India’s Giant Metrewave Radio Telescope (GMRT) has managed to detect a radio signal, made up of atomic hydrogen emissions that originated billions of years ago. This hydrogen signal breaks the previous distance record and could provide new information about the origins of the universe, which is estimated to be approximately 13.8 billion years old.
A science record
Hydrogen is a key component of the cosmos. Whether reduced to its charged nucleus or stacked into a molecule, the nature of its presence can tell you a lot about the characteristics of the universe on the largest of scales. “A galaxy emits different types of radio signals”, says cosmologist Arnab Chakraborty of McGill University in Canada. “Until now, it has only been possible to capture this particular signal from a nearby galaxy, limiting our knowledge to those galaxies closest to Earth”.
In this case, the radio signal emitted by atomic hydrogen is a light wave with a length of 21 centimeters. Long waves are not very energetic, nor is the light intense, which makes it difficult to detect them from a distance; the previous record time stood at just 4.4 billion years.
Due to the great distance it traveled before being intercepted by GMRT, the 21-centimeter emission line was stretched by expanding space to 48 centimeters, a phenomenon described as a redshift of light. “In this specific case, the signal is deflected by the presence of another massive body, another galaxy, between the target and the observer”, says astrophysicist Nirupam Roy of the Indian Institute of Sciences. “This effectively results in magnifying the signal by a factor of 30, allowing the telescope to pick it up”.
New looks to the farthest frontiers
The results of this study will give astronomers hope that they will be able to make other similar observations in the near future: distances and retrospective times that were previously out of bounds are now within reason. If the stars align, that is.
Atomic hydrogen forms when hot ionized gas from around a galaxy begins to fall on it, cooling on the way. Eventually, it turns into molecular hydrogen and then stars.
Being able to look back in time can teach us more about how our own galaxy formed in the beginning, as well as guide astronomers toward a better understanding of how the universe behaved when it was just beginning to exist.