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Ceres (optimized image from the Hubble Space telescope)

Today’s post topic is located in the depths of space far far away from the bats, pumpkins, and haunted deserts I have been writing about for October. The dwarf planet Ceres is located in the midst of the asteroid belt between Jupiter and Mars.  The only dwarf planet in the inner solar system, Ceres is only 950 km (590 miles) in diameter, but it is sufficiently large to have become spherical from its own gravity (and it is by far the largest asteroid). Named after Ceres (Demeter), the mythological goddess of growing things whose daughter was abducted by Hades and who gave the secrets of agriculture to humankind through the farmer Triptolemus, the dwarf planet was discovered in 1801 by Italian astronomer Giuseppe Piazzi, a Roman Catholic priest of the Theatine order.  Ceres was the first asteroid to be discovered and it comprises a third of the asteroid belt’s total mass.

A comparison of the sizes of the Earth, Moon, and Ceres

The nebular hypothesis proposes that the solar system formed as a great cloud of space dust and gas coalesced into a disk which then further coagulated into small clumps, then into planetesimals, then into moon-sized planetary embryos, and finally into planets. Ceres is one of the few (or maybe the only) planetary embryos which formed four and a half billion years ago but somehow did not get smushed together with other like bodies to form a planet or hurled off into deep space. The dwarf planet probably consists of a rocky core surrounded with an icy mantle of frozen water.  Ceres is believed to contains 200 million cubic kilometers of water–more fresh water than in all the lakes, rivers, clouds, swamps, ponds (and everything else) on Earth. The Hubble telescope has photographed several mysterious surface features on Ceres including a dark spot believed to be a crater (now informally named after Piazzi) and several bright spots, the nature of which is unknown.

Image of the bright spots on Ceres (taken by the Hubble Space telescope)

Astronomers are profoundly curious about Ceres and hope to better understand the history of the solar system by examining this surviving planetary embryo.  Additionally, the chemical makeup of Ceres is similar to that of Earth. Scientists seeking extraterrestrial life have concentrated on Europa and Mars, but Ceres is next on their short list.

Astronomers will soon have some of their answers about Ceres.  The asteroid probe Dawn is currently orbiting the asteroid Vesta–but its mission there is scheduled to end in July of 2012.  At that point Dawn will power up its ion thrusters and fly to Ceres. In February of 2015 Dawn will enter permanent orbit around the little planet and we will finally have some of our answers.

The Hannover Military Band

The Electorate of Brunswick-Lüneburg (colloquially known as the Electorate of Hanover) was a principality within the Holy Roman Empire.  In the mid eighteenth century, the region was ruled by the Prince Elector, Georg II.  A series of religious wars and a strange quirk of fate had made the house of Brunswick-Lüneburg the heirs to the British throne.  Prince Elector Georg II was therefore better known to his English subjects and to history as King George II.  In 1755, George II ordered his Hanoverian Guards Regiment to England.  The Hanover Military band went with the Guards.  One of the oboists of the band was named Friedrich Wilhelm Herschel.  Friedrich was something of a musical prodigy: he also played the violin, the cello, the harpsichord and the organ.   When the guards came to England, he liked the country and he left the band to move there permanently.  He accepted the position as first violin and soloist for the Newcastle orchestra and later became the organist of the Octagon Chapel in Bath (a chapel attached to a very fashionable spa).  Throughout his career Frederick William Herschel (for he had anglicized his name) composed a great many musical works including 24 symphonies, numerous concertos, and a large canon of church music.

Frederick’s music is forgotten today, but later in his life he found his true calling.  As his musical career progressed, he became more and more deeply fascinated by lenses and mathematics. At the age of 35, he met the Reverend Dr. Nevil Maskelyne who was Astronomer Royal and Director of the Royal Observatory in Greenwich. Herschel began making mirror telescopes for Maskelyne, personally grinding the lenses and mirrors for up to 16 hours a day.  He also looked at the universe through the telescopes he had made and reported his discoveries. What he found made him one of the preeminent scientists in history (he also became extremely wealthy and was granted a knighthood).

The Planet Uranus (or "Georgium sidus" as Herschel originally named it)

Herschel is most famous for discovering Uranus, the first planet to be found since the depths of antiquity.  His other discoveries and ideas are perhaps even more remarkable. He was first to find out that the solar system is moving through space.  He coined the word “asteroid” as a name for such objects.  By observing Mars he determined its axial tilt and found that the Martian ice caps fluctuate in size. His attempts to determine if there was a link between solar activity and the terrestrial climate were unsuccessful (because of a lack of data), but formed the basis for successful work concerning both climatology and stellar physics.  Astonishingly, Herschel discovered infrared radiation, the first non-visible electromagnetic radiation to be known.  He accomplished this by passing sunlight through a prism and holding a thermometer just beyond the red end of the visible spectrum.  He found two new moons of Saturn and two moons of Uranus.  He correctly concluded that the Milky Way is a disk.  He debunked the notion that double stars were optical doubles and showed that they are truly binary stars (thus demonstrating that Newton’s laws extend beyond the solar system).

Sir Frederick William Herschel, 1738 - 1822 (painted by Lemuel Francis Abbott in 1785)

In honor of his amazing career, numerous objects, devices, institutes and features around the solar system and beyond are named after Herschel (including the giant crater on Saturn’s moon Mimas). Few people have contributed so greatly to science or changed the conception of everything as much as this gifted Saxon oboist!

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August 2022