Magazine

Dark Day: Your fanciful explanations

The Magazine's recent piece on the mystery of Dark Day prompted lots of readers to email fanciful explanations as to what caused it.

The strange event , which took place on May 19, 1780 in New England and parts of eastern Canada, turned morning to night.

Here are 15 readers' theories. Many would not stand up to a moment's scientific scrutiny.

Aliens

Image caption Many unexplained mysteries have been attributed to aliens

1. Perhaps on a galactic scale, Earth is a nature preserve, a tourist and scientific destination for other-worldly species. Maybe a UFO had a breakdown and a distraction was needed until planet-side assistance could arrive. Krista Riccioni, Falmouth, Maine, USA

2. Obviously caused by alien invaders erecting a huge sun shield in an attempt to induce a new ice age and so wipe out humankind. Fortunately, Dr Who quickly triggered the self destruct sequence intended to remove the shield after its work was done and the defeated aliens moved on to look for easier pickings. Graham, Canada

3. I would like to believe that the Dark Day was caused by a large spaceship, disguised as a large cloud, that obscured the sun. Perhaps aliens came to visit us and decided we weren't that interesting and went on their way. Joyce, Los Angeles, USA

Solar system

Image caption The universe has long been the subject of intrigue

4. Following the Dr Who scenario, maybe a concentrated mass of dark matter passed very close to the sun, blocking its light as it passed. Ordinary matter constitutes about 4% of the universe - so dark matter theoretically should dominate. Logically this may have caused this event - who knows. As they say: If you eliminate the impossible, whatever remains, however improbable, must be the truth. Richard Greaves, Milton Keynes, UK

5. A huge eruption on the sun could have burnt up a planet that was close to the sun. Although our magnetic field would have protected our world it would still have caused many disruptions on earth. The ash and debris from the sun's destruction would have blocked the sun's rays which in turn would have turned Day into Night. John Lukanik, Stafford, UK

6. How about a comet. It is certain that if it approached from the north, it would be seen as a harbinger of doom. Dust from the comet could cause the effects described. Edward Scott, Carmel, NY, USA

Natural phenomenon

Image caption Could hurricane clouds cause a blackout?

7. Hurricane. It was early in our history and numerous storms would have passed up the east coast. By the time it came to New England the rain/winds may have diminished, but the clouds could have stayed. Especially if early settlers had never experienced a hurricane, it might have seemed like the end of the world. Marc, Virginia, US

8. Sometime in the late 1950s on a weekend day, the sky became as dark as night around noon in north Surrey (I witnessed this at Purley). The street lights came on. On the evening news this occurrence was attributed to the coming together of warm moist air with cold air causing an accumulation of continuous cloud from low levels all the way to 40,000 feet. Rodney Nicholson, Edmonton, Canada

9. Maybe an intense temperature inversion with a great deal of smoke pollution, like what happened in Donora, Pennsylvania, many years ago? Shelby Brooke, Virginia, US

Fires

Image caption The forest fire hypothesis is popular

10. Twice in the period from 1990 to the present we have had dimmed and smoky days from forest fires that were 800 miles away in the heart of Quebec. 1780 was a particularly dry year, and it would not be surprising to have a set of "super-fires" that year. Tom Moffatt, St Stephen, Canada

11. The dim red sun gives it away. I live in Southern California where there are often brush fires. When I read about the red sun and low light, it reminded me of days here when large brush fires are burning - the sun turns a dim reddish orange, the light level dims to dusk-like, the air is smoky and a thin layer of ash settles on all surfaces, but very visibly on cars and pools. It can be very eerie, and people often comment about it looking like the end of the world and/or post nuclear. Andrew Shannon, Laguna Beach, USA

12. I have been a forest fire fighter in Ontario for 11 years, and I believe that forest fire is the most likely cause of this "Dark Day". However, for the entire sky to grow dark enough for it to look like night, it would have had to have been a huge fire or perhaps a series of large fires. If there had only been one large fire, the smoke column (and therefore the source) would have been obvious. A few larger and perhaps somewhat distant fires may have had enough of an effect to darken the sky in the way. Alain Joseph, Nipigon, Canada

Insects and other things

Image caption Surely swarming insects couldn't be responsible?

13. Was anywhere in the world being eaten by vast swarms of insects not long after these dark days? Bugs have been found flying at astonishing altitudes. Steve Dobson, Bideford, Devon, UK

14. It was an early sign of the coming of an over-powering dark lord - in modern times we call him Simon Cowell. Matthew Buckland, Chatham, UK

15. The universal computer that ran the matrix holograph had a short - like a pixel burn out on a computer screen - and had to be replaced. John Lee, Kowloon, Hong Kong