Episode 26 - Essay on the Universe No. 1

This week we contemplate the universe from quarks to galaxies and everything in between.

Also, better photosynthesis and maybe Pluto has a slushy ocean.

Better Photosynthesis

(University of Illinois)

Pluto might have an ocean


Essay on the Universe No. 1

The full text of the show is below. It's lightly edited so I make no guarantees that the spelling and grammar are all spot on, or that what's written is exactly what came out of my mouth.


If things that blow your mind also grab your attention and make your mind wander you might not want to drive or operate heavy machinery during this segment.

Quarks and electrons are the smallest known things. They may be made of things even smaller, like quantum strings, but we don’t know yet. Some experimental data shows Quarks to have, at the smallest, a radius of .43x10^-16 cm. That’s 2000 times smaller than a proton, which is 40 times smaller than the radius if a DNA double helix, which is itself a million times smaller than a grain of sand.

Within the human body there are about 37 trillion cells. Almost every one of those cells contains the DNA blueprint to make more humans. I am one of over 7 billion humans, and one of many billions of living things on the earth. All those living things exist on a tiny fraction of the surface of the earth, with has a diameter of over 12,000km, a surface area of over 500 million square km and a volume of 1.08x10^12 cubic km. The Earth is about 150 million km from the sun, one of 8 planets, many dwarf planets, and countless asteroids and comets. The sun’s diameter is 109 times that of earth, and 1.3 million Earths would fit inside the sun. Some of the largest stars we know of would extend out to the orbit of Jupiter, 778.5 million km from the sun. A star like that exploded to make all of us. The Oort cloud, a suspected collection of mostly comets, a loosely bound last stop from our own solar system, the very limits of our sun’s gravitational influence, is so far away it could take light from our sun 3 years to reach it. A light year is a measure of distance. One light year is 9.46 trillion km. Our Milky Way Galaxy is 100-180 ly across. There are between 100 and 400 billion stars in our galaxy. The Sagittarius Dwarf Spheroidal Galaxy, a satellite galaxy to our milky way is 70,000 ly away. Our nearest large galaxy neighbor, Andromeda, is 2.5 million ly away, is about 220 ly across, and contains perhaps as many as 1 trillion stars.

There are perhaps 500 billion galaxies in the known universe. Each of them containing billions to trillions of stars. The more we look, the more we find planets around other suns. There may be billions, hundreds of billions of planets in each galaxy. The visible universe is estimated to be 93 billion light years in diameter. Even if life is rare, with such large number there could be thousands, tens of thousands of planets in each galaxy with life. And if there is life, there is a chance for intelligence. If there is intelligence there is a chance for curiosity and exploration. If there is curiosity there is a chance for understanding. 500 billion galaxies, even with one intelligent species in each is a lot of life looking out on the universe trying to make sense of it all. Somewhere in the Andromeda Galaxy right now Grubniya Plogrubenhut is recording her Lkritcast about the latest in Planet Wibnik’s technology for her listeners. But that’s not all. It’s actually possible that there are an infinite number of universes, an endless list of possibilities made manifest, where everything that could happen does. In some universe somewhere, I am president of the United States. In another, I died when I was 4 years old.

And yet, all of that, all of those billions and trillions, from tiny quarks to massive galaxies and everything in between account for only 4% of the stuff we can see in the universe. 96% of the universe is stuff we can’t see, can’t interact with. Dark Energy and Dark Matter are hypothesized explanations for observations made about the universe that don’t match up with what the math tells us. The way gravity works, the speed of stars orbiting their galactic centers and the speed at which the universe is expanding are examples of observations that didn’t work out with the math we had when we thought what we could see was all there is. For the math to work out, 96% of the universe is stuff we can’t yet detect, let alone understand. Maybe these hypotheses will be proved wrong, since these gravity problems were first observed in the 1960s by Vera Rubin, we haven’t figured out a way to test this. A newer hypothesis suggests that we don’t have gravity quite right, that it’s an emergent phenomenon, not a fundamental force, and a new theory of gravity dispels the need for dark matter. That’s a topic for another day, but either way, there is very very little stuff out there in all that vastness. Matter isn’t really solid, molecules are mostly empty space held together by the strong nuclear force and electromagnetism, and the universe is mostly stuff we can’t see. All those atoms, all those cells, all those people and planets and stars by the billions and trillions, a whole lot of something made of nothing, floating thought a lot more nothing.

But wait, there’s more. It is possible that all of this is a computer simulation. It’s a suggestion that cropped up again a few months ago but originates, I think, in 2003. Oxford philosopher Nick Bostrum made the argument that perhaps a very advanced civilization could run simulations of their ancestors with enormous computing power. As silly as it sounds, it can’t be dismissed out of hand, although it lies is a question realm of something that may be impossible to test. Like knowing if there are other universes from within the only one we know, how can we find out if we are a program from within the program? There are actually ways in which observations we make might provide evidence (primarily in “program shortcuts” that clearly violate our understanding of physics). Frankly this crazy idea is more testable than string theory right now. Ultimately, it doesn’t change the fact that the world is what it is and we should continue living our lives.

One universe of many, only universe, computer program. One of many sentient life forms, or solitary stowaways on the only lifeboat in all the universes, we owe it to ourselves and all future generations to be better, learn, explore, survive, thrive, and share with all. You, and I, and all of us, are here, now, only for a short time, and we’ve evolved the curiosity to wonder, the intellect to understand, the will to find significance in our own insignificance, and the heart to love our lives, our planet, and our fellow travelers in the universe.
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