Galileo's Double Star: The Experiment That "Proved" the Earth Did Not Move

Christopher M. Graney

Home/Archive/arXiv

arXiv · physics/0606255

Galileo's Double Star: The Experiment That "Proved" the Earth Did Not Move

Christopher M. Graney

View original source ↗Read source document ↗Export metadata ↓

Abstract

Great opportunities arise for teaching physics, astronomy, and their histories when new discoveries are made that involve concepts accessible to students at every level. Such an opportunity currently exists thanks to the fact that notes written by Galileo indicating that he observed the double star Mizar in the "Big Dipper" have recently come to light. His measurements of this star, given the scientific knowledge at the time, strongly supported the theory that the Earth was fixed in space and not moving. Had Galileo published these results, it is likely that widespread acceptance of the heliocentric theory in scientific circles would have been significantly delayed. In light of these notes, his later reference in his Dialogue to using double stars as a means of proving that the Earth was in motion is puzzling. The physics and mathematics behind Galileo's work is easily within reach of students in introductory physics and astronomy courses, so discussion of Galileo's Mizar work and its interesting implications can be used in virtually any class.

Explore related subjects

physics.hist-ph astro-ph physics.ed-ph

Keep this discovery

BibTeX RIS

Christopher M. Graney. 2006-12-20. Galileo's Double Star: The Experiment That "Proved" the Earth Did Not Move. https://arxiv.org/abs/physics/0606255

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Scientific Promise

Scientists constantly face decisions about what lines of research to pursue. This Element introduces the philosophical debate about scientific pursuitworthiness. It explains how it can be rational to pursue a theory even if the theory is less well supported than its rivals, and it discusses existing philosophical frameworks for guiding pursuit decisions. The Element also develops a new perspective. Existing accounts focus predominantly on theories, while experiments are largely neglected. This is an important shortcoming. Theoretical promise depends on experimental promise, and experimental promise raises questions of its own. Drawing on the epistemology of experimentation, the Element advances an account of experimental pursuitworthiness. It is argued that such pursuitworthiness depends on experimental virtues like a clear signal and simplicity of design. Moreover, the kinds of uncertainty that constrain the assessment of scientific pursuits are examined. Finally, the Element highlights open questions in the philosophy of scientific pursuitworthiness.

physics.hist-ph↗

arXiv2026

Is Black Hole Evaporation Prediction Friendly?

Manchak and Weatherall (2018) formulate the black hole information paradox as a failure of predictability in black hole evaporation spacetimes, diagnosed by non-global hyperbolicity. I offer a strategy for resolving this paradox. I argue that failures of predictability in black hole evaporation are not well diagnosed by non-global hyperbolicity. I then consider two weakenings of global hyperbolicity: prediction and retrodiction friendliness, the failure of which could ground a new paradox. However, deidealized black hole evaporation models can be prediction and retrodiction friendly. Therefore, the information paradox cannot be based upon failures of global hyperbolicity, nor either retrodiction or prediction unfriendliness.

physics.hist-ph↗

arXiv2026

The Crab Nebula progenitor: recovering the 1054 AD supernova event as galactic Gamma-ray burst

In 1054 AD a daytime star appeared in the constellation of Taurus, for three weeks, and it was reported in various sources from Europe to China/Japan: it was one of the few documented galactic supernovae of the last two millenia. This paradigm has been established about sixty years ago, as the comprehension of the physics of supernovae progressed with enough observational data. The Gamma-ray bursts were discovered in the same period, but only in the past few years have their observations become daily and their distances have been fully understood as cosmological. After the explosion, the exponential decay of the luminosity in gamma-rays and X-rays has been followed with telescopes onboard dedicated satellites. Also the exponential decay of the afterglow's optical and radio frequencies have been observed with the largest optical and radio telescopes. Within the binary-driven hypernova framework, successful in explaining all the observed phases of the Gamma-ray bursts, the universal exponential decay can be extended to 1000 years after the burst, to account for the present values of Gamma and X-rays as well as optical and radio frequencies of the Crab Nebula. Both the daytime visibility of the burst, and the simultaneous radiation plagues appeared in Constantinople and Cairo is a strong evidence of the presence of Gamma-rays in the lower atmosphere, coming from the same source originating the Crab nebula. The association to the daytime visibility of that star and the following plague meets exactly the etymology of the word dis-aster, bad star.

physics.hist-ph↗