Milk-Way in the Southern Hemisphere
by Derek Rowley


More than 100 billion stars in the Milky-Way

  • on clear sky, dark nights – Milky-Way can be seen as a pale glowing band that stretches right across the sky.
  • the center of the Milky Way cannot be seen because it is blocked by a lot of gas and dust.
  • 100,000 light-years to cross from one side of the Milky Way to the other.

100,000 light-years to cross.

  • center of the Milky-Way contains a black hole that sucks up anything that crosses it.
  • until 1924, the Milky Way was the only known galaxy, and the shape of the Milky Way was discovered by Edwin Hubble.
  • the Milky Way is so named because across the night sky, it has a milky appearance.
  • in roughly 4 billion years times, the Milky Way galaxy will collide with one of its neighbouring galaxy – Messier 31 (The Andromeda Galaxy) – see below.

  • the oldest star in the Milky Way galaxy is over 13 million years old.
  • it takes between 225 million and 250 million years for the Sun to orbit the Milky Way.
  • the time it takes for the Sun to orbit the Milky Way one time is known as a Galactic Year.

Galactic Year



Did you know?

Image result for milky way rotation 225 million years

  • Milky Way’s rotation – our solar system inside the Milky Way rotating speed at 140 miles per seconds!
  • the speed at which it rotates does not vary very greatly depending on the distance on the distance from the core.
  • one circuit of our Sun around the centre of the galaxy is estimated to take around 225-250 million years.

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