James Webb: astronomers link Natal to cosmic phenomena – 12/20/2023 – Science

For astronomers peering into the depths of the Universe, Christmas came a little early this year.

Using data from the James Webb Telescope, NASA last month released an image of the cluster called the Christmas Tree, a twinkling 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 first lady Jill Biden as part of a new White House calendar.

These images and others follow a tradition of astronomers and other stargazers connecting the holiday season with cosmic phenomena occurring light years from Earth. But there is also a scientific nature involved in some of these observations.

When the Christmas Tree cluster was identified, astronomers also detected 14 stars that twinkle over the course of days or months — like the lights on a Christmas tree.

“Seeing an individual star in a distant galaxy is a big deal,” said Haojing Yan, an astronomer at the University of Missouri who led the study. “Almost like a miracle.”

Detecting distant stars used to be a rarity. “With Webb, this has become routine,” said Rogier Windhorst, an astronomer at Arizona State University who was involved in the discovery.

The observations are possible due to layers of gravitational lensing, an effect by which the gravity of structures in the Universe distorts and magnifies the light from objects in the background, making them visible to astronomers. The twinkling of stars is the result of these “lenses” coming in and out of focus.

Windhorst draws attention to the fact that the Earth and the Sun are approximately the same age as the light arriving from this sparkling cluster, which, at the time the light was emitted, was already 9 billion years old. Data about stars so far away helps astronomers compare the composition of ancient galactic neighborhoods with those closer to us, and how our Solar System fits into what Windhorst calls the cosmic circle of life.

Unlike the Christmas Tree cluster, Cassiopeia A is much closer to home. Scientists have long studied the violent stellar explosion and others like it to discover their role in cosmic evolution.

“They help galaxies grow,” wrote Danny Milisavljevic, an astrophysicist at Purdue University who studies Cassiopeia A, in an email. Supernova remnants also create the elements needed to sustain life, such as “the oxygen we breathe, the iron in our blood, the calcium in our bones.”

Located 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 Webb’s new infrared vision offers a better picture.

In April, NASA released an image of the supernova remnant using the telescope’s mid-infrared instrument. The last photo uses Webb’s near-infrared camera, which captured gas, dust and molecules radiating at warmer temperatures.

The pink and orange structures, wrapped in smoky material against a glittering background of stars, resemble an ornament hanging from a tree branch.

“Two years ago, Webb launched perfectly on Christmas morning,” Milisavljevic said. “At the time, I thought it was the best Christmas present ever.” But the telescope, he added, “is the gift that keeps on giving.”

Long before the James Webb launch, astronomers often encountered the seasonal spirit in space.

In 2008, the European Southern Observatory shared an image of a star cluster that resembles the shiny ornaments you might put on a Christmas tree. Captured by the 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.

NASA’s Hubble Space Telescope also spread holiday cheer. In 2010, the space agency released an image of a red blob that looked like an ornament floating among the stars.

This bubble is gas expelled at millions of miles per hour by a supernova. Astronomers believe the explosion was triggered by a white dwarf — the core of a star that has run out of fuel — feeding on material from a neighboring star.

A year later, Hubble released a stunning image of a cosmic snow angel: a star in our galaxy surrounded by delicate blue “wings” of hot gas.

Even Cosmos is wishing you a merry Christmas.