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Facts about The Sun

1. The SUN is just ONE of about 100 billion STARS in our GALAXY.

2. It has a DIAMETER of 1,390,000 km

3. Its CORE temperature is 15 million º C.

4. Its SURFACE temperature is 5,500 ºC. Cooler (3,800 ºC) surface areas are called SUN SPOTS.

5. It is the LARGEST object in the SOLAR SYSTEM and makes up 99.8% of the total MASS of the Solar System.

6. It consists of 75% HYDROGEN and 25% HELIUM.

7. The ENERGY output of the Sun is about 386 billion megawatts and is produced by NUCLEAR FUSION, using Hydrogen as fuel.

8. Apart from HEAT and LIGHT, the Sun also emits a stream of CHARGED PARTICLES called the SOLAR WIND. The Solar Wind:-

a. - Causes Radio INTERFERENCE at certain times
b. - Produces the AURORA BOREALIS or "The NORTHERN LIGHTS"
c. - Causes the characteristic TAILS of COMETS.
d. - Alters the TRAJECTORY of SPACECRAFT

9. The Sun is about 4.5 BILLION YEARS old. It will probably continue to exist in its present FORM for about another 5 BILLION YEARS before RUNNING out of HYDROGEN.

10. There are NINE planets orbiting the SUN (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto)

QUESTIONS ON THE SUN

1. Why do Sun Spots appear to be DARK in colour?

2. The average POWER PRODUCTION of all the Power Stations in the USA is about 320,000 megawatts. How many MORE times POWER does the Sun GENERATE than this?

3. How LONG does LIGHT take to travel from the Sun to the Earth? (the Earth is 150 million km from the Sun and light travels at 300,000 km per second).

4. Why must the SOLAR WIND be taken into account when planning SPACE MISSIONS?

5. Is the Sun a SOLID body like the Earth? Explain your answer.

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The EIA Team / Tel:+44 (0)1274 384070 / 25 Sept 1995