When will it happen? We work it out, in public.

The best current analysis puts the human limit two hundredths below 9.58, and nothing measured since 2009 suggests that margin will be run before 2100.

The question is one of margins, so the margins should be stated first. Measured. Einmahl and He collected fast times from thousands of top athletes between 1991 and 2023, several per athlete, and fitted a heterogeneous extreme-value model to them. Their value for the ultimate men's record is 9.56 s; the 95% lower conf...

Every long wait in the 100m record book has ended, and this one ends too, just not this cycle: I defend the 2040s, around 2044.

The record stands at 9.58. Berlin, 16 August 2009. It is already the longest-held men's 100m record in history, past Jim Hines and his 9.95 from 1968. Hines's wait ended. Long waits in this event always have. Now the clock. Fastest time since 2015? Kishane Thompson's 9.75 in June 2025, sixth on the all-time list. Thi...

Returns to the Moon have been announced and dropped before, and every remaining step is a first that one failure or one budget can stop.

In 1989 a president announced a permanent lunar base: "Back to the Moon, back to the future, and this time back to stay." Twenty-one years later another president set the Moon aside in four words: "We've been there before." Neither speech turned on engineering. Both turned on will, and will is what this question rests...

It happens a year or two behind the targets: the first walk most likely comes around 2030, from NASA or China, whichever lander is ready first.

2024. That was the landing date when the White House set the goal in March 2019, five years out. Then no later than June 2027. Then the inspector general, March 2026: SpaceX's lander will not be ready for a June 2027 landing. Now Artemis IV, 2028, after an Earth-orbit test flight in 2027. Three dates in seven years. F...

The long decline, the IPCC's assessment and projections scaled to the observed record point to a first ice-free September in the 2040s, later if the pause runs on, but well before 2100.

The indicator here is the September mean sea ice area in NSIDC's Sea Ice Index. Area counts only the ice itself, whereas extent, the figure most headlines quote, also takes in the open water between the floes; that is why this September's area was 3.12 million km² against an extent of 4.81 million. The line is 1 millio...

September ice area has barely fallen in twenty years and is still three times the threshold; with the pause, wide model spreads and low-emission paths, the ice can outlast the century.

After the record lows of 2007 and 2012, some polar scientists projected ice-free summers before 2020; the date came and went with the ice still there, and the lesson is that a steep line drawn through a few dramatic years is not a forecast. The newer dates, mostly the 2030s to the 2050s, may be a better line; they may...

Even the IMF's best five years, extended without a break, give a first Chinese lead in 2051, and after that a shrinking population raises the bar every year.

Threshold: China's GDP in current dollars above the US figure in any one year through 2099. Source: IMF WEO. Starting point: 64.4% in 2026. Direction so far is wrong. China at 76.6% of the US in 2021, 64.4% in 2026 The IMF path narrows it, slowly. China grows 5.7% a year in dollars to 2031, the US 3.8%, ratio 70.4%. E...

The dollar gap is mostly prices and the exchange rate, both started turning in 2026, and the crossing most likely comes in the mid-to-late 2040s.

Count what comes off the line and China is already the bigger economy. At purchasing power parity it's been ahead of the US since 2016. The dollar gap is a gap in prices and in the exchange rate, and for three years both ran against China. That's turning. Nominal GDP grew 5.9% in the second quarter and the deflator we...