Student Projects/Galaxies

Galaxies :-

Our Sun belongs to a giant whirpool of stars called the Milky Way. Huge collection of stars are called galaxies, and like all galaxies the Milky Way is unimaginably vast.

Galaxies come in many shapes and sizes. Some are spirals like our own galaxy, but others are fuzzy balls or shapeless clouds. The largest contain trillions. Although they look packed with stars, galaxies are mostly empty space. If you made a scale model of the nearest star to the Sun would be 6 km(4 miles) away. The furthest would be 130,000 km (80,000 miles) away. The stars in a galaxy are held together by gravity and travle slowly around the galactic heart. In many galaxies, including ours, a supermassive black hole lies hidden in the centre. Stars and other material are sucked into this cosmic plughole by gravity and disappear forever.

Galaxy shapes :- Astronomers classify galaxies into just a few main type, depending on the shape we observe from Earth.

• Spiral :- A central hub of stars is surrounded by spiral arms curving out.
• Barred Spiral :- A straight bar runs across the centre, connecting spiral arms.
• Elliptical :- More than half of all galaxies are simple ball shapes.
• Irregular :- Galaxies with no clear shape are classified as irregular.
• Colliding galaxies :- Sometimes galaxies crash and tear each other apart. Individual stars don't collide, but gas clouds do, and gravity pulls the colliding galaxies into new shapes.