iiinova — where your digital self keeps evolving

Alan Nathan @pobguy.bsky.social · 28/09/2026

Today we celebrate the 66th anniversary of Ted's last game and his home run in his final plate appearance. Time for my annual read of John Updike's essay, Hub Fans Bid Ted Adieu: www.newyorker.com/magazine/196..., some of the best sports writing ever.

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Alan Nathan @pobguy.bsky.social · 12/09/2026

Followup on my drag analysis. Plots below show monthly-average fly ball distance for narrow range of EV,LA. Top graph is plotted vs average Cd. But Cd alone does not determine drag. Bottom graph is plotted vs. average air density-corrected Cd. Much more clear-cut correlation, as I would expect.

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Alan Nathan @pobguy.bsky.social · 10/09/2026

Here is my latest update on drag coefficients for the 2026 season.

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Alan Nathan @pobguy.bsky.social · 27/08/2026

Paying homage to one of my heroes: Statue of Muhammad Ali in Lewiston ME, site of the 2nd Clay-Liston fight in 1965. I listened to the radio broadcast of that fight as no home TV was available.

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Alan Nathan @pobguy.bsky.social · 10/08/2026

Here I am on the mound ar Field of Dreams, August 1991

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Alan Nathan @pobguy.bsky.social · 01/08/2026

I don't think day-to-day fluctuation in Cd is larger this year than in ealier years. What is different is the overall trend seen in the weekly average.

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Alan Nathan @pobguy.bsky.social · 01/08/2026

One more related graph shows normalized home run rate vs Cd (both monthly averages). The home run rate is controlled for exit velocity, launch angle, and air density (especially temperature), so that these factors do not enter into the rate. Rates are ~20% greater in June,July than in April,May.

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Alan Nathan @pobguy.bsky.social · 01/08/2026

July update on Cd values, which seem to be trending upward. Fly ball distances for given LA are same in July as in June, with both greater than April and May. I will continue to post monthly update for remainder of season.

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Alan Nathan @pobguy.bsky.social · 27/07/2026

And Bill Russell has more rings than fingers.

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Alan Nathan @pobguy.bsky.social · 11/07/2026

Update with drag data through July 9. Cd has stabilized at a level a bit above the 2019 levels. In July, both Cd and fly ball distances essentially the same as in June. Home runs per batted ball at 0.050 in June-July, up from 0.042 in April-May, partly due to higher temp, partly lower Cd

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Alan Nathan @pobguy.bsky.social · 01/07/2026

There still seems to be a lot of interest in drag coefficients (Cd) this season. I have now looked at all the data through June 30. Results shown below. Bottom plot shows monthly mean of Cd, which is ~4% smaller in June than in April.

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Alan Nathan @pobguy.bsky.social · 25/06/2026

More on drag coefficients. Graph shows fly ball distance for EV=104 mph, LA=25-30 deg plotted versus Cd, all monthly averages. Very clear correlation.

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Alan Nathan @pobguy.bsky.social · 23/06/2026

One more: Weekly averages at Tropicana Field, sorted by years. That is the best case scenario for constant atmospheric effects.

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Alan Nathan @pobguy.bsky.social · 23/06/2026

You can see from the daily (or weekly) trend of Cd that after an initial period when Cd was pretty stable, it has been on a downward trend since about day 112 (April 22). So the standard deviation is increasing over time.

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Alan Nathan @pobguy.bsky.social · 23/06/2026

Here is plot of average daily Cd standard deviation

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Alan Nathan @pobguy.bsky.social · 23/06/2026

Much more variation this year than previous. Below are year, mean and std dev of daily Cd: 2017 0.3348 0.0058 2018 0.3371 0.0044 2019 0.3278 0.0039 2020 0.3404 0.0057 2021 0.3410 0.0053 2022 0.3468 0.0045 2023 0.3416 0.0042 2024 0.3433 0.0047 2025 0.3516 0.0046 2026 0.3464 0.0087

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Alan Nathan @pobguy.bsky.social · 21/06/2026

To get some idea of the relationship between Cd and HR probability (pHR), see the plot I last updated in August 2024, showing relationship between pHR (controlling for EV and LA) and "density-corrected" Cd (monthly averages). The correlation is quite clear. Need to update with 2025,2026.

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Alan Nathan @pobguy.bsky.social · 21/06/2026

Here's what I have found. Top plot is drag Cd, bottom plot is lift Cl. Cd shows steady decrease by nearly 10% since start of season. Cl does not. So it's not simply an air density effect, which should affect both quantities. Next step would be to see whether HR rates track with Cd. Later.

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Alan Nathan @pobguy.bsky.social · 02/06/2026

Here a a picture of Wilson Compton, former president of WSU and brother of physicist and Nobel Laureate Arthur Compton, who first unraveled the secrets of Compton scattering from the electron. I spent much of my career in nuclear physics ( pre baseball) using Co.pton scattering ...

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Alan Nathan @pobguy.bsky.social · 02/06/2026

A sign outside the baseball stadium at WSU.

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Alan Nathan @pobguy.bsky.social · 12/04/2026

My issue is that the no-wind distance is only ~390 ft whereas actual is 422, a difference of only 32, not 65. BTW, in my "analysis", I did a linear extrapolation of D-vs-EV for LA=41 and EV>90. See data below.

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Alan Nathan @pobguy.bsky.social · 12/04/2026

Best Red Sox game so far. And I was there with great seats (see picture of the view from my seat), courtesy of my friends in the Cards organization. Other pic shows a closeup of one set of Hawkeye cameras. Lovely evening for baseball.

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Alan Nathan @pobguy.bsky.social · 07/04/2026

I did an analysis (others probably did the same analysis) showing the Hendricks had two different changeups (4S and 2S). Same spin axis in both cases. The 2S had a big ssw effect; not so for the 4S.

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Alan Nathan @pobguy.bsky.social · 02/04/2026

Just attended my first baseball-themed Passover seder.

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Alan Nathan @pobguy.bsky.social · 30/03/2026

My latest project. I have already read the Rhodes book on the making of the atomic bomb. This book is much more technical, although quite accessible given my nuclear physics background.

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Alan Nathan @pobguy.bsky.social · 19/03/2026

Attending a session devoted to the legacy of C. N. Yang, one of the towering. theoretical physicists of the latter half of the 20th century.

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Alan Nathan @pobguy.bsky.social · 12/03/2026

After nearly 39 years (and 17 years since retirement), I have vacated my office at Loomis Lab, home of the UIUC Physics Department. I used the office very regularly prior to Covid and hardly at all since. Time to turn it over to someone else. I left my parting words on the chalkboard.

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Alan Nathan @pobguy.bsky.social · 12/03/2026

Congratulations to Team Italy!

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Alan Nathan @pobguy.bsky.social · 01/03/2026

Treating the bat as a rigid object (i.e., no vibrations) does not tell the whole story. A rigid bat would have the ball-bat coefficient of restitution (BBCOR) independent of impact location, unlike our recent data.

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Alan Nathan @pobguy.bsky.social · 28/02/2026

In the current issue of Physics Today, there is a very nice article about David Gagnon, the team leader in Baseball Sciences for the Nats. This confirms my long-held belief that there is a place in MLB organizations for people with strong physics backgrounds.

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Alan Nathan @pobguy.bsky.social · 23/02/2026

ICYMI 🧵1st results of the Torpedo bat study by Lloyd Smith, @drussellpsu.bsky.social, and me. Measurements done at WSU Sports Science Lab and PSU. Will be presented at ISEA Conference in June. BBCOR, a surrogate for exit velocity, measured for 1 Standard and 2 Torpedo bats via high-speed impact.

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Alan Nathan @pobguy.bsky.social · 21/02/2026

Two more things: Dan Russell's tag: @drussellpsu.bsky.social And a plot that emphasizes the primary result. I have shifted both Torpedo bats by -0.6". The resulting plot shows that Torpedo-1 and Standard overlap perfectly and that Torpedo-2 is broader (i.e., a larger sweet spot, by ~0.4").

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Alan Nathan @pobguy.bsky.social · 21/02/2026

1st results of the Torpedo bat study by Lloyd Smith, @drussell@engr.psu.edu, and me. Measurements done at WSU Sports Science Lab and PSU. Will be presented at ISEA Conference in June. BBCOR, a surrogate for exit velocity, measured for Standard and 2 Torpedo bats via high-speed impact.

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Alan Nathan @pobguy.bsky.social · 20/02/2026

Re-upping this today, celebrating the return of baseball and (finally) a good decision from the Supreme Court. Next up: Opening Day at the end of March and oral arguments in birthright citizenship case on April 1.

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Alan Nathan @pobguy.bsky.social · 12/02/2026

Happy President's Day, the first 6 of whom are in my portrait gallery of founders.

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Alan Nathan @pobguy.bsky.social · 23/01/2026

I'll be wearing my Bates Baseball cap in the coming days, in solidarity with my friends from Lewiston ME, home of Bates College and many American citizens of Somali origin.

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Alan Nathan @pobguy.bsky.social · 09/01/2026

Here's a great story for these troubled times: share.google/s6IPE19JdMNL... I met Donell today. He's one great guy!

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Alan Nathan @pobguy.bsky.social · 12/12/2025

Not sure if it's far side but it's my favorite

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Alan Nathan @pobguy.bsky.social · 16/11/2025

We had a couple of law professors over for dinner last night. They are among the nation's experts in constitutional law. They presented me with this baseball, which I will proudly display with the rest of my very extensive collection of baseball memorabilia.

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Alan Nathan @pobguy.bsky.social · 18/10/2025

No Kings, Urbana IL...just getting started

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