Australian astronomers said Thursday that they have discovered the oldest stars ever seen, formed just 300 million years after the birth of the universe.

The stars lie at the heart of the Milky Way but were formed long before the galaxy grew around them.

“These pristine stars are among the oldest surviving stars in the universe and certainly the oldest stars we have ever seen,” said Louise Howes from the Australian National University in Canberra, lead author of the study published in the journal Nature.

“These stars formed before the Milky Way, and the galaxy formed around them,” Howes said Thursday in a statement.

“The stars have surprisingly low levels of carbon, iron and other heavy elements, which suggests the first stars might not have exploded as normal supernovae. Perhaps they ended their lives as hypernovae — poorly understood explosions of probably rapidly rotating stars producing 10 times as much energy as normal supernovae.”

Project leader Martin Asplund from the ANU Research School of Astronomy and Astrophysics said finding such rare relic stars among the billions of stars in the Milky Way was like finding a needle in a haystack.

 

Fossil of our mysterious cousin

A tooth fossil discovered in a Siberian cave has yielded DNA from a vanished branch of the human tree, mysterious cousins called the Denisovans.

The analysis pushes back the oldest known evidence for Denisovans by 60,000 years, suggesting that the species thrived in harsh climates for thousands of generations.

Todd Disotell, a paleoanthropologist at New York University who was not involved in the new study, said the report added to growing evidence that our species kept company with many near relatives. The world, he said, “was a lot like Middle-earth. There you’ve got elves and dwarves and hobbits and orcs.”

 

Parasites closely tied to jellyfish

In recent studies, a group of parasites called myxozoans have earned the surprising (and controversial) classification of Cnidarians — making them close relatives of jellyfish. But how did the same creatures that would evolve into tentacled, weirdly beautiful sea creatures also evolve into microscopic parasites, just a few cells apiece, that live inside of other animals?

A study published Monday in the Proceedings of the National Academy of Sciences takes a crack at the mystery. According to their genomic analysis, this group of parasites represents a degeneration in body and genome size. In other words, these guys actually made themselves smaller and more simplistic.

Why would an animal become less like an animal? For a parasite, it’s a good strategy: The more you can rely on your host for energy and reproduction, the more your species can flourish.

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