dark matter for 24 April 2025

Dark Matter Latest News

A recent study led by the Indian Institute of Astrophysics (IIA) has focused on the peculiar case of galaxy NGC 1052-DF2, which appears to lack dark matter—a component traditionally considered essential for galaxy formation.

About Dark Matter

• Dark matter is a hypothetical form of matter that does not emit, absorb, or reflect light, making it invisible and detectable only through its gravitational effects.
• It constitutes about 27% of the universe’s total mass-energy content, while visible matter accounts for only about 5%.
• Dark matter is essential for explaining the observed structure and formation of galaxies, galaxy clusters, and the overall large-scale structure of the universe.
• It acts as a cosmic “scaffolding,” holding galaxies together and influencing their rotation and movement.
• Unlike ordinary (baryonic) matter, dark matter does not interact with electromagnetic forces, only gravity.
• The leading candidates for dark matter include:
  • Weakly Interacting Massive Particles (WIMPs)
  • Axions (hypothetical ultralight particles)
  • Massive astrophysical compact halo objects (MACHOs) such as black holes, white dwarfs, and neutron stars.

Dark Energy

• Dark energy makes up approximately 68% of the universe and appears to be associated with the vacuum in space. It is distributed evenly throughout the universe, not only in space but also in time – in other words, its effect is not diluted as the universe expands. 
• The even distribution means that dark energy does not have any local gravitational effects, but rather a global effect on the universe as a whole. This leads to a repulsive force, which tends to accelerate the expansion of the universe. 
• The rate of expansion and its acceleration can be measured by observations based on the Hubble law. 
• These measurements, together with other scientific data, have confirmed the existence of dark energy and provide an estimate of just how much of this mysterious substance exists.

Source: TH