Astronomy picture of the day - 2017 October 3 - Ice Ring around Nearby Star Fomalhaut

Ice Ring around Nearby Star Fomalhaut 
Image Credit: ALMA (ESO/NAOJ/NRAO), M. MacGregor; NASA/ESA Hubble, P. Kalas; B. Saxton (NRAO/AUI/NSF)

Explanation: Why is there a large ice ring around Fomalhaut? This interesting star -- easily visible in the night sky -- lies only about 25 light-years away and is known to be orbited by at least one planet, Dagon, as well as several inner dust disks. More intriguing, perhaps, is an outer ring, first discovered about 20 years ago, that has an unusually sharp inner boundary. The featured recent image by the Atacama Large Millimeter Array (ALMA) shows this outer ring with complete and unprecedented detail -- in pink -- superposed on a Hubble image of the Fomalhaut system in blue. A leading theory holds that this ring resulted from numerous violent collisions involving icy comets and planetesimals, the component objects of planets, while the ring boundaries are caused by the gravity of yet unseen planets. If correct, any interior planets in the Fomalhaut system are likely being continually pelted by large meteors and comets -- an onslaught last seen in our own planetary system four billion years ago in an episode called the Late Heavy Bombardment.

Playing For Change - "Haiti oh" - Video - Music - Live outside

"Haiti oh"

Tom Petty - "Learning to fly" - Video - Music

"Learning to fly"

Sitios lindos de Portugal - Bosque no Jardim Publico - Evora

Bosque no Jardim Publico

Astronomy picture of the day - 2017 October 2 - Two Comets and a Star Cluster

Two Comets and a Star Cluster 
Image Credit & Copyright: Damian Peach

Explanation: Two unusual spots are on the move near the famous Pleiades star cluster. Shifting only a small amount per night, these spots are actually comets in our nearby Solar System that by chance wandered into the field of thelight-years distant stars. On the far left is comet C/2017 O1 ASAS-SN, a multi-kilometer block of evaporating ice sporting a bright coma of surrounding gas dominated by green-glowing carbon. Comet ASAS-SN1 shows a slight tail to its lower right. Near the frame center is comet C/2015 ER61 PanSTARRS, also a giant block of evaporating ice, but sporting a rather long tail to its right. On the upper right is the Pleiades, an open cluster dominated by bright blue stars illuminating nearby reflecting dust. This exposure, taken about two weeks ago, is so deep that the filamentary interstellar dust can be traced across the entire field. The Pleiades is visible to the unaided eye, but it should require binoculars to see the comets.

Astronomy picture of the day - 2017 October 1 - Concept Plane: Supersonic Green Machine

Concept Plane: Supersonic Green Machine 
Illustration Credit: NASA, Lockheed Martin Co.

Explanation: What will passenger airplanes be like in the future? To help brainstorm desirable and workable attributes, NASA sponsors design competitions. Shown here is an artist's depiction of a concept plane that was suggested in 2010. This futuristic plane would be expected to achieve supersonic speeds, possibly surpassing the speeds of the supersonic transport planes that ran commercially in the late twentieth century. In terms of noise reduction, the future aircraft has been drawn featuring an inverted V wing stretched over its engines. The structure is intended to reduce the sound from annoying sonic booms. Additionally, future airplanes would aim to have relatively little impact on our environment, including green limits on pollution and fuel consumption. Aircraft utilizing similar design concepts might well become operational by the 2030s.

Estatisticas - Os Paises que mais seguiram este blogue desde o seu inicio

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Sitios lindos de Portugal - Fonte na rua Serpa Pinto - Evora

Fonte na rua Serpa Pinto

Astronomy picture of the day - 2017 September 30 - Portrait of NGC 281

Portrait of NGC 281 
Image Credit & Copyright: Eric Coles and Mel Helm

Explanation: Look through the cosmic cloud cataloged as NGC 281 and you might miss the stars of open cluster IC 1590. Still, formed within the nebula that cluster's young, massive stars ultimately power the pervasive nebular glow. The eye-catching shapes looming in this portrait of NGC 281 are sculpted columns and dense dust globules seen in silhouette, eroded by intense, energetic winds and radiation from the hot cluster stars. If they survive long enough, the dusty structures could also be sites of future star formation. Playfully called the Pacman Nebula because of its overall shape, NGC 281 is about 10,000 light-years away in the constellation Cassiopeia. This sharp composite image was made through narrow-band filters, combining emission from the nebula's hydrogen, sulfur, and oxygen atoms in green, red, and blue hues. It spans over 80 light-years at the estimated distance of NGC 281.

Sitios lindos de Portugal - Rua Miguel Bombarda, Evora

Rua Miguel Bombarda, Évora