If you held a grain of sand up to the night sky at arm’s length and focused the world’s biggest space telescope on that one small region for about 12 hours, here’s the image you’d get! Nearly all of the objects here are individual galaxies — thousands of them — the farthest one so far away the light from it left 13 billion years ago. The circular swirls around the middle of the picture are the tell-tale signs of “gravitational lensing,” where the bright white cluster of galaxies in the center have so distorted space and time that they magnify more distant galaxies behind them, letting us see what we otherwise wouldn’t be able to.
This is how we can nearly see back to the Big Bang!
Really big stars finally blow themselves up in supernova explosions. But more modestly sized stars come to gentler ends, like the one at the center of this fringed and ragged circle of stellar ash that is the Southern Ring Nebula. What’s left at the center is a “white dwarf” star — a slowly cooling ember that has no more nuclear fuel to burn. Moving rapidly outward from it (at 15 miles per second!) is an expanding shell of chemical elements — stuff it couldn’t burn along with stuff it made as by-products of it’s burning, like Oxygen. And elements like Oxygen are good things to have spreading across the cosmos, since they come in handy when new solar systems and planets are forming, like they did for our Sun and Earth 4.6 billion years ago.
This is how the circle of stellar life goes on!
Just under a hundred years ago, when galaxies were first found to be collections of billions of stars, they were dubbed “island universes.” But, just as the old saying declares that “no man is an island,” neither are most galaxies. They’re not isolated islands left alone on their own. Instead they come in groups and clusters and, over vast stretches of time and distance, interact with each other through the pull of their mutual gravity. Stephan’s Quintet drives this point home to us across 300 million light years of space. The galaxy at the center of the action is actually two, entwined in mid-collision so that their respective bright cores look like they’re nearly touching. Streaming out from them, toward their right and upward, is a reddish region where the collision has clumped gas together and is igniting a fast and furious burst of new star formation. This is how galaxies evolve!
While JWST’s image of Stephan’s Quintet includes the signature reddish regions of new star formation happening in other galaxies, the Carina Nebula picture brings the point much closer to home. At 7,500 light years distance, it’s one of the closer clouds of new star formation within our own galaxy. Picture what we’re seeing in the image as just the “bottom” edge of a roughly round cloud of dust and gas with a huge hole in the center — a kind of cosmic donut 300 light years in diameter. The hole is created where hot, bright new stars have formed within the nebula, their fierce solar winds and intense radiation pushing all the gas around them outward, collecting it into a densely packed ring. Where the gas is shoved more closely together, that, in turn, begins another wave of new star formation. This is how new suns are born!
– Ron Settle, VP of Innovative Technology and Interpretation