Come to think of it, I don’t know what dark matter really is, although it turns out nobody else does either.
The latest photos from the James Webb telescope have caused a lot of head-scratching among the astronomers because they’ve realised that dark matter has been dominating clearances from the midfield since the very start of things.
It is just a year since the Webb unfurled the 18 gold hexagons that make up its huge mirror and started peering into the most ancient known galaxies in the universe.
The Boss says it has taken around 13 billion years for the light from the infant universe to reach the Webb telescope, give or take a day here and there, and shows the oldest galaxy as it appeared a mere 320 million years after the Big Bang.
The Webb has shown scientists that this dark matter — stuff that no-one can actually see but which exerts a gravitational pull, telling us it is there — was powering the formation of stars and galaxies much earlier than astronomers had imagined.
One astronomer from the University of Arizona, Kevin Hainline, told The Guardian: “We have observed the earliest galaxies in the universe and it has been thrilling. It has opened an entirely new chapter in the history of astronomy. It is telling us the universe was dynamic from the beginning.”
Astrophysicist Sandro Tacchella from Cambridge remarked on the clarity of the telescope’s images, saying that astronomers’ theories predicted that complex cosmological process would have been taking place at this time — but now they can actually see this complexity in operation.
“Dark matter assembled first after the Big Bang and began creating halos of unseen material, which then attracted hydrogen and helium atoms to create gas clouds from which stars and galaxies eventually formed,” he said.
Sandro said if it hadn’t been for dark matter, stars and galaxies would not have appeared until much later in the universe’s history. “Now we have the James Webb, we can study how that happened in detail and hopefully get a better understanding of the role of dark matter in shaping the cosmos.”
These stargazers get almost as excited as I do looking at the night sky, even if they need a little more technology and their close-up pictures. Sandro said the magnificently sharp images from Webb were surprising — “and very gratifying”.
Kevin went a step further when talking about the oldest known galaxy the Webb had peered into: “It is already a complex structure, and that is mind-blowing. We can see that it is a growing galaxy, and that is a really beautiful thing.”
Only a handful of ancient galaxies had been discovered before the launch of the Webb telescope but it has now identified 717 such objects in the year it has been operating.
The scientists have concluded that many of these early galaxies merged with others over time, which is what happened to our Milky Way. Now they can see the remnants of other galaxies that were pulled in and added to our own galaxy.
But there is plenty they can’t explain or put into words. Take this Webb image of the Rho Ophiuchi cloud complex, the closest star-forming region to Earth. I see a billowing cloud, a couple of dark smudges — and what the scientists are sensibly calling “a huge, glowing dog bone”. Woof!
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