As Aristotle (384-322 BC) informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500–428 BC) and Democritus (450–370 BC) proposed that the Milky Way might consist of distant stars. However, Aristotle himself believed the Milky Way to be caused by "the ignition of the fiery exhalation of some stars which were large, numerous and close together" and that the "ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions." The Arabian astronomer, Alhazen (965-1037 AD), refuted this by making the first attempt at observing and measuring the Milky Way's parallax, and he thus "determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere."

The Persian astronomer, Abū Rayhān al-Bīrūnī (973-1048), proposed the Milky Way galaxy to be a collection of countless nebulous stars. Avempace (d. 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in the Earth's atmosphere.^[42] Ibn Qayyim Al-Jawziyya (1292-1350) proposed the Milky Way galaxy to be "a myriad of tiny stars packed together in the sphere of the fixed stars" and that that these stars are larger than planets.

Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate "galaxies" themselves, similar to our own.