-Bopp’s blue ion tail, consisting of ions from the comet’s nucleus, is pushed out by the solar wind. The white dust tail is composed of larger particles of dust from the nucleus driven by the pressure of sunlight, that orbit behind the comet. Comet Hale-Bopp (C/1995 O1) remained visible to the unaided eye for 18 months — longer than any other comet in recorded history. The large comet is next expected to return around the year 4385. This month, Comet Leonard is brightening and may soon become visible to the unaided eye. [via NASA] https://ift.tt/3lKdeld

Ninety Gravitational Wave Spectrograms and Counting

Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves. Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 — during the first three observing runs. Featured above are the spectrograms — plots of gravitational-wave frequency versus time — of these 90 as detected by the giant detectors of LIGO (in the USA), VIRGO (in Europe), and KAGRA (in Japan). The more energy received on Earth from a collision, the brighter it appears on the graphic. Among many science firsts, these gravitational-radiation chirps are giving humanity an unprecedented inventory of black holes and neutron stars, and a new way to measure the expansion rate of our universe. A fourth gravitational wave observing run with increased sensitivity is currently planned to begin in 2022 December. [via NASA] https://ift.tt/3rCin2y

Space Station Silhouette on the Moon

What’s that unusual spot on the Moon? It’s the International Space Station. Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit gibbous Moon last month. The featured composite, taken from Payson, Arizona, USA last month, was intricately composed by combining, in part, many 1/2000-second images from a video of the ISS crossing the Moon. A close inspection of this unusually crisp ISS silhouette will reveal the outlines of numerous solar panels and trusses. The bright crater Tycho is visible on the upper left, as well as comparatively rough, light colored terrain known as highlands, and relatively smooth, dark colored areas known as maria. On-line tools can tell you when the International Space Station will be visible from your area. [via NASA] https://ift.tt/3prSMXn

Total Solar Eclipse Below the Bottom of the World

Yesterday there was a total solar eclipse visible only at the end of the Earth. To capture the unusual phenomenon, airplanes took flight below the clouded seascape of Southern Ocean. The featured image shows one relatively spectacular capture where the bright spot is the outer corona of the Sun and the eclipsing Moon is seen as the dark spot in the center. A wing and engine of the airplane are visible across the left and bottom of the image, while another airplane observing the eclipse is visible on the far left. The dark area of the sky surrounding the eclipsed Sun is called a shadow cone. It is dark because you are looking down a long corridor of air shadowed by the Moon. A careful inspection of the eclipsed Sun will reveal the planet Mercury just to the right. The next total solar eclipse shadow will cross parts of Australia and Indonesia in April of 2023, while the one after that will cross North America in April of 2024. [via NASA] https://ift.tt/32QFV9q

Iridescent by Moonlight

In this snapshot from November 18, the Full Moon was not far from Earth’s shadow. In skies over Sicily the brightest lunar phase was eclipsed by passing clouds though. The full moonlight was dimmed and momentarily diffracted by small but similar sized water droplets near the edges of the high thin clouds. The resulting iridescence shines with colors like a lunar corona. On that night, the Full Moon was also seen close to the Pleiades star cluster appearing at the lower left of the iridescent cloud bank. The stars of the Seven Sisters were soon to share the sky with a darker, reddened lunar disk. [via NASA] https://ift.tt/3pjqheo

Comet Leonard and the Whale Galaxy

Sweeping through northern predawn skies, on November 24 Comet Leonard (C/2021 A1) was caught between two galaxies in this composite telescopic image. Sporting a greenish coma the comet’s dusty tail seems to harpoon the heart of NGC 4631 (top) also known as the Whale Galaxy. Of course NGC 4631 and NGC 4656 (bottom, aka the Hockey Stick) are background galaxies some 25 million light-years away. On that date the comet was about 6 light-minutes from our fair planet. Its closest approach to Earth (and even closer approach to Venus) still to come, Comet Leonard will grow brighter in December. Already a good object for binoculars and small telescopes, this comet will likely not return to the inner Solar System. Its perihelion, or closest approach to the Sun, will be on January 3, 2022. [via NASA] https://ift.tt/3pkHvrP

NGC 6822: Barnard s Galaxy

Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small galaxies form stars too, like nearby NGC 6822, also known as Barnard’s Galaxy. Beyond the rich starfields in the constellation Sagittarius, NGC 6822 is a mere 1.5 million light-years away, a member of our Local Group of galaxies. A dwarf irregular galaxy similar to the Small Magellanic Cloud, NGC 6822 is about 7,000 light-years across. Brighter foreground stars in our Milky Way have a spiky appearance. Behind them, Barnard’s Galaxy is seen to be filled with young blue stars and mottled with the telltale pinkish hydrogen glow of star forming regions in this deep color composite image. [via NASA] https://ift.tt/3loEUM7

A Blue Banded Blood Moon

What causes a blue band to cross the Moon during a lunar eclipse? The blue band is real but usually quite hard to see. The featured HDR image of last week’s lunar eclipse, however — taken from Yancheng, China — has been digitally processed to equalize the Moon’s brightness and exaggerate the colors. The gray color of the bottom right is the Moon’s natural color, directly illuminated by sunlight. The upper left part of the Moon is not directly lit by the Sun since it is being eclipsed — it in the Earth’s shadow. It is faintly lit, though, by sunlight that has passed deep through Earth’s atmosphere. This part of the Moon is red — and called a blood Moon — for the same reason that Earth’s sunsets are red: because air scatters away more blue light than red. The unusual blue band is different — its color is created by sunlight that has passed high through Earth’s atmosphere, where red light is better absorbed by ozone than blue. A total eclipse of the Sun will occur tomorrow but, unfortunately, totality be visible only near the Earth’s South Pole. [via NASA] https://ift.tt/32NNlue

In Motion: Uranus and Moons

What’s that moving across the sky? A planet just a bit too faint to see with the unaided eye: Uranus. The gas giant out past Saturn was tracked earlier this month near opposition — when it was closest to Earth and at its brightest. The featured video captured by the Bayfordbury Observatory in Hertfordshire, UK is a four-hour time-lapse showing Uranus with its four largest moons in tow: Titania, Oberon, Umbriel and Ariel. Uranus’ apparent motion past background stars is really dominated by Earth’s own orbital motion around our Sun. The cross seen centered on Uranus is called a diffraction spike and is caused by light diffracting around the four arms that hold one of the telescope’s mirrors in place. The rotation of the diffraction spikes is not caused by the rotation of Uranus but, essentially, by the rotation of the Earth. During the next few months Uranus itself will be visible with binoculars, but, as always, to see its moons will require a telescope. [via NASA] https://ift.tt/3d4C8aC

The Extraordinary Spiral in LL Pegasi

What created the strange spiral structure on the upper left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns, has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other. The star system that created it is most commonly known as LL Pegasi, but also AFGL 3068 and IRAS 23166+1655. The featured image was taken in near-infrared light by the Hubble Space Telescope. Why the spiral glows is itself a mystery, with a leading hypothesis being illumination by light reflected from nearby stars. [via NASA] https://ift.tt/3D6qPJo