The Return of Halley’s Comet

18 May 1910

Years before the return of Halley’s Comet, astronomers around the world including at the Dominion Observatory at the Experimental Farm began to prepare for its arrival. The comet was scheduled to return in the spring of 1910, seventy-five years after its previous brush with Earth in 1835. Unlike that earlier year, astronomers now had the instruments to track, conduct spectroscopic research, and photograph this celestial visitor. Beyond knowing that its trajectory would take the comet between the Earth and the Sun, a scant 14 million miles from our planet, they were largely ignorant about it. Experts estimated that the head of the comet was as big as 42 Earths with a tail 62 million miles long and 600,000 miles wide. So close was it to come, astronomers expected that the Earth would pass through the comet’s tail. This was enough to send a frisson of alarm through the general public. Doom-laden views of certain observers, combined with long-standing superstitions that comets were portents of disaster, meant that there was a genuine fear that the end of the world was nigh.

Halley's Comet Yerkes, 29-5-1910 Prof Edward Barnard NYT 3-7-10

Halley’s Comet 29 May 1910, taken by Professor Edward Barnard, Yerkes Observatory, appearing in New York Times, 3 July 1910.

Newspaper coverage was also unhelpful. Although the vast majority of astronomers viewed the return of Halley’s Comet with delight, seeing it as a once-in-a-lifetime opportunity to view close-up a celestial event of remarkable beauty, considerable column inches were given over to the apocalyptical views of the few. This was an early example of seemingly balanced coverage providing a decidedly unbalanced view of what was likely to transpire. Of course, articles portending disaster sold papers, a phenomenon noted by the Ottawa Evening Citizen. In a swipe of its competitors, most likely the Ottawa Evening Journal, the Citizen remarked after the Comet’s safe passage “There was no collision, as the superstitious and the ignorant feared, and, if truth must be told, some newspapers unfortunately traded in those fears by more or less veiled stories and hints.”

Halley’s Comet was named after Edmond Halley, an English astronomer and friend of Sir Isaac Newton, who was the first to describe the periodic nature of the comet in 1705, and predicted its return in 1758. Sadly, Halley, who died in 1742, was not alive to witness the event. However, the return of his comet, visible to the naked eye on Christmas Day 1758, immortalized him. Looking at historical records from China, historians have dated the first known recorded appearance of Halley’s Comet to 240BC.

We now know Halley’s Comet has a peanut-shaped nucleus roughly 15 kilometres long with a diameter of 8 kilometres, considerably smaller than the late 19th century estimates. Nonetheless, a collision with Earth would have been disastrous. The Chicxulub asteroid that likely led to the extinction of the dinosaurs sixty-five million years ago is believed to have been smaller. Halley’s Comet, a remnant from the formation of our solar system 4.6 billion years ago, consists of dust, rock and ice. Its tail is made up of dust and sublimated gases that spew off as it approaches the Sun. The comet spends much of its time in the Kuiper Belt that circles the Solar System.

By 1909, the world’s telescopes were trained to the western sky shortly after sunset to watch for the comet’s return. When it was first spotted by telescope is a bit murky. The Ottawa Evening Journal reported that the Dominion Observatory in Ottawa received a telegram that a German astronomer had seen Halley’s Comet as early as mid-September 1909. The first Canadian spotting apparently occurred mid-January 1910 in British Columbia. At this point, the comet was hurtling towards the Sun reaching its perihelion (closest approach) on 20 April before commencing its return to the outer Solar System, but not before brushing close to the Earth. It was not yet visible to the naked eye.

With the return of Halley Comet, many newspapers, including the Ottawa Evening Journal, ran articles linking previous appearances of the comet to wars, plagues and other disasters of the past. One story managed to ascribe the biblical Deluge, dated to 2349 BC, to the comet as well as the destruction of Sodom and Gomorrah in 1900 BC. Other world-changing events linked to the comet included the sack of Jerusalem by the Romans in 70 AD, the sack of Rome by Attila the Hun in 451 AD, the Norman Conquest of England in 1066, the War of the Roses in 1456, and Wolfe’s Conquest of New France in 1759. For 1910, the article noted the return of the comet coincided with threatened war in the Balkans and labour unrest and socialist demonstrations in America and Europe. Coincidentally, King Edward VII died on May 6th, another apparent “victim” of the comet.

Halley' Comet Fight 13-4-10 OEJ

Cartoon, The Ottawa Evening Journal, 13 April, 1910.

Halley’s Comet’s appearance in the night sky allowed astronomers to use state-of-the art equipment to photograph it and to conduct spectroscopic analyses. In February 1910, the Yerkes Observatory in Wisconsin announced the discovery of cyanogen gas, a chemical compound related to cyanide, in the comet’s tail. This stoked comet fears to new heights, especially when a French astronomer, Camille Flammarion, opined that all of the earth’s inhabitants would suffocate owing to the gas when the earth passed through the comet’s tail. He reportedly added that if there was also a “diminution of nitrogen and an excess of oxygen,” “the human race would perish in a paroxysm of joy and delirium, probably delighted at their fate.”  Professor Pickering of Harvard University suggested that Flammarion could be right. “The consequences of a collision of the earth with the comet’s tail may mean destruction to us,” he said. Another French astronomer, M. Deslandres of the Paris Observatory thought that the comet’s tail crossing the Earth’s atmosphere would led to an incalculable number of X-rays that would cause the water vapour in the atmosphere to condense leading to rains not “seen since the days of Noah’s great deluge.”

These were minority views within the astronomical profession. The famed American astronomer, Percy Lowell, said “Nothing can occur to the earth in consequence of its passing through the tail of the comet. The consistency of the tail is probably less than any vacuum procurable on earth.” (Mind you, Lowell also spotted “canals” on Mars that supposedly were a desperate attempt by Martians to tap water at the dying planet’s poles.) A similar sanguine view was expressed by Sir Robert Ball of Cambridge University. A Columbia University professor argued “the Maker of the universe” would not allow any harm to come to “the home of the highest form of life that He has fashioned.” Astronomers at the Dominion Observatory patiently addressed the questions of concerned Ottawa citizens. They also lectured at the Y.M.C.A. and other locales about the harmlessness of the comet’s return. At St Mathias Church, Dominion astronomer John Plaskett in a lecture titled “Wonders of Creation” rejected Flammarion’s thesis, echoing Lowell and Ball that there was no danger from the cyanogen gas as it was too rarefied to have any impact.

Halley's Comet Mary Proctor, San Fran Sunday Call

Mary Proctor, astronomer and author, member of the American Association for the Advancement of Science and Fellow of the Royal Astronomical Society, 1862-1957, San Francisco Sunday Call. University of California, Riverside.

One of the most reasoned, scientific assessments of the return of Halley’s Comet that appeared in the popular North American press was by a respected amateur astronomer, Mary Proctor. In an October 1909 Ottawa Journal article, Proctor said that “the fulfillment of the [Halley’s] prediction may be awaited serenely.” She added “Woe betide it, however, should it come too near to Jupiter, which has the reputation of being the greatest comet capturer of the skies.” (In 1994, this prophetic comment was captured on film when astronomers observed the tidal forces of Jupiter pulling apart the Shoemaker-Levy comet, causing it to plunge into the planet.) Later, after Flammarion’s dire prediction of the end of all life, she reiterated her views even more forcefully, adding “Astronomers are being suspected as conspiring together to keep the uninitiated in ignorance of the true fate awaiting our planet.” Instead of believing in conspiracy theories, she urged people to enjoy the comet’s approach, and “experience a spectacular display of cometary glory.”

After been lost in the light of the Sun for a couple of weeks, Halley’s Comet reappeared in the morning sky shortly before dawn in mid-April, 1910. Its reappearance was noted by Mr Robert Motherwell at the Dominion Observatory on 13 April using the observatory’s 15-inch aperture telescope. Owing to intense sunlight, it was not visible to the naked eye, and wouldn’t be for some days. Motherwell discredited reports from around Canada that the comet had been spoted. He ascribed such sightings to confusion with Venus.

Halley's Comet OEJ 16-4-1910

Illustration for serial on a comet striking the Earth, The Ottawa Evening Journal, 16 April 1910.

The Journal took this opportunity to run a fanciful serialized story that had initially appeared in the Aldine Magazine of New York in the 1870s about a fictitious collision of Plantamour Comet with the Earth. In the story, the collision split the Earth into three pieces, with Asia completely vapourized, leaving America the only habitable part of the globe. When the clouds finally lifted, there were two new moons in the sky—Europa and Africa—that had split away from the Earth complete with their own seas and atmosphere. Now separated forever, the remaining people of America could only communicate with the survivors of Europa and Africa by using ten-foot high letters made of tin.

Halley’s Comet became visible to the naked eye in Ottawa early in the morning of 29 April 1910, when it was spotted by Mr Motherwell at the Dominion Observatory. It was visible in the eastern sky at a declination of eight degrees north of the equator. While the two Ottawa newspapers agreed on the sighting, they agreed on little else. The Journal reported that Motherwell got only a partial view of the comet at shortly after 3am in a break in the clouds that lasted just sixty seconds. The Citizen reported that the comet was located by Motherwell at about 4.20am and that the astronomer had a good view for about 30 minutes before the Sun became too bright. By early May, the comet was visible to all who got up early enough. It was to be seen low on the horizon with its tail pointing nearly upwards.

With the comet visibly bearing down on the Earth, the focus of attention shifted to what might happen when the Earth moved through the Comet’s tail, scheduled to occur sometime around May 20th. In preparation for the event, it was reported that restaurants in New York and Paris were hosting comet parties. Recalling Flammarion’s dire prediction, one enterprising restauranteur advertised that pure oxygen would be blown into the dining room to counteract the effects of cyanogen gas. More seriously, Dr Koltz at the Dominion Observatory said that it would take several hours for the Earth to pass through the tail. He rejected any concerns that this transit would have on the Earth, though there may be some magnetic effects. He warned of the possibility that telephone and telegraph service might be adversely affected. Dr King, the chief of the Dominion Observatory, thought there might be a “sort of aurora borealis, but nothing outside of that.” Parliament Hill was deemed a good vantage point to see the comet at its best.

Halley's Coment OEJ 19-5-10

Cartoon, The Ottawa Evening Journal, 19 May 1910

In the event, both the Ottawa Evening Journal and the Ottawa Evening Citizen reported that Ottawa was in the comet’s tail for several hours during the night of May 18th. As expected, the Earth’s passage through the tail was uneventful. There was no cyanogen gas, and there was no deluge of biblical proportions, though cloudy skies and rain made comet watching in Ottawa difficult. Telecommunications were unaffected. Dr Kloz said that instruments at the Dominion Observatory detected some slight magnetic effects, but that was all. Newspaper accounts again differed on whether the comet sparked a viewing of the Northern Lights. According to the Journal, shortly after midnight the clouds broke and there was “a magnificent display of the Aurora” that spread across the “entire dome of heaven” before disappearing again as the clouds returned. The newspaper added that the aurora was most brilliant in Toronto and contained “all the colours of the rainbow.” Contrarily, the Citizen reported that “there was none of the auroral effects some had predicted.” There was also no mention of an aurora borealis in Toronto’s Globe newspaper.

Halley’s Comet got progressively fainter during the following days as it continued its journey back out the Kuiper Belt. It returned to the inner Solar System in 1986. This time, however, the comet’s reappearance was unremarkable as it and the Earth were on opposite sides of the Sun when it occurred. For those who missed Halley’s Comet, you’re next opportunity will be July 2061. The showing is expected to be better this time.


Astronomical Society of the Pacific, 1986. What have we learnt about Halley’s Comet?,

Curran, Kevin, 2012. Halley’s Comet,

Globe (The) 1910. “Through A Comet’s Tail,” 19 May.

Ottawa Evening Citizen (The), 1910. “Halley’s Comet Has Been Discovered,” 17 January.

————————————, 1910.  “Halley’s Comet Is Located By Dominion Observatory,” 13 April.

————————————, 1910. “The Earth Takes Its Bath In the Comets Tail Tonight,” 18 May.

———————————–, 1910. “Ottawa Thro’ Comet’s Tail From 8.30 Last Night to 12.30,” 19 May.

Ottawa Evening Journal (The), 1906. “The Star of Bethlehem,” 29 December.

————————————-, 1909. “More About Halley’s Comet,” 19 March.

————————————-, 1909. “Astronomers Preparing For The Return of Halley’s Comet,” 30 April.

————————————, 1910. “Halley’s Comet Said To Be Full Of Cyanogen Gas,” 8 February.

————————————, 1910. “Gas From Halley’s Comet Could Not Affect Earth,” 10 February.

————————————, 1910. “Lectures on Halley’s Comet,” 18 February.

————————————, 1910. “Ottawa and District Will Soon See Halley’s Comet, 14 March.

————————————, 1910. “Harmlessness of Halley’s Comet,” 21 March.

————————————, 1910. “It’s Mighty Little Wisest Men Know About Comets,” 2 April.

————————————, 1910. “Must be Pretty Scrappy Stuff in Halley’ Comet,” 13 April.

————————————-, 1910. “Halley’s Comet Was Seen At the Observatory This Morning, 13 April.

————————————-, 1910. “When the Comet Struck,” by W. T. Alden, 14 April.

————————————-, 1910. “Comet Seen One Minute,” 29 April.

————————————-, 1910. “Comet History, And Why Halley’s Is Harmless,” by Mary Proctor, 14 May.

————————————-, 1910. “Comet Night Preparations,” 17 May.

————————————-, 1910. “Comet Passes Very Quietly,” 19 May.

Simon, Kevin, 2015. Fantastically Wrong: That Time People Thought A Comet Would Gas Us All To Death,


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