For astronomers looking deep into the universe, Christmas came a little early this year.
Using data from the James Webb Space Telescope, NASA took out a picture last month of the Christmas Tree Galaxy Cluster, a twinkling collection of galaxies 4.3 billion light-years from Earth. And last week, an image of Cassiopeia A, the remnants of a star that exploded 340 years ago, was also announced of the first lady, Jill Biden, as part of a new White House arrivals calendar.
These images and others follow a long tradition of astronomers and other stargazers associating periods of light with cosmic phenomena occurring light-years from Earth. But there is real scientific wonder involved in some of these happy observations.
Underneath the Christmas Tree Galaxy Cluster is a discovery by astronomers of 14 stars that twinkle over days or months — like Christmas tree lights.
“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 a miracle,” he added.
This isn’t the first time distant stars have been detected, but it’s a rare treat. “With Webb, it became 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 in which the gravity of structures in the universe distorts and magnifies the brightness of background objects, making them visible to astronomers. The twinkling of the stars is the result of the “lenses” going in and out of focus.
said Dr. Windhorst that the Earth and the sun are about as old as the light coming from this twinkling cluster, which, at the time that light was emitted, was 9 billion years old. Data about distant stars helps astronomers compare the makeup of ancient galactic neighborhoods with those closer to us, and how our solar system fits into what Dr. Windhorst cosmic circle of life.
Unlike the Christmas Tree Galaxy Cluster, Cassiopeia A is closer to home. Scientists have long studied violent star explosions and the like to understand their role in cosmic evolution.
“They help galaxies grow,” 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, such as “the oxygen in our breath, the iron in our blood, the calcium in our bones,” he added.
At 11,000 light-years from Earth, Cassiopeia A has been observed by various space telescopes in visible, X-ray and infrared wavelengths. But Webb’s new infrared vision provides a better view.
In April, NASA released a photo of the supernova remnant using the telescope’s mid-infrared instrument. The latest snapshot uses Webb’s near-infrared camera, which captured gas, dust, and molecules heating to warmer temperatures.
The pink and orange structures, shrouded in smoky material against a glittering backdrop of stars, resemble an ornament hanging from a tree branch.
“Two years ago, Webb launched flawlessly on Christmas morning,” said Dr. Milisavljevic. “At the time I thought it was the best Christmas present.” But the telescope, he added, “is the gift that keeps on giving.”
Long before Webb was launched, astronomers often found seasonal spirits in space.
In 2008, the European Southern Observatory shared a photo a cluster of stars that resemble the glittering trinkets you might put on a Christmas tree. Captured by the La Silla Observatory in Chile, the cluster is scattered among crimson clouds of gas. Below the picture is the aptly named one Cone Nebulaa star-forming region about 2,500 light-years from Earth.
The Hubble Space Telescope from NASA also spread holiday cheer. In 2010, the space agency released an image of a red bubble that looks like an ornament floating among the stars.
That bubble is gas blasted at millions of miles per hour by a supernova. Astronomers think the explosion was triggered by a white dwarf – the core of a star that has run out of fuel – eating material from a nearby star.
A year later, Hubble dropped a stunning image of a cosmic snow angel: a star in our galaxy flanked by thin blue “wings” of hot gas. Located within a stellar nursery, this region is home to hundreds of brown dwarfs, objects that have not accumulated enough material to become a star.
Even the cosmos wishes you a happy holiday.
