How hot is the Sun, its surface and core? How long does it take the Sun's rays to reach the Earth?

The Sun is VERY hot! The core of the Sun, or the center of the Sun, is 27,000,000 degrees Fahrenheit. Compare this to the temperature on a hot summer day, about 90 degrees Fahrenheit. The surface of the Sun is cooler than the core of the Sun. Its temperature is 10,000 degrees Fahrenheit. That's still very hot!

Sunlight travels at the speed of light. The speed of light doesn't change. The speed of light is 186,282 miles per second or 299,792,458 meters per second. This means the light from the Sun takes eight minutes to travel to Earth. It travels a very long distance in eight minutes because it travels so fast. If the world's fastest land animal were to travel that same distance, it would take a cheetah over 151 years to reach the Earth!

How hot is the Sun, its surface and core? How long does it take the Sun's rays to reach the Earth?

A process called fusion heats the Sun. Fusion happens in the core of the Sun. It is very hot there. In fact, the core's average temperature is around 27,000,000 degrees Fahrenheit. The surface of the Sun is cool compared with the core, only 10,000 degrees Fahrenheit.

This fusion process not only heats the Sun, it makes the sunlight we see here on Earth. This sunlight travels the speed of light which is 186,282 miles per second or 299,792,458 meters per second. This means the light from the Sun takes 8.4 minutes to travel 93 million miles to Earth. If the world's fastest land animal were to travel that same distance, it would take a cheetah over 151 years to reach the Earth running about 70 mph nonstop!

How hot is the Sun, its surface and core? How long does it take the Sun's rays to reach the Earth?

The continuous fusion of hydrogen into helium keeps the core of the Sun cooking at 27,000,000 degrees Fahrenheit. The surface of the Sun, also known as the photosphere, is relatively cool, only 10,000 degrees Fahrenheit.

This fusion process, which is the same thermonuclear process that lies at the heart of the hydrogen bomb, produces the Sun's light we see here on Earth. This sunlight travels the speed of light which is 186,282 miles per second or 299,792,458 meters per second. This means the light from the Sun takes 8.4 minutes to travel 93 million miles to Earth. If the world's fastest land animal were to travel that same distance, it would take a cheetah over 151 years to reach the Earth running about 70 mph nonstop!

Last modified prior to September, 2000 by the Windows Team

The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). © The Regents of the University of Michigan. Windows to the Universe® is a registered trademark of UCAR. All Rights Reserved. Site policies and disclaimer