What is the Difference Between Stars and Planets?

• Stars make their own light and heat with nuclear fusion, but planets do not.
• Stars are mostly hydrogen and helium, while planets are rock or gas.
• Stars are bigger and heavier than planets.
• Stars go through a life cycle. Planets stay stable much longer.
• Stars have hot gas atmospheres. Planets have different kinds of atmospheres.

Size of Stars and Planets

Stars are much bigger than planets. Their size can change a lot, from smaller ones to huge giants. The mass of a star affects its size – heavier stars are larger. For example, Betelgeuse is about 1,400 times larger than the Sun.

Planets are smaller when compared to stars. They vary in size too, with rocky planets like Earth being smaller. Jupiter, the biggest planet, is about 11 times Earth’s size.

Temperature of Stars and Planets

Stars are super hot because of nuclear fusion in their cores. Their temperature can be different. For instance, red dwarfs are cooler, while blue supergiants are very hot. This also changes their color.

Planets are cooler than stars. Their surface temperature depends on how far they are from their sun, their atmosphere, and greenhouse gases. Mercury, for example, gets really hot and cold.

Mass of Stars and Planets

The mass of a star tells us a lot, like how long it will live. Bigger stars live shorter lives. The mass also controls its gravity and interactions with others in space.

Planets are much lighter and don’t have nuclear fusion. Their mass affects their gravity and if they can hold an atmosphere. Bigger planets can have thick atmospheres, while smaller ones might not have any.

Origin, Composition, and Orbit

Stars begin their life in huge clouds of gas and dust. Under gravity’s force, these clouds collapse. They start spinning and form a disk named a protoplanetary disk. The center of this disk becomes dense and turns into a star.

Planets are made from leftovers in the protoplanetary disk not used in making stars. These leftovers stick together, growing bigger over time. This process is called accretion, leading to planet formation.

Stars mainly consist of hydrogen and helium. Through nuclear fusion in their cores, stars release light and heat. This process is vital for a star’s energy.

Planets, however, are more varied in what they’re made of. Some are rocky like Earth. Others, like Jupiter and Saturn, are gas giants with heavy gas layers and solid cores.

Stars and planets follow different paths in space. Stars don’t orbit planets. It’s the planets that orbit stars. The star’s gravity keeps the planets in steady orbits.

Composition of Stars

Composition of Planets