About Solar Energy

Theoretically, the Sun’s solar energy can be used at infinitely large distances from it provided we have infinitely large collector plates for gathering the light.

However there are obvious problems like space dust which largely obscure and scatter this light. So let us look into more practical ways to use solar energy.

The total luminosity of the Sun is about 3.8 X 10 ^ 26 watts. It radiates this energy outwards into space, and apparently, places nearer to it receive more energy per unit area than places far from it, according to the inverse square rule.

But the total energy radiated in a unit of time is constant and so the energy generated in one second can be divided by the surface area of the theoretical sphere that we seek to find its power in. At Earth the value per m^2 is about 1400 Watts. This is enough to run about 23 60-watt bulbs at the same time.

If we were to move to Jupiter, which is at a distance of 5.2 times the distance of Earth from Sun, the intensity would drop by 25 times to about 55 W per m^2. As it can be seen it would be able to run a meagre single light bulb.

Moving away even further to Pluto, at a distance of 40 AUs at maximum, the energy received would be a paltry 1 Watt. Thus we would require an area of 60 m^2, which can be considered to be the size of about 4 average sized living rooms, to power a single light bulb.

If you think that is not far enough let’s go to the Voyager 1 spacecraft drifting away from us at about 150 AUs. It would receive only about 0.06 Watts of solar power. To light the same bulb, we would require an area of about 1000m^2. This space could contain 10 average sized houses in it.

( an artist’s illustration of Voyager-1 )