In the days when the night sky used to be devoid of aspects like light pollution, smog, and aggregation of emissions from machines, stargazing was as captivating a pastime for ordinary folks as it was for astronomers. Children would spend hours drawing shapes and faces among the twinkling stars, sometimes catching a glimpse of a shooting star.
But with eyes fixed permanently on screens and air pollution reducing visibility to a bare minimum, no one has the time to look up at that ethereal world anymore. Thankfully, astronomers continue to do so. And it is their continued observation that has helped them look farthest than ever before and discover the most distant galaxy in the known universe.
Keep Looking
Advancements in space exploration technologies have opened new vistas of discoveries for scientists studying deep space and how the universe affects our galaxy and, eventually, our solar system. Most of these advancements resulted from improved telescopes like James Webb and have been helping astronomers see much farther.
One recent delve into the deep universe has unearthed a remarkable jewel lying far away — a galaxy that could well be the most distant object humans have ever seen. It could also be the oldest. The discovery was made by an international team of scientists that included researchers at the Center for Astrophysics, a collaboration between Harvard College and the Smithsonian.
The researchers have dubbed the galaxy HD1, which is about 13.5 billion light years away. The scientists believe that given its distance, HD1 may be home to some of the oldest stars in the universe, formed only a few million years after the Big Bang.
Its discovery took more than 1,200 hours of observation with the Subaru Telescope, VISTA Telescope, UK Infrared Telescope, and Spitzer Space Telescope.
But as soon as the team discovered the galaxy, they began wondering what it was. In two corresponding studies published in The Astrophysical Journal and Monthly Notices of the Royal Astronomical Society Letters, scientists have offered two parallel theories about HD1.
They say HD1 “may be forming stars at an astounding rate and is possibly even home to Population III stars, the universe’s first stars — which, until now, have never been observed. Alternatively, HD1 may contain a supermassive black hole about 100 million times the mass of our Sun,” the Centre for Astrophysics reported.
A Guessing Game
While it is one thing to detect galaxies nestled deep inside distant corners of our universe, determining their existence’s purpose is another matter, as explained by Fabio Pacucci, a scientist at the Centre for Astrophysics and an author of both papers: “Answering questions about the nature of a source so far away can be challenging. It’s like guessing the nationality of a ship from [its flag,] […] far away ashore, with the vessel in the middle of a gale and dense fog.”
Scientists noted that HD1 was extremely bright in ultraviolet light and thought “some energetic processes are occurring there or, better yet, did occur some billions of years ago,” Pacucci added.
At first observation, the researchers believed HD1 was merely creating stars at a high rate. But later calculations left scientists astounded. They estimated that HD1 would be forming more than 100 stars every year — at least 10 times more than other starburst galaxies. So, HD1 might not be another starburst galaxy producing average stars at all.
Pacucci explained that the first stars produced in the universe were much more massive, hotter and luminous than later-year stars. “If we assume the stars produced in HD1 are these first, or Population III, stars, then [their] properties could be explained more easily. In fact, Population III stars are capable of producing more UV light than normal stars, which could clarify the extreme ultraviolet luminosity of HD1,” he said.
Black Magic
But HD1’s luminance could also result from a supermassive black hole at its center. As massive black holes eat up immense volumes of gas, regions around them generate high-energy photons that the scientists managed to observe in HD1. If that is true, scientists say HD1 could be housing the earliest supermassive black hole, observed much closer to the Big Bang than the current record-holder. That makes HD1 one of the first babies born in the early universe and proof that technology is aiding humans to shape the future and empower them to look back at the universe’s origins.
Scientists revalidated the findings using Chile’s ALMA Radio Telescope, discovering that HD1 was at least 100 million light years further than GN-z11, the current furthest galaxy observed. They will now rely on the James Webb space telescope to verify their findings further.
The study of space is an extension of the quintessential human spirit of curiosity and exploration and is critical to expanding our knowledge about the Earth and the universe. Discoveries like HD1 are indicators that the human quest for understating the universe’s past is headed in the right direction and taking us closer to the Big Bang, the mother of all astronomical theories.
Maybe in a few years, we will gather new information that may well upend everything we know about ourselves, our world, and the ever-expanding universe.
How will that be for a discovery?