Energy

Definition

Energy is the ability to do work or produce change. In astronomy, it often refers to the energy produced by nuclear reactions in stars like the Sun.

5 Must Know Facts For Your Next Test

1. The Sun generates energy through nuclear fusion, primarily converting hydrogen into helium.
2. Einstein's theory of relativity (E=mc^2) explains how mass can be converted into energy.
3. The Sun's core temperature must reach approximately 15 million degrees Celsius for nuclear fusion to occur.
4. Energy from the Sun reaches Earth in the form of electromagnetic radiation, including visible light and ultraviolet rays.
5. The process of nuclear fusion in stars balances the gravitational forces that would otherwise cause them to collapse.

Review Questions

• What process does the Sun use to generate energy?
• How does Einstein’s theory of relativity relate to the conversion of mass into energy?
• Why is high temperature essential for nuclear fusion in the Sun's core?

Related terms

Nuclear Fusion:

A reaction where two atomic nuclei combine to form a heavier nucleus, releasing energy.

Electromagnetic Radiation:

Energy propagated through space as electric and magnetic fields, including light from the Sun.

Theory of Relativity:

Einstein's theory describing how matter and energy are interchangeable (E=mc^2).