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Daily News Analysis


3rd July, 2023 Science and Technology

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Context: Scientists have discovered a new phenomenon in the cosmos: low-frequency gravitational waves. These are ripples in space-time that are caused by massive events such as collisions and mergers of black holes and neutron stars. Albert Einstein predicted their existence more than a century ago, but they have eluded detection until now.


  • Unlike high-frequency gravitational waves, which have been detected by laser interferometers on Earth, low-frequency gravitational waves require a different approach.


  • Scientists used radio telescopes to observe pulsars, which are rapidly spinning neutron stars that emit beams of radio waves. By measuring the precise timing of these pulses, scientists can detect tiny changes in the distance between Earth and the pulsars, which could be caused by passing gravitational waves.


  • The results, published in The Astrophysical Journal Letters, are based on data from five international collaborations of radio astronomers. They suggest that the universe is filled with a background of low-frequency gravitational waves, which create a faint cosmic hum.

Cosmic background hum

  • The cosmic background hum is a faint, low-frequency sound that fills the entire universe. It is not audible to human ears, but it can be detected by sensitive instruments such as radio telescopes.
  • The cosmic background hum is a remnant of the cosmic microwave background (CMB), which is the oldest light in the universe. The CMB was emitted about 380,000 years after the Big Bang when the universe became transparent to radiation.
    • The CMB has been stretched by the expansion of the universe, and its wavelength has increased from microwaves to radio waves. The cosmic background hum is essentially the CMB in sound form.
  • The detection of the cosmic background hum was a remarkable achievement, as it required filtering out all the other sources of noise in the sky, such as stars, galaxies, and human-made signals.


  • It confirms the standard model of cosmology, which describes how the universe evolved from a hot and dense state to its current state.
  • It provides information about the early stages of the universe, such as its temperature, density, and composition.
  • It reveals clues about the origin and nature of dark matter and dark energy, which are mysterious components that make up most of the mass and energy of the universe.
  • It offers a new way to test theories of quantum gravity and extra dimensions, which are beyond the scope of conventional physics.


  • The cosmic background hum is one of the most fascinating phenomena in modern science. It allows us to hear the echoes of creation and to probe the secrets of the cosmos. It is a testament to the power of human curiosity and ingenuity, and a reminder of our place in this vast and wonderful universe.

Must-Read Articles:

LIGO INDIA PROJECT: https://www.iasgyan.in/daily-current-affairs/ligo-india-project

Gravitational Lensing: https://www.iasgyan.in/daily-current-affairs/gravitational-lensing


Q. What is the main source of the COSMIC BACKGROUND HUM?

1. The Big Bang

2. The Sun

3. The Earth

4. The Galaxy

How many of the above statements is/are correct?

A) Only 1

B) Only 2

C) Only 3

D) All

Answer: A

Explanation: The COSMIC BACKGROUND HUM is the faint sound of the primordial fluctuations that occurred during the Big Bang.