Traditional solar cells made from silicon only respond to a small portion of the electromagnetic spectrum, around 1.1 electron volts (eV). A new photovoltaic solar cell material developed at the Lawrence Berkeley National Laboratory reacts with nearly the entire spectrum to potentially double power output.
Courtesy NASA's Solar Dynamics Observatory
A multiwavelength extreme ultraviolet image of the sun.
From sun surface to solar panelThe sun is a massive fusion engine, one of the most dramatic manifestations of Einstein’s famous equation E=mc2.
Essentially, the formula shows that a portion of any atom’s mass comes from the energy binding it together.
The force that holds subatomic particles together is, strangely enough, much more powerful than gravity. It allows for the formation of all matter. Unleashing that nuclear force generates massive amounts of energy.
This is the principle that inspired the atomic bomb, an awesome and terrible eruption of that binding energy. But the explosions that ended World War II were the product of nuclear fission, or the splitting of an atom.
The fission process, as engineered by humans, is powerful but very inefficient. Significant energy releases as unusable and dangerous radiation. The reaction is more efficient than the burning of fossil fuels, certainly, but far from ideal.
In the dense heart of the sun, however, two smaller atoms are actually fused into one. The abundant hydrogen atoms are most commonly converted into helium, releasing binding energy as light-bearing photons.
Nuclear fusion occurs in the sun's core under extreme pressure from gravity and at temperatures of nearly 27 million degrees Fahrenheit. Scientists are still struggling to replicate the process. The photons fire outward through the solar system, traveling about 93 million miles to bombard the earth with energy.
“[Photons] interact with matter and make things move faster, which generates heat,” said astrophysicist Ronald Taam of Northwestern University.
The energy generated by the impact of these photons can be harnessed by solar cells and transformed into electricity.