- 3719 - PILLARS OF CREATION - Organic molecules in space? For Webb, the Pillars are still just the beginning, providing only a glimpse of what the $10 billion telescope can accomplish. Everybody in the astronomical community is very excited about what the future holds for Webb.
--------- 3719 - PILLARS OF CREATION - Organic molecules in space?
- The James Webb Telescope sees organic molecules in the hearts of galaxies. When the Webb Telescope (JWST) launched, one of its jobs was studying galactic formation and evolution. Around the Universe galaxies take the shape of grand spirals like the Whirlpool galaxy and giant ellipticals like M60. But galaxies didn’t always look like this.
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- We don’t see these shapes when we look at the most distant and most ancient galaxies. Early galaxies are lumpy and misshapen and lack the structure of modern galaxies.
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- The molecules are “polycyclic aromatic hydrocarbons” (PAHs). They’re important building blocks for prebiotic compounds. Those compounds may have played a role in the early formation of life.
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- They are not only attractive to scientists because of their connection to life. When PAHs are illuminated with optical and UV radiation from stars, they get excited and are very bright in infrared emission bands. So observing them tells astronomers a lot about conditions inside the galaxy.
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- The JWST’s Mid-Infrared Instrument (MIRI) is tuned to observe in the 5 to 28-micron range of the electromagnetic spectrum and can provide wide-field imaging. It can also perform medium-resolution spectroscopy.
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- The structural evolution of galaxies is dependent on so many other properties of a galaxy, like star formation, stellar mass, and metallicity. Throughout the lifetime of a galaxy, it will undergo multiple processes that alter its structure and morphology. These include the formation of galactic bulges and disks, and the end of active star formation. They also include gas inflow, which drives the formation of spiral arms. The main event that drives galaxy evolution is probably mergers with other galaxies.
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- Since PAHs are widespread in space in different environments and objects, their ubiquitous nature makes them valuable to scientists because they can compare how different PAHs behave in different places and understand more about the environments they’re in.
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- Because PAHs get excited by stars and become luminous in infrared, astronomers use them to trace activity inside galaxies. They are excellent tracers for star formation in star-forming galaxies. They also trace activity in active galactic nuclei (AGN,) the luminous regions at the center of galaxies where the luminosity doesn’t come from stars.
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- Theory predicts how PAHs should behave. Previous research predicted that PAHs couldn’t survive near the centers of galaxies with active black holes. They should be destroyed in that environment, where energetic photons can shred them.
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- But, thanks to the power of the JWST we now know that’s not true. The researchers think the PAHs can survive near the black holes because there might be a large amount of molecular gas near the galactic nucleus.
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- Supermassive black holes (SMBH) are enormous strange and powerful objects that literally warp space time. They also emit powerful radiation, sometimes as high energy photons in x-ray and gamma-ray wavebands. So even though PAHs can survive near black hoes, they don’t all survive. Smaller molecules and charged molecules were destroyed in this environment, but larger and more neutral molecules did survive.
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- It is incredible to think that we can observe PAH molecules in the nuclear region of a galaxy and the next step is to analyze a larger sample of active galaxies with different properties. This will enable us to better understand how PAH molecules survive and which are their specific properties in the nuclear region.
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- Floral formations of newborn stars areonly a few hundred thousand years old, the creation inside the “Pillars of Creation“. For Webb's predecessor, the Hubble Telescope, which observes the universe mostly in visible light these pillars were impenetrable, menacing dark formations rising from the Eagle Nebula, a cloudy cluster of stars in the constellation Serpens less than 6,000 light-years away from Earth. But Webb, with its infrared, heat-detecting gaze, peered through the darkness to reveal how light in the universe is being born.
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- Webb's images are providing a unique window into the dark and freezing clouds where stellar embryos are being incubated from a hydrogen-rich dust. Webb's images will advance our understanding of how stars form and where our own sun came from.
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- The red dots visible in Webb's images are protostars, cocoons of dust and gas so dense that they are collapsing together under the weight of their own gravity. As the clouds collapse, they form rotating balls, which will eventually become so dense that the hydrogen atoms in their cores will begin to fuse together in the process of nuclear fusion, which makes stars shine.
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- The protostars that Webb sees are not fully there yet, only beginning to glow in the infrared light as they warm above the coldness of the surrounding cloud, which is no warmer than minus 390 degrees Fahrenheit.
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- These young stars that we see are not yet burning hydrogen, but 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 35 million degrees Fahrenheit.
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- The Pillars of Creation are one of the closest regions of active star formation to Earth. The site provides the best opportunity to study star-forming processes.
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- The image was taken by NIRCam in six different filters, showing the Pillars in different colors than they would appear to the human eye. The only wavelength in the image that the human eye would detect is that of the color red, which is represented as blue in the image. The longest wavelengths in this image are six times longer than the human eye could see."
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- With each color, a different component of the physical processes taking place in the nebula appears. The bluish wisps of gas and dust that emanate like thin veils out of the nebula's edges are clouds of ionized hydrogen, electrons stripped from the colder atomic hydrogen forming the dark dense clouds by intense ultraviolet light streaming from nearby massive stars.
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- Ionized hydrogen billowing out of the dense clouds of molecular dust that forms the Pillars of Creation. With Webb's ability to reveal the structure of the dust cloud astronomers will also be able to study the processes that sculpted the towering clouds over millions of years.
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- The material that the pillars are made of is what we call the “interstellar medium“, the medium between the stars. It becomes more transparent as you go to longer infrared wavelengths. The Hubble images told us only where the material was, but Webb now shows us where it's thicker and where it's thinner. It's almost like making an X-ray of a human.
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- Astronomers know that the Pillars are not a stable cosmic sculpture but rather a constantly changing flow of material, similar to the constantly changing surface of a sandy beach. What shapes the pillars are powerful stellar winds emanating from a cluster of large stars.
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- Strong cosmic magnetic fields hold the clouds together, protecting them from being dispersed by the stellar winds. Still, within several million years, the Pillars will no longer resemble the iconic images that we see today.
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October 26, 2022 PILLARS OF CREATION - Organic molecules in space? 3719
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