Nebula: Definition and Types of Nebulae

A nebula is a cloud or collection of interstellar medium in one location in space. Nebulae are produced in different ways. For instance, they can be gathered together by gravity, dispersed by stars, or lit up by a powerful radiation ..

Key Facts and Comparison of Milky Way and Andromeda Galaxies

The Milky Way is the galaxy we live in. It contains the Sun and 100 to 500 billion other stars. It is a barred spiral galaxy as grouped in the Hubble tuning fork diagram. It is located at the  outskirts ..

Galaxies: Types, Distribution, Clusters and Super Clusters

A galaxy is a vast collection of stars, gas, dust, and dark matter that forms a cohesive gravitational unit in the universe. In a way, galaxies are to the universe what cells are to the human body: each galaxy has ..

Dark Matter and Dark Energy

In 1930s, astronomers noticed that in some galaxy clusters, some of the galaxies were moving extra fast than possible with available matter (and its gravitational force). The question was – Is there any matter which is not visible to us ..

Black Holes : Key Facts and Types of Black Holes

Each object has its own gravity which depends on its size and mass. The objects which have highest mass in smallest size would exert most gravity. The ultimate combination of large mass and small size is called a black hole. ..

Hubble Constant, Doppler Effect, Blue and Red Shift in Galaxies

The expansion rate of the universe is called the Hubble Constant in honor of Edwin Hubble (1889–1953). Currently the best measured value of the Hubble Constant is about 73 kilometers per second per megaparsec. This implies that if a location ..

Key Facts about Universe

The universe is all of space, time, matter, and energy that exist. Universe is not just space, but space is just the framework or the scaffolding in which the universe exists. As Space and time are intimately connected in a ..