nLab Milky Way




physics, mathematical physics, philosophy of physics

Surveys, textbooks and lecture notes

theory (physics), model (physics)

experiment, measurement, computable physics



Our galaxy.

Democritus [[holds]] that it is the splendor which ariseth from the coalition of many small stars, which, being firmly united amongst themselves, do mutually enlighten one another.

Δημόκριτος πολλῶν καὶ μικρῶν καὶ συνεχῶν ἀστέρων συμφωτιζομένων ἀλλήλοις συναυγασμὸν διὰ τὴν πύκνωσιν.

(Pseudo Plutarch ~ 400 AD, attributing to Democritus \sim 400 BC – original Greek here)


The Milky Way is made up of a very large number of small, tightly-clustered stars, which, on account of their concentration and smallness, seem to be cloudy patches. Because of this, it was likened to milk in color.

(Naṣīr al-Dīn al-Ṭūsī in Tadhkira 1261 AD, as translated in Ragep 1993, p. 128)


the Galaxy [Milky Way] is nothing else than a congeries of innumerable stars distributed in clusters. To whatever region of it you direct your spyglass, an immense number of stars immediately offer themselves to view, of which very many appear rather large and very conspicuous but the multitude of small ones is truly unfathomable.

(Galileo Galilei in Sidereus Nuncius 1610, as translated in Van Helder 1989, p. 34)


In antiquity and the middle ages:

Modern survey

  • Susan Gardner, Samuel D. McDermott, Brian Yanny, The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter (arXiv:2106.13284)

See also

Last revised on August 22, 2021 at 20:47:22. See the history of this page for a list of all contributions to it.