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  • Elizabeth Cocking

In this month: January

1st January 1801

Italian astronomer Giuseppe Piazzi of the Palermo Observatory discovers Ceres, the first asteroid to be discovered and the largest asteroid in the main asteroid belt. At 940 kilometres in diameter, it is the only asteroid large enough for its gravity to make it spheroid in shape. The Photograph below was taken by NASA's Dawn Spacecraft in 2015 and is courtesy NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Ceres follows an orbit between Mars and Jupiter, near the middle of the asteroid belt, the only one always inside the orbit of Neptune. It takes Ceres 4.6 Earth years, to orbit the Sun and completes one rotation every 9 hours making its day length one of the shortest in the solar system. In 2006, it was reclassified as a dwarf planet, along with Pluto and Eris, by the International Astronomical Union. Ceres is named for the Roman goddess of corn and harvests. The word “cereal” comes from the same name.

6th January 1978

Comet Wild 2 is discovered by Swiss astronomer Paul Wild. The comet, measuring about 1.65 x 2 x 2.75 kilometres, is the shape of a flattened sphere and takes nearly six and a half years to orbit the Sun. Originally its orbit lay between Uranus and Jupiter, however on the 10th September 1974 gravitational interactions between the comet and Jupiter pulled its trajectory into a new shape and it now orbits between Mars and Jupiter. In 2004 NASA sent the Stardust mission to fly by the comet and gather particles. What remains of Wild 2, along with the fragments captured by Stardust, is considered pristine. As this is the comet's first trip to the inner solar system, its composition has been mostly unaltered for the billions of years it spent in the depths of space. The study of these stardust samples could provide clues about the early days of the solar system.

30th January 2020

The Spitzer Space Telescope is turned off.

Launched on the 25th August 2003 to study the universe in infrared light it exceeded expectations over its 17 year mission. The telescope studied comets and asteroids, the solar system, and found a previously unidentified ring around Saturn. It also studied star and planet formation, the evolution of galaxies, the composition of interstellar dust and proved to be a powerful tool in detecting exoplanets, notably the seven Earth-size planets in the TRAPPIST-1 system. Due to its specific orbit Spitzer faces a different fate to other decommissioned spacecraft. Trailing about 254 million kilometres behind Earth, to keep it away from interfering heat, it will fly by Earth in about 53 years and then drift off in the opposite direction into the emptiness of space.


14th January 1911 Edward George "Taffy" Bowen CBE.

Welsh physicist. He was an early radio astronomer playing a crucial role in the establishment of radio astronomy in Australia.

He was invited to come to Australia to join the CSIRO Radiophysics Laboratory and in May 1946 was appointed Chief of the Division of Radiophysics. He encouraged the new science of radioastronomy and played a key role in the design and construction of the 64 metre radio telescope at Parkes, New South Wales. He also played an important role in guiding the optical Anglo-Australian Telescope project during its design phase.

Taffy Bowen was made an officer of the Order of the British Empire in 1941, then promoted to commander in 1962. He became a fellow of the Australian Academy of Science in 1957 and of the Royal Society in 1975.

6th January 1915 Liisi Oterma.

Finnish astronomer. In 1955 she earned her PhD with a dissertation on telescope optics, the first Finnish woman to obtain a Ph.D. degree in astronomy. She discovered or co-discovered several comets and is also credited by the Minor Planet Centre with the discovery of 54 minor planets between 1938 and 1953. She ranks 153rd on the Minor Planet Centre’s all-time discovery chart. The Hildian asteroid 1529 Oterma, discovered by Finnish astronomer Yrjö Väisälä in 1938, is named in her honour. The image below shows Oterma preparing a telescope lens and is from the Technology Museum in Finland.

4th January 1977 John Asher Johnson.

American astrophysicist and professor of astronomy at Harvard University.

He is the first African-American physical science professor in the history of the university.

Johnson is well known for discovering three of the first known planets smaller than the Earth outside of the solar system, including the first Mars-sized exoplanet. In 2012 Johnson's team discovered the three small rocky exoplanets in a red dwarf star system. The system was renamed Kepler-42 and the outermost planet was found to be nearly as small as Mars, making it the smallest known exoplanet at the time.

He is the founder of a program at the Harvard-Smithsonian Centre for Astrophysics that provides funding opportunities for undergraduate students with backgrounds under-represented in astronomy. Image left courtesy Wikipedia.


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