Friday, January 20, 2023

3832 - WEBB DISCOVERIES - new teachings from Webb

 

        3832 -   WEBB  DISCOVERIES   -  new teachings from Webb.  The launch and subsequent operation of the James Webb Space Telescope (Webb or JWST) is one of the most exciting scientific events in decades. When Webb launched on Christmas Day of 2021, it was the culmination of decades of work by NASA scientists and engineers. In mid-July, 2022, Webb released its stunning first images.


            ---------  3832  -  WEBB  DISCOVERIES   -  new teachings from Webb

            -    Within days of the telescope coming online in late June 2022, researchers began discovering thousands of new galaxies more distant and ancient than any previously documented, some more than 150 million years older than the oldest identified by Hubble.

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            -   Webb is capable of collecting enough light from astronomical objects, ranging from birthing stars to exoplanets, to reveal what they are made of and how they are moving through space.  This data has already begun to reveal the atmospheric composition of planets hundreds of light-years from Earth in great detail, offering hints as to their ability to potentially support life as we know it.

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            -     STARS BORN IN THE PILLARS OF CREATION  in the Eagle Nebula has long been one of the Hubble Space Telescope's most iconic images. But though the telescope, which detects mostly visible light, captured the structure’s impressive clouds, the "creation" happening within them was hidden.

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            -    Webb's infrared imaging has managed to capture it in the form of numerous protostars. Appearing as tiny red dots against the smoky backdrop of the pillars, these collections of dust and gas, each many times larger than our solar system, are stars being born.

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            -    Gradually, as more and more material falls in, the middle becomes denser and denser, and then suddenly, it becomes so dense that the hydrogen burning switches on, and then suddenly their temperature jumps up to about 2 million degrees Celsius.

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            -     WEBB'S FIRST DIRECT IMAGE OF AN EXOPLANET.  Scientists discovered the first exoplanets in the 1990s, and today there are over 4,000 known worlds orbiting faraway stars. Still, only around two dozen of these have been imaged directly. Most exoplanets are so far away that they can only be detected through a dip in the light of the star they are orbiting, when that planet passes in front of its host star.

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            -   The planet, called “HIP 65426 b”, was discovered in 2017. To view it, scientists used two of Webb's cameras, several filters, and the telescope’s coronagraphs, tools which blocked out the light of the central star. Along with the telescope's exceptional sensitivity, the planet has several features that make it easier to observe.

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            -    At 100 times the distance from our sun to the Earth, this planet is much farther away from its host star than any planet in our solar system ( Pluto is only 40 times that sun-Earth distance from our sun). A colossal gas giant, it’s also exceptionally large, about 12 times the size of Jupiter.

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            -     RE-IMAGING THE PHANTOM GALAXY.    Though the “Phantom Galaxy” is difficult to find in the night sky, its brilliance is far from invisible, especially when captured in infrared with Webb. Hubble's optical image of the galaxy, also called M74, shows the galaxy's perfect spiral structure and its distribution of stars, arms extending outward from a radiant center.

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            -    But,  a new Webb image reveals fiber-like structures of heat-emitting dust and gas, emanating from a bright center rendered in vivid electric blue. The addition of crystal-clear Webb observations at longer wavelengths will allow astronomers to pinpoint star-forming regions in the galaxies, accurately measure the masses and ages of star clusters, and gain insights into the nature of the small grains of dust drifting in interstellar space.

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            -     MYSTERIOUS, BOXY RIPPLES SURROUND WOLF-RAYET STAR.  In July, 2022, Webb captured an image of a distant star, a Wolf-Rayet star, which featured Webb's signature diffraction pattern, an imaging artifact. But around the star,”WR140”, is a pattern that looks equally unreal, a ripple-like pattern of concentric rings that have a peculiar, slightly boxy shape. Unlike the diffraction pattern, the unlikely-shaped rings are real features.

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            -    Wolf-Rayet stars are massive stars nearly the end of their lives, already having released much of their hydrogen into space. The strangely shaped rings are caused by the interaction between WR140 and its smaller companion star.

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            -    FINDING THE MOST DISTANT GALAXIES EVER.  Webb was made to observe the most distant galaxies in the universe, Webb observed the galaxies as they appeared about 13.4 billion years ago, when the universe was only 350 million years old, about 2% of its current age.

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            -    Scientists suspected that the four galaxies were incredibly ancient, like hundreds of others identified by Webb. As part of the JWST Advanced Deep Extragalactic Survey (JADES) researchers confirmed their age, analyzing data from the telescope’s Near Infrared Spectrograph to find out how fast the galaxies were moving away from the telescope.

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            -    This is the galaxies’ redshift, how much the wavelengths of light they shed have lengthened as the universe expands. Their redshift was 13.2, the highest ever measured. 

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            -   LOOKING AT AN EXOPLANET’S ATMOSPHERE IN DETAIL.  A planet orbiting a star in the constellation Virgo is now the most-explored world outside our solar system. The planet is called WASP-39b and is about 700 light years from Earth. It is a boiling gas giant about the size of Saturn, orbiting its host star at an absurdly close distance, about eight times closer to its host star than the planet Mercury is to our sun.

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            -    Using Webb's main camera and two of its spectrographs, scientists identified carbon dioxide in its atmosphere, the first time the gas has ever been found in an exoplanet's atmosphere, though the planet's thick atmosphere is dominated by thick clouds containing sulfur and silicates, including sulfur dioxide.

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            -    Researchers were also able to use what they learned about the planet’s atmosphere to infer aspects of its history and formation. Scientists think the planet formed from a collision of smaller planetesimals, and because it has more oxygen in its atmosphere than carbon, formed much farther from its star than it currently is. 

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            -    GLIMPSING TITAN’S CLOUDS.  Saturn's moon Titan is a weird. The moon has "rock" made of water ice, as well as rivers, lakes, and seas made of liquid methane and ethane. It is also the only moon in our solar system to have a thick atmosphere, a hazy one dotted with methane clouds. Scientists got a glimpse of some of those clouds in November, 2022,  when Webb captured atmospheric data from the weird moon.

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            -     THE SECRETS OF THE SOUTHERN RING NEBULA.   Scientists always thought of the “Southern Ring Nebula” as rather unremarkable. The thinking went that the nebula was simply a dying star, called a white dwarf, that had expelled its outer layers, which glow brightly as white dwarf radiates waves of energy.

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            -   Scientists also knew that another, non-dying star, part of a binary system, was largely obscured beneath the brightly-lit gas. But Webb's stunning image of the nebula, released as part of its first images and data, made it clear that it wasn't that simple.

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            -    Webb imaged the cloud with two of its instruments, the Near Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI). With MIRI, researchers saw that the white dwarf wasn’t invisible, as they’d expected in that wavelength, but glowing red, surrounded by a haze of cool gas. Where had the gas come from?

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            -    The only logical explanation, it seemed, was that the nebula hid a third star, which was the source of the gas. The telescope's main camera also captured intriguing shells around the out edges of the nebula, somewhat like those around WR140. They think a third star, somewhere between the two known ones, could have caused the ripple-like shells. 

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            -    We think all that gas and dust we see thrown all over the place in the Southern Ring Nebula must have come from that one star, but it was tossed in very specific directions by the companion stars.

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            -    WEBB DISCOVERS BROWN DWARF WITH SAND CLOUDS. Though many telescopes have identified exoplanets, Webb wasn't designed to. But discover one it did and it's an exceptionally weird one. For one, “VHS 1256 b” isn't a planet at all. It's a brown dwarf, bigger than a planet, but too small to be a proper star.

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            -    This one gives off a dim, reddish glow, a product of the modified form of fusion that happens on objects that are very massive, but too small to fuse hydrogen. Still stranger, Webb observed that the brown dwarf has sandy, silicate clouds, a first for this kind of object. The exoplanet is also small for a brown dwarf and therefore young.

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            -    As with WASP-39b, Webb was able to identify individual chemicals in the brown dwarf’s strange atmosphere, such as water, methane, carbon dioxide, and potassium, among others. Ratios of the different compounds suggest that the object has a turbulent atmosphere.

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            -    In a calm atmosphere, there is an expected ratio of, say, methane and carbon monoxide,  But in many exoplanet atmospheres we're finding that this ratio is very skewed, suggesting that there is turbulent vertical mixing in these atmospheres, dredging up carbon dioxide from deep down to mix with the methane higher up in the atmosphere.

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            -     A NOT-SO-CLOUDLESS PLANET.  As part of its first release of images and data from Webb, NASA released the telescope's first spectrum of the atmosphere of an exoplanet, from a planet called WASP-96b. Webb's spectrographs analyzed the light of the planet’s star filtered through the planet's atmosphere as it crossed in front, obtaining a spectrum, a kind of “bar code” of the wavelengths of light absorbed by the planet's atmosphere.

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            -    The spectrum detected signs of hazy skies, clouds, and water vapor on the planet. This is strange, considering that scientists previously thought the planet didn’t have any clouds at all. The planet's atmosphere has a strong sodium signature, something that researchers thought until recently meant it had unique, entirely cloudless skies. The results are so contradictory that scientists are reanalyzing the Webb and previous data, trying to figure out how to reconcile the seemingly opposite conclusions.

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            -    The signs of water on the distant planet almost definitely don't indicate that it could have life. The planet is a "hot Jupiter", a gas giant half as massive but slightly larger than our solar system's largest planet, it's very close to its host star, orbiting it every 3.4 days. The surface temperature? Exceeding a  1,800 degrees Fahrenheit.

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            -     HIDDEN STAR FORMATION AS GALAXIES COLLIDE.  One of Webb's strengths as an infrared telescope is its ability to peer through dust, revealing things hidden from telescopes like Hubble, which use mostly visible light. When Webb captured an image of two galaxies colliding, it saw something Hubble had missed, an area of intense star formation, which scientists say is producing stars 20 times faster than in our own galaxy.

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            -    In the new image, the merging galaxies, called “IC 1623”, contain an area of star formation that shines so bright with infrared radiation that it produces Webb's typical pointed-star diffraction pattern, which is usually the result of its observing bright stars. The area makes up a completely new layer of the image, hidden from Hubble behind a thick layer of dust.

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            -    Scientists think that the merging of the galaxies, which are about 270 million light-years away from the Earth, may also be creating a supermassive black hole, which is not visible in the Webb image.

            January 10, 2022   WEBB  DISCOVERIES   -  new teachings from Webb       3821                                                                                                                             

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            --------------------- ---  Friday, January 20, 2023  ---------------------------

             

             

             

             

                     

             

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