Which of the following astronomers actually met in person?

Nicolaus Copernicus (1473-1543)

Tycho Brahe (1546-1601)

Giordano Bruno (1548-1600)

Galileo Galilei (1564-1642)

Johannes Kepler (1571-1630)

Copernicus couldn't meet with any of the remaining ones, because he died in 1543. From the remaining four any two could meet. It is well known that Brahe met Kepler in Bohemia.

Both Bruno and Brahe have been to Wittenberg and Prague, but I don't think they met there.

Thank you.

  • 3
    Maybe it would be simpler to just edit Copernicus out of this question altogether ?
    – Evargalo
    Sep 19, 2022 at 12:02
  • 1
    Note that Bruno wasn't a scientist -- he was basically a misch-mash occultist who dabbled in many things including astronomical speculations. If he lived today he'd have been a New Age guru.
    – Mark Olson
    Sep 19, 2022 at 12:44
  • Your guesses are probably correct: the only pair that met was Brahe and Kepler. Galileo and Kepler corresponded but never met personally. Bruno was not really an astronomer, but a philosopher, and there is no evidence that he met any of the rest.
    – Alex
    Sep 19, 2022 at 14:04
  • @MarkOlson - I would clasiffy Bruno as a scientist in a heartbeat. But... Not that I do not agree with the rest of your characterization. ;-) But it is well known that Bruno was a good philosopher and he had some good ideas, unfortunately he preferred to be mostly political. And had a poor taste in patrons, too...
    – AcePL
    Sep 21, 2022 at 7:53

1 Answer 1


Just as mentioned in the comments, Copernicus doesn't really fit in the timeline, so we can skip him.

So let's examine timeline and geopolitics here:

  1. Bruno is under arrest for the last 9 years of his life, before that he - due to his beliefs - travels in mostly Protestant countries. So he would have no problem meeting both Brahe and Kepler, but don't know if it did him any good - Kepler would be at most 19 when he would have last chance for that encounter. Galileo would be 26 and while was not quite fresh out of college when Bruno was back, already accomplished, but employed elsewhere. They technically could meet in Padua in 1592, but it is unlikely due to a lot of factors. He was also travelling all around Europe and could technically visit Copenhagen on the way to Germany or Prague from Paris or England, but there are no records he ever met Brahe.
  2. Galileo was a jerk, but not as stupid. So he worked more or less in peace, but he was barely starting in 1592, when he could meet Bruno. He stayed mostly in Italy until his Affair starts, when he definitely keeps to Italy. He corresponds with Kepler, but never meets him or Brahe.
  3. Kepler, after leaving Prague in 1611 was offered a position that Galileo vacated (for which he was recommended by Galileo), but he declined, not wanting to leave Germany, especially after his private life complications started. Then he was hit with an excommunication and this really made his life difficult, further limiting his choices, yet he kept to Germany. So besides Brahe, he had no chance of meeting anyone else.
  4. Brahe travelled around until 1571, when Bruno was in a monastery still, and stayed in Denmark until his exile in 1597, so chance meeting of them was unlikely. Kepler was just born in 1571, Galileo was a child, so barring an event during a relocation to Prague (which would be quite a detour, anyway), meeting Galileo was highly unlikely, and, of course, there are no records such happened.

The "optimal window" for any of them to meet would be 1590-1610 (for obvious reasons), yet this is the window when we know is unavailable completely for Bruno, half-available for Brahe and mostly improbable for Kepler and Galileo. Shame, really, but kind of unlucky time it was in general, geopolitically, so not really surprising.

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