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For astronomers peering into the depths of the universe, Christmas came a little early this year.<\/p>\n
Using data from the James Webb Space Telescope, NASA released an image last month of a Christmas Tree Galaxy Cluster, a winking collection of galaxies 4.3 billion light-years from Earth. And last week, an image of Cassiopeia A, the remains of a star that exploded 340 years ago, was also unveiled by the first lady, Jill Biden, as part of a new White House advent calendar.<\/p>\n
These images and others follow a long tradition of astronomers and other stargazers connecting the season of light with cosmic phenomena occurring light-years from Earth. But there is genuine scientific wonder involved in some of these festive observations.<\/p>\n
Underlying the Christmas Tree Galaxy Cluster was a detection by astronomers of 14 stars that flicker over days or months \u2014 like the lights on a Christmas tree.<\/p>\n
\u201cSeeing an individual star in a faraway galaxy is a big deal,\u201d said Haojing Yan, an astronomer at the University of Missouri who led the study. \u201cAlmost like a miracle,\u201d he added.<\/p>\n<\/div>\n<\/div>\n
It\u2019s not the first time distant stars have been detected, but it used to be a rare treat. \u201cWith Webb, this has become routine,\u201d said Rogier Windhorst, an astronomer at Arizona State University who was involved in the discovery.<\/p>\n
The observations are possible because of layers of gravitational lensing, an effect by which the gravity of structures in the universe distorts and magnifies the light of objects in the background, making them visible to astronomers. The flickering of the stars is a result of those \u201clenses\u201d moving in and out of focus.<\/p>\n
Dr. Windhorst notes that Earth and the sun are about as old as the light arriving from this twinkling cluster, which, at the time that light was emitted, was already 9 billion years old. Data about such distant stars helps astronomers compare the makeup of ancient galactic neighborhoods with those that are nearer to us, and how our solar system fits into what Dr. Windhorst calls the cosmic circle of life.<\/p>\n<\/div>\n<\/div>\n
Unlike the Christmas Tree Galaxy Cluster, Cassiopeia A is a lot closer to home. Scientists have long studied the violent stellar explosion and others like it to figure out their role in cosmic evolution.<\/p>\n<\/div>\n<\/div>\n
\u201cThey help galaxies grow,\u201d Danny Milisavljevic, an astrophysicist at Purdue University who studies Cassiopeia A, wrote in an email. Supernova remnants also create the elements needed to sustain life, like \u201cthe oxygen we breathe, the iron in our blood, the calcium in our bones,\u201d he added.<\/p>\n
At 11,000 light-years from Earth, Cassiopeia A has been observed by a variety of space telescopes in visible, X-ray and infrared wavelengths. But the Webb\u2019s new infrared vision affords a better view.<\/p>\n
In April, NASA released an image of the supernova remnant using the telescope\u2019s mid-infrared instrument. The latest snapshot makes use of the Webb\u2019s near-infrared camera, which captured gas, dust and molecules radiating at warmer temperatures.<\/p>\n<\/div>\n<\/div>\n
The pink and orange structures, enveloped in smoky material against a glittering backdrop of stars, resemble an ornament hanging from a tree branch.<\/p>\n<\/div>\n<\/div>\n
\u201cTwo years ago, Webb launched flawlessly on Christmas morning,\u201d Dr. Milisavljevic said. \u201cAt the time I thought it was the best Christmas gift ever.\u201d But the telescope, he added, \u201cis the gift that keeps giving.\u201d<\/p>\n
Long before the Webb launched, astronomers often found seasonal spirit in space.<\/p>\n
In 2008, the European Southern Observatory shared an image of a cluster of stars resembling the sparkling trinkets you might put on a Christmas tree. Captured by La Silla Observatory in Chile, the cluster is scattered among crimson clouds of gas. At the bottom of the image is the aptly named Cone Nebula, a star-forming region about 2,500 light-years from Earth.<\/p>\n<\/div>\n<\/div>\n
The Hubble Space Telescope from NASA has also spread the holiday cheer. In 2010, the space agency released an image of a red bubble that looked like an ornament floating amid the stars.<\/p>\n
That bubble is gas blasted away at millions of miles an hour by a supernova. Astronomers think the explosion was triggered by a white dwarf \u2014 the core of a star that has run out of fuel \u2014 gorging on material from a neighboring star.<\/p>\n<\/div>\n<\/div>\n
One year later, the Hubble dropped a breathtaking image of a cosmic snow angel: a star in our galaxy flanked by wispy blue \u201cwings\u201d of hot gas. Nestled inside a stellar nursery, this region is home to hundreds of brown dwarfs, objects that don\u2019t accrete enough material to form into a star.<\/p>\n
Even the cosmos is wishing you a happy holidays.<\/p>\n<\/div>\n<\/div>\n