Category: physics

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Forget About Electrons And Protons; The Unstab…

Forget About Electrons And Protons; The Unstable Muon Could Be The Future Of Particle Physics

“Humanity can always choose to build a bigger ring or invest in producing stronger-field magnets; those are easy ways to go to higher energies in particle physics. But there’s no cure for synchrotron radiation with electrons and positrons; you’d have to use heavier particles instead. There’s no cure for energy being distributed among multiple constituent particles inside a proton; you’d have to use fundamental particles instead.

The muon is the one particle that could solve both of these issues. The only drawback is that they’re unstable, and difficult to keep alive for a long time. However, they’re easy to make: smash a proton beam into a piece of acrylic and you’ll produce pions, which will decay into both muons and anti-muons. Accelerate those muons to high energy and collimate them into beams, and you can put them in a circular collider.”

There are lots of possibilities being discussed for how we could build a next-generation particle collider, capable of pushing past the frontiers where the LHC will be fundamentally limited. We could go to a larger proton collider, we could go back to doing high-precision collisions of electrons and positrons to create large numbers of the known, existing particles, or we could push the frontiers in an entirely new way: by colliding muons with anti-muons.

“But they only live for 2.2 microseconds,” you correctly object. Good thing we understand physics. If we can get the technology there, it’s the best option imaginable.

How Do We Know How Small An Elementary Particl…

How Do We Know How Small An Elementary Particle Is?

“But here’s the thing: we don’t know that this is true. Sure, the Standard Model says that this is the way that things are, but we know that the Standard Model doesn’t give us the final answer to everything. In fact, we know that at some level, the Standard Model must break down and be wrong, because it doesn’t account for gravity, dark matter, dark energy, or the preponderance of matter (and not antimatter) in the Universe.

There has to be something out there more to nature than this. And maybe it’s because the particles that we think are fundamental, point-like, and indivisible today actually aren’t. Perhaps, if we go to high-enough energies and small-enough wavelengths, we’ll be able to see that at some point, between our current energy scales and the Planck energy scale, there’s actually more to the Universe than we presently know.”

Are the fundamental particles that we know of truly fundamental? Are they point-like entities, with no finite size, no internal structure, and no capacity to ever be split apart into smaller entities? According to the Standard Model, they are. But observationally, we know that the Standard Model isn’t all that there is. Moreover, we’ve got a long way to go (some 16 orders of magnitude) from our present experimental limits to the Planck scale, and what we think of as “fundamental” could undergo a revolution at any place, without any warning, if only we dare to look.

Right now, the particles we know of appear fundamental down to a limit of about 10^-19 meters, but it’s a long way down to forever. Here’s what we know today.

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The 5 Lessons Everyone Should Learn From Ein…

The 5 Lessons Everyone Should Learn From Einstein’s Most Famous Equation: E = mc^2

“3.) Einstein’s E = mc2 is responsible for why the Sun (like any star) shines. Inside the core of our Sun, where the temperatures rise over a critical temperature of 4,000,000 K (up to nearly four times as large), the nuclear reactions powering our star take place. Protons are fused together under such extreme conditions that they can form a deuteron — a bound state of a proton and neutron — while emitting a positron and a neutrino to conserve energy.

Additional protons and deuterons can then bombard the newly formed particle, fusing these nuclei in a chain reaction until helium-4, with two protons and two neutrons, is created. This process occurs naturally in all main-sequence stars, and is where the Sun gets its energy from.”

Even if you don’t know any physics at all, there’s a good chance that there’s at least one equation you know of: Einstein’s E = mc^2. It tells us that energy and mass are equivalent quantities, and that c^2 (the speed of light squared) is the constant that enables you to convert from one to the other. Along for the ride, we learn some amazing things, including that mass is not conserved, that bound objects have less mass than the same objects when they’re not bound, and that you can spontaneously create matter/antimatter pairs if you have enough available energy under the right conditions.

Einstein may be synonymous with “this is too hard for most people to understand,” but it doesn’t have to be this way. Get the 5 lessons everyone should know about E = mc^2 today!

Ask Ethan: Can Free Quarks Exist Outside Of …

Ask Ethan: Can Free Quarks Exist Outside Of A Bound-State Particle?

“In our low-energy, modern-day Universe, we only find quarks and antiquarks in bound, hadronic states: baryons, anti-baryons and mesons. But that’s only because the quarks that conventionally exist are long-lived, at low densities, and at low enough energies and temperatures. If we change any one of those three, the existence of free quarks is not only possible, but mandatory.

If the conditions for forming a bound state aren’t met, then confinement is impossible. The four ways we know how to get there are to create a top quark, to look to the early stages of the hot Big Bang, to collide heavy ions together at relativistic speeds, or to look inside the densest objects (like neutron stars or the hypothetical strange quark stars) to find the quark-gluon plasma inside. It’s not an easy feat to accomplish, but if you want to create matter in the most extreme states we know of, you have to go to extreme ends to get there.”

Have you ever wondered, if protons and neutrons are made of quarks, whether it’s possible to have a quark (or antiquark) exist outside of a bound-state system? There are lots of ways that we’ve tried to separate quarks out from their bound states that fail. Split a proton apart and it will split, but into other bound states. Take a meson and pull the quark and antiquark apart, and a new antiquark/quark pair will snap into existence to give you two new mesons instead. Even if you create a quark/antiquark pair in a collider that move in opposite directions, they hadronize and only produce the baryons and mesons we can detect: bound states.

But that’s not the end of the tricks up our (and the Universe’s) sleeve. We can create free quarks after all. If you’re curious, you can now find out how.

This Is Why Black Holes Must Spin At Almost …

This Is Why Black Holes Must Spin At Almost The Speed Of Light

“Realistically, we can’t measure the frame-dragging of space itself. But we can measure the frame-dragging effects on matter that exist within that space, and for black holes, that means looking at the accretion disks and accretion flows around these black holes. Perhaps paradoxically, the smallest mass black holes, which have the smallest event horizons, actually have the largest amounts of spatial curvature near their horizons.

You might think, therefore, that they’d make the best laboratories for testing these frame dragging effects. But nature surprised us on that front: a supermassive black hole at the center of galaxy NGC 1365 has had the radiation emitted from the volume outside of it detected and measured, revealing its speed. Even at these large distances, the material spins at 84% the speed of light. If you insist that angular momentum be conserved, it couldn’t have turned out any other way.”

Have you ever wondered how black holes, ranging from a few times our Sun’s mass up to billions of times as massive, can spin so rapidly? Most black holes, as far as we can tell, are spinning very close to the speed of light: the ultimate speed limit of the Universe. Yet most stars, like our Sun, rotate extremely slowly: just once over a period of many days (or even longer).

So how does a slowly-rotating star, which goes supernova and forms a black hole, give rise to an object spinning near the cosmic speed limit? Find out today.

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