Falling bodies: Galileo sets up Aristotle to the fall

Galileo GALILEI
Portrait of Galileo Galilei by Giusto Sustermans in 1636 – image from public domain via Wikimedia Common.

As seen twice with a view from here, works from Nicolaus Copernicus (1473 – 1543), Giordano Bruno (1548 – 1600), Johannes Kepler (1571 – 1630) and Galileo Galilei (1564 – 1642), which have been preceded by those of Nicole Oresme (circa 1320-1322 – 1382), completely challenged the Aristotelian model. In this questioning, Galileo did not settle with astronomy. He also tackled several other fundamental subjects, one of which has a great influence on my areas of research: the fall of bodies.

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Everything is relative, my dear Bruno!

Giordano Bruno
Portrait of Giordano Bruno (nineteenth century, after an engraving published in the Book of the President, 1578) – image in public domain via Wikimedia Commons.

Even if special1A. Einstein, 1905. Zur Elektrodynamik bewegter Körper, Annalen der Physik, n° 17, pp. 891 – 921. It can be read on line. An English version translated by George Barker Jeffery is available on line. and general relativity2A. Einstein, 1916. Die Grundlage der allgemeinen Relativitätstheorie, Annalen der Physik, n° 49, pp. 769 – 822. It can be read on line. An English version translated by Alfred Engel can be read on line. theories were introduced by Albert Einstein (1879 – 1955), the principle of relativity were introduced in Physics much earlier. It is called Galilean relativity and were introduced by … Giordano Bruno (1548 – 1600).

Of course, if this first form of physical relativity is qualified “Galilean,” it is because Galileo had something to do in its formulation. The introduction of this principle is one of the main elements of the epistemological revolution to which I referred earlier. This article is therefore a continuation of the series on the history of science that I started. It will also be the occasion, once again, to introduce some concepts that will be useful for future popularisation articles to come.

Continue reading Everything is relative, my dear Bruno!

Notes

Notes
1 A. Einstein, 1905. Zur Elektrodynamik bewegter Körper, Annalen der Physik, n° 17, pp. 891 – 921. It can be read on line. An English version translated by George Barker Jeffery is available on line.
2 A. Einstein, 1916. Die Grundlage der allgemeinen Relativitätstheorie, Annalen der Physik, n° 49, pp. 769 – 822. It can be read on line. An English version translated by Alfred Engel can be read on line.

How I extended Galileo’s work!

Spring tide in Wimereux
Spring tide in Wimereux (Pas-de-Calais, France) – photo by Marc Ryckaert under licence CC BY 3.0 via Wikimedia Commons.

I have already mentioned it: it is about time that I present the topics that I am interested in my work. As I have indicated on this site home page and as can be deduced from my resume, my areas of expertise are applied mathematics and theoretical computer science. My scope is physical oceanography. Specifically, I am reproducing ocean dynamics on computers.

However, though being a still evolving discipline, the study of ocean dynamics has a long history. The oldest references I have found were written during the antique times. The main topic on ocean dynamics they address is tide. I intend to present this story here. Much of the information you will find in the following comes from Bernard Simon’s La Marée océanique côtière1B. Simon, 2007. La Marée océanique côtière, collection “Synthèses”, Institut océanographique éditeur.. The following is an extract from the introduction of my Ph.D. thesis2Y. Le Bars, 2010. Modélisation de la dynamique océanique barotrope dans l’estuaire et le plateau amazoniens, Ph.D. thesis, Université de Toulouse III – Paul Sabatier.. This thesis focused on the development of an ocean model and its application to the estuary of the Amazon, so I do not claim to have achieved a definitive historical study: the following is a summary, albeit detailed, but with all the limitations of this exercise.

Continue reading How I extended Galileo’s work!

Notes

Notes
1 B. Simon, 2007. La Marée océanique côtière, collection “Synthèses”, Institut océanographique éditeur.
2 Y. Le Bars, 2010. Modélisation de la dynamique océanique barotrope dans l’estuaire et le plateau amazoniens, Ph.D. thesis, Université de Toulouse III – Paul Sabatier.

The Big Bang: when the Universe is not banging!

The microwave sky
The microwave sky, one of the oldest known radiation, as seen by the Planck mission – © esa.

Is it because it concerns the origins of things? Anyway, the Big Bang is a scientific subject which everyone seems to have heard of. However, it appears that general ideas about it are not really clear.

As it will be question of the Big Bang in the subjects I will address soon in this website, here is an opportunity to inaugurate scientific popularisation articles in my blog: I propose to present the basics of the Big Bang, using simple experiments that everyone can do at home.

Continue reading The Big Bang: when the Universe is not banging!