6 | Cosmic Dust and Nebulae

Cosmic Dust

  • Cosmic dust (also known as star dust or stellar dust) refers to microscopic, solid particles that exist throughout the universe.
  • Cosmic dust primarily originates from dying and exploding stars. It is also produced by comets and asteroid collisions.
  • Although not considered as distinct bodies, these tiny grains are the building blocks from which new stars, planets and other astronomical bodies can form.
  • The composition of cosmic dust varies and includes silicate, metallic, carbonaceous and icy materials.
  • Cosmic dust can be classified based on where it occurs.
  • For example:
  • Circumplanetary dust orbits planets in planetary rings or disks.
  • Interplanetary dust occurs between planets.
  • Interstellar dust occurs between stars.
  • Intergalactic dust occurs between galaxies.
cosmic dust horsehead nebula cosmic dust particle

Cosmic dust originates from old stars and other astronomical bodies, and forms the building blocks of new stars and other astronomical bodies.

(Images: NASA; Amara, Wikimedia Commons)

 

Nebulae

  • A nebula is a giant cloud of interstellar gas and dust, consisting mostly of hydrogen and helium.
  • Nebulae are the remnants of dying or exploding stars.
  • They are often sites where new stars form, known as ‘stellar nurseries‘.
orion nebula

Nebulae are giant clouds of interstellar gas and dust.

(Image: NASA)