Jump to ContentJump to Main Navigation
Show Summary Details
More options …

Open Astronomy

formerly Baltic Astronomy

Editor-in-Chief: Barbuy, Beatriz

IMPACT FACTOR 2018: 0.350

CiteScore 2018: 0.24

SCImago Journal Rank (SJR) 2018: 0.202
Source Normalized Impact per Paper (SNIP) 2018: 0.144

ICV 2017: 121.03

Open Access
See all formats and pricing
More options …
Volume 12, Issue 4


The Depth of the Heavens – Belief and Knowledge During 2500 Years

Erik Høg
Published Online: 2017-02-08 | DOI: https://doi.org/10.1515/astro-2017-0063


For Dante Alighieri (1265-1321) the spiritual cosmos contained the Heavens, Earth and Hell, and it was compatible with the physical cosmos known from Aristotle (384-322 B.C.). Dante’s many references in his Divine Comedy to physical and astronomical subjects show that he wanted to treat these issues absolutely correctly. Tycho Brahe proves three hundred years later by his observations of the Stella Nova in 1572 and of comets that the spheres of heavens did not really exist. It has ever since become more and more difficult to reconcile the ancient ideas of a unified cosmos with the increasing knowledge about the physical universe. Ptolemaios derived a radius of 20 000 Earth radii for the sphere of fixed stars. This radius of the visible cosmos at that time happens to be nearly equal to the true distance of the Sun, or 14 micro-light-years. Today the radius of the visible universe is a million billion (1015) times larger than Tycho Brahe believed. The lecture gave an overview of astronomical distances and their dramatic change during two and a half millennia, the following text is an extract hereof.

Keywords: history and philosophy of astronomy; astrometry; cosmology; distance scale


  • Dreyer J. L. E. 1953, A History of Astronomy from Thales to Kepler, Dover Publications, Inc.Google Scholar

  • Pedersen O. 1992, The Book of Nature, Vatican Observatory PublicationsGoogle Scholar

  • Pedersen O. 1993, Early Physics and Astronomy, a Historical Introduction, Cambridge University PressGoogle Scholar

  • Stephenson B. 1994, The Music of the Heavens, Kepler’s Harmonic Astronomy, Princeton University PressGoogle Scholar

  • Van Helden A. 1985, Measuring the Universe, Cosmic Dimensions from Aristarchus to Halley, The University of Chicago PressGoogle Scholar

  • WMAP 2003, Wilkinson Microwave Anisotropy Probe, http://map.gsfc.nasa.govGoogle Scholar

About the article

Received: 2003-11-10

Published Online: 2017-02-08

Published in Print: 2003-12-01

Citation Information: Open Astronomy, Volume 12, Issue 4, Pages 451–453, ISSN (Online) 2543-6376, DOI: https://doi.org/10.1515/astro-2017-0063.

Export Citation

© 2017. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. BY-NC-ND 4.0

Comments (0)

Please log in or register to comment.
Log in