ASTRONOMY - M87's Central Black Hole in Polarized Light

 2021 March 31

M87's Central Black Hole in Polarized Light
Image Credit: Event Horizon Telescope Collaboration; Text: Jayanne English (U. Manitoba)

Explanation: To play on Carl Sagan’s famous words "If you wish to make black hole jets, you must first create magnetic fields." The featured image represents the detected intrinsic spin direction (polarization) of radio waves. The polarizationi is produced by the powerful magnetic field surrounding the supermassive black hole at the center of elliptical galaxy M87. The radio waves were detected by the Event Horizon Telescope (EHT), which combines data from radio telescopes distributed worldwide. The polarization structure, mapped using computer generated flow lines, is overlaid on EHT’s famous black hole image, first published in 2019. The full 3-D magnetic field is complex. Preliminary analyses indicate that parts of the field circle around the black hole along with the accreting matter, as expected. However, another component seemingly veers vertically away from the black hole. This component could explain how matter resists falling in and is instead launched into M87’s jet.

ASTRONOMY - M64: The Evil Eye Galaxy

 2021 March 29

M64: The Evil Eye Galaxy
Image Credit: ESA/Hubble & NASA & the PHANGS-HST Team; Acknowledgement: Judy Schmidt

Explanation: Who knows what evil lurks in the eyes of galaxies? The Hubble knows -- or in the case of spiral galaxy M64 -- is helping to find out. Messier 64, also known as the Evil Eye or Sleeping Beauty Galaxy, may seem to have evil in its eye because all of its stars rotate in the same direction as the interstellar gas in the galaxy's central region, but in the opposite direction in the outer regions. Captured here in great detail by the Earth-orbiting Hubble Space Telescope, enormous dust clouds obscure the near-side of M64's central region, which are laced with the telltale reddish glow of hydrogen associated with star formation. M64 lies about 17 million light years away, meaning that the light we see from it today left when the last common ancestor between humans and chimpanzees roamed the Earth. The dusty eye and bizarre rotation are likely the result of a billion-year-old merger of two different galaxies.

ASTRONOMY - SuitSat-1: A Spacesuit Floats Free

 2021 March 28

SuitSat-1: A Spacesuit Floats Free
Image Credit: ISS Expedition 12 Crew, NASA

Explanation: A spacesuit floated away from the International Space Station 15 years ago, but no investigation was conducted. Everyone knew that it was pushed by the space station crew. Dubbed Suitsat-1, the unneeded Russian Orlan spacesuit filled mostly with old clothes was fitted with a faint radio transmitter and released to orbit the Earth. The suit circled the Earth twice before its radio signal became unexpectedly weak. Suitsat-1 continued to orbit every 90 minutes until it burned up in the Earth's atmosphere after a few weeks. Pictured, the lifeless spacesuit was photographed in 2006 just as it drifted away from space station.

ASTRONOMY - The Medusa Nebula

 2021 March 26

The Medusa Nebula
Image Credit & Copyright: Josep Drudis

Explanation: Braided and serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend above and right of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

ASTRONOMY - Curiosity: Sol 3048

 2021 March 25

Curiosity: Sol 3048
Image Credit: NASA/JPL-Caltech - Processing: Elisabetta Bonora & Marco Faccin / aliveuniverse.today

Explanation: Before Perseverance there was Curiosity. In fact, the Curiosity rover accomplished the first sky crane maneuver touchdown on Mars on August 5, 2012. March 2, 2021 marked Curiosity's 3,048th martian day operating on the surface of the Red Planet. This 360 degree panorama from sol 3048 is a mosaic of 149 frames from Curiosity's Mastcam above the rover's deck. It includes 23 frames of icy, thin, high clouds drifting through the martian sky. The cloudy sky frames were recorded throughout that martian day and are digitally stitched together in the panoramic view. Near center is a layered and streaked Mont Mercou. The peak of central Mount Sharp, rising over 5 kilometers above the floor of Gale Crater, is in the distant background on the left.

ASTRONOMY - Aurorae and Lightning on Jupiter

 2021 March 24

Aurorae and Lightning on Jupiter
Image Credit: NASA, JPL-Caltech, SwRI; Text: Natalia Lewandowska

Explanation: Why does so much of Jupiter's lightning occur near its poles? Similar to Earth, Jupiter experiences both aurorae and lightning. Different from Earth, though, Jupiter's lightning usually occurs near its poles -- while much of Earth's lightning occurs near its equator. To help understand the difference, NASA's Juno spacecraft, currently orbiting Jupiter, has observed numerous aurora and lightning events. The featured image, taken by Juno's Stellar Reference Unit camera on 2018 May 24, shows Jupiter's northern auroral oval and several bright dots and streaks. An eye-catching event is shown in the right inset image -- which is a flash of Jupiter's lightning -- one of the closest images of aurora and lightning ever. On Earth (which is much nearer to the Sun than Jupiter), sunlight is bright enough to create, by itself, much stronger atmospheric heating at the equator than the poles, driving turbulence, storms, and lightning. On Jupiter, in contrast, atmospheric heating comes mostly from its interior (as a remnant from its formation), leading to the hypothesis that more intense equatorial sunlight reduces temperature differences between upper atmospheric levels, hence reducing equatorial lightning-creating storms.

SANTé/MéDECINE - Pourquoi l'oreille humaine ne capte pas les ultrasons ?

La fonction principale de notre appareil auditif est de capter les sons. En dehors des cas de déficiences auditives comme la surdité, cette fonction a des limites naturelles, notamment en ce qui concerne sa capacité à capter les ultrasons. Mais à quoi est due cette incapacité ?

Une configuration naturelle de l’oreille

L’appareil auditif de l’homme est composé de plusieurs organes chargés les uns de conduire, les autres de traduire les ondes sonores perçues. Selon leur configuration, ces différents organes sont naturellement limités dans leur capacité à percevoir et traduire les sons.

L’oreille humaine perçoit les ondes sonores comprises entre 20 Hz correspondant aux sons graves et 20 000 Hz représentant les sons aigus. On parle donc d’ultrasons lorsque les ondes sont supérieures à 20 000 Hz.

Une protection naturelle

L’incapacité de perception des ultrasons n’est en rien une défaillance. La nature étant bien faite, elle a fait en sorte que ça soit le cas pour protéger nos oreilles en limitant la capacité des organes internes.

Pour être traduites, les ondes sont d’abord amplifiées sur la base d’une fréquence de résonnance qui varie entre 1000Hz et 4000 Hz et l’énergie acoustique est convertie en énergie électrique.

À un certain seuil, les organes les plus sensibles peuvent subir des dommages irréversibles. C’est pour cette raison qu’une barrière naturelle est formée par les muscles du marteau et de l’étrier se contractent pour limiter l’intensité des sons perçus.

ASTRONOMY - From Auriga to Orion

 2021 March 22

From Auriga to Orion
Image Credit & Copyright: Alistair Symon

Explanation: What's up in the sky from Auriga to Orion? Many of the famous stars and nebulas in this region were captured on 34 separate images, taking over 430 hours of exposure, and digitally combined to reveal the featured image. Starting on the far upper left, toward the constellation of Auriga (the Chariot driver), is the picturesque Flaming Star Nebula (IC 405). Continuing down along the bright arc of our Milky Way Galaxy, from left to right crossing the constellations of the Twins and the Bull, notable appearing nebulas include the Tadpole, Simeis 147, Monkey Head, Jellyfish, Cone and Rosette nebulas. In the upper right quadrant of the image, toward the constellation of Orion (the hunter), you can see Sh2-264, the half-circle of Barnard's Loop, and the Horsehead and Orion nebulas. Famous stars in and around Orion include, from left to right, orange Betelgeuse (just right of the image center), blue Bellatrix (just above it), the Orion belt stars of Mintaka, Alnilam, and Alnitak, while bright Rigel appears on the far upper right. This stretch of sky won't be remaining up in the night very long -- it will be setting continually earlier in the evening as mid-year approaches.

ASTRONOMY - The Antikythera Mechanism

 2021 March 21

The Antikythera Mechanism
Image Credit & License: Marsyas, Wikipedia

Explanation: No one knew that 2,000 years ago, the technology existed to build such a device. The Antikythera mechanism, pictured, is now widely regarded as the first computer. Found at the bottom of the sea aboard a decaying Greek ship, its complexity prompted decades of study, and even today some of its functions likely remain unknown. X-ray images of the device, however, have confirmed that a main function of its numerous clock-like wheels and gears is to create a portable, hand-cranked, Earth-centered, orrery of the sky, predicting future star and planet locations as well as lunar and solar eclipses. The corroded core of the Antikythera mechanism's largest gear is featured, spanning about 13 centimeters, while the entire mechanism was 33 centimeters high, making it similar in size to a large book. Recently, modern computer modeling of missing components is allowing for the creation of a more complete replica of this surprising ancient machine.

ASTRONOMY - The Leo Trio

 2021 March 20

The Leo Trio
Image Credit & Copyright: Francis Bozon

Explanation: This popular group leaps into the early evening sky around the March equinox and the northern hemisphere spring. Famous as the Leo Triplet, the three magnificent galaxies found in the prominent constellation Leo gather here in one astronomical field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (right), M66 (upper left), and M65 (bottom). All three are large spiral galaxies but tend to look dissimilar, because their galactic disks are tilted at different angles to our line of sight. NGC 3628, also known as the Hamburger Galaxy, is temptingly seen edge-on, with obscuring dust lanes cutting across its puffy galactic plane. The disks of M66 and M65 are both inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the group have left telltale signs, including the tidal tails and warped, inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans over 1 degree (two full moons) on the sky in a frame that covers over half a million light-years at the trio's estimated distance of 30 million light-years. Of course the spiky foreground stars lie well within our own Milky Way.

ASTRONOMY - Central Lagoon in Infrared

 2021 March 19

Central Lagoon in Infrared
Image Credit & License: NASA, ESA, Hubble; Data Archive: MAST, Processing: Alexandra Nachman

Explanation: Stars fill this infrared view, spanning 4 light-years across the center of the Lagoon Nebula. Visible light images show the glowing gas and obscuring dust clouds that dominate the scene. But this infrared image, constructed from Hubble Space Telescope data, peers closer to the heart of the active star-forming region revealing newborn stars scattered within, against a crowded field of background stars toward the center of our Milky Way galaxy. This tumultuous stellar nursery's central regions are sculpted and energized by the massive, young Herschel 36, seen as the bright star near center in the field of view. Herschel 36 is actually a multiple system of massive stars. At over 30 times the mass of the Sun and less than 1 million years old, the most massive star in the system should live to a stellar old age of 5 million years. Compare that to the almost 5 billion year old Sun which will evolve into a red giant in only another 5 billion years or so. The Lagoon Nebula, also known as M8, lies about 4,000 light-years away within the boundaries of the constellation Sagittarius.

ASTRONOMY - Stardust in the Perseus Molecular Cloud

 2021 March 18

Stardust in the Perseus Molecular Cloud
Image Credit & Copyright: Kerry-Ann Lecky Hepburn, Stuart Heggie

Explanation: Clouds of stardust drift through this deep skyscape, across the Perseus molecular cloud some 850 light-years away. Dusty nebulae reflecting light from embedded young stars stand out in the nearly 2 degree wide telescopic field of view. With a characteristic bluish color reflection nebula NGC 1333 is at center, vdB 13 at top right, with rare yellowish reflection nebula vdB 12 near the top of the frame. Stars are forming in the molecular cloud, though most are obscured at visible wavelengths by the pervasive dust. Still, hints of contrasting red emission from Herbig-Haro objects, the jets and shocked glowing gas emanating from recently formed stars, are evident in NGC 1333. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago. At the estimated distance of the Perseus molecular cloud, this cosmic scene would span about 40 light-years.

PRATIQUE - Un Remède Naturel Contre la Gueule de Bois

 

1. Pendant la soirée Pensez à faire des gestes simples : buvez un maximum d'eau pendant et avant la soirée. C'est peut-être le meilleur conseil que l'on puisse vous donner. Idéalement, il faudrait boire un verre d'eau entre chaque verre d'alcool. Mais si vous en avez bu beaucoup avant, vous pouvez espacer. N'oubliez pas de boire beaucoup d'eau avant de vous coucher. La première cause du mal de tête est la déshydratation. 

2. Le lendemain matin À votre réveil, évitez tout ce qui est acide, type jus de citron, orange, pamplemousse... Et surtout, gardez en tête que le produit miracle est le thé vert. Connu pour ses nombreux bienfaits, le thé vert est un excellent remède contre la gueule de bois. Il permet d'apaiser le mal de tête grâce à ses propriétés reconnues. Plus vous en consommerez, et plus la durée de votre gueule de bois (qui peut durer plusieurs jours) en sera diminuée. 

Résultat Nausée, vomissements... Tout ça c'est du passé : vous ne ressemblerez plus jamais à un zombie le lendemain d'une fête :-) Mais attention ! Ce n'est pas parce que vous savez maintenant comment lutter contre la gueule de bois qu'il faut augmenter votre consommation d'alcool. Le mieux est de toujours éviter de boire trop d'alcool pour ne pas être malade.

www.comment-economiser.fr

PRATIQUE - Tête de vis abîmée ? Dévissez-la quand même

 

ASTRONOMY - IC 1318: The Butterfly Nebula in Gas and Dust

2021 March 16

IC 1318: The Butterfly Nebula in Gas and Dust
Image Credit & Copyright: Alan Pham

Explanation: In the constellation of the swan near the nebula of the pelican lies the gas cloud of the butterfly next to a star known as the hen. That star, given the proper name Sadr, is just to the right of the featured frame, but the central Butterfly Nebula, designated IC 1318, is shown in high resolution. The intricate patterns in the bright gas and dark dust are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity. The featured telescopic view captures IC 1318's characteristic emission from ionized sulfur, hydrogen, and oxygen atoms mapped to the red, green, and blue hues of the popular Hubble Palette. The portion of the Butterfly Nebula pictured spans about 100 light years and lies about 4000 light years away. 

ASTRONOMY - SuperCam Target on Ma'az

 2021 March 13

SuperCam Target on Ma'az
Image Credit: NASA/JPL-Caltech/LANL/CNES/CNRS

Explanation: What's the sound of one laser zapping? There's no need to consult a Zen master to find out, just listen to the first acoustic recording of laser shots on Mars. On Perseverance mission sol 12 (March 2) the SuperCam instrument atop the rover's mast zapped a rock dubbed Ma'az 30 times from a range of about 3.1 meters. Its microphone recorded the soft staccato popping sounds of the rapid series of SuperCam laser zaps. Shockwaves created in the thin martian atmosphere as bits of rock are vaporized by the laser shots make the popping sounds, sounds that offer clues to the physical structure of the target. This SuperCam close-up of the Ma'az target region is 6 centimeters (2.3 inches) across. Ma'az means Mars in the Navajo language.

ASTRONOMY - Zodiacal Light and Mars

 2021 March 11

Zodiacal Light and Mars
Image Credit & Copyright: Joshua Rhoades

Explanation: Just after sunset on March 7, a faint band of light still reaches above the western horizon in this serene, rural Illinois, night skyscape. Taken from an old farmstead, the luminous glow is zodiacal light, prominent in the west after sunset during planet Earth's northern hemisphere spring. On that clear evening the band of zodiacal light seems to engulf bright yellowish Mars and the Pleiades star cluster. Their close conjunction is in the starry sky above the old barn's roof. Zodiacal light is sunlight scattered by interplanetary dust particles that lie near the Solar System's ecliptic plane. Of course all the Solar System's planets orbit near the plane of the ecliptic, within the band of zodiacal light. But zodiacal light and Mars may have a deeper connection. A recent analysis of serendipitous detections of interplanetary dust by the Juno spacecraft during its Earth to Jupiter voyage suggest Mars is the likely source of the dust that produces zodiacal light.

ASTRONOMY - NGC 1499: The California Nebula

 2021 March 10

NGC 1499: The California Nebula
Image Credit & Copyright: Yannick Akar

Explanation: Could Queen Calafia's mythical island exist in space? Perhaps not, but by chance the outline of this molecular space cloud echoes the outline of the state of California, USA. Our Sun has its home within the Milky Way's Orion Arm, only about 1,000 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei just to the right of the nebula. A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark sky toward the constellation of Perseus, not far from the Pleiades.

PRATIQUE - Comment ouvrir une bouteille sans tire-bouchon

Il fait soif... et pas de tire-bouchon

ASTRONOMY - Stereo Eros

 2021 Mars 09

Stereo Eros
Image Credit: NEAR Project, JHU APL, NASA

Explanation: Get out your red/blue glasses and float next to asteroid 433 Eros. Orbiting the Sun once every 1.8 years, the near-Earth asteroid is named for the Greek god of love. Still, its shape more closely resembles a lumpy potato than a heart. Eros is a diminutive 40 x 14 x 14 kilometer world of undulating horizons, craters, boulders and valleys. Its unsettling scale and unromantic shape are emphasized in this mosaic of images from the NEAR Shoemaker spacecraft processed to yield a stereo anaglyphic view. Along with dramatic chiaroscuro, NEAR Shoemaker's 3-D imaging provided important measurements of the asteroid's landforms and structures, and clues to the origin of this city-sized chunk of Solar System. The smallest features visible here are about 30 meters across. Beginning on February 14, 2000, historic NEAR Shoemaker spent a year in orbit around Eros, the first spacecraft to orbit an asteroid. Twenty years ago, on February 12 2001, it landed on Eros, the first ever landing on an asteroid's surface. NEAR Shoemaker's final transmission from the surface of Eros was on February 28, 2001.

ASTRONOMY - Three Tails of Comet NEOWISE

 2021 March 8

Three Tails of Comet NEOWISE
Image Credit & Copyright: Nicolas Lefaudeux

Explanation: What created the unusual red tail in Comet NEOWISE? Sodium. A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a surprisingly striated white dust tail and a pleasingly patchy blue ion tail. Some color sensitive images showed an unusual red tail, and analysis showed much of this third tail's color was emitted by sodium. Gas rich in sodium atoms might have been liberated from Comet NEOWISE's warming nucleus in early July by bright sunlight, electrically charged by ultraviolet sunlight, and then pushed out by the solar wind. The featured image was captured in mid-July from Brittany, France and shows the real colors. Sodium comet tails have been seen before but are rare -- this one disappeared by late July. Comet C/2020 F3 (NEOWISE) has since faded, lost all of its bright tails, and now approaches the orbit of Jupiter as it heads back to the outer Solar System, to return only in about 7,000 years.

PRATIQUE - Repasser facilement une chemise

PEINTURE SPACE ART - Tempête martienne

 

Tempête martienne 

Crédit : Luděk Pešek

ASTRONOMY - Pillars of the Eagle Nebula in Infrared

 2021 March 7

Pillars of the Eagle Nebula in Infrared
Image Credit: NASA, ESA, Hubble, HLA; Processing: Luis Romero

Explanation: Newborn stars are forming in the Eagle Nebula. Gravitationally contracting in pillars of dense gas and dust, the intense radiation of these newly-formed bright stars is causing surrounding material to boil away. This image, taken with the Hubble Space Telescope in near infrared light, allows the viewer to see through much of the thick dust that makes the pillars opaque in visible light. The giant structures are light years in length and dubbed informally the Pillars of Creation. Associated with the open star cluster M16, the Eagle Nebula lies about 6,500 light years away. The Eagle Nebula is an easy target for small telescopes in a nebula-rich part of the sky toward the split constellation Serpens Cauda (the tail of the snake).

ASTRONOMY - A Little Like Mars

 2021 March 5

A Little Like Mars
Image Credit & Copyright: Robert Barsa

Explanation: The surface of this planet looks a little like Mars. It's really planet Earth though. In a digitally stitched little planet projection, the 360 degree mosaic was captured near San Pedro in the Chilean Atacama desert. Telescopes in domes on the horizon are taking advantage of the region's famously dark, clear nights. Taken in early December, a magnificent Milky Way arcs above the horizon for almost 180 degrees around the little planet with Orion prominent in the southern sky. A familiar constellation upside down for northern hemisphere skygazers, Orion shares that southern December night almost opposite the Large and Small Magellanic clouds. But the Red Planet itself is the brightest yellowish celestial beacon in this little planet sky.

PRATIQUE - Comment faire les symboles sur un clavier

 

ASTRONOMY - Mars in Taurus

 2021 March 4

Mars in Taurus
Image Credit & Copyright: Petr Horalek / Institute of Physics in Opava

Explanation: You can spot Mars in the evening sky tonight. Now home to the Perseverance rover, the Red Planet is presently wandering through the constellation Taurus, close on the sky to the Seven Sisters or Pleiades star cluster. In fact this deep, widefield view of the region captures Mars near its closest conjunction to the Pleiades on March 3. Below center, Mars is the bright yellowish celestial beacon only about 3 degrees from the pretty blue star cluster. Competing with Mars in color and brightness, Aldebaran is the alpha star of Taurus. The red giant star is toward the lower left edge of the frame, a foreground star along the line-of-sight to the more distant Hyades star cluster. Otherwise too faint for your eye to see, the dark, dusty nebulae lie along the edge of the massive Perseus molecular cloud, with the striking reddish glow of NGC 1499, the California Nebula, at the upper right.

ASTRONOMY - Stars over an Erupting Volcano

 2021 March 3

Stars over an Erupting Volcano
Image Credit & Copyright: Giuseppe Vella

Explanation: Mt. Etna has been erupting for hundreds of thousands of years. Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high. Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, measuring over 50 kilometers at its base and rising nearly 3 kilometers high. Pictured erupting last month, a lava plume shoots upwards, while hot lava flows down the volcano's exterior. Likely satellite trails appear above, while ancient stars dot the sky far in the distance. This volcanic eruption was so strong that nearby airports were closed to keep planes from flying through the dangerous plume. The image foreground and background were captured consecutively by the same camera and from the same location.

PRATIQUE - La magie du calcul !

 

ASTRONOMY - Ingenuity: A Mini-Helicopter Now on Mars

 2021 March 2

Ingenuity: A Mini-Helicopter Now on Mars
Illustration Credit: NASA, JPL-Caltech, Mars 2020 - Perseverance

Explanation: What if you could fly around Mars? NASA may have achieved that capability last month with the landing of Perseverance, a rover which included a small flight-worthy companion called Ingenuity, nicknamed Ginny. Even though Ginny is small -- a toaster-sized helicopter with four long legs and two even-longer (1.2-meter) rotors, she is the first of her kind -- there has never been anything like her before. After being deployed, possibly in April, the car-sized Perseverance ("Percy") will back away to give Ginny ample room to attempt her unprecedented first flight. In the featured artistic illustration, Ginny's long rotors are depicted giving her the lift she needs to fly into the thin Martian atmosphere and explore the area near Perseverance. Although Ingenuity herself will not fly very far, she is a prototype for all future airborne Solar-System robots that may fly far across not only Mars, but Titan.

ASTRONOMY - The Pelican Nebula in Red and Blue

2021 March 1

The Pelican Nebula in Red and Blue
Image Credit & Copyright: M. Petrasko, M. Evenden, U. Mishra (Insight Obs.)

Explanation: The Pelican Nebula is changing. The entire nebula, officially designated IC 5070, is divided from the larger North America Nebula by a molecular cloud filled with dark dust. The Pelican, however, is particularly interesting because it is an unusually active mix of star formation and evolving gas clouds. The featured picture was processed to bring out two main colors, red and blue, with the red dominated by light emitted by interstellar hydrogen. Ultraviolet light emitted by young energetic stars is slowly transforming cold gas in the nebula to hot gas, with the advancing boundary between the two, known as an ionization front, visible in bright red across the image center. Particularly dense tentacles of cold gas remain. Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will surely leave something that appears completely different.