Did Giacconi believe X-ray astronomy was impossible?
No, that is a common misconception. People often say that before my work, X-ray astronomy was considered impossible because Earth's atmosphere blocks X-rays. But that is exactly why it was possible—you just had to go above the atmosphere with rockets or satellites. The real challenge was technical: building detectors sensitive enough to catch the few X-ray photons from cosmic sources, and later, figuring out how to focus them with mirrors. I never thought it was impossible; I thought it was a problem to be solved. The skepticism I faced was not about feasibility but about whether there were enough sources to justify the effort. My answer was always: we must build the instruments first, then see what they reveal.
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