Here's a mind-blowing fact. The sun releases more energy in just 1.5 millionth of a second than we humans on planet Earth consume in a year.
That's a lot of power. Which is why solar will likely play a huge role in our quest for a cleaner, more secure energy future. The sun generates all of this energy through a process called fusion. But what exactly is fusion, and how does the sun generate so much energy?
The sun is a massive nuclear powerhouse that can raise temperatures in the Australian Outback to an incredible 50.7 degrees Celsius.
Incredibly, the power source that makes all of this possible is 150 million kilometers away and involves subatomic particles. You may know that atoms, which make up all matter, have a nucleus at the center made up of protons and neutrons, with electrons zipping around the nucleus in a small cloud. Fusion happens when two atomic nuclei are forced together in extremely high-energy conditions.
Now, keep in mind, this is different from what happens when atoms link together using their electrons, like when two hydrogen atoms and an oxygen atom come together to form water. That's called bonding. But in fusion, the nuclei of the atoms themselves need to smash together to form a single nucleus, and this process releases massive amounts of energy.
So, now that we've got our heads wrapped around the very basics of how fusion works, let's take a look at how it happens in the sun. First off, it takes a lot of energy to force the nuclei to come together in the first place, because protons, all with the same positive charge, repel each other. You know, like magnets. You may recall that principle that like charges repel while opposite charges attract.
However, the sun is so massive, roughly 1.392 million kilometers in diameter, that it has an insane amount of gravity, meaning there's an incredible amount of pressure exerted on all those hydrogen atoms that make up the sun.
Now, solar fusion happens inside the sun's core, where the pressure is so intense and the density is so great that those like-charged protons of those hydrogen nuclei smash together to form helium. If we want to break things down in even greater detail, which we do, we'll have to talk about something called the proton-proton cycle. The energy radiated by the sun is really the result of a series of thermonuclear reactions.
The first step in the reaction... two hydrogen nuclei collide to produce what's called deuterium, a hydrogen nucleus with one proton and one neutron. See, most hydrogen atoms have only one proton and no neutrons.
Next, a third hydrogen proton smashes into the deuterium nucleus to make a tritium nucleus, or a triton, a nucleus with one proton and two neutrons. When two of these tritium nuclei fuse together, they form a helium-4 nucleus with two protons and two neutrons.
This fusion also releases two protons, allowing the cycle to continue. Two hydrogen protons collide, a third hydrogen proton joins the party, two of these tritium nuclei fuse together, two protons are released. Repeat, and repeat, and repeat until the sun runs out of hydrogen. Got it? Great.
It is a complicated process. After all, it's literally thermonuclear physics.
Now, you may be asking, how much energy does this process generate? Well, scientists have calculated that at any given moment, the sun releases an estimated 384 yotta watts of energy. Never heard of a yotta watt before? Because me neither. But using scientific notation, that's 3.84 times 10 to the 26th power. So, 384 with 24 zeros behind it. Saying that's a "yotta" power would be a gross understatement and a groanable pun.
And because nuclear fusion doesn't produce unstable, long-lived radioactive waste like nuclear fission does, that's the splitting of an atom, instead, fusion results in a stable, non-radioactive by-product of helium. So, scientists are exploring how to develop this as a viable energy source. But as many of our secret viewers have noted, fusion technology always feels like it's just a few decades away.
Now, while most of the sun's energy is scattered across our solar system, researchers have estimated that 430 quintillion joules of the sun's energy hits the surface of the Earth roughly every hour, or hour-and-a-half. With current estimates of total world energy consumption at 580 million terajoules annually, that means, theoretically, if we could effectively harness all of the sun's energy that hits Earth for just two hours, we could power our entire planet for more than a year.
Clearly, this isn't a reality, at least not anytime soon, but solar energy is helping power a worldwide shift to cleaner, more sustainable energy. And there have been some incredible innovations in recent years as the technology has become more and more efficient.
So, next up, we take a closer look at solar panels and break down the technology that powers our homes and cities, and can transform sunlight into horsepower.