An international team of astronomers led by Pascal Oesch of Yale University has measured the distance to the farthest galaxy ever known. Named EGS-zs8-1, it is one of the earliest galaxies, formed just 670 million years after the Big Bang. It lies 13.1 billion light-years away in the Bootes constellation. A light-year equals approximately 5.8 trillion miles.
One of the brightest galaxies in early universe
It took more than 13 billion years for the light from that galaxy to reach Earth-based telescopes. So, data available shows EGS-zs8-1 in its infancy. According to a study published in The Astrophysical Journal, it is one of the most massive and brightest galaxies in the early universe. Since the universe continues to expand, the galaxy is now approximately 30 billion light years away.
Despite its relatively younger age, the galaxy already has a mass about 16% that of our Milky Way, which is 10 billion years old. When astronomers are looking further away from our planet, they are looking further back in time. EGS-zs8-1 is generating stars 80 times faster than Milky Way. Scientists were conducting a survey called Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) using Hubble and Spitzer space telescopes when the new galaxy stuck out.
Researchers saw the galaxy as it was 13.1 billion years ago
They used a powerful spectrograph called MOSFIRE on the Keck I telescope to precisely measure its redshift, which revealed its distance. Pascal Oesch said in a statement that though they saw the galaxy as it was 13.1 billion years ago, it was giving birth to new stars at an exponential rate.
The observations see the galaxy when the universe was undergoing critical changes such as hydrogen between galaxies transitioning from a neutral to an ionized state. Rychard Bouwens of the Leiden Observatory said that young stars in early galaxies might have been the main drivers for this transition called re-ionization.
The new generation of instruments such as Thirty Meter Telescope and James Webb Telescope will help how galaxies were able to form so quickly after the Big Bang, which remains a mystery.