On the occasion of the 400th anniversary of Thomas Harriot's Moon drawings

In late 1609 Galileo Galilei made astronomical drawings of the Moon. However it would seem that he was not the first person to do so. 400 years ago today, Englishman Thomas Harriot (above)trained his lens on the Moon and after several hours later he had produced an intricate map of the Moon’s surface, showing craters, mountains and the planet’s empty “seas” (see below).

However, Harriot never saw the need to publish his work. If he had done so, he may well have had fame. “He had a nice annual pension from the Earl of Northumberland and he was just interested in the pursuit of knowledge,” said Alison McCann, assistant county archivist for the Sussex Record Office, which holds all of Harriot’s Moon drawings, made on behalf of Lord Egremont.



Harriot’s very first recording was made using hand-held device, known as the “Dutch trunke” telescope, which was only six times more powerful than the naked eye. It would have shown a small pinpoint of sky and Harriot would have had to inch the telescope across the sky, recording as he went.

By 1613 he had a telescope with a magnification of 36 times, and was able to record some of the most striking features of the solar system including Jupiter’s spot, Saturn’s rings and the dark sunspots that we now know correspond to magnetic activity on the Sun’s surface. He is also credited with the discovery of Snell’s Law, which describes the refraction of light through a lens, 20 years before Willebrord Snellius published his own theory. In addition he made important contributions to the development of algebra and wrote a treatise on navigation.

Harriot's achievements are now being recognised finally. Two of his Moon drawings, along with recordings of Jupiter and sunspots, have been unveiled at the Science Museum. Lord Rees, president of the Royal Society and Astronomer Royal, described Harriot as astronomy’s unsung hero. “It is good that his reputation is being restored,” he said.

It does seem that Harriot was a superb scientist but he hid his light under a bushel, so to speak, and so his achievements were never given the credit they were clearly due. Then again theat is nobody’s fault but his own. That Harriot made the first astronomical drawings of the Moon does not reduce Galileo’s achievements one jot.

Did Galileo beat Le Verrier to the discovery of Neptune?

Science Daily reports that a Melbourne physicist has put forward a theory that Galileo knew he had discovered a new planet in 1613, 234 years before its official discovery date.
Professor David Jamieson, Head of the School of Physics, is investigating the Galileo’s notebooks and believes that he discovered a new planet that we now know as Neptune.

Galileo was observing the moons of Jupiter in the years 1612 and 1613 and recorded his observations in his notebooks. Over several nights he also recorded the position of a nearby star which does not appear in any modern star catalogue.

"It has been known for several decades that this unknown star was actually the planet Neptune. Computer simulations show the precision of his observations revealing that Neptune would have looked just like a faint star almost exactly where Galileo observed it," Professor Jamieson says.
But a planet is different to a star because planets orbit the Sun and move through the sky relative to the stars. It is remarkable that on the night of January 28 in 1613 Galileo noted that the "star" we now know is the planet Neptune appeared to have moved relative to an actual nearby star."

There is also a mysterious unlabeled black dot in his earlier observations of January 6, 1613, which is in the right position to be Neptune. "I believe this dot could reveal he went back in his notes to record where he saw Neptune earlier when it was even closer to Jupiter but had not previously attracted his attention because of its unremarkable star-like appearance."

If the mysterious black dot on January 6 was actually recorded on January 28, Professor Jamieson proposes this would prove that Galileo believed he may have discovered a new planet.

"Galileo may indeed have formed the hypothesis that he had seen a new planet which had moved right across the field of view during his observations of Jupiter over the month of January 1613," Professor Jamieson says."If this is correct Galileo observed Neptune 234 years before its official discovery."

But there could be an even more interesting possibility still buried in Galileo's notes and letters."Galileo was in the habit of sending a scrambled sentence, an anagram, to his colleagues to establish his priority for the sensational discoveries he made with his new telescope. He did this when he discovered the phases of Venus and the rings of Saturn. So perhaps somewhere he wrote an as-yet undecoded anagram that reveals he knew he discovered a new planet," Professor Jamieson speculates.

Well there you have it.

Source: University of Melbourne (2009, July 9). Galileo's Notebooks May Reveal Secrets Of New Planet. ScienceDaily. Retrieved July 12, 2009, from http://www.sciencedaily.com¬ /releases/2009/07/090709095427.htm