Category: physics

The Physics Of Why Timekeeping First Failed In…

The Physics Of Why Timekeeping First Failed In The Americas

“As soon as the clock arrived and was set up, it began keeping time more accurately than any timepiece before ever located on the North American continent. At least, that was what everyone assumed was happening for about a week or so. But after that amount of time, it became clear that something was amiss. The Sun and Moon weren’t rising at their predicted times, but rather were off by a bit.

Even worse, the amount that the clock was off by appeared to be getting worse over time: whatever error was at play was accumulating. Instead of these reliable, celestial events occurring at the predicted times on the clock, they were occurring earlier, according to the clock. Something was wrong. The clock was not only running slow, but appeared to be losing close to a minute per day.”

Imagine the news in 17th century America: a new form of timekeeping has been developed, and instead of an uncertainty of around 15 minutes a day (like you get with sundials), you can keep time accurately to within seconds per day. It would be an incredible advance! So you place an order to the Netherlands, where they’ve developed it, and they build you a clock. You send it across the ocean, set it up, and start it working. It seems to work great! But then you realize, after about a week, that the Sun and Moon aren’t rising and setting when they should. Something about your pristine clock is off. So you send it back, and when they start it up back in Amsterdam, it works perfectly.

Sounds like a mystery! But this mystery is something special, because the problem wasn’t with the clock, after all, but with the Earth. Come get the bizarre but educational story of how timekeeping first failed in the Americas!

Ask Ethan: Does The Measurement Of The Muon&rs…

Ask Ethan: Does The Measurement Of The Muon’s Magnetic Moment Break The Standard Model?

“[There’s a notable] difference between theory and experiment [for the muon’s magnetic moment]. Is the fact that the [uncertainties are large] more meaningful than the >3 sigma significance calculation? The Mercury precession must have a very small sigma, but is cited as a big proof of relativity. What is a good measure of significance for new physics results?”

Whenever theoretical predictions and experimental results disagree, that’s surely a sign of something interesting. If we’re extremely lucky, it might be a sign of new fundamental physics, which could mean new laws of nature, new particles, new fields, or new interactions. Any of these would be revolutionary, and certainly it’s the great hope of anyone who works on these projects: to peel back the curtain of reality and find the next layer inside. But there are two other possibilities, far more conservative and mundane, that must be ruled out first. One is an error, either on the theoretical or experimental side, that has simply been overlooked. The other is even more subtle, though: an effect from a known physical cause that’s at the heart of this discrepancy, which we haven’t thought we needed to include until now.

The muon’s anomalous magnetic moment might be a harbinger of new physics. But it might also be a subtle effect of gravity that’s appearing for the first time. Come look at the evidence and see for yourself!

Ask Ethan: When Were Dark Matter And Dark Ener…

Ask Ethan: When Were Dark Matter And Dark Energy Created?

“Today [normal matter] is only 4.9% while Dark Matter and Dark Energy takes the rest. Where did they come from?”

The Universe, as we know it, got its start in earnest when the hot Big Bang began. Space was filled with all the particles and antiparticles of the Standard Model, up at tremendous energies, while the Universe then expanded, cooled, and gave rise to all we know. But when did dark matter and dark energy, which make up 95% of the Universe we know today, come into the picture? Was the Universe born with these components of energy? Or were they created at a later time? We have some inklings that dark matter was likely created in the extremely early stages, but may not have been present from the Universe’s birth. On the other hand, all theoretical signs point to dark energy always existing, but observationally, we have about 4 billion years where we cannot measure its presence at all.

Where do dark matter and dark energy come from? It’s a great cosmic mystery, but we do know something about it. Find out where we are today!

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The Greatest Mistake In The History Of Physics

The Greatest Mistake In The History Of Physics

“Poisson attempted to disprove Fresnel’s theory by showing that it led to a logical fallacy: reductio ad absurdum. Poisson’s idea was to derive a prediction made by the light-as-a-wave theory that would have such an absurd consequence that it must be false. If the prediction was absurd, the wave theory of light must be false. Newton was right; Fresnel was wrong. Case closed.

Except, that itself is the greatest mistake in the history of physics! You cannot draw a conclusion, no matter how obvious it seems, without performing the crucial experiment. Physics is not decided by elegance, by beauty, by the straightforwardness of arguments, or by debate. It is settled by appealing to nature itself, and that means performing the relevant experiment.”

It’s now been 200 years since one of the most embarrassing moments in the history of physics. The famed scientist Simeon Poisson, at a conference on the nature of light, discounted one of the entrant’s theories because its predictions were completely absurd. He attempted to have the contestant, a young civil engineer named Fresnel, laughed out of the competition because his theory predicted that, at the center of a shadow, a bright spot of light should appear. Yet Poisson made these moves without ever performing the experiment that would decide whether Fresnel was right or wrong!

You can’t do that in science, no matter how sure you are that you know what is or isn’t absurd. Nature must decide. And that, in science, is always the lesson.

Summer schools be like

Summer schools be like

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imsureiforgotsomething:

physicsforbunnies:

physicsforbunnies:

I’ve been thinking about this for days but… Chemistry really is just a branch of physics which has been historically separated from it because quantum mechanics and the finer detailes of atomic physics are relatively recent discoveries.

What i’m saying is that chemistry is clumsy physics. A vulgar version of physics. F*ck chemistry.

Guys… The second part of this post was obviously sarcastic. Did I really need to write this down. Fucking chill.

source

Basically

Regular

physicsforbunnies:

I’ve been thinking about this for days but… Chemistry really is just a branch of physics which has been historically separated from it because quantum mechanics and the finer detailes of atomic physics are relatively recent discoveries.

What i’m saying is that chemistry is clumsy physics. A vulgar version of physics. F*ck chemistry.

Guys… The second part of this post was obviously sarcastic. Did I really need to write this down. Fucking chill.

Fading total lunar eclipse, Munich, 28.7.18

Fading total lunar eclipse, Munich, 28.7.18

Would you say that a physics major would have …

Would you say that a physics major would have a fair amount of job options available (or y’know, existent) after a Masters degree? Or do most physics jobs require a PhD? I want to major in physics by I’m not sure if I could really handle that much school, and I know Chemistry has a fair amount of job opportunities accessible with a Masters.

Hey, sorry for the late reply, my life is a mess. Also I read this after writing the previous stupid chemistry-dragging post. 

I think you can go after a fair amount of jobs after a Masters in physics. It depends

whether

you want to continue working in a strictly physics-related field or not. When I got a Masters I did a ton of job interviews and got hired in a major Bank to be a data analyst (even though I don’t know the first thing about finance),

but i then decided to pursue a PhD and never work in my life. Anyway as a physicist you can get really good big corp. jobs, and maybe – maybe – even end up working on some interesting projects such as: machine learning, robotics and AI, blockchain, etc. These big corporations really want physicists for these jobs not only because of our programming skills (they look mainly for Python, C, C++, SQL) but also for analysis skills and statistics, which a non-physicist programmer usually lacks. If you are interested in that kind of thing you can contact corporations such as IBM, KPMG, Deloitte, Accenture, Microsoft,Google, basically every bank etc. If being a manager/consultant isn’t your dream job, there are corporations that deal with research in physics, like STMicroelectronics, for example.

But if you want like a proper physics job like working in a lab for research and not selling your soul to capitalism for big money, then you almost certainly need a PhD. But I guess it depends what field you’re in.

As for chemistry, the best you can aspire to is to do product control for a factory, or spend your days in a hospital lab checking urine for diabetes and regretting not doin physics 😉