Local Bubbles

Relevance:

Researchers from the Center for Astrophysics (CfA) | Harvard & Smithsonian have generated a 3D magnetic map of the cavity called Local Bubble that could reveal the universe’s secrets, including questions about the origins of stars.

About Local Bubbles:

• A 1,000-light-year-wide cavity or a superbubble.
• A large, low-density region in the interstellar medium (ISM) of our galaxy, the Milky Way. ISM fills the space between the stars.
• It contains the closest of celestial neighbours and among others, the Local Interstellar Cloud (which contains the Solar System), the neighboring G-Cloud, the Ursa Major Moving Group (the closest stellar moving group) and the Hyades (the nearest open cluster).
• There are many other superbubbles that exist in the Milky Way.
• It is a cavity that is thought to have been created by a series of supernovae explosions that occurred about 30 to 50 million years ago.
• Resemblance – An enormous slice of Swiss cheese.
• 3D Map of a Gigantic Cavity of Local Bubbles –
  • Used Gaia and Planck space based observatories launched by the European Space Agency (ESA).
  • Gaia was used to identify the location and local concentration of cosmic dust which helped them trace the boundaries of the Local Bubble.
  • Planck provided information on the magnetic alignment of cosmic dust which indicated the orientation of the magnetic field acting on the dust particles.

About Supernova:

• It is a powerful and luminous explosion that occurs at the end of the life of a massive star.
• It is caused by the collapse of the core of the star, which can trigger a massive release of energy.
• It enriches the interstellar medium with heavy elements and propagate cosmic rays.
• 2 types –
  • Type I:
    • Thermonuclear explosion of a white dwarf star that is part of a binary system.
    • The white dwarf accretes material from its companion star, and when its mass exceeds a certain limit, it becomes unstable and detonates.
  • Type II:
    • Gravitational collapse of the core of a massive star.
    • When a star has exhausted the nuclear fuel in its core, its outer layers collapse inward, and the core becomes incredibly hot and dense.
    • Impacts –
      • Outshine an entire galaxy for a brief period of time
      • Explosion debris can cause the formation of nebulae, dust and heavy elements.

Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation? (2019)

• ‘Higgs boson particles’ were detected.
• ‘Gravitational waves’ were detected.
• Possibility of inter-galactic space travel through ‘wormhole’ was confirmed.
• It enabled the scientists to understand ‘singularity’.

Reference: Down to Earth