Dark Matter


    In News

    • Motion of some stars holds clue of dark matter shape in barred galaxies.


    • Dark matter: It is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. It forms the skeleton on which galaxies form, evolve, and merge.
    • Various astrophysical observations including gravitational effects: that accepted theories of gravity cannot explain unless more matter is present than can be seen imply dark matter’s presence.
      • For this reason, most experts think that dark matter is abundant in the universe and has had a strong influence on its structure and evolution.
    • Dark matter is called “dark” because: it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation (like light) and is, therefore, difficult to detect.
    • The primary evidence for dark matter: comes from calculations showing that many galaxies would fly apart, that they would not have formed, or that they would not move as they do if they did not contain a large amount of unseen matter.
    • Buckling: Scientists investigating how the shape of dark matter halo affects the motion of stars in stellar bars have found that out-of-plane bending events of the bar explain the shape of dark matter halos in barred galaxies.
      • Out of plane bending of the bar in barred galaxies is a rare violent bar thickening mechanism known as buckling.

    Source: PIB