Trying to make astronomy seem more relevant to the average man, the astronomer Carl Sagan tried to popularize the slogan "we are all star stuff," a slogan that many people have since repeated. But there are several reasons why the slogan "we are all star stuff" is a poor slogan to be using.
Reason #1: We Don't Really Know How the Elements in Our Bodies Originated
Scientists sometimes boast about understanding how the elements originated. Their claim is that the three lightest elements (hydrogen, helium and lithium) originated in the Big Bang, the sudden origin of the universe. They claim that other elements such as carbon and oxygen originated in stars.
But the Big Bang theory does not correctly predict the amount of lithium. This shortfall is called the cosmological lithium problem. A university press release tells us, "The standard models of the Big Bang that are currently used predict an abundance of Li-7, the main lithium isotope, which is three or four times more than that determined via astronomical observations."
The biggest failure of the Big Bang theory is that it incorrectly predicts the universe should consist of equal amounts of matter and antimatter. We know from experiments in particle accelerators that when two high-energy photons collide at very high speeds, they produce matter and antimatter in equal amounts. In the first instants of the Big Bang, the universe should have consisted of such very high-energy photons, colliding with each other constantly, leaving equal amounts of matter and antimatter. A web page of the leading particle physics organization CERN starts out by saying, "The Big Bang should have created equal amounts of matter and antimatter in the early universe." But it is known that the amount of matter in the universe is actually at least 10,000 times greater than the amount of antimatter in the universe. If even a tiny bit of antimatter came into contact with some matter here on our planet, it would create an explosion vastly bigger than a hydrogen bomb explosion.
It seems the Big Bang theory is a far-from-perfected work-in- progress, and currently way, way off in its prediction about the ratio of matter and antimatter in the universe, and also way off in its predictions about lithium. So we cannot rule out the possibility that future refinements of the Big Bang theory will claim that the Big Bang produced not just the first three elements on the periodic table (hydrogen, helium and lithium) but the first eight elements on the periodic table (hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen and oxygen). If that were to happen, then scientists would stop claiming that most of the mass in our bodies comes from stars.
No one would be terribly surprised if scientists were to stop claiming that most oxygen and carbon came from stars. The current theory to explain the origin of oxygen and carbon has a rather fishy smell to it. The theory is that the oxygen and carbon on Earth came from one or more other stars. But the problem is that stars are very, very far apart. The nearest star is 25 trillion miles away. There has always been the problem of accounting for how so much material from other stars could have got here. An average star will not shoot out matter that far away from it.
There are rare events called supernova explosions in which stars explode violently and shoot out matter far away. Scientists claim that such explosions can account for planets like Earth getting elements such as oxygen. Such claims may not be warranted.
The Crab Nebula is a nebula caused by a supernova explosion nearly 1000 years ago:
The NASA web page here lists the width of the Crab Nebula as six light-years. In the calculation below I'll assume a supernova casts heavy elements across an area of about 1000 light-years (more than the roughly 200 cubic light-years of the Crab Nebula).
Below we see some very rough calculations on the topic on how much of the galaxy should have been seeded with heavy elements from supernova explosions. I'll use the estimate of about 3 supernova explosions per century given by several sources.
Length of our galaxy, light years |
100000 |
Cubic size of galaxy, light years |
1000000000000000 |
Number of supernova per year in our galaxy |
0.03 |
Number of supernova in past 6 billion years in our galaxy |
180000000 |
Number of cubic light years that get heavy elements from one supernova |
1000 |
Number of cubic light years in our galaxy getting supernova heavy elements (past 6 billion years) |
180000000000 |
Fraction of our galaxy getting heavy elements such as oxygen from supernovas during the past 6 billion years |
.000180 |
Also, the entire universe could have been divinely created ten thousand years ago, a million years ago, a billion years ago, or any number of years ago, in some state of organization far greater than the hot, disorganized state of the Big Bang. In that case it would be false that the carbon and oxygen in our bodies came from stars. Similarly, a builder can create a Colonial-style house in Vermont that looks like it is 200 years old, but which is actually only three months old.
"Our study suggests that the Earth itself has been able to create lighter elements by nuclear transmutation,' said Mikio Fukuhara, a co-author from Tohoku University's New Industry Creation Hatchery Center in Japan. If accurate, this is a revolutionary discovery because 'it was previously theorized that all of these elements were sourced from supernova explosions, whereas we postulate a supplementary theory,' Fukuhara said."
Apparently there are three possible ways in which the oxygen and carbon in our bodies might have naturally originated: in the Big Bang, in stars, or through earthly processes. Since we don't know how the elements in our bodies originated, we should not be saying "we are all star stuff," as if we knew how the elements in our bodies originated.
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