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March 31, 2020

12 April 1633

The inquisition of Galileo by the Roman Catholic church begins. He was ordered to turn himself in to the Holy Office to begin trial for holding the belief that the Earth revolves around the Sun, which was deemed heretical by the Catholic Church. He was found guilty and agreed to stop teaching and spent the...

March 1, 2020

7 March 1831

The Royal Astronomical Society receives its Royal charter from King William IV. The society was founded in 1820 as the Astronomical Society of London to promote astronomical research. At that time, most members were 'gentleman astronomers' rather than professionals. In 1915 A Supplemental Charter granted by...

December 31, 2019

7 January 1610

Galileo discovers four moons orbiting the planet Jupiter. Looking at what he thought were a group of stars, he noted the objects appeared to move in a regular pattern and realised they were in orbit around Jupiter. Today, Jupiter’s four largest satellites—Io, Europa, Ganymede, and Callisto—are named the G...

September 30, 2019


31st October 1992

Pope John Paul II pardons Galileo for his views. The Catholic church condemned Galileo in 1633 for his subversive views, namely that the Earth revolved around the Sun. He lived under house arrest for the rest of his life. Pope John Paul II formally apologized for the "Galileo Case" in the first o...

August 31, 2019

26th September 1905

Einstein’s Theory of Special Relativity is published. It is the generally accepted and experimentally confirmed physical theory regarding the relationship between space and time and contains one of the most famous equations, e=mc2, which in simple terms means if you multiply a specific amount of mass...

June 30, 2019

5th July 1687

The book Principia is published by Sir Isaac Newton. Written in Latin with the title Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) it is often referred to simply as the Principia. The book contains Newton's laws of motion, Newton's law of universal gravitation...

May 31, 2019

13th June 1983   

Pioneer 10 becomes the first human-made object to pass outside Pluto's orbit and leave the solar system. It was the farthest human-made object in existence until Voyager 1 exceeded its range in February 1998. It continues its journey through interstellar space heading in the general direction of A...

April 30, 2019

2nd May 1780

Sir William Herschel discovers the first binary star, Xi Ursae Majoris, also named Alula Australis, in the constellation of Ursa Major. It was the first visual double star for which an orbit was calculated. Xi Ursae Majoris is found in the left hind paw of the Great Bear

1st May 1930

Pluto (picture above) is...

April 27, 2019

Sara Cabrera is a Sydney City Skywatcher member and an active observer. Her curiousity to always learn more about astronomy took her recently to the United States where, amongst many other adventures, Sara attended a lecture in San Jose by renowned astrophysicist Neil deGrasse Tyson titled 'Why an Astrophysicist should...

January 31, 2019

13 February 1633

Italian astronomer Galileo Galilei arrived in Rome to face charges of heresy for advocating the Copernican theory, which stated that the Earth revolves around the Sun. Galileo officially faced the Roman Inquisition in April of that same year and agreed to plead guilty in exchange for a lighter sentence....

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June 30, 2020

April 30, 2020

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