Okay, so it’s like the author of this has actually been watching me watch Big Bang Theory…
No, that is not a Bob Sinclair song. It is a revelation of divine proportions. Only, THIS concept, which is grounded in the soils of the Big Bang Theory, bears more gravity than Creationism. A lot more.
What Exactly ARE Stars?
Stars are actually tiny, tiny little fireflies trapped against a velvety blanket of night.
Bet they didn’t teach you THAT in Astronomy 101!
Seriously though… stars are aggregations of mass bound together by gravity. Immense gravity. Let’s take a look at our own Earth: the deeper you dig, the hotter it gets. Why do you think that is? The incredible amount of pressure exerted by the millions upon billions of tonnes of soil, rock and Kim Kardashian’s bum on the Earth’s core have actually rendered it so hot that it’s become a giant oozy ball of molten magma.
If the Earth was bigger, MUCH bigger – bigger even than Jupiter – the pressure exerted on the core of the planet would be so immense that it would initiate spontaneous nuclear reactions. Yes, as in atomic bomb-sized explosions. But instead of the singular blast that wiped out Hiroshima and instantly incinerated 70,000 people, these reactions would be continuous, with the prodigious amounts of heat generated by one nuclear explosion feeding several others in a chain reaction of fire and brimstone that would make Lucifer green with envy.
And this is a star! Stars are giant accumulations of mass, just like a planet really. The key different is that they are far more massive than planets. And because of the incredible gravity, heat and pressure exerted on the core of the star, it initiates spontaneous and unending nuclear reactions, generating all that delicious light and heat we feel when we walk outside into the sun.
Here’s a fun fact: While our planet TOTALLY bombed out on its stellar exam, Jupiter only failed by a margin. Jupiter and Saturn, the gas giants in our solar system, could have been stars if they were a little heavier. But alas. Can you imagine that, though? Three suns? Norway would be stoked!
In the Beginning…
Alright, so you know what stars are and that a summer vacation on the Sun wouldn’t be all the tourist brochures paint it to be. But, how does this explain where we come from?
When the universe was formed a couple of seconds after the cataclysmic boom started the ball rolling, there was hydrogen and helium. The first thing you need to know is that protons, which are positively charged particles, occupy mass. So, as ridiculously small as they are, they do weigh something and therefore, the more protons an atom has, the heavier it will be.
With only one proton, hydrogen is the lightest element in the universe. Helium is the next in line to the throne with only two protons. Lithium is next with three and then beryllium with four protons and so on and so forth. Here, we come full circle. At the formation of the universe, there was hydrogen, helium and trace amounts of lithium and beryllium (and yes, God, there was light. Lots of it.)
But there weren’t any other elements, certainly not the heavier ones we know are necessary for life, like carbon and oxygen. Where did these come from?
Einstein Drops the Bomb (Metaphorically Speaking of Course)
“Atombombe Little Boy”. Licensed under Public Domain via Wikimedia Commons
On August 6th 1945, a 4,000 kg bomb sadistically dubbed ‘Little Boy’ was dropped on a city in southwest Honshu, Japan. Of the bomb’s 4,000 kg (8,900 lbs) mass, only 64 kg (141 lbs) consisted of uranium, a notoriously radioactive element coveted by innumerable comic book villains. But get this…
Of the 64 kg of uranium, only 0.7 kg (1.5 lbs) actually underwent fission. And of the 700 grams of super critical uranium, only 0.6 grams of matter got converted into pure energy. It was this energy – not ANYTHING ELSE – that instantly disintegrated 70,000 people, flattened the city and, as a result of injury and radiation, claimed a further 70,000 lives.
Think about that: 600 milligrams – 0.6 grams of matter – when converted directly into energy just about punched a hole in the face of the Earth.
How? How it is possible for this tiny amount of mass to liberate enough energy to level an entire city in Japan? And how does this bring us closer to understanding where we come from and that ridiculous title about being star people?!
Because E = mc^2. That’s why.
It doesn’t take very much matter to create explosions that even at a distance of 150 million kilometres could leave you looking like a boiled lobster. Just ask anyone who has ever fallen asleep in the sun.
Einstein’s famous equation explains this. The mass of matter multiplied by the square of the speed of light equals the amount of energy contained by that mass. In the case of the atom bomb that was dropped on Hiroshima 30 years ago, the mass that was converted into energy only weighed 0.6 g. But use Einstein’s equation to calculate the corresponding amount of energy and you’re effectively multiplying this mass by 90,000,000,000,000,000 m/s (the speed of light squared.)
The Answer: 54,000,000,000,000,000 Joules.
Holy CRAP that’s a lot!
This brings us back to stars. In the very bowls of a star where these nuclear reactions are taking place, hydrogen atoms are smooshed together by pressure to form a helium atoms. But if you look closely at the atomic mass of these elements – their weight really – you’ll see that this equation doesn’t work out exactly. For every four hydrogen atoms mashed together to form helium, there is a tiny amount of excess mass and it is this that gets converted into pure energy via Einstein’s famous equation.
This is the energy that we see as light, feel as heat and, if we were within earshot of a star, would hear as sound too. Unfortunately space is a vacuum and sound doesn’t travel in a vacuum. So there goes that idea.
Honey, We’re Outta Gas!
Forget what happens in a single fusion reaction of 4 hydrogen atoms = 1 helium atom. Our star, the sun, is a main sequence star (middle-aged) that fuses 620,000,000 metric tons of hydrogen EVERY second! The equivalent amount of energy just boggles the mind and the zeros required to write that number down would occupy an entire book.
Now what happens? Well, the amount of hydrogen contained in a star is finite. Eventually a star will run out of fuel. Via the hydrogen fusion reactions we discussed, a star accumulates vast oceans of helium throughout its lifetime, which it will start to burn when it runs out of hydrogen. And via the same kind of fusion reaction, the immense heat and pressure in a star will mash together atoms of helium to form heavier elements, such as iron, oxygen and carbon.
Eventually, however, a star will burn out and when it does, it implodes upon itself. Then, depending upon its size, it goes supernova, which is science speak for “shit hitting the fan.” The dying star, in one last melodramatic gesture of sheer awesomeness, explodes outwards, sending a shower of heavy elements into the cosmos.
Class Dismissed: Your Take Home Message
Hydrogen, oxygen, carbon, calcium and magnesium and so on… these are the elements from which we are made. All of these elements were forged in the hearts of stars over the millennia via nuclear reactions.
This is why we are star people: literally created from the guts of exploded stars.
Your homework is to watch this video. If it doesn’t make you smile then you were born without a limbic system. Now take it away, Neil!
Video Source: “We Are Star Dust” by Symphony of Science on YouTube channel https://youtu.be/8g4d-rnhuSg