Tuesday, July 1, 2008

Solar Power

Our sun provides light and heat, and energy in other forms not immediately recognized. For instance, winds: winds are a result of uneven heating of the surface of the earth which causes them. Another instance: oil and coal are produced by plant material growing, falling over and decaying in deep deposits that over long time periods turn into oil and coal. Where does the sun come in? Without the sun, plants would not grow. Rain is produced by water evaporating, condensing in the air and falling out of the sky. Rain water collects in rivers and lakes and oceans. Power is taken from falling or flowing water in the form of electricity or mechanical power. Sun light can be converted into electricity by photovoltaic panels. In fact, all power we use comes from the sun.

The sun does other things besides provide power. One of those things is it's effect on the upper atmosphere where various radio (that includes TV which is actually a form of radio) signals pass through. The photons from the sun strip electrons from gases, mostly oxygen causing ionization. Depending on where the ionized layer is, radio signals will either be bent back toward the earth or pass thought to outer space or be almost completely absorbed. There are several layers of ionization in the upper atmosphere, each with it's own effect on radio signals.

Over long periods of scientific study, it has been learned that sun spots seem to be responsible for some of the effects. The sun spots come and go in an eleven year cycle. Well, about eleven years, but not always. It can vary by a couple of years either side of eleven. Right now we are at the minimum or bottom of the cycle. That means that radio signals on some frequencies don't bend back to the earth very well and communication on those frequencies are scarce. When sunspots are active, with lots of daily numbers, those frequencies come alive with long range communication. In fact, on occasion a radio signal will bend back to the earth and reflect back to the ionized layer several times allowing the signal to go completely around the earth.

Amateur radio operators, "Hams," look forward to lots of sun spots. It allows them to talk all over the world to like minded hams. The predictions for the start of the new cycle, #24, keep getting adjusted a little. It was supposed to start about the start of this year, or maybe sometime in March, or maybe sometime in the middle of summer, or maybe even as late as next year. No one knows for sure. The sun does what the sun does and we can only forecast based on past experience. I occasionally look at the video from SOHO satellites positioned out at the L1 points. They keep an eye on the doings of the sun so we can see whats coming at us. Check'em out at: http://sohowww.nascom.nasa.gov/data/realtime/mpeg/

The video shows the sun from 06-07-08 to 07-01-08 as it rotates. About 1/2 way through you can see a little, tiny sun spot creep across the face of the sun, but it fades out before it get all the way across. Video courtesy of SOHO (EAS/NASA).

As I indicated, we are at the minimum. It is so minimum that we go several days with NO sun spots, then we'll see a miserly little sun spot that "evaporates" and we go several more days with out another sunspot. Hams are anxious for the cycle to pick up and get going. Come on sun!

C U later ._._.


Eric Haas said...

In fact, all power we use comes from the sun.

That’s not entirely true. Nuclear and geothermal energy do not come from the sun.

Pop said...

I'll nit-pick on this. Let's go back to the formation of the Solar system. During the formation the large mass becoming the sun, it's gravitational effects helped pull the gases and possibly smaller chunks of matter in to loose orbits. Over time it all came together. OK, now the ENERGY from the proto-sun provided the impetus for various elements to gather into the Earth. As things progressed, radioactive elements clumped together, and as pressure increased due to compression of matter, geothermal sources became available.

Sooo, while we do not now draw our energy directly from the early gravitationl energy of the proto-solar system, we are reaping the benefits from the nuclear and geothermal formed in the early Solar system. Oh-ho, long stretch, that. But, I'll concede that we don't get all our energy from the sun in the sense you meaan.