In 1998 two related but independent groups sent balloon‐borne microwave telescopes aloft to study fluctuations in the cosmic microwave background (CMB) at fine angular resolution. In August of that year, the Maxima telescope spent one night at 40 km above Texas. And at the end of the year, its “sister” telescope, called Boomerang, took advantage of the steady circumpolar winds of the austral summer to complete a 10‐day stratospheric circumnavigation of Antarctica.

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