Stars in the Milky Way so old they predate it

Astronomers have discovered stars inside the Milky Way that are thought to be so old that they were formed prior to the existence of the galaxy, and that the Milky Way formed around them.

The stars, found near the centre of the Milky Way, are surprisingly pure but contain material from an even earlier star, which died in an enormous explosion called a hypernova. “These pristine stars are among the oldest surviving stars in the Universe, and certainly the oldest stars we have ever seen,” said Louise Howes, lead author of the study published in the latest issue of Nature. “These stars formed before the Milky Way, and the galaxy formed around them,” said Ms Howes, a PhD student at the ANU Research School of Astronomy and Astrophysics.

Not surprisingly, the discovery challenges theories that describe the early universe.

Astronomers have identified two of the oldest known stars, about 12 billion years old, both only a hundred light years away.

Astronomers have identified two of the oldest known stars, about 12 billion years old, both only a hundred light years away.

What is intriguing about this discovery is that these two white dwarfs had to have formed very soon after the Big Bang, long before the Milky Way galaxy existed as we know it today. How they ended up here is an interesting puzzle.