What is the difference between a planet and a star?

The distinction between a planet and a star comes down to how they generate energy and their role in space.

A star is a massive celestial body that produces its own light and energy through nuclear fusion. Inside a star, hydrogen atoms combine to form helium, releasing enormous amounts of energy. The Sun is the closest example of a star.

A planet, on the other hand, does not produce its own light. It:

• Orbits a star
• Reflects the star’s light
• Has a relatively smaller mass compared to stars

For example, Earth shines in the sky only because it reflects sunlight; it does not emit light on its own.

Another key difference:

• Stars are extremely hot and gaseous
• Planets can be rocky, gaseous, or icy, depending on their type

Quick comparison insight:
If an object shines by itself, it is a star. If it shines by reflecting light and revolves around a star, it is a planet.