Context
- An international team, including researchers from the Raman Research Institute (RRI), Bengaluru, used the CHIME radio telescope to detect the faint 21-cm radio glow of hydrogen emitted about 9 billion years ago.
CHIME: Design and Scientific Purpose
- CHIME (Canadian Hydrogen Intensity Mapping Experiment) is a radio telescope located at the Dominion Radio Astrophysical Observatory in British Columbia, Canada.
- It was designed primarily to map the distribution of neutral hydrogen in the distant universe and study the history of cosmic expansion.
- CHIME operates in the 400–800 MHz frequency range, enabling it to detect highly redshifted radio signals from ancient hydrogen.
- It consists of four large fixed cylindrical reflectors and has no moving parts.
- Instead of mechanically pointing at different regions, CHIME uses digital signal processing and Earth’s rotation to scan a large portion of the sky every day.
- Its wide field of view also makes it useful for studying transient radio phenomena such as Fast Radio Bursts (FRBs).
Ancient Hydrogen Detection and Its Significance
- Neutral hydrogen emits characteristic radio radiation at a wavelength of about 21 cm, making it an important tracer of cosmic matter.
- As the universe expands, this radiation is redshifted to lower frequencies, allowing astronomers to study hydrogen from very distant epochs.
- CHIME has now detected the cosmological hydrogen signal from an epoch corresponding to roughly 9 billion years of look-back time.
- The observation helps map the distribution of matter in the universe and provides clues about how galaxies formed and evolved.
- It can also improve understanding of the universe’s expansion history and support studies of dark energy.
- The participation of RRI researchers highlights India’s contribution to advanced radio astronomy and cosmology.
FAQs
Q1. What is CHIME?
CHIME is the Canadian Hydrogen Intensity Mapping Experiment, a radio telescope in British Columbia, Canada.
Q2. What does CHIME primarily study?
It maps neutral hydrogen in the distant universe to study cosmic structure and expansion.
Q3. What frequency range does CHIME operate in?
It operates approximately between 400 and 800 MHz.
Q4. What did CHIME recently detect?
It detected the faint 21-cm radio glow of hydrogen from about 9 billion years ago.
Q5. Why is the 21-cm hydrogen signal important?
It helps scientists study the distribution of matter, galaxy evolution and expansion history of the universe.
