“A mathematician and a physicist walk into Burning Man…” could be the start of a really good joke. Instead, it was just a real-life scenario for our anonymous physicist (we’ll call him “P”) and his mathematician friend. A little nervous that Burning Man wouldn’t be their scene, P & M decided to set up a tent and embrace their inner nerd. Burning Man runs off of a gift economy and P & M decided they wanted to contribute to that.
“Basically I’ve spent so much time just learning and being in school that I don’t have many applicable skills,” P tells us with a laugh. “The only thing we had to give is, we know a bunch of math and physics. So we set up a booth.”
To the duo’s surprise, the booth was a huge hit. But what they noticed even more than the question seekers were the number of festival goers who just wanted to hang around and listen to the answers. It made them realize that there wasn’t much of an outlet for regular people to ask their questions about math/physics and get comprehensible answers back.
“I think everybody’s had the experience,” P explains, “where you’re taking a class, and the professor or the teacher is saying things as though they should be obvious. The problem is that if you do a thing a lot, like math teachers do, then pretty soon it is obvious to you. So what I try to do is to remember just how incredibly frustrating it was when I was learning it the first time and usually that’s a pretty good guide.”
After their booming success at Burning Man, P and M decided to bring their skills to the masses. In order to combat the image that physics and math are too dense to understand, they began answering people’s questions on the internet. They set up the site, “Ask a Mathematician,” and soon had questions pouring in.
From the start, they decided to stay anonymous (even in interviews and media coverage). P says that’s because he wanted their answers to be taken and examined at face value rather than accepted as gospel because of their credentials. Or discredited for the same reason.
“By removing the ability to call to authority, you force people to judge what you write based on exactly what it is. So I always try to cite examples and actually derive the relevant math when I put together an article. That way, if anybody has a complaint, it’s not, ‘You didn’t go to Harvard three times.’ It has to be, ‘You did the math wrong.’ That’s where I think the discussion should be.”
P’s current work involves working out the mathematical side of quantum physics, which sounds really complicated, but P describes it fairly simply. What he does is create mathematical tools or equations so that quantum physicists are able to use them. Then these quantum algorithms can be applied to research.
It’s a profession P loves, though he tried to avoid it as a kid. His father was a physicist and so to rebel, he decided to major in creative writing in college. Eventually, like many of us who have realized that we’ve totally turned into our parents, he soon found himself gravitating back towards math and physics. He started taking math classes just for a fun credit (!) and was quickly drawn back in to the physicist life.
That’s not to say that the energy from writing classes has been put to waste. With “Ask a Mathematician,” P gets to put some of that creative writing to good use, blending both of those passions into a fun site that answers questions in a creative, easy to understand way. The site will soon be turned into a book though P is yet to think of a really good pen name. But until then, he’ll continue to be a STEM warrior on the internet, answering the questions that you’ve always wanted to know (so that you can sound just a little smarter at dinner parties).
Since we had P on the phone, we brought him physics questions from the Uproxx writing staff. P kindly answered them for us. Read our questions and his answers below!
The Uproxx Staff’s Burning physics questions:
What did people get wrong about the recent study in concluding that scientists had discovered negative mass?
That’s deeply funny stuff. I can give you my wild guess. The way you define things physically is in terms of how you measure them. So for example when a physicist asks, “What is time?” They don’t mean it in a grand philosophical sense but they mean literally how can you tell the difference between time and not time? And the answer is: you measure it with a clock and the exact same thing for space. When you say, “How could you tell that there’s more space or less space?” The answer is you measure it with a ruler and that’s literal. Whenever you’re talking about relativity and twists, space-time, and that sort of thing, those are the exact definitions they are talking about, measure it with a clock, measure it with a ruler, that sort of thing.
With mass, the way you measure it is basically in terms of Newton’s law. F equals to ma. The question is if you push on it, how much does it accelerate? If there’s very little mass and you push on it, it should accelerate a lot and if there’s a lot of mass like a truck — when you push on it, it shouldn’t accelerate very much. Negative mass, if you put force on it, accelerates in the wrong direction.
It looks like they’ve managed to come up with some stuff that does that but whether or not that actually means that there’s negative matter present or they’ve just created a thing that acts in this bizarre way is probably where the subtlety comes in. What they’ve probably done is created something where if you push on it, it accelerates in the wrong direction because of the very bizarre conditions that it’s presently in, as opposed to actually being a blob of negative matter.
What is dark matter?
So you may have noticed that there are protons and neutrons in the nucleus of atoms and that there are electrons that whip around the nucleus.
[Writer’s note: I had not noticed, but that’s neither here nor there.]
So a good question to ask is why aren’t there electrons stuck inside of the nucleus? It turns out that the answer is the protons and the neutrons interact with the strong nuclear force. So in addition to the electromagnetic force that takes the protons and tries to push them apart because they are like charges, there’s also a strong nuclear force that holds them together and that strong nuclear force is completely invisible to the electron. They don’t see it at all. All that they see is the electric force. So the protons and the neutrons are stuck together because of the strong force but the electron doesn’t see it, so it’s allowed to leave the nucleus.
The whole point of this is to say that there are different forces. And different particles care about different combinations of those forces. So like a proton cares about the electric force and the strong nuclear force but an electron cares about the electromagnetic force and not the strong force. So wouldn’t it be weird if there was a kind of particle that didn’t care about any of the forces?
A particle that didn’t care about the strong force, you wouldn’t tend to find it inside of the nuclei and if it didn’t care about the electromagnetic force, it would be invisible to light. Light is the electromagnetic moderator so it would just pass right on through it. It also wouldn’t tend to interact with normal matter because basically all of our interactions with matter are electromagnetic.
So hypothetically if there was some kind of a particle that didn’t interact with electromagnetism or strong force, you basically just wouldn’t see it. It would be invisible but more than that, it wouldn’t even cling together. The reason that atoms and chemicals and buildings hold together is that there’s an electromagnetic force that holds one atom to the next to the next. So that was kind of an interesting philosophical puzzle until astronomers started looking around the universe and noticed that the stars and galaxies were turning too fast. But more than that… you can look at stars and you can see how fast they are orbiting a galaxy and you can figure out about how much mass is inside of their orbit. But the galaxies and the stars were just streaming along way too fast. If you looked at the stars closer and closer to the center, they should be slower but they weren’t really slower, as though they were on a disc.
They were moving as though the matter was spherically distributed and the reason the galaxy is a disc is that matter tends to run into itself and accrete. That’s why Saturn has rings. It’s why the solar system is flat. It’s why things tend to be flat around space but the matter in galaxies, the vast majority of it, is all spread out as though it never bothered to run into itself and turn into flat sheets…. the way matter does. And so that implies that there is a big cloud of matter around, I think every galaxy we’ve looked at, a big cloud of matter that doesn’t interact with itself. That sounds a lot like this hypothetical matter that doesn’t interact with any of the forces. It looks like it’s real but unfortunately it is dark matter so it’s very difficult to study.
If we were to theoretically ride a string through a black hole, would it cause a paradox?
Not particularly. Generally speaking, if you want a paradox, you’ve got to get a time machine and a suicidal grandfather.
Running a string down into a black hole. That seems fine. When you dangle a rope into gravitational field, it tends to point down. The problem with the event horizon (where time gets weird with a black hole) is that at the event horizon, time — the direction of the future — literally points down. So as a result being lower on the rope, past the horizon is in every way exactly the same as moving into the future. And since things tend to move into the future whether you want them to or not, that has a way of snapping ropes as you lower them through the event horizon. Aside from that, I shouldn’t see any particular paradox.
Finally, do you think neutrinos have mass?
Yes. This is actually really sleek. The neutrino detectors that we’ve managed to build all over the world detect most of their neutrinos coming from the sun because in the process of turning hydrogen into helium you’ve got to turn some protons into neutrons and that process releases an electron neutrino. There are actually three different kinds of neutrinos. The electron is part of a lepton group. It also has a kind of sister particle, the muon, and the tau that are heavier. Each of those has an associated neutrino. When an electron neutrino is released, it likes to interact with other electrons. The muon and tau neutrinos don’t particularly.
The problem is that the detectors here on earth are detecting about almost exactly one third as many neutrinos coming out of the sun as they should. Here’s what’s happening. An electron neutrino is released and it oscillates between the states of being an electron, a tau, or a muon neutrino. It oscillates between all three of those states. The problem is, this is very obscure particle physics stuff, but the reason that happens is that the masses of the neutrinos tend to be a little bit different and that difference in mass, that difference in energy, causes them to, in some sense, cycle at a slightly different speed. Because they are all turning at slightly different speeds, that causes the thing to kind of wobble back and the forth.
The point is, and this is the weird part, they have to have mass in order to have different masses so the evidence seems to indicate they do have mass but they are always traveling at the speed of light. When we look at supernovas, the light from a supernova gets to us at almost exactly the same time that the neutrinos from that supernova get to us. That means that the neutrinos are not exactly losing pace to light. They are moving at almost the same speed but that weird kind of turning from one state into another implies that although they are moving at basically the speed of light, they also have mass that’s close but not quite zero. They are ghost particles.
You can read more fascinating physics and math questions (and their answers!) at Ask a Mathematician/Ask a Physicist.