For the first time, the NASA/ESA/CSA James Webb Space Telescope has detected and “weighed” a galaxy that not only existed about 600 million years after the Big Bang, but also has a mass that is similar to what our Milky Way galaxy’s mass might have been at the same stage of development.

Other galaxies Webb has detected at this period in the history of the universe are significantly more massive. Nicknamed the Firefly Sparkle, this galaxy is gleaming with star clusters—10 in all—each of which researchers examined in great detail. Their work is published in Nature.

“I didn’t think it would be possible to resolve a galaxy that existed so early in the universe into so many distinct components, let alone find that its mass is similar to our own galaxy’s when it was in the process of forming,” said Lamiya Mowla, co-lead author of the paper and an assistant professor at Wellesley College in Massachusetts. “There is so much going on inside this tiny galaxy, including so many different phases of star formation.”

There might not be a mysterious ‘dark’ force accelerating the expansion of the Universe after all. The truth could be much stranger – bubbles of space where time passes at drastically different rates.

The passage of time isn’t as constant as our experience with it suggests. Areas of higher gravity experience a slower pace of time compared with areas where gravity is weaker, a fact that could have some pretty major implications on how we compare rates of cosmic expansion according to a recently developed model called timescape cosmology.

Discrepancies in how fast time passes in different regions of the Universe could add up to billions of years, giving some places more time to expand than others. When we look at distant objects through these time-warping bubbles, it could create the illusion that the expansion of the Universe is accelerating.

Back when the Universe was new, following the Big Bang some 13.8 billion years ago, galaxies took a bit of time to assemble themselves from the surrounding primordial soup.

A new discovery right at the end of the Cosmic Dawn is challenging how long we thought that assembly took. JWST has spotted a huge, ultramassive galaxy as it appeared 12.8 billion years ago, so intricately structured that it can only belong to the most spectacular category of galaxies: the grand design spiral.

The galaxy’s name is Zhúlóng, after the Torch Dragon of Chinese myth, and its discovery has been detailed in a paper uploaded to preprint server arXiv ahead of peer review and publication.

The white dwarf’s brightness plunges in a mere 30 minutes—faster than any observed before.

A group of astronomers from numerous institutions have investigated a recently discovered nearby tidal disruption event known as ASASSN-22ci. They detected two luminous flares from this event. The finding was reported in a paper published Dec. 19 on the preprint server arXiv.

Tidal disruption events (TDEs) are astronomical phenomena that occur when a star passes close enough to a supermassive black hole and is pulled apart by the black hole’s tidal forces, causing the process of disruption.

Such tidally disrupted stellar debris starts raining down on the black hole and radiation emerges from the innermost region of accreting debris, which is an indicator of the presence of a TDE. All in all, the debris stream–stream collision causes an energy dissipation, which may lead to the formation of an accretion disk.