All posts tagged: glimpsed

We may have just glimpsed the universe’s first stars

We may have just glimpsed the universe’s first stars

Published by skeptic

An artist’s impression of star formation in the early universe Adolf Schaller for STScI/NASA Astronomers have had the most compelling glimpse yet of some of the universe’s first stars. These are unlike any other stars we have seen and could help us understand crucial properties about the early universe, such as how massive the earliest stars were and how they shaped those that formed later. It is thought that the first stars to form in our universe were made from almost entirely from hydrogen and helium, with no heavier elements. They were also enormous and blazingly hot, hundreds of times more massive and tens of thousands degrees hotter than the sun. But because most of these so-called Population III stars lived for only a relatively short amount of time before blowing up, astronomers have yet to conclusively find a galaxy filled with them because they existed so early in the universe’s history. Now, Roberto Maiolino at the University of Cambridge and his colleagues have found that the galaxy Hebe, a group of stars that existed …

We’ve glimpsed before the big bang and it’s not what we expected

We’ve glimpsed before the big bang and it’s not what we expected

Published by skeptic

Imagine we had somehow filmed the whole history of the universe and you could play the movie in reverse. It would start off much as things stand today: a vast and elegant web of galaxies and nebulae. But as the tape rewinds, everything begins to shrink until it reaches an evanescent pinprick of energy – a point everyone knows as the big bang. And that is where the screen goes blank. To ask what came before this is to invite the scorn of scientists and philosophers alike. It is like asking what’s north of the North Pole – a meaningless, impossible question. Or is it? Over the past few years, a few physicists have honed a way to lift this curtain and peek at what lies beyond. It involves the realisation that, although we can’t solve the equations that describe this epoch exactly, we can sometimes do so roughly – and in many cases, that might still be informative. Eugene Lim at King’s College London, one of the foremost proponents of these ideas, says this …

Astronomers may have glimpsed evidence of the biggest stars ever seen

Astronomers may have glimpsed evidence of the biggest stars ever seen

Published by skeptic

Artist’s impression of a field of Population III stars 100 million years after the big bang NOIRLab/NSF/AURA/J. da Silva/Spaceengine/M. Zamani The James Webb Space Telescope (JWST) is allowing astronomers to examine distant galaxies in the far reaches of the early universe for the first time. Some of these have chemical signatures that seem to point to exotic supermassive stars with masses up to 10,000 times that of the sun. These behemoths are bizarre because for stars in the nearby universe, there seems to be an innate size limit. “All of our evolution models of the galaxies… rely on the fact that stars cannot be more massive than 120 solar masses or so,” says Devesh Nandal at the Harvard-Smithsonian Center for Astrophysics in Massachusetts. “There, of course, have been theoretical ideas that explore stars… more massive than that, but never has there ever been a real observation that one can point to.” That is, until now. Nandal and his colleagues examined JWST observations of a distant galaxy called GS 3073 and found unusually high amounts of …