Halley's Comet Strikes Back!

Halley’s Comet Strikes Back! Larry Halstead [email protected] 810-449-1357

What is a comet? Or, better yet – What is a comet – not?

• A comet is not a mother ship of the Galactic Federation (e.g. comet Elenin)

A comet is not a member of a rock & roll band

Klau Klettner / Hydra Records

A comet is not a sign from God

The Anunciation – Fra Angelico ca 1432

A comet is not a meteor (although a meteor may have come from a comet)

Johnpane (Holmes)

A comet IS many things.

A comet is an integral part of human history

A comet is an object of rare beauty

A comet is a potential threat

A comet is a chunk of rock and ice orbiting the Sun

Protoplanetary Disks

ESO/L Calcada

Typical comet trajectory / tail behavior

Most comets have two tails

Hans Bernhard (Schnobby)

The Comet known as Halley

Nicholas Copernicus • Conceived of heliocentric solar system. • Published his work in the year of his death (1543)

Tycho Brahe • Understood Copernican model. • Official astronomer of the Holy Roman Empire • Died in 1601.

Joe Huber

Johannes Kepler • Born in 1571. • Worked with Tycho Brahe and succeeded him as Imperial Astronomer and mathematician of the Holy Roman Empire. • Survived political upheaval and personal tragedy in Austria. • Used Tycho’s observations to develop laws of planetary motion. NASA

Kepler’s Laws of Planetary Motion Planets orbit in an elliptical path

PERIHELION SUN AT 1 FOCUS

T

T

That path sweeps out equal areas during equal times.

Kepler’s Laws (continued) • The ratio defined by (time to complete one orbit)2 (average distance to the Sun)3 is a constant.

• This number is constant for each orbiting system • Note that mass is not included.

Mass change does not affect the orbit

NASA / ESA

Isaac Newton • Born in 1642. • Revolutionized optics. He thought of light as “corpuscles” moving through an “aether” 1666. • Invented calculus (in parallel with Leibniz) 1666. • Wrote Laws of Classical Mechanics (Principia 1687) at the insistence of Halley. • Wrote Law of Universal Gravitation.

Edmond Halley • Born in England in 1656. • MA at Oxford, Fellow of the Royal Society, second Astronomer Royal of England. • Happily married to Mary Took, they raised 3 children. • Attempted to date the ruins at Stonehenge. • Initiated actuarial science and demography.

Edmond Halley (continued) • Discussed proof of Kepler’s Laws with Newton. • Newton had found the solution years earlier, but had never published his results (!!?!?!). • Outlived his theological enemies at Oxford, appointed as professor and Astronomer Royal. • Concluded that sightings in 1456, 1533, 1607, and 1682 were actually the same comet. • Predicted its return in 1758, but did not live to see it (died in 1742).

Notable Halley Historical Sightings • 466 BC – recorded by Greeks • 240 BC - Chinese Empress died • 164 BC, 87 BC – recorded by Babylonians

• 11 BC, 66 AD – closest to Christ’s lifetime • 451 AD – fall of Attila the Hun • 684 AD – accompanied by 3 months of rain and plague in Europe (Nuremburg Chronicles)

• 1066 – forecast of doom for King Harold, and of victory for William the Conqueror at the Battle of Hastings (Bayeux Tapestry)

• 1145 – sketched by Canterbury Cathedral monk Eadwine in his psalter • Text shown: “Concerning the star ‘comet’. The star ‘comet’ has a ray such as this, and in English it is called the long-haired star. It appears rarely during the course of many years, and then as a portent.”

• 1222 – may have encouraged Genghis Khan to invade Europe • 1301 – inspired Giotto in his “Adoration of the Magi”

• 1456 – Provided the basis for illustration of plagues in Europe as documented in the Lucerne Chronicles (Schilling, 1513)

• 1533 – Henry VIII marries Anne Boleyn, and is excommunicated by Clement VII

• 1607 –English settlers (including John Smith) land and establish a colony at Jamestown, Virginia • 1456, 1533, 1607, 1682 – used by Halley to predict next appearance in 1758. • 1759 - actual appearance of Halley’s prediction reached perihelion in March

• 1835 – perihelion 2 weeks prior to Mark Twain’s birth • 1910 – perihelion 1 day prior to his death “I came in with Halley's comet in 1835. It is coming again next year, and I expect to go out with it. It will be the greatest disappointment of my life if I don't go out with Halley's comet. The Almighty has said, no doubt: 'Now here are these two unaccountable freaks; they came in together, they must go out together.” Ca 1909

• 1910 - world wide panic initiated by the announcement that cyanogen was found in the spectroscopic analysis of the tail. – Earth was expected to pass through the tail. – Poisoning of “all life on Earth” predicted. – Run on gas masks

ESO

• 1986 Most recent (dimmest on record) sighting • 2003 observed by ESO at 2.6 billion miles distance • 2061 Next expected sighting

Orbit of Halley’s Comet

Graphics courtesy of Starry Night® Pro 6 Imaginova® Corp.

Graphics courtesy of Starry Night® Pro 6 Imaginova® Corp.

Nucleus of Halley’s Comet as imaged by Giotto probe in 1986

Copyright 2000–2008 © European Space Agency. All rights reserved.

Modern Information • Halley is a “short period” comet (orbital period less than 200 years) • There are over 500 short period comets documented. • There are over 120 known non-periodic comets. • We keep finding new ones. • It is not unusual to see 10 visual comets in a year. • There are currently about 80 known comets in the evening sky in Florida, perhaps 3 are visible using a good amateur telescope.

2013 – a good year for comets • Two comets are expected to be visible to the naked eye in 2013. • They are both too dim to see now. • Comet PAN–Starrs: Mid March to mid April. • Comet ISON: Early November to late December. • Best seen with binoculars.

Where to look

Comet PAN Starrs: Mar 12, 2013 @ 8:10 PM looking west

Comet ISON: Nov 26, 2013 @ 8:38 AM looking east Graphics courtesy of Starry Night® Pro 6 Imaginova® Corp.

Photo Credits •

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{{Information |Description={{en|1=Bill Haley and his Comets during a TV-appearance.}} {{de|1=Bill Haley and his Comets während eines Fernsehauftrittes.}} |Source=This image was provided with the friendly permission by Mr. Klau Klettner from Hydra Records {{Information |Description=Comet 17P/Holmes 19-night composite with constellation stick figure |Source=self-made |Date=2007-10-25 to 2008-03-09 |Author= Johnpane |Permission= |other_versions=[Image:17P Holmes composite JPane.jpg] |attrib {{Information |Description={{en|1=Comet Hale-Bopp over Munich. Analog photo with 1:4 / f=300mm, converted with NIKON D90}} |Source={{own}} |Author=Hans Bernhard (Schnobby) |Date=1997 |Permission={{Ingeborg Bernhard permission}} | {{Non-free image data |Description = The nucleus of Halley's Comet, taken by the Giotto probe in 1986 |Source = http://www.esa.int/esaSC/120392_index_1_m.html#subhead6 |Portion = All |Low_resolution = Yes. 292x300 pix (free of charge for educational or informational purposes. – fair use license)