ASTRONOMY - Pleiades: The Seven Sisters Star Cluster

 2021 November 24

Pleiades: The Seven Sisters Star Cluster
Image Credit & Copyright: Damien Cannane

Explanation: Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure, taken from Florida, USA, covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the Pleiades lies about 400 light years away toward the constellation of the Bull (Taurus). A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six of the sister stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the observer's eyesight.

ASTRONOMY - The Sun in X-rays from NuSTAR

 2021 November 23

The Sun in X-rays from NuSTAR
Image Credit: NASA, NuSTAR, SDO

Explanation: Why are the regions above sunspots so hot? Sunspots themselves are a bit cooler than the surrounding solar surface because the magnetic fields that create them reduce convective heating. It is therefore unusual that regions overhead -- even much higher up in the Sun's corona -- can be hundreds of times hotter. To help find the cause, NASA directed the Earth-orbiting Nuclear Spectroscopic Telescope Array (NuSTAR) satellite to point its very sensitive X-ray telescope at the Sun. Featured here is the Sun in ultraviolet light, shown in a red hue as taken by the orbiting Solar Dynamics Observatory (SDO). Superimposed in false-colored green and blue is emission above sunspots detected by NuSTAR in different bands of high-energy X-rays, highlighting regions of extremely high temperature. Clues about the Sun's atmospheric heating mechanisms come from NuSTAR images like this and shed light on solar nanoflares and microflares as brief bursts of energy that may drive the unusual heating.

ASTRONOMY - Lunar Eclipse over a Skyscraper

 2021 November 22

Lunar Eclipse over a Skyscraper
Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN)

Explanation: Why is the Moon on top of this building? Planning. It took the astrophotographer careful planning -- including figuring out exactly where to place the camera and exactly when to take the shot -- to create this striking superposition. The single image featured was taken in the early morning hours of November 19, near the peak of the partial lunar eclipse that was occurring as the Moon passed through the Earth's shadow. At this time, almost the entire Moon -- 99.1 percent of its area -- was in the darkest part of the Earth's shadow. The building is the Gran Torre Santiago building in Chile, the tallest building in South America. Although the entire eclipse lasted an impressive six hours, this image had to be taken within just a few seconds to get the alignment right -- the Earth's rotation soon moved the building out of alignment. The next Earth-Moon eclipse will be a total eclipse of the Sun that will occur on December 4 -- but only be visible from the bottom of our world.

CATASTROPHES MARITIMES - Titanic foi filmado pela primeira vez em 4K, veja como ele está hoje

O explorador que tirou as fotos de alta qualidade foi Victor Vescovo, já a empresa responsável foi a Triton Submarines.

O material obtido deverá ser utilizado na produção de um documentário da Atlantic Productions, que ainda não conta com data de lançamento.

De acordo com a empresa, as imagens do navio devem ajudar não só a avaliar a condição atual do Titanic, como também projetar seu futuro.

Além disso, segundo a nota divulgada pela Triton Submarines, as imagens devem possibilitar a visualização do naufrágio com a realidade aumentada (AR) e a tecnologia de realidade virtual (VR).

engenhariahoje

ASTRONOMY - Introducing Comet Leonard

 2021 November 21

Introducing Comet Leonard
Image Credit & Copyright: Dan Bartlett

Explanation: Here comes Comet Leonard. Comet C/2021 A1 (Leonard) was discovered as a faint smudge in January 2021 when it was out past Mars -- but its orbit will take the giant shedding ice-ball into the inner Solar System, passing near both Earth and Venus in December before it swoops around the Sun in early January 2022. Although comets are notoriously hard to predict, some estimations have Comet Leonard brightening to become visible to the unaided eye in December. Comet Leonard was captured just over a week ago already sporting a green-tinged coma and an extended dust tail. The featured picture was composed from 62 images taken through a moderate-sized telescope -- one set of exposures tracking the comet, while another set tracking the background stars. The exposures were taken from the dark skies above the Eastern Sierras (Mountains), near June Lake in California, USA. Soon after passing near the Earth in mid-December, the comet will shift from northern to southern skies.

ASTRONOMY - An Almost Total Lunar Eclipse

 2021 November 20

An Almost Total Lunar Eclipse
Image Credit & Copyright: Robert Fedez

Explanation: Predawn hours of November 19 found the Moon in partly cloudy skies over Cancun, Mexico. Captured in this telephoto snapshot, the lunar disk is not quite entirely immersed in Earth's dark umbral shadow during a long partial lunar eclipse. The partial eclipse was deep though, deep enough to show the dimmed but reddened light in Earth's shadow. That's a sight often anticipated by fans of total lunar eclipses. Wandering through the constellation Taurus, the eclipsed Moon's dimmer light also made it easier to spot the Pleiades star cluster. The stars of the Seven Sisters share this frame at the upper right, with the almost totally eclipsed Moon.

ASTRONOMY - NGC 281: Starless with Stars

 2021 November 19

NGC 281: Starless with Stars
Image Credit & Copyright: Wido Oerlemans - X-ray: Chandra, Infrared: Spitzer

Explanation: In visible light the stars have been removed from this narrow-band image of NGC 281, a star forming region some 10,000 light-years away toward the constellation Cassiopeia. Stars were digitally added back to the resulting starless image though. But instead of using visible light image data, the stars were added with X-ray data (in purple) from the Chandra X-ray Observatory and infrared data (in red) from the Spitzer Space Telescope. The merged multiwavelength view reveals a multitude of stars in the region's embedded star cluster IC 1590. The young stars are normally hidden in visible light images by the natal cloud's gas and obscuring dust. Also known to backyard astro-imagers as the Pacman Nebula for its overall appearance in visible light, NGC 281 is about 80 light-years across.

ASTRONOMY - Full Moonlight

 2021 November 18

Full Moonlight
Image Credit & Copyright: Zhengjie Wu and Jeff Dai (TWAN)

Explanation: A photographer in silhouette stands in bright moonlight as the Full Moon rises in this well-planned telephoto image. Of course, the Full Moon is normally the brightest lunar phase. But on November 18/19, the Full Moon's light will be dimmed during a deep partial lunar eclipse seen across much of planet Earth. At maximum eclipse only a few percent of the lunar disk's diameter should remain outside the Earth's dark umbral shadow when the Moon slides close to the shadow's southern edge. Near apogee, the farthest point in its orbit, the Moon's motion will be slow. That should make this second lunar eclipse of 2021 an exceptionally long partial lunar eclipse. For most of North America the eclipse partial phases will be visible in predawn hours. Since eclipses tend to come in pairs, this lunar eclipse will be followed by a solar eclipse in two weeks on December 4.

ASTRONOMY - NGC 3314: When Galaxies Overlap

 2021 November 17

NGC 3314: When Galaxies Overlap
Image Credit: NASA, ESA, Hubble; Processing & Copyright: William Ostling (The Astronomy Enthusiast)

Explanation: Why doesn't the nearby galaxy create a gravitational lensing effect on the background galaxy? It does, but since both galaxies are so nearby, the angular shift is much smaller than the angular sizes of the galaxies themselves. The featured Hubble image of NGC 3314 shows two large spiral galaxies which happen to line up exactly. The foreground spiral NGC 3314a appears nearly face-on with its pinwheel shape defined by young bright star clusters. Against the glow of the background galaxy NGC 3314b, though, dark swirling lanes of interstellar dust can also be seen tracing the nearer spiral's structure. Both galaxies appear on the edge of the Hydra Cluster of Galaxies, a cluster that is about 200 million light years away. Gravitational lens distortions are much easier to see when the lensing galaxy is smaller and further away. Then, the background galaxy may even be distorted into a ring around the nearer. Fast gravitational lens flashes due to stars in the foreground galaxy momentarily magnifying the light from stars in the background galaxy might one day be visible in future observing campaigns with high-resolution telescopes.

ASTRONOMY - Light Pillar over Volcanic Etna

 2021 November 15

Light Pillar over Volcanic Etna
Image Credit & Copyright: Giancarlo Tinè

Explanation: What happening above that volcano? Something very unusual -- a volcanic light pillar. More typically, light pillars are caused by sunlight and so appear as a bright column that extends upward above a rising or setting Sun. Alternatively, other light pillars -- some quite colorful -- have been recorded above street and house lights. This light pillar, though, was illuminated by the red light emitted by the glowing magma of an erupting volcano. The volcano is Italy's Mount Etna, and the featured image was captured with a single shot a few hours after sunset in mid-June. Freezing temperatures above the volcano's ash cloud created ice-crystals either in cirrus clouds high above the volcano -- or in condensed water vapor expelled by Mount Etna. These ice crystals -- mostly flat toward the ground but fluttering -- then reflected away light from the volcano's caldera.