In this month: December

23rd December 1672

Rhea, the second-largest moon of Saturn and the ninth-largest moon in the Solar System, is discovered by Giovanni Cassini. It was the second moon of Saturn that Cassini discovered, and the third moon discovered around Saturn overall. Rhea is named after the Titan, Rhea, of Greek mythology, the wife of Kronos and the Greek counterpart of the god Saturn. Image Right: NASA/JPL/Space Science Institute, 2007.

25th December 2003

The spacecraft Beagle 2 was supposed to land on Mars on the 25th December 2003 but did not make contact with Earth and it was assumed the spacecraft had crashed. Beagle 2 is named after HMS Beagle, the ship used by Charles Darwin.

Beagle 2's fate remained a mystery until January 2015 when it was located on the surface of Mars in a series of images from NASA's Mars Reconnaissance Orbiter. The images suggest that it landed safely, but two of the spacecraft's four solar panels failed to deploy, blocking the spacecraft's communications antenna. The image below is an artist's impression, of Beagle 2 Lander Image Credit: ESA/Denman productions

10th December 2011

Brian Schmidt jointly receives the Nobel Prize in Physics along with Professor Adam Reiss, for “ the discovery of the accelerating expansion of the universe through observations of distant supernovae”.

Schmidt was born in the USA but moved to Australia after receiving his PhD where he was involved in building the High-Z Supernova Search Team, as a part of his Nobel Prize-awarded work. He is a Professor at the Australian National University in Canberra.

BORN

11th December 1863

Annie Jump Cannon. American astronomer. Her cataloguing work was instrumental in the development of contemporary stellar classification. With Edward C. Pickering, she is credited with the creation of the Harvard Classification Scheme where she classified about 350,000 stars manually.

She became the first woman to receive a Doctor of Astronomy degree from Groningen University,

the first woman ever to receive an honorary degree from Oxford University, and in 1931 she became the first woman to be awarded the Henry Draper Medal of Honour from the National Academy of Sciences.

28th December 1882

(Sir) Arthur Stanley Eddington. English astronomer, physicist, and mathematician. He is best known for his measurements of the 1919 solar eclipse that confirmed Einstein’s General Theory of Relativity.

The Eddington limit - the natural limit to the luminosity of stars - is named in his honour.

28th December 1929

Maarten Schmidt. Dutch-American astronomer. In 1963 he discovered what are now called quasars. These source of ultra-intense radio emissions are no bigger than stars, yet they produce more energy than an entire galaxy. Schmidt, who retired as a professor in 1996 still continues to investigate quasars his aim being to find the "red shift cutoff," above which no quasars exist. Image of a quasar above by Artist, courtesy Hubble Space telescope/NASA.

Asteroid 10430 Martschmidt is named after him.