ESA’s Gaia space telescope has further disentangled the history of our galaxy, discovering two streams of stars that formed and wove together over 12 billion years ago.
The two streams, named Shakti and Shiva, helped form the infant Milky Way. Both are so ancient that they likely formed before even the oldest parts of our present-day galaxy’s spiral arms and disc. This image shows the location and distribution of Shakti (yellow) and Shiva (blue) stars throughout the Milky Way.
The streams were discovered using ESA’s billion-star surveyor, Gaia. Gaia observations enabled the researchers to determine the content and composition of the individual stars, which in turn revealed more of their properties and showed their movements through space.
[Image description: Illustration showing a real view of the Milky Way band across the sky. Yellow dots show the location of the stars from the Shakti stream. Blue dots show the location of the stars from the Shiva stream.]