Solar Energy Information

Make It Solar Science Fair Projects

The Sun and Energy

The sun is a star.  It is the largest object in our solar system and one of the larger stars in our galaxy.  The source of energy in the Sun is at its core where hydrogen is converted to helium in a thermonuclear reaction.  This energy travels from the core to the surface of the Sun and is released into space primarily as light.  The energy that comes to the Earth is in 2 main forms, heat and light.

Every hour, enough sunlight energy reaches the Earth to meet the world’s energy demand for a whole year.

--- U.S. Department of Energy ---

The amount of energy from the Sun that reaches the Earth annually is 4 x 1018 Joules.***

4 x 1018 Joules/ Year ÷ 365 Days/ Year = 1 x 1016 Joules/ Day

1 x 1016 Joules/ Day ÷ 24 Hours/ Day = 4 x 1014 Joules/ Hour

The amount of energy consumed annually by the world's population is about 3 x 1014 Joules.

Speed of Light Energy from the Sun to Earth.

The earth is the third planet from the sun at a distance of about 93,000,000 (93 million) miles.  If you could pitch a fast baseball to the sun at 100 miles per hour (mph) it would take the ball over 100 years to get there.  On the other hand, it only takes light energy 8½ minutes to reach the earth from the surface of the sun, traveling at the speed of light of course.

Pitching a Baseball at 100 mph to the Sun***

93,000,000 miles ÷ 100 miles/ hour

= 930,000 hours to reach the Sun.;

930,000 hours ÷ 24 hours/ day

= 38,750 days to reach the Sun;

38,750 days ÷ 365 days per year

= 106.16 years to reach the Sun.

Light Energy traveling to Earth***

The speed of light is equal to about 11,000,000 (11 million) miles/ minute. 

93,000,000 miles ÷ 11,000,000 miles/ minute

= 8.45 minutes for light  to travel from the Sun to Earth.

***Calculations are rounded for simplicity.

Additional Reading:

The Sun Word Search Puzzle (PDF)