Nombre total de pages vues

15/11/2019

Science & Technology - Astronomy picture of the day : M16 and the Eagle Nebula

See Explanation.  Clicking on the picture will download
the highest resolution version available.
M16 and the Eagle Nebula 
Image Credit & Copyright: Martin Pugh

Explanation: A star cluster around 2 million years young surrounded by natal clouds of dust and glowing gas, M16 is also known as The Eagle Nebula. This beautifully detailed portrait of the region was made with groundbased narrow and broadband image data. It includes cosmic sculptures made famous in Hubble Space Telescope close-ups of the starforming complex. Described as elephant trunks or Pillars of Creation, dense, dusty columns rising near the center are light-years in length but are gravitationally contracting to form stars. Energetic radiation from the cluster stars erodes material near the tips, eventually exposing the embedded new stars. Extending from the ridge of bright emission at lower left is another dusty starforming column known as the Fairy of Eagle Nebula. M16 lies about 7,000 light-years away, an easy target for binoculars or small telescopes in a nebula rich part of the sky toward the split constellationSerpens Cauda (the tail of the snake).

14/11/2019

Science & Technology - Astronomy picture of the day : Curiosity Rover Finds a Clay Cache on Mars

2019 October 29
See Explanation.  Clicking on the picture will download
the highest resolution version available.
Curiosity Rover Finds a Clay Cache on Mars 
Image Credit: NASAJPL-CaltechMSSS
Explanation: Why is there clay on Mars? On Earth, clay can form at the bottom of a peaceful lake when specific minerals trap water. At the pictured site on Mars, the robotic rover Curiosity drilled into two rocks and found the highest concentration of clay yet. The clay cache is considered addition evidence that Gale Crater once held water in the distant past. Pictured, 57 images taken by Curiosity have been combined into a selfie. The images were taken by a camera at the end of its robotic arm. Many details of the car-sized rover are visible, including its rugged wheels, numerous scientific instruments, and a high mast that contains camera "eyes", one of which can shoot out an infrared laser beam. Curiosity continues to roll around and up Mount Sharp -- in the center of Gale Crater -- in a search for new clues about the ancient history of Mars and whether or not the red planet once had conditions that could support life.

13/11/2019

Science & Technology - Astronomy picture of the day : Comet Halley's Nucleus

November 13, 2019
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.
Comet Halley's Nucleus
Credit:
 Halley Multicolour Camera Team, GiottoESA
CopyrightMPAE
Explanation: Here is what a comet nucleus really looks like. For all active comets except Halley, it was only possible to see the surrounding opaque gas cloud called the coma. During Comet Halley's most recent pass through the innerSolar System in 1986, however, spacecraft Giotto was able to go right up to the comet and photograph its nucleus. The above image is a composite of hundreds of these photographs. Although the most famous comet, Halley achieved in 1986 only 1/10th the brightness that Comet Hyakutake did last year, and a similar comparison is likely with next year's pass of Comet Hale-Bopp. Every 76 years Comet Halley comes around again, and each time the nucleus sheds about 6 meters of ice and rock into space. This debris composes Halley's tails and leaves an orbiting trail that, when falling to Earth, are called the Orionids Meteor Shower.

12/11/2019

Musica - Video - Monteverdi : "Lamento della Ninfa"

"Lamento della Ninfa"

Science & Technology - Astronomy picture of the day : NGC 3717 : A Nearly Sideways Spiral Galaxy

2019 November 12
See Explanation.  Clicking on the picture will download
the highest resolution version available.
NGC 3717: A Nearly Sideways Spiral Galaxy 
Image Credit: ESA/Hubble & NASAProcessing: D. Rosario
Explanation: Some spiral galaxies are seen nearly sideways. Most bright stars in spiral galaxies swirl around the center in a disk, and seen from the side, this disk can be appear quite thin. Some spiral galaxies appear even thinner thanNGC 3717, which is actually seen tilted just a bit. Spiral galaxies form disks because the original gas collided with itself and cooled as it fell inward. Planets may orbit in disks for similar reasons. The featured image by the Hubble Space Telescope shows a light-colored central bulge composed of older stars beyond filaments of orbiting dark brown dustNGC 3717 spans about 100,000 light years and lies about 60 million light years away toward the constellation of the Water Snake (Hydra).

11/11/2019

Science & Technology - Astronomy picture of the day : Lunar Craters Langrenus and Petavius

2019 November 11
See Explanation.  Clicking on the picture will download
the highest resolution version available.
Lunar Craters Langrenus and Petavius 
Image Credit & Copyright: Eduardo Schaberger Poupeau
Explanation: The history of the Moon is partly written in its craters. Pictured here is a lunar panorama taken from Earth featuring the large craters Langrenus, toward the left, and Petavius, toward the right. The craters formed in separate impactsLangrenus spans about 130 km, has a terraced rim, and sports a central peak rising about 3 km. Petavius is slightly larger with a 180 km diameter and has a distinctive fracture that runs out from its center. Although it is known that Petravius crater is about 3.9 billion years old, the origin of its large fracture is unknown. The craters are best visible a few days after a new Moon, when shadows most greatly accentuate vertical walls and hills. Thefeatured image is a composite of the best of thousands of high-resolution, infrared, video images taken through a small telescope. Although mountains on Earth will likely erode into soil over a billion years, lunar craters Langrenus and Petavius will likely survive many billions more years, possibly until the Sun expands and engulfs both the Earth and Moon.

10/11/2019

Science & Technology - Astronomy picture of the day : A Mercury Transit Sequence

2019 November 10
See Explanation.  Clicking on the picture will download
the highest resolution version available.
A Mercury Transit Sequence 
Image Credit & Copyright: Dominique Dierick
Explanation: Tomorrow -- Monday -- Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2016. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun. The featured time-lapse sequence, superimposed on a single frame, was taken from a balcony in Belgium shows the entire transit of 2003 May 7. That solar crossing lasted over five hours, so that the above 23 images were taken roughly 15 minutes apart. The north pole of the Sun, the Earth's orbit, and Mercury's orbit, although all different, all occur in directions slightly above the left of the image. Near the center and on the far right, sunspots are visible. After Monday, the next transit of Mercury will occur in 2032.

09/11/2019

Sciece & Technology - Astronomy picture of the day : Saturn the Giant

2019 November 9
See Explanation.  Clicking on the picture will download
the highest resolution version available.
Saturn the Giant 
Image Credit: NASA
Explanation: On May 25, 1961 U.S. president John Kennedy announced the goal of landing astronauts on the Moon by the end of the decade. By November 9, 1967 this Saturn V rocket was ready for launch and the first full test of its capabilities on the Apollo 4 mission. Its development directed by rocket pioneer Wernher Von Braun, the three stage Saturn V stood over 36 stories tall. It had a cluster of five first stage engines fueled by liquid oxygen and kerosene which together were capable of producing 7.9 million pounds of thrust. Giant Saturn V rockets ultimately hurled nine Apollo missions to the Moon and back again with six landing on the lunar surface. The first landing mission, Apollo 11, achieved Kennedy's goal on July 20, 1969.

07/11/2019

Science & Technology - Astronomy picture of the day - Messier 45: The Daughters of Atlas and Pleione

2019 November 7
See Explanation.  Clicking on the picture will download
the highest resolution version available.
Messier 45: The Daughters of Atlas and Pleione 
Image Credit & Copyright: Adam BlockSteward Observatory, University of Arizona
Explanation: Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters open star cluster is well-known for its striking blue reflection nebulae. It lies in the night sky toward the constellation Taurus and the Orion Arm of our Milky Way Galaxy. The sister stars and cosmic dust cloud are not related though, they just happen to be passing through the same region of space. Known since antiquity as a compact grouping of stars, Galileo first sketched the star cluster viewed through his telescope with stars too faint to be seen by eye. Charles Messier recorded the position of the cluster as the 45th entry in his famous catalog of things which are not comets. In Greek myth, the Pleiades were seven daughters of the astronomical Titan Atlas and sea-nymph Pleione. Their parents names are included in the cluster's nine brightest stars. This deep and wide telescopic image spans over 20 light-years across the Pleides star cluster.

06/11/2019

Science & Technology - Astronomy picture of the day : 21st Century M101

2019 November 6
See Explanation.  Clicking on the picture will download
the highest resolution version available.
21st Century M101 
Image Credit: NASAESACXCJPL - CaltechSTScI
Explanation: One of the last entries in Charles Messier's famous catalog, big, beautiful spiral galaxy M101 is definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy. M101 was also one of the original spiral nebulae observed with Lord Rosse's large 19th century telescope, the Leviathan of Parsonstown. In contrast, this multiwavelength view of the large island universe is a composite of images recorded by space-based telescopes in the 21st century. Color coded from X-rays to infrared wavelengths (high to low energies), the image data was taken from the Chandra X-ray Observatory (purple), theGalaxy Evolution Explorer (blue), Hubble Space Telescope(yellow), and the Spitzer Space Telescope(red). While the X-ray data trace the location of multimillion degree gas around M101's exploded stars and neutron star and black hole binary star systems, the lower energy data follow the stars and dust that define M101's grand spiral arms. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

ASTRONOMY - Mimas: Small Moon with a Big Crater

 2025 January 12 Mimas: Small Moon with a Big Crater Image Credit:  NASA ,  JPL-Caltech ,  Space Science Institute ,  Cassini Explanation:  ...