What blows me away about the universe? How is it all connected? How does universality give physics the power to explain everything? I discuss these questions and more in today’s Ask a Spaceman!
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EPISODE TRANSCRIPTION (AUTO-GENERATED)
Today's question comes from Iva nine eight seven on Twitter, and it's a little bit different, but I just couldn't pass it up. So I wanted to just jump right in. The question is, what's the most amazing thing about the universe? Of course, everyone has their own answer, but this is my podcast. So you're going to get my answer, and I'm gonna tell you my answer right now and use the rest of the episode to prove my point so that you all end up agreeing with me and I'm not the only one who thinks this way.
I think that the most amazing thing about the universe is the very universality of physics. Of how we can learn something here on the surface of the Earth in our little rooms, in little laboratories, in our chalkboards, in our experiments, and what we learn applies throughout all of space and time. And this isn't obvious. Nobody really thought this way for a long time. But once we began to realize it, the concept exploded our ability to understand the universe.
And it didn't have to be this way. There's no reason whatsoever that different parts of the universe or different times in the universe have to obey the same set of physics. What applies here on the surface of the earth doesn't have to apply when the universe was a second old or over in the Andromeda galaxy or anywhere or anyone else. It is just amazing. So let me give you some examples to show just how amazing it really is.
Let's start with gravitation because that's where everything started in this whole universality of physics thing. For centuries, for millennia, for basically all of human existence, the assumption was that gravity, our attraction to the earth, was just a thing that you experience close to the earth. That there were certain rules and patterns and laws that apply to here. And then up there in the sky, in the celestial realm, in the heavens with the planets and the stars and all that, had their own set of rules. And we could figure out what those rules were.
We could look for patterns. We can look for, say, cycles and regularities in the lunar eclipses and the solar eclipses and the motions of the stars and all that. But we just assumed it was those rules, and it had nothing to do with what we've realized or thought were the rules down here. That started to break down with Johannes Kepler, and I know I did a whole episode on Kepler. But just to give you the quick recap, Kepler Johannes Kepler believed as a fully mystical and not very scientific concept at all, but he still believed that there were natural harmonies, there were natural rhythms, there were natural patterns that did apply both in the heavens, in the celestial realm, in the stars, and down here on Earth.
And he felt it was his job to look for patterns in the motions of the planets to help him understand patterns in our daily lives. If that sounds a lot like horoscopes, it is exactly horoscopes in astrology because that's what he was the king of. He was like the best horoscope astrologer of his day. He also did some very cool science that revealed some very important patterns in the motions of the planets. The whole connecting the motions of the planets to our daily lives didn't really work out well for him.
He wasn't able to make as strong as a connection as he hoped, but it planted the seed. Because once he was able to realize that there were regular motions, or or there were simple laws, simple rules that the planets obeyed, that just started the avalanche of this thinking, and it culminated a hundred years later with Newton. And I know I just did an episode on Newton, but it's part of this larger story. Newton realized that gravity is universal. Newton realized that the gravity that we experience here on the Earth is the exact same force that keeps the moon in orbit around the Earth, that keeps the Earth in orbit around the sun, that makes all the planets do all the planetary things.
He elevated the concept of gravity to a universal physical law. A simple statement. Like, Newton's gravity is simple. You can write it down. You can put it on a t shirt if you wanted to.
I don't know why you'd want to, but you're free to do so. This simple expression of Newton's law of gravity applied throughout the entire universe and throughout time. No matter where you were, if you were on the surface of the Earth, if you were in orbit around the sun, if you were at the edge of the known cosmos, it still applied. And that was the first time and one of the reasons Newton is such a big deal. That was the first time that we had a simple mathematical law that could express and explain a lot of behavior throughout the cosmos.
Einstein took that whole gravity journey one step further with general relativity, fixed some upgraded Newton's laws to make it even more applicable to explain some things that he wasn't able to explain, gave us this entire language of space time, which we still use today, and that is the gravity that we know and experience. Now Einstein's equations, they can be written in a way that can be printed on a t shirt. It is a very compact notation. Einstein's equations are a little bit more complex than Newton's equations, but, you know, that's the price you pay for being able to explain so much more than Newton was able to explain. But you can use Einstein's theories, Einstein's equations, Einstein's general relativity, Einstein's gravity.
This one expression or set of expressions, you can use it to explain the motion of an apple falling from a tree. You can use it to explain throwing a baseball. Yes. I understand for practical purposes, we would use Newton's laws rather than Einstein's, but you can still use Einstein's there. You can use the exact same equations to study the orbit of the moon.
You can use the exact same equations to study the tides. You can use the exact same equations to look for planets around other stars. Right? You can't see the planet itself, the exoplanet orbiting a star, but that planet is tugging on the star with its gravity, and you can see the wobble of the star itself. Same gravity.
We can use these exact same laws to discover the existence of dark matter. Right? You see stars in orbit in their galaxies, but they're going way too fast. Given the amount of material that you see, there has to be some hidden unseen component. Same applies to galaxies.
Same thing. Black holes. The exact same let that sink in folks. The exact same equations that we can use to understand the orbit of Mercury around the sun or the cycles of our tides applies to black holes. 100% completely unchanged.
The same equations. The same gravity. The largest structures in the universe, the cosmic web. The galaxies in our universe are not scattered around randomly. They form a pattern.
We understand the shape of this pattern through gravity. The exact same gravity that tells us how fast the moon goes in orbit around the earth tells us how over billions of years the largest structures in our universe assemble themselves. In fact, the Big Bang itself is really a story of gravity. It's a story of expanding space time. The same set of equations that describe the early history of our universe and the present day nature of the universe describe baseballs being thrown from one person to another.
That's what I mean when I say physics is universal and why it's so amazing. Because right here, boom, one set of equations describes all this phenomena that at first glance have absolutely nothing whatsoever to do with each other. Are you really saying the tides have something, some sort of connection to clusters of galaxies? Yes. I am saying exactly that because they are both understood through gravity, because it's a universal physical law.
Gravity is cool and all, but let's talk about something a little bit more simple. Stuff smashing into each other. How do physicists understand stuff smashing into each other? They understand it through the concepts of conservation of energy and momentum. Right?
If I if I have one ball and it bounces against another ball, I use conservation of energy. I use conservation momentum to understand their behavior, what happens after the collision. I know that the total amount of momentum before the collision has to equal the total amount of momentum after the collision. I can use that simple idea to make predictions as to how these objects will behave. I can use these exact same principles to study car crashes.
Right? If if you come up on an accident scene, and you see the wreckage everywhere, and you're the investigator trying to understand the the cause of this accident, you're going to use physics. You're going to use conservation of energy and conservation of momentum. One car will be heavier than the other. One car will have been pushed a different distance than the other.
Pieces of one car will have gone farther than pieces of another car. You will trace out the history of that event using conservation of energy and momentum. If you're an investigator not looking at car crashes, but looking at the fundamental components of reality in a giant atom smasher, guess what? You are using conservation of energy and momentum. When you're slamming together two protons at nearly the speed of light, and say something like the Large Hadron Collider, you are setting things up.
You are understanding things. You are probing reality based on your understanding of conservation of energy and momentum completely unchanged. The concepts are the same, just a different application, slightly more energetic. You know that, Kuiper belt object that the New Horizons spacecraft buzzed by? Originally, it was called Ultima Thule, and then it the official name now is Arrokoth.
If you ever look at a picture of it, it looks like a lumpy peanut because there were two icy bodies that glued themselves together. They they hit each other, but not fast enough to obliterate and not slow enough that they just bounced off just right where they hit each other. They heated up a little that melted the ices and that and then they refroze and they got glued together. Guess how we understand that picture. No points awarded for guessing correctly because the answer is conservation of energy and momentum.
It's right there in the papers describing it. Planet formation itself or the formation of the moon. Right, is from little bits of stuff gluing onto each other, crashing into each other, transferring energy, transferring momentum, losing energies through certain processes. Like, this is just plain old fashioned physics, just applied in different scenario. Two black holes merging together.
Yes. That's a story of gravity. But guess what's buried inside that story of gravity? A story of conservation of energy and momentum. Unchanged.
The same concept. I can say momentum is conserved. The total amount of momentum you have coming into a situation is the equal to the total amount of momentum you have coming out of a situation. That applies everywhere throughout time, throughout space. And I can use that wherever I find it useful.
Let's crank it up a notch. Let's talk about nuclear physics. Right? In the thirties, forties, and fifties, we started to crack the nuclear code. We started to split atoms and put them back together again.
We figured out the strong nuclear force. We figured out how atoms work, how atomic nuclei work. We figured out nuclear bombs. How to make a nuclear reaction go haywire in a very spectacular way. We figured out how to make nuclear reactions go haywire in a very controlled and sedate way and turn that into a source of energy in nuclear reactors.
We understand fission and fusion. You know, this had definitely had a lot of real world practical consequences once we understood nuclear physics. We can use the exact same physics, the exact same principles to understand how the sun works. The sun works through nuclear fusion, from the fusion of hydrogen into helium, and it releases a little bit of energy and it powers itself for billions of years. Boom.
We didn't know that until we knew nuclear physics. But once we understand understood nuclear physics, we were able to understand how the sun works. The exact same physics that might be powering your home right now are the exact same physics that we use to understand how stars work. We use the exact same physics to understand how supernova work. Right?
When, giant stars start building heavier and heavier elements, and then they reach iron, and they can't extract energy anymore, and it goes haywire. Big boom. Understood through nuclear physics. Or or the type one a supernova where you have a white dwarf, and it builds up a layer of hydrogen, and it gets reaches a critical threshold, and it collapses in on itself and it triggers a nuclear fireball. Nuclear physics again and again and again.
Big bang nucleosynthesis. When our universe was ten minutes old, it was fusing. It was forming hydrogen and helium. Think about that. The exact same physics that we use to power your home, to give you electricity is the exact same physics we use to understand the entire universe when it was ten minutes old.
The physical laws, our physical theories, the mathematics are the same. It's just in a different scenario. But it's not just the big stuff. It's the little stuff too, like thermodynamics, heat, and pressure, and work, like your car engine. We understand how car engines work through concepts of thermodynamics.
There's a little bit of fuel, a little bit of oxygen. You make a little spark. It makes a little boom. It drives a piston. The piston makes your wheels go.
Yes. I understand that cars are more complex than that, but that's the physics view of how a car works. Thermodynamics, heat, pressure, energy, entropy, work. Do you know how many papers in astronomy? And just to give you a sense, there's about 50 papers written in all of astronomy every single day.
There's 50 new papers written every day. Do you know how many of them mention things like heat or pressure or work or entropy or any concept related to thermodynamics? I'm gonna ballpark it here. I'm guessing somewhere around 90%. I'm guessing.
And it is just a guess just based on my own experience, but I'm guessing around 90% of all papers in astronomy. And let's just go ahead and say all physics and astronomy mention in some form, in some way, find some utility in expressions of thermodynamics. Like, oh oh, when you have a gas cloud and it's expanding, it's gonna cool off. How do we understand that? Through thermodynamics.
If it's collapsing, it's gonna heat up. How do we understand that? Through thermodynamics. How do we understand transfers of heat and energy and flows through radiation, conduction, or convection? It's through thermodynamics.
How do I we identify the habitable zone around a star where it's just the right temperatures, where liquid water can stay liquid? We understand it through thermodynamics. It's all the same. The same mathematics that we use to understand what's happening inside of your car engine, we can use to predict where we might find life around another star. Unchanged.
That is power. That is universality. Let's go to something more practical like Patreon. Patreon is universal. Patreon.com/pmsudder.
Wherever you are in the universe, you can contribute. Keep these episodes going. That's patreon.com/pmsudder. It's my name, and it's Patreon, p a t r e o n. That's universal.
No matter where you are in the world, you can contribute. It's just it's just that magical. It's magical. Alright? It is a universal law of physics.
Oh my gosh. And don't even get me started on electromagnetism, which is how astronomy is astronomy. Like, look at radio. Your car radio. You you tune your little dial.
I don't know if any of you listen to radio anymore. I don't. But you turn your little dial, okay, and you've got the antenna, and it picks up a radio signal. Okay. We understand the physics of that.
We understand the physics of radio because we're able to build radios. The sun emits radio waves. Jupiter emits radio waves. Active galactic nuclei by powering these giant jets that's that reach out for tens of thousands of light years, they emit radio waves. Neutral hydrogen emits a certain kind of radio wave.
We understand all of this through electrodynamics. What about x rays? You go to your dentist. Your dentist shoots x rays at you, and the x rays plow right through your delicate soft little flesh and then bounce off of your hard teeth, and you get a picture of your teeth, and it's really cool. Okay.
X rays. Novae. When stars go novae, they release tremendous amounts of X rays. When the sun has flares, it emits tremendous amount of x rays. Pulsars emit tremendous amounts of x rays.
How do we understand how these x rays behave, originate, operate, move throughout the cosmos? With the exact same physics that we use to understand how your dentist takes a picture of your teeth. Do you have a fluorescent light bulb in your house? We have physics that explains how fluorescence works, where you have a bunch of atoms hanging out or molecules just doing their thing, and then you zap it with some energy, and it emits light at a very specific frequency. The physics that we use to understand your fluorescent light bulb is the exact same physics that we use to understand how nebulae glow.
Like a planetary nebula. How it glows is through the exact same physics. You've got lasers, all over the place fiber optic cables. Okay. Guess what?
The universe is able to make mazers. Microwave lasers. Lasers, but in the microwave. Oh, yeah. In microwave ovens, the universe, hello, the cosmic microwave background, the single largest source of radiation in the entire universe is in the microwaves.
Very similar frequencies to the radiation that is cooking up your leftovers. Unchanged. And the physics we use to understand the microwave radiation inside of your microwave oven is the exact same physics we use to understand the microwave radiation in the cosmic microwave background. Emission, absorption, LEDs, lasers, physics, physics, physics of optics and electromagnetism. Boom.
All over the place. You pour cream and a little bit of coffee. What do you see? You see the cream curl up on itself. That's a form of turbulence.
Turbulence is what happens when a fluid becomes I should do a whole episode on turbulence. If when it when it becomes too unstable and it starts tripping over itself and it can't just flow cleanly, a fire in your backyard is turbulent. It's fun to watch because it's random and chaotic and turbulent. You can have usually, the flow of blood in your arteries is nice and smooth, but sometimes it can become turbulent and give you a arrhythmia. Sometimes flows of gas, light years across, can become turbulent and ignite the formation of stars.
And the exact same understanding that we have of turbulence from the rough ride in your flight to the cream in your coffee to a fire in your backyard to the flow of blood in your heart, we use to understand how gas clouds collapse to form stars. I'm talking to you right now using sound waves. Right? Bits of my throat are wiggling and flapping together, creating pressure waves. Sound waves are waves of pressure in the air.
And those waves of pressure hit your eardrum, make it vibrate, and that gets translated to an electrical signal, and you understand what I'm saying. The great red spot on Jupiter is generating sound waves strong enough to heat the atmosphere above it by 500 degrees. Sound waves in the early universe were so gigantic, so loud that they shaped the evolution of the entire cosmos. They shaped where galaxies form. Sound waves.
And you know what? We use the exact same physics to understand sound waves moving through the air to sound waves moving through the early universe. That's what I think is so amazing about the universe. That it's vast, it's complex, and it's knowable. And it's knowable from our vantage point here on Earth.
And the physics that you encounter in your everyday life, from the engine in your car to dropping a book on your big toe, apply across billions of light years of distance and billions of years of cosmic time. In a sense, the most amazing thing about the universe to me is how we're all connected, And not in a vague hippie way, but in a real physical way. In a way of understanding, we can draw threads of knowledge from here to every galaxy in the cosmos. We can figure it out. We can draw conclusions.
We can concoct physical laws that are universal in their applicability, and we can go and apply them and understand. We can expand our understanding. We can expand our knowledge. We can expand our mastery of the universe from here on little old Earth using our chalkboards and our computers and our experiments. That's amazing.
Thank you to all my top Patreon contributors. All of you are amazing. All of you who contributed to patreon.com/pmcenter are amazing. But I'd like to especially thank Matthew k, Justin z, Justin g, Kevin o, Duncan m, Corey d, Barbara k, Newdude, Chris c, Robert m, Nate h, Andrew f, Chris l, Cameron l, Nalia, Aaron s, and Kirk t. That's right.
You can go to patreon.com/p. I'm sorry to keep this show on the air. I do sincerely appreciate all of your contributions. If you can't contribute, no big sweat. Don't worry about it.
You go to iTunes and leave a review. That's always helpful. Tell your friends about the show. Go to askaspaceman.com. Send me questions there.
Send me questions to askaspaceman@Gmail.com. Find me on social media at paul matt sutter. Go read my book, How to Die in Space. Isn't it all wonderful? We're all connected, and the universe is still trying to kill us, but that's life.
That's How to Die in Space, available in bookstores nationwide. And I'll see you next time for more complete knowledge of time and space.