Astronomy picture of the day - 2017 April 17 - Two Million Stars on the Move

Two Million Stars on the Move 
Video Credit: ESA, Gaia, DPAC Explanation: If you could watch the night sky for one million years -- how would it change? Besides local effects caused by the Earth's spin and the reorientation of the Earth's spin axis, the stars themselves will move. Combining positional data of unprecedented accuracy for two-million stars taken over years by ESA's Earth-orbiting Hipparcos (now defunct) and Gaia satellites, a future extrapolation of star movements was made over millions years. As shown in the featured video, many stars make only small angular adjustments, but some stars -- typically those nearby -- will zip across the sky. Once familiar constellations and asterisms will become unrecognizable as the bright stars that formed them move around. Not shown are many local nebulas that will surely dissipate while new ones will likely form in different places. Perhaps reassuringly, future Earth inhabitants will still be able to recognize thecentral band of our Milky Way Galaxy.

Astronomy picture of the day - 2017 April 16 - Life-Enabling Plumes above Enceladus

Life-Enabling Plumes above Enceladus 
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Does Enceladus have underground oceans that could support life? The discovery of jets spewing water vapor and ice was detected by the Saturn-orbiting Cassini spacecraft in 2005. The origin of the water feeding the jets, however, was originally unknown. Since discovery, evidence has been accumulating that Enceladus has a deep underground sea, warmed by tidal flexing. Pictured here, the textured surface of Enceladus is visible in the foreground, while rows of plumes rise from ice fractures in the distance. These jets are made more visible by the Sun angle and the encroaching shadow of night. A recent fly-through has found evidence that a plume -- and so surely the underlying sea -- is rich in molecular hydrogen, a viable food source for microbes that could potentially be living there.

Cyndi Lauper - "Girls, just want to have fun" - Video - Music

"Girls, just want to have fun" 

Rui Veloso - "Porto sentido" - Audio - Musica

"Porto sentido"

Astronomy picture of the day - 2017 April 15 - Luminous Salar de Uyuni

Luminous Salar de Uyuni 
Image Credit & Copyright: Stephanie Ziyi Ye

Explanation: A scene in high contrast this thoughtful night skyscape is a modern composition inspired by M. C. Escher's lithograph Phosphorescent Sea. In it, bright familiar stars of Orion the Hunter and Aldebaran, eye of Taurus the Bull, hang in clear dark skies above a distant horizon. Below, faintly luminous edges trace an otherworldly constellation of patterns in mineral-crusted mud along the Uyuni Salt Flat of southwest Bolivia. The remains of an ancient lake, the Uyuni Salt Flat, Salar de Uyuni, is planet Earth's largest salt flat, located on the Bolivian Altiplano at an altitude of about 3,600 meters. Escher's 1933 lithograph also featured familiar stars in planet Earth's night, framing The Ploughor Big Dipper above waves breaking on a more northern shore.

Billy Joel - "Piano man" - Video - Music

"Piano man"

Astronomy picture of the day - 2017 April 14 - Earth Shadow over Damavand

Earth Shadow over Damavand 
Image Credit & Copyright: Majid Ghohroodi

Explanation: Through crystal clear skies this beautiful panorama follows the curve of planet Earth's shadow rising across the top of the world. The tantalizing twilight view is composed of eight single frames captured from 4,000 meters above sea level at sunset on April 6. Just above the dark grey Earth-shadow boundary lies a fading, pinkish, anti-twilight arch. Also known as the belt of Venus, its reddened and back-scattered sunlight finally merges with the still blue eastern sky. Standing tall near center along the rugged horizon line is the distant sharp peak of Mount Damavand in the snowy Alborz mountains. A feature in Persian mythology and literature, Damavand is a stratovolcano reaching 5,610 meters above sea level, the highest peak in Iran and the Middle East.

Now, it's time to say goodbye. Ciao, ciao, ciao!

             "CIAO, CIAO, CIAO..."

David Bowie - "Valentine's day" - Video - Music

"Valentine's day"

Construção de Ponte 25 de Abril - Video - Documentario

A ponte sobre o Rio Tejo que inicialmente tinha o nome de Ponte Salazar, e que depois do 25 de Abril teve o seu nome alterado para Ponte 25 de Abril, foi uma das maiores obras de sempre no nosso Portugal. Miguel Pais foi quem lançou a ideia em 1876, mas só quase um século depois é que a mesma viria a ficar finalizada.

Tendo começado a ser construída em 1962 e terminada em 1966, mais precisamente no dia 6 de Agosto de 1966 quando foi inaugurada, foi uma das poucas obras no nosso país desde então que foi projectada e construída, sem que houvessem derrapagens no orçamento. Foi uma obra feita há quase meio século, mas feita com pés e cabeça, note-se por exemplo que só várias décadas após a construção é que foi implementada a circulação de comboios, mas a ponte já estava preparada para isso. Se fosse actualmente mandava-se abaixo e construía-se outra…

Construção de Ponte 25 de Abril