What’s the smallest thing in the universe?
That's a complicated question. After all, fundamental particles are what physicists call the most basic building blocks of matter, and they are so minute that no current technology--nor any technology we can even envision--can pinpoint their size.
"The question is a little hard to answer as you have put it, since fundamental particles don’t have measurable sizes," Dr. Andy Parker, the particle physicist who heads the department of physics at the University of Cambridge in the U.K., told The Huffington Post in an email. "Physicists call them 'point-like' to indicate that no size has so far been detected."
But if the universe's smallest particles are that small, how do scientists know about them? To find the answer to that question, I sat down with Dr. Joe Lykken, deputy director of the Fermi National Accelerator Laboratory, the huge particle collider facility located 35 miles west of Chicago.
Check out the video above and/or click below to read the transcript. Don't forget to leave your thoughts in the comments. Talk nerdy to me!
JACQUELINE HOWARD: The universe is a gigantic place, but just about everything in it is made of very tiny particles. What may be the smallest, most fundamental particle in the universe?
Hey everyone. Jacqueline Howard here. I’m 330 feet underground at the Fermi National Accelerator Laboratory in Illinois. It’s where scientists are seeking out the smallest building blocks of all matter, which can enhance our understanding of everything we see around us, and even ourselves. Yeah, you probably thought, well we’re made of tiny molecules, which are made of atoms, which are made of particles like protons, neutrons, and electrons. That must be the end of it, right? Wrong. In the 1950s and ‘60s, scientists discovered the existence of even smaller particles, naming them fundamental particles, which include quarks, neutrinos, bosons, and others. Then the Standard Model of Particle Physics was developed in the 1970s to explain how these fundamental particles and the four fundamental forces of nature -- gravity, electromagnetism, weak force, and strong force -- relate to each other. This journey into the subatomic realm continues with scientists working here at Fermilab, the Large Hadron Collider in Switzerland, and other research labs around the world.
DR. JOE LYKKEN: The way that we try to find out what the smallest things are is by smashing particles in what we call particle accelerators, particle colliders. And we smash them at higher and higher energies trying to break them into smaller and smaller pieces, and for some of these particles we haven’t succeeded to do that.
JH: That’s theoretical physicist and the Fermilab’s deputy director Dr. Joe Lykken. And yes, physicists literally send particles on a collision course like two race cars, crashing into each other, to find out whether they’re made up of even smaller particles. After all, that’s how scientists realized protons and neutrons are actually made of quarks. That’s also how scientists discover new elementary particles that confirm the existence of things that were once only theory.
JL: Two years ago we discovered a completely new kind of particle, the Higgs boson, which is a completely different kind of thing than anything we’ve seen before. I think that that tells us we’re just scratching the surface of what these teeny tiny particles are really like.
JH: But what is the tiniest particle of all? It’s complicated. Whatever it is, it has to be something that can’t be smashed into anything smaller than itself, no matter how powerful the collision. And, physicists know it must be smaller than the size limit given to all fundamental particles, which is around 10 to the minus 19 meters. That’s a zero, followed by 18 more zeros, followed by 1. That’s so small that some physicists say the only way to make sense of it is through what’s called string theory -- the idea that fundamental particles actually may be one-dimensional strings about a millionth of a billionth of a billionth of a billionth of a centimeter. If a single atom was blown up to be the size of our solar system, a string would be the size of one tree. That’s so small that physicists actually call fundamental particles “point-like” to indicate that no technology that exists, and that we can even imagine, is able to make that measurement. But what happens when we do develop such technology?
JL: I think it’ll put us in a very similar situation to the way we were at the beginning of the 1900s when they suddenly started to understand what was inside atoms, and they suddenly realized that there were all kinds of things, new kinds of experiments that you could do that would open up whole new worlds that people hadn’t even suspected.
JH: But until then, what is the smallest particle we know of? It could be a quark, or maybe a neutrino, or even a string? Or maybe we’re all wrong, and it just may be something we have yet to encounter. What other secrets do you think the smallest, most elemental particles of matter may reveal? Let me know in the comments. C’mon, talk nerdy to me!
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