Scientists have discovered two “previously unseen” galaxies about 29 billion light-years from Earth.
Two ‘dust-overshadowed’ galaxies, REBELS-12-2 and REBELS-29-2, were discovered during observations by ALMA radio telescopes in the Atacama Desert in Chile.
Alma (ESO / NAOJ / NRAO), NASA / ESA Hubble Space Telescope
Both were previously undetected by NASA and the European Space Agency’s Hubble Space Telescope’s optical lens because they were hidden behind “screens” of cosmic dust.
Astronomers who made this discovery estimate that up to 20% of the universe’s galaxies are similarly obscured, and have not yet been discovered by mankind.
But many of these “lost” galaxies can one day be found with equipment, including the forthcoming James Webb Space Telescope.
“We were looking at a model of the farthest galaxy we already know from the Hubble Space Telescope,” said Pascal Oaks, an assistant professor at the Niels War Institute at the University of Copenhagen. Both neighboring galaxies are covered in dust, and some of their light is obscured, making it invisible to the Hubble Space Telescope. “
It is noteworthy that the most advanced “ALMA” telescope had five times better spatial resolution than the Hubble Space Telescope, the main reason for its invention.
By combining the light of all 66 antennas to create a high-resolution image and spectrum of the sky, ALMA can capture radio waves emitted from the cold and dark depths of the universe.
The study team says that the light from both REBELS-12-2 and REBELS-29-2 traveled about 13 billion years to reach Earth.
By comparing REBELS-12-2 and REBELS-29-2 with previously known sources in the very early universe (about 13 billion years ago), the team found that 10-20% of these early galaxies may still be hidden behind cosmic dust.
“Our discovery shows that up to one-fifth of the oldest galaxies are missing from our sky map,” Professor Oaks said.
The James Web Space Telescope is expected to be launched into orbit on December 22 this year, after 25 years of development, to help experts better understand when and how galaxies formed.
It is generally believed that the first galaxies appeared in the first hundred million years after the Big Bang, although astronomers still do not fully understand how galaxies formed.
Professor Oaks revealed: “The next step is to identify unnoticed galaxies because there are so many more than we thought. And here the James Webb Telescope would be a bigger step. Allow clusters to be easily hidden.
The new study is published in detail in the journal Nature.
Source: Daily Mail
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