News

Battle of the Eclipse (585 BC) – The Birth of Science

posted Thursday, 28 May 2015

The Greek philosopher Thales of Miletus (Θαλής ο Μιλήσιος) predicted the occurrence of an eclipse on this day in 585 BC. The eclipse occurred during the Battle of Halys (also known as the Battle of the Eclipse) between a Greek tribe (the Lydians) and a Persian tribe (the Medes). The sight of the sun disappearing brought the battle to a halt and the warring factions made peace immediately.

Thales’ prediction probably played no role whatsoever in the political events of this day. The armies stopped fighting because they thought the eclipse was an omen of bad fortune. They believed the eclipse was supernatural. Thales thought exactly the opposite. He is generally credited with saying something like “every observable effect has a physical cause”.

An eclipse occurs whenever the moon passes between the sun and the earth in such a way that the moon is able to cast a shadow on the earth. The period between such events is roughly 18 years and is known as the Saros cycle. Thales may have known about this cycle or he may have made observations of the moon a few days before the eclipse and projected its path across the face of the sun. I don’t know if anyone knows the answer to this part of the story. What we do know is that Thales did not consult an oracle, or divine the answer by looking at the entrails of a goat, or receive a message from Zeus. He saw the eclipse as a natural event dictated by natural laws and made a testable prediction based on observations. (NASA has a great website that both predicts and retrodicts eclipses.)

Thales of Miletus was the earliest known person to think scientifically. In essence, he was the first scientist. His prediction of the eclipse is the earliest recorded example of hypothesis testing. In essence, it was the first scientific event. This makes 28 May 585 BC the day on which science was born.

physics.info/news/?p=1620

First unofficial Pakistani nuclear weapon test (1990)

posted Tuesday, 26 May 2015

Date: 26 May 1990 (4:00 PM China Standard Time)
Code name: unknown
Type: uranium fission
Yield: 40 thousand tons of TNT
Site: Lop Nur, China
Earthquake magnitude: 5.4

The first test of a Pakistani built nuclear weapon was conducted in the Chinese test site of Lop Nur in Xin Jiang. At the time it was thought to be a purely Chinese test and Pakistan’s involvement was not made public until 2008. The first official test of a Pakistani nuclear weapon was conducted 26 May 1998, 17 days after India tested its first thermonuclear weapon.

physics.info/news/?p=1537

Star Wars Premiers (1977)

posted Monday, 25 May 2015

The movie Star Wars (later known as Star Wars Episode IV: A New Hope) premiered on 25 May 1977. An excellent example of the sub-genre of science fiction known as space opera, it is more fiction than science.

physics.info/news/?p=1563

De Revolutionibus Orbium Cœlestium published (1543)

posted Sunday, 24 May 2015

tee shirt
heliocentric tee shirt

Mikołaj Kopernik, usually known by his latinized name Nicolaus Copernicus, was the first astronomer to formally develop a heliocentric model of the solar system. The final version of his theory was published on the day of his death, 24 May 1543, under the title De Revolutionibus Orbium Cœlestium (On the Revolutions of the Celestial Spheres). The most famous line from this book is …

In medio uero omnium residet Sol. (In the center of all rests the Sun.)

physics.info/news/?p=1624

Smiling Buddha: First Indian nuclear weapon test (1974)

posted Sunday, 17 May 2015

Date: 18 May 1974 (8:05 AM Indian Standard Time)
Code name: Smiling Buddha
Type: plutonium fission
Yield: 5 to 12 thousand tons of TNT
Location: Pokhran, India
Earthquake magnitude: 5.0

physics.info/news/?p=1524

Skylab Launched (1973)

posted Thursday, 14 May 2015

Skylab was the second manned space station to orbit the earth (the first for the US). It was launched from Kennedy Space Center atop a modified Saturn V rocket. It returned to earth over the Australia as a fiery swarm of debris during a controlled reentry on 11 July 1979.

physics.info/news/?p=1517