Of Particular Significance

Tag: relativity

Public Talk at the University of Michigan Dec 5th

This week I’ll be at the University of Michigan in Ann Arbor, and I’ll be giving a public talk for a general audience at 4 pm on Thursday, December 5th. If you are in the area, please attend! And if you know someone at the University of Michigan or in the Ann Arbor area who might be interested, please let them know. (For physicists: I’ll also be giving an expert-level seminar at the Physics Department the following day.)

Here are the logistical details:

The Quantum Cosmos and Our Place Within It

Thursday, December 5, 2024, 4:00-5:00 PM ; Rackham Graduate School , 4th Floor Amphitheatre

When we step outside to contemplate the night sky, we often imagine ourselves isolated and adrift in a vast cavern of empty space—but is it so? Modern physics views the universe as more full than empty. Over the past century, this unfamiliar idea has emerged from a surprising partnership of exotic concepts: quantum physics and Einstein’s relativity. In this talk I’ll illustrate how this partnership provides the foundation for every aspect of human experience, including the existence of subatomic particles (and the effect of the so-called “Higgs field”), the peaceful nature of our journey through the cosmos, and the solidity of the ground beneath our feet.

POSTED BY Matt Strassler

ON December 2, 2024

Speaking at Brown University Nov 18th

Just a brief note, in a very busy period, to alert those in the Providence, RI area that I’ll be giving a colloquium talk at the Brown University Physics Department on Monday November 18th at 4pm. Such talks are open to the public, but are geared toward people who’ve had at least one full year of physics somewhere in their education. The title is “Exploring The Foundations of our Quantum Cosmos”. Here’s a summary of what I intend to talk about:

The discovery of the Higgs boson in 2012 marked a major milestone in our understanding of the universe, and a watershed for particle physics as a discipline. What’s known about particles and fields now forms a nearly complete short story, an astonishing, counterintuitive tale of relativity and quantum physics. But it sits within a larger narrative that is riddled with unanswered questions, suggesting numerous avenues of future research into the nature of spacetime and its many fields. I’ll discuss both the science and the challenges of accurately conveying its lessons to other scientists, to students, and to the wider public.

POSTED BY Matt Strassler

ON November 15, 2024

Answers to Two Cosmic Questions From A Reader

Recently a reader, having read my post about why the speed of light seems so fast, sent me two questions that highlight important cosmic issues.

Is there in fact anything within physics as it’s presently understood that indeed prevents […] there existing something other than atoms as some basic “unit”?
I’ve long wondered why it is that despite the seeming brilliance of humans at building such complex understanding, we are still pushing at such limits as the time it would take to fly a space ship to another galaxy. Is it really true that nothing could ever exceed ‘c’ and thus we are indeed doomed to take lifetimes to travel beyond our solar system? Or is it because we have not yet discovered something much more fundamental about the universe, such as an ‘alternative to’ the atom?

These deep questions are examples of an even broader pair of questions about reality.

Which aspects of the cosmos are contingent?—in that one could easily imagine a similar universe in which these details are thoroughly altered.
Which aspects of the cosmos appear rock solid?—in that they are so deeply integrated into the universe that it is difficult to imagine changing them without ruining everything.

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POSTED BY Matt Strassler

ON October 28, 2024

New Scientific Commentaries Added to Website

Though I’ve been busy with a number of physics and writing tasks, I’ve been beefing up the “Reader Resources” section of this website, devoted to extending the experience of readers of my book. [BTW, the audiobook is due out at the end of September.]

The book has many endnotes (available separately here, in case [like me] you hate paging back and forth between the text and the endnotes, and would like to have the endnotes more easily available on a separate screen.) A number of these endnotes have asterisks, and for those endnotes I promised to provide more information here on this website. Well, that information is going up, step by step.

For example:

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POSTED BY Matt Strassler

ON August 20, 2024

Answering Listeners’ Questions About “Particles”

A couple of months ago, I was on Daniel Whiteson’s podcast, which is called “Daniel and Jorge Explain the Universe“. During the two-part episode in which I appeared, entitled “Is the Universe Made of Waves?” (Part 1 and Part 2), I explained some of the key points made in my book, “Waves in an Impossible Sea.”

One thing I emphasized is that while photons [“particles” of light] moving across empty space are always traveling waves moving at the speed of light c, electrons are different. When in motion they too are traveling waves, but unlike photons, they can slow down, and even be stationary. When stationary, they are standing waves, of a somewhat unfamiliar sort (as described here and here). All of this is discussed in detail in the book’s chapters 16 and 17.

Whiteson has sent me a couple of questions that listeners raised with him, and since I imagine some of you might have similar questions, I decided to answer them publicly here.

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POSTED BY Matt Strassler

ON May 21, 2024

Running Circles Around One Another

Are you sitting or lying down? Perhaps you’re moving around at a walking pace? I probably am. And yet, unless you live in the northeastern US or in southern South America, you and I are moving relative to each other at hundreds of miles per hour.

In Chapter 2 of the book “‘Waves in an Impossible Sea”, I remarked on the this fact. (See below for the relevant passage.) At first glance it might seem puzzling. After all, the distance between your town and my town is constant; it never changes. And yet our relative motion is comparable to or faster than a jet aircraft. How can both of these things be true?

And then there’s another question: if we’re all moving so fast relative to one another, why don’t we feel the motion?

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POSTED BY Matt Strassler

ON May 2, 2024

A Relatively Important Question from a Reader

Recently, a reader raised a couple of central questions about speed and relativity. Since the answers are crucial to an understanding of Einstein’s relativity in particular and of the cosmos in general, I thought I’d bring them to your attention, in case you’ve had similar questions.

The Questions

I understand that the vacuum speed of light [“c“] is constant throughout the Universe, and I’m familiar with the math that shows that the energy required to accelerate a particle becomes infinite as the speed approaches c. But what physical effect enforces this behavior? If a proton, for example, gets ejected in a supernova explosion, how does it “know” that it’s getting close to c and can’t go any faster?

And as a corollary to this question, what is the reference frame for measuring these relativistic velocities? For example, when a particle beam at CERN is said to be moving at 99.99% the speed of light, is that speed relative to the infrastructure at CERN? Or does it somehow account for the velocity components that arise from the rotation of the Earth, the orbital motion of the Earth around the Sun, the galactic motion of the Sun in the Milky Way, and so on?…

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POSTED BY Matt Strassler

ON March 6, 2024

“Moving” Faster than the Speed of Light?

Nothing goes faster than the speed of light in empty space, also known as the cosmic speed limit c. Right? Well, umm… the devil is in the details.

Here are some of those details:

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POSTED BY Matt Strassler

ON February 20, 2024

How to Tell that the Earth Spins

Continuing with the supplementary material for the book, from its Chapter 2. This is in reference to Galileo’s principle of relativity, a central pillar of modern science. This principle states that perfectly steady motion in a straight line is indistinguishable from no motion at all, and thus cannot be felt. This is why we don’t feel our rapid motion around the Earth and Sun; over minutes, that motion is almost steady and straight. I wrote

. . . Our planet rotates and roams the heavens, but our motion is nearly steady. That makes it nearly undetectable, thanks to Galileo’s principle.

To this I added a brief endnote, since the spin of the Earth can be detected, with some difficulty.

As pointed out by the nineteenth-century French physicist Léon Foucault, the Earth’s rotation, the least steady of our motions, is reflected in the motion of a tall pendulum. Many science museums around the world have such a “Foucault pendulum” on exhibit.

But for those who would want to know more, here’s some information about how to measure the Earth’s spin.

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POSTED BY Matt Strassler

ON September 21, 2023

Dismantling Common Sense, Twice

In my last post I raised a question about the pros and cons of common sense. I left it as a wide-open question, as I was curious to see how readers would react.

Many aspects of common sense affect how we relate to other people, and it’s clear they have considerable value. But the intuitions we have for nature, though sometimes useful, are mostly wrong. These conceptual errors pose obstacles for students who are learning science for the first time.

It’s also interesting that once these students learn first chemistry and then Newtonian-era physics, they gain new intuitions for the natural world, a sort of classical-physics common sense. Much of this newfound common sense also turns out to be wrong: it badly misrepresents how the cosmos really works. This is a difficulty not only for students but also for many adults. If you’ve read about or even taken a class in basic astronomy or physics, it can then be challenging to make sense of twentieth-century physics, where Newtonian intuition can fail badly.

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POSTED BY Matt Strassler

ON June 20, 2023

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Tag: relativity

The Quantum Cosmos and Our Place Within It

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

The Questions

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

POSTED BY Matt Strassler

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Order Waves In An Impossible Sea