Science & Technology - Astronomy picture of the day : Planetary Nebula Abell 78

 2020 October 16

Planetary Nebula Abell 78
Image Credit & Copyright: Bernhard Hubl

Explanation: Planetary nebula Abell 78 stands out in this colorful telescopic skyscape. In fact the colors of the spiky Milky Way stars depend on their surface temperatures, both cooler (yellowish) and hotter (bluish) than the Sun. But Abell 78 shines by the characteristic emission of ionized atoms in the tenuous shroud of material shrugged off from an intensely hot central star. The atoms are ionized, their electrons stripped away, by the central star's energetic but otherwise invisible ultraviolet light. The visible blue-green glow of loops and filaments in the nebula's central region corresponds to emission from doubly ionized oxygen atoms, surrounded by strong red emission from ionized hydrogen. Some 5,000 light-years distant toward the constellation Cygnus, Abell 78 is about three light-years across. A planetary nebula like Abell 78 represents a very brief final phase in stellar evolution that our own Sun will experience ... in about 5 billion years.

Science & Technology - Tour of Asteroid Benn

 

Science & Technology - Astronomy picture of the day : Galaxies in Pegasus

 2020 October 15

Galaxies in Pegasus
Image Credit & Copyright: Robert Eder

Explanation: This sharp telescopic view reveals galaxies scattered beyond the stars of the Milky Way, at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On the sky, the quintet and NGC 7331 are separated by about half a degree.

Science & Technology - Astronomy picture of the day : The Colorful Clouds of Rho Ophiuchi

 2020 October 14

The Colorful Clouds of Rho Ophiuchi
Image Credit & Copyright: Amir H. Abolfath

Explanation: The many spectacular colors of the Rho Ophiuchi (oh'-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the Rho Ophiuchi star system and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth's daytime sky appears blue for the same reason. The red and yellow regions shine primarily because of emission from the nebula's atomic and molecular gas. Light from nearby blue stars - more energetic than the bright star Antares - knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark brown regions are caused by dust grains - born in young stellar atmospheres - which effectively block light emitted behind them. The Rho Ophiuchi star clouds, well in front of the globular cluster M4 visible here on the upper right, are even more colorful than humans can see - the clouds emits light in every wavelength band from the radio to the gamma-ray.

Ciência e Tecnologia - Morte por 'esparguetificação'. Como um buraco negro engoliu uma estrela - Video

 ‘Esparguetificação’ quer dizer exatamente aquilo que parece. Imagine um fio de esparguete nos lábios e sugue-o até ele desaparecer dentro da boca. Basicamente foi isto que o buraco negro fez à estrela e os telescópicos do Observatório Astronómico do Sul (ESO), o Very Large Telescope (VLT) e o New Technology Telescope (NTT), estavam de lentes postas na situação.

Quando uma estrela infeliz se aproxima demasiado de um buraco negro supermassivo situado no centro de uma galáxia, a extrema atração gravitacional exercida pelo buraco negro desfaz a estrela em finas correntes de matéria,” explica Thomas Wevers, autor do estudo e bolseiro do ESO em Santiago do Chile, em comunicado de imprensa.

A estrela AT2019qiz, estava localizada num galáxia em espiral na constelação de Erídano, a cerca de 215 milhões de anos-luz da Terra. A estrela tinha uma massa equivalente à do nosso Sol, mas ficou reduzida a metade depois do encontro com o buraco negro que tinha mais de um milhão de vez a massa da estrela.

Observador - Portugal

Science & Technology - Astronomy picture of the day : Mars, Pleiades, and Andromeda over Stone Lions

 2020 October 13

Mars, Pleiades, and Andromeda over Stone Lions
Image Credit & Copyright: Cem Özkeser

Explanation: Three very different -- and very famous -- objects were all captured in a single frame last month. On the upper left is the bright blue Pleiades, perhaps the most famous cluster of stars on the night sky. The Pleiades (M45) is about 450 light years away and easily found a few degrees from Orion. On the upper right is the expansive Andromeda Galaxy, perhaps the most famous galaxy -- external to our own -- on the night sky. Andromeda (M31) is one of few objects visible to the unaided eye where you can see light that is millions of years old. In the middle is bright red Mars, perhaps the most famous planet on the night sky. Today Mars is at opposition, meaning that it is opposite the Sun, with the result that it is visible all night long. In the foreground is an ancient tomb in the Phygrian Valley in Turkey. The tomb, featuring two stone lions, is an impressive remnant of a powerful civilization that lived thousands of years ago. Mars, currently near its brightest, can be easily found toward the east just after sunset.

Science & Technology - Astronomy picture of the day : Descending Toward Asteroid Bennu

 2020 October 12

Descending Toward Asteroid Bennu
Video Credit: NASA, OSIRIS-REx, NASA's Scientific Visualization Studio; Data: NASA, U. Arizona, CSA, York U., MDA

Explanation: What would it be like to land on an asteroid? Although no human has yet done it, NASA's robotic OSIRIS-REx spacecraft is scheduled to attempt to touch the surface of asteroid 101955 Bennu next week. The goal is to collect a sample from the nearby minor planet for return to Earth for a detailed analysis in 2023. The featured video shows what it looks like to descend toward the 500-meter diamond-shaped asteroid, based on a digital map of Bennu's rocky surface constructed from image and surface data taken by OSIRIS-REx over the past 1.5 years. The video begins by showing a rapidly spinning Bennu -- much faster than its real rotation period of 4.3 hours. After the rotation stops, the virtual camera drops you down to just above the rugged surface and circles a house-sized rock outcrop named Simurgh, with the flatter outcrop Roc visible behind it. If the return sample reaches Earth successfully, it will be scrutinized for organic compounds that might have seeded a young Earth, rare or unusual elements and minerals, and clues about the early history of our Solar System.

Science & Technologie - Astronomy picture of the day : The Very Large Array at Moonset

 2020 10 octobre

The Very Large Array at Moonset
Image Credit: Jeff Hellermann, NRAO / AUI / NSF

Explication : Un spectacle inspirant, ces antennes géantes du Karl G. Jansky Very Large Array (VLA) s’élèvent au-dessus du désert du Nouveau-Mexique à moonset. Montées sur des piliers mais transportables sur les voies ferrées pour modifier la configuration du VLA, ses 27 antennes de fonctionnement sont chacune de la taille d’une maison (25 mètres de diamètre) et peuvent être organisées en un réseau couvrant la taille d’une ville (35 kilomètres). Un cheval de bataille prolifique de radioastronomie, le VLA a été utilisé pour découvrir l’eau sur la planète Mercure,coronae radio-brillante autour des étoiles, micro-quasars dans notre galaxie, gravitationnellement induit anneaux Einstein autour des galaxies lointaines, et les homologues radio à cosmologiquement lointains sursauts gamma. Sa grande taille a permis aux astronomes d’étudier les détails des galaxies radio, des jets cosmiques ultra-rapides, et de cartographier le centre de notre propre Voie lactée. Aujourd’hui, 40 ans après son dévouement, le VLA a été utilisé dans plus de 14 000 projets d’observation et a contribué à plus de 500 thèses de doctorat. Le 10 octobre, l’Observatoire national de radioastronomie organisera une journée de célébration en ligne de l’ALV à 40 ans avec des visites virtuelles et des présentations sur l’histoire, les opérations, la science et l’avenir du Very Large Array.

Science & Technologie - Astronomy picture of the day

2020 October 8

Mare Frigoris
Image Credit & Copyright: Matt Smith

Explanation: Lighter than typically dark, smooth, mare the Mare Frigoris lies in the far lunar north. Also known as the Sea of Cold, it stretches across the familiar lunar nearside in this close up of the waxing gibbous Moon's north polar region. Dark-floored, 95 kilometer wide crater Plato is just left of the center. Sunlit peaks of the lunar Alps (Montes Alpes) are highlighted below and right of Plato, between the more southern Mare Imbrium (Sea of Rains) and Mare Frigoris. The prominent straight feature cutting through the mountains is the lunar Alpine Valley (Vallis Alpes). Joining the Mare Imbrium and Mare Frigoris, the lunar valley is about 160 kilometers long and up to 10 kilometers wide.

Corn Moon Rising - (Science & Technology - Astronomy picture of the day)

2020 September 14
Corn Moon Rising 
Image Credit & Copyright: Zarcos Palma

Explanation: A rising moon can be a dramatic sight. A rising Full Corn Moon was captured early this month in time-lapse with a telephoto lens from nearly 30 kilometers away -- making Earth's ascending half-degree companion appear unusually impressive. The image was captured from Portugal, although much of the foreground -- including lights from the village of Puebla de Guzmán -- is in Spain. A Full Corn Moon is the name attributed to a full moon at this time of year by cultures of some northern indigenous peoples of the Americas, as it coincides with the ripening of corn. Note that the Moon does not appear larger when it is nearer the horizon -- its seemingly larger size there is only an illusion. The next full moon -- occurring at the beginning of next month -- will be known as the Full Harvest Moon as it occurs nearest in time to the northern autumnal equinox and the northern field harvests.