History of Halley’s Comet

Halley’s Comet is arguably the most celebrated celestial object. It does in a sense, provide the link between humanity’s belief in superstition and science. In its previous appearances, Halley’s Comet was often viewed as a bad omen. The most famous case its appearance before the Battle of Hastings in 1066. King Harold II viewed it as a bad omen and suffered mortal wounds during the battle. Halley’s Comet also represents a triumph of science. Utilizing Kepler’s Laws of Motion, Edmond Halley predicted the comet that had appeared in 1682 would reappear in 1759. Halley died in 1743, but when the comet made its predicted appearance, it was named in Halley’s honor.

The Mawangdui silk, showing the shapes of comet tails and the different disasters associated with them, compiled in around 300 BC. Credit: NASA/JPL via phys.org

The first known recorded appearance of Halley’s Comet was in 240 B.C. Chinese astronomers referred to comets as “Broom stars” that appeared in the sky for weeks at a time. The comet has returned roughly every 76 years since. The size and brightness of the comet varies on each visit due to its distance from the Earth on each visit and increasing light pollution on Earth. The closest the comet has been to the Earth was in 837. Halley’s came within 4 million miles of Earth and its tail was 90 degrees. This is the equivalent distance from the horizon to directly overhead. Halley’s last appearance in 1985-86 was somewhat disappointing. Its closest approach to Earth was 38 million miles and while visible, was not quite the remarkable sight that it had been in earlier visits. However, it was during that approach the Giotto probe was able to take photographs 376 miles from the comet nucleus. Below are images of Halley’s Comet recorded during its prior visits.

Credit: Wiki Commons

This is part of the Bayeux Tapestry commemorating the Battle of Hastings in 1066. The comet appears in the image top center. King Harold II of England took it as a bad omen and indeed, he was killed in the battle. William the Conqueror of Normandy won the battle and pronounced himself King of England.  This tapestry can be viewed by the public in the Bayeux Tapestry Museum.  Bayeux, incidentally, is located just a few miles from the American D-Day landing site on Omaha Beach.

Credit: Wiki Commons

This painting by Giotto di Bondone of Italy called Adoration of the Magi.  A comet is used to represent the Star of Bethlehem.  Painted in 1304, three years after Halley’s appearance in 1301, the comet appears top center and is generally believed to be derived from the appearance of Halley’s Comet. It is located in the Cappella degli Scrovegni in Padua, the same town Galileo would make historic observations with his telescope in 1610. In 1986, the European Space Agency (ESA) named it’s Halley’s Comet space probe Giotto, in honor of the artist.

Credit: Wiki Commons

This is a painting by Samuel Scott in 1759. The scene depicts Halley’s Comet over London. Westminster Abbey is visible to the far left. This was the appearance predicted by Edmond Halley, who had passed away 15 years earlier.

Credit: Mt. Wilson Observatory.

Halley’s appearance in 1910 provided astronomers with the first opportunity to photograph the comet. This series of photographs shows the comet over a two month period as it approached and then receded from Earth.  The images were taken from Mt. Wilson’s 60-inch telescope.  This was one of Halley’s most celebrated appearances. It’s tail stretched 30 degrees across the night sky.  In fact, on May 18, 1910, the Earth passed through the tail of Halley’s Comet. Entrepreneurs sold “comet pills” which were supposed to counteract the effects of cyanide gas which had been detected in the tail. Of course, the tail is far too tenuous to have any effect on life on Earth.

Comet Halley as seen over New York City on May 14, 1910. Although electric lights were making inroads, the stars could still be seen in the Big Apple. Credit: New York Times.

The front page article from the New York Times of this event is quite interesting.  Mark Twain, who was born a couple of weeks after the previous visit by Halley’s Comet in 1835, predicted in 1909 that, “I came in with Halley’s Comet in 1835…and I expect to go out with it.” Mark Twain died on April 21, 1910.

Credit: ESA.

While Halley’s last appearance in 1986 may have been disappointing to earthbound viewers, it provided us with the first space mission (Giotto) to a comet. The nucleus of the comet is approximately 16 x 8 x 8 kilometers. The closest image was taken 95 seconds prior to Giotto’s nearest approach, which was 376 miles.  The nucleus itself is one of the darkest objects in the solar system. It is, in fact, darker than coal. The jets are emanating from the sunlit side are not uniform in nature. This could account for some of the irregularities detected in the orbit of Halley’s Comet. The comet will begin its next approach to the Sun in 2024, and will be visible on Earth again in 2061.

*Image atop post is engraving from Halley’s 1682 visit. Edmund Halley was 26 years old during this visit.

Science’s First Rough Draft

It has often been said that newspapers are “history’s first rough draft.”  The same is true of science.  One could argue that journals fill the role, but historically, the vast majority of the public reads of scientific discoveries and/or events in the newspaper.  It is quite interesting to see how these events were interpreted at the time without the benefit of hindsight.  The New York Times online archive dates back to the paper’s origins in the 1850’s and represent a rich source of historical material that can be used in the class or for personal research.  Here are some historical articles pertaining to astronomy and physics.

Auroral Phenomena – September 5, 1851.  This article describes the aftermath of the Carrington Event, the most powerful magnetic storm in recorded history.  The aurora was seen across America and telegraph operators could still send messages even after disconnecting the batteries.  Below, NASA presents a computer model of the 1859 magnetic storm.

Glowing After – Sunset SkiesDecember 1, 1883.  Three months after the Krakatoa eruption, the skies around the world appeared deep red after sunset as a result of aerosols ejected into the atmosphere.  The cause of these sunsets were not known at the time – the article never refers to the Krakatoa eruption.

A Comet Visible by DaylightSeptember 20, 1882.  The Great Comet of 1882, considered the brightest comet of the past 1,000 years, is visible during the day.  The image atop this post is this comet.  In 2015, the Rosetta mission became the first to attempt a landing on a comet.

The Roentgen DiscoveryFebruary 7, 1896.  The discovery of x-rays and possible applications in the medical field.  A century later, astronomers would use the orbiting Chandra X-Ray Observatory to discover the universe to be a violent place.

Wireless Signals Across the OceanDecember 15, 1901Guglielmo Marconi receives radio signals in Newfoundland from London to open the era of mass communication.  Decades later, astronomers use radio telescopes to discover pulsars and peer into the center of the galaxy.

The Greatest Telescope in the WorldJanuary 27, 1907.  Plans to build a 100-inch telescope on the summit of Mt. Wilson in California.  Opened in 1917, this telescope is where Edwin Hubble discovered the universe was expanding.

Mt. Wilson 100-inch telescope. Credit: Gregory Pijanowski
Mt. Wilson 100-inch telescope. Credit: Gregory Pijanowski

Comet Gazers See Flashes –  May 19, 1910.  Report on Earth passing through tail of Halley’s Comet.  The comet tail was 100 degrees long and 10 degrees wide in the sky.  Whatever was seen that night, comet tails are much too tenuous to cause flashes in the atmosphere.

Lights All Askew in the Heavens – November 10, 1919.  Eddington Expedition proves Einstein’s General Relativity theory correct by measuring the bending of starlight during a total solar eclipse.  Relativity has passed every test since, including the recent observation of gravity waves.

Ninth Planet Discovered on Edge of Solar System – March 14, 1930.  Pluto is discovered.  Since reclassified as a dwarf planet, the New Horizons mission gave us the first close up images of Pluto in 2015.

Nebula Velocities Support EinsteinJune 12, 1931.  Edwin Hubble discovers the expansion of the universe as predicted by Einstein’s relativity theory.  Actually, Einstein was originally skeptical the universe could expand.  It was Fr. Georges Lemaitre, Catholic priest and physicist, who proposed what was later called the Big Bang theory.  The word nebula in the title refers to what we now call galaxies.

Lemaitre Follows Two Paths to TruthFebruary 19, 1933Fr. Georges Lemaitre does not find a conflict between science and religion.  Einstein and Lemaitre, “Have a profound respect and admiration for each other”.  Article quotes Einstein as stating, “This is the most beautiful and satisfactory explanation of creation to which I have ever listened” regarding Lemaitre’s Big Bang theory.

Fr. Georges Lemaitre (center) and Albert Einstein, January 10, 1933. To the left is Robert Millikan who was the first to measure the charge of an electron. Credit: California Institute of Technology.

Bohr and Einstein at OddsJuly 28, 1935.  The conflict between relativity and quantum mechanics.  The quest to unify the theory of relativity, which governs large objects, and quantum mechanics, which explains physics on an atomic scale, continues to this day.

Science and the BombAugust 7, 1945.  One day after Hiroshima, nuclear fission as a weapon and the implications for humanity are explained.

Palomar Observers Dazzled in First Use of 200-inch LensJune 5, 1948.  Delayed by World War II for five years, Mt. Palomar Observatory finally opens for business.

Palomar
Mt. Palomar 200-inch telescope. Largest in the world from 1948-97. Credit: Gregory Pijanowski

Radio Telescope to Expose SpaceJune 19, 1959.  Navy to build largest radio telescope in West Virginia.  The current radio observatory in Green Bank, WV is surrounded by a 13,000 square mile (slightly larger than the state of Maryland) radio quiet zone, meaning no cell phones, radio, or microwave ovens.

New Clues to the Size of the UniverseMarch 26, 1963.  The brightest objects in the universe, dubbed quasars, are discovered.  Located over 10 billion light years away, these objects are so bright some astronomers thought they must reside within the Milky Way.  However, further research would prove quasars to be the most distant objects observed by humans.

Signals Imply a Big Bang UniverseMay 21, 1965.  The discovery of the cosmic microwave background radiation (CMB) proves the universe was born in a hot, dense state aka the Big Bang.  The CMB was most recently mapped by the ESA Planck mission.  The map shows the state of the universe when it was 380,000 years old.

*Image on top of post is the Great Comet of 1882 from the Cape of Good Hope.  Credit:  David Gill.