Universe Overview: Explore Galaxies, Stars, and Constellations | Studento

Universe

• The Universe includes everything from Galactic Mega Clusters to subatomic particles.
  • The Universe is approximately 13.79 billion years old (as of 2015).
  • There are around 100 billion galaxies in the visible Universe.
  • The Big Bang Theory is the most accepted explanation for the origin of the Universe.

Galaxy

• A Galaxy is a collection of millions or billions of stars and planets held together by gravitational pull.
  • The Milky Way is a spiral galaxy that contains Earth and appears as a river of milky light in the sky.
  • The nearest galaxy to the Milky Way is Andromeda, about 2.5 million light-years from Earth.

Stars

• Stars are luminous heavenly bodies made of extremely hot burning gases, emitting their own light and radiant energy.
  • Star colors indicate temperature: Red (low), Yellow (higher), Blue (very high).
  • Stars form from clouds of dust and gas (Nebula) which condense into ProtoStars, leading to nuclear fusion and star formation.
  • After hydrogen is depleted, stars fuse helium into carbon. When fusion stops, the star's core contracts, forming a White Dwarf.
    • A White Dwarf can cool into a Black Dwarf, becoming a dead star.
    • Massive stars can become Red Supergiants, eventually exploding as Supernovae or transforming into Neutron Stars or Black Holes.
  • The Sun is the nearest star to Earth, followed by Proxima and Alpha Centauri (4.35 light-years away).

Constellations

• Constellations are groups of stars forming imaginary shapes in the night sky, aiding in navigation.
  • Examples include Orion, Big Dipper, Great Bear, and Cassiopeia.
  • Orion is visible in late evenings during winter, Cassiopeia in the Northern Sky during winter, and Great Bear in the early night during summer (Ursa Minor and Ursa Major).