12,800 Years Ago, Earth Was Struck by a Disintegrating Comet, Setting Off Global Firestorms

According to modern theories of geological evolution, the last major ice age (known as the Pliocene-Quaternary glaciation) began about 2.58 million years ago during the late Pliocene Epoch. Since then, the world has experienced several glacial and interglacial periods, and has been in an inter-glacial period (where the ice sheets have been retreating) ever since the last glacial period ended about 10,000 years ago.

According to new research, this trend experienced a bit of a hiccup during the late Paleolithic era. It was at this time – roughly 12,800 years ago, according to a new study from the University of Kansas – that a comet struck our planet and triggered massive wildfires. This impact also triggered a short glacial period that temporarily reversed the previous period of warming, which had a drastic affect on wildlife and human development.

The study in question, “Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ~12,800 Years Ago”, was so large that it was divided into two parts. Part I. Ice Cores and Glaciers; and Part II. Lake, Marine, and Terrestrial Sediments, were both recently published by The Journal of Geography, part of the the University of Chicago Press’ series of scientific publications.

New research shows that some 12,800 years ago, an astonishing 10 percent of the Earth’s land surface, or about 10 million square kilometers, was consumed by fires. Credit: Pexels.com

For the sake of their study, the team combined data from ice core, forest, pollen and other geochemical and isotopic markers obtained from more than 170 different sites across the world. Based on this data, the team concluded that roughly 12,800 years ago, a global disaster was triggered when a stream of fragments from a comet measuring about 100 km (62 mi) in diameter exploded in Earth’s atmosphere and rained down on the surface.

As KU Emeritus Professor of Physics & Astronomy Adrian Melott explained in a KU press release:

“The hypothesis is that a large comet fragmented and the chunks impacted the Earth, causing this disaster. A number of different chemical signatures — carbon dioxide, nitrate, ammonia and others — all seem to indicate that an astonishing 10 percent of the Earth’s land surface, or about 10 million square kilometers, was consumed by fires.”

Ice ages are characterized by a drop in average global temperatures, resulting in the expansion of ice sheets globally. Credit: NASA

According to their research, these massive wildfires also caused a massive feedback in Earth’s climate. As fires rushed across much of the planet’s landscape, the smoke and dust clogged the sky and blocked out sunlight. This triggered rapid cooling in the atmosphere, causing plants to die, food sources to dwindle, and ocean levels to drop. Last, but not least, the ice sheets which had been previously retreating began to advance again.

This quasi-ice age, according to the study, lasted about another thousand years. When the climate began to warm again, life began to recover, but was faced with a number of drastic changes. For example, fewer large animals survived, which affected the hunter-gather culture of humans all across North America. This was reflected in the different types of spear points that have been dated to this period.

What’s more, pollen samples obtained from this period indicate that pine forests were likely burned off and were replaced by poplar forests, a species that colonizes cleared areas. The authors also suggest that this impact could have been responsible for the so-called Younger Dryas cool episode. This period occurred roughly 12,000 years ago, where gradual climatic warming was temporarily reversed.

Intrinsic to this period was an increase of biomass burning and the extinctions of larger species during the late Pleistocene period (ca. 2,588,000 to 11,700 years ago). These sudden changes are believed to be what led to severe shifts in human populations, causing a decline during the 1000-year cold period, and leading to the adoption of agriculture and animal husbandry once the climate began to warm again.

Pleistocene of Northern Spain showing woolly mammoth, cave lions eating a reindeer, tarpans, and woolly rhinoceros. Credit: Wikipedia Commons/Mauricio Antón

In short, this new theory could help explain a number of changes that made humanity what it is today. As Mellot indicated:

“Computations suggest that the impact would have depleted the ozone layer, causing increases in skin cancer and other negative health effects. The impact hypothesis is still a hypothesis, but this study provides a massive amount of evidence, which we argue can only be all explained by a major cosmic impact.”

These studies not only provide insight into the timeline of Earth’s geological evolution, they also sheds light on the history of the Solar System. According to this study, the remnants of the meteor which struck Earth still persist within our Solar System today. Last, but not least, the climate shifts that these impacts created had a profound effect on the evolution of life here on Earth.

Further Reading: Kansas University

Astronaut Captures Incredible Images of Australian Bush Fires

Intense wild fires, or bush fires as they are called in Australia, are burning out of control across southeast Australia with authorities describing the condition as “catastrophic.” The huge fires were easily visible from the International Space Station on Tuesday and onboard, Canadian astronaut Chris Hadfield has been watching from above.

See more of his images below:

A long line of bush fires range in Australia, and are visible from space. Credit: NASA/Chris Hadfield

Officials say more than 130 fires, many uncontained, are burning in the heavily populated New South Wales state, where dry conditions are fueling the fires as temperatures reached 45 degrees and wind gusts reached more than 100 kilometers per hour.

Huge plumes of smoke from bush fires in Australia were visible from the International Space Station. Credit: NASA/Chris Hadfield.
Huge plumes of smoke from bush fires in Australia were visible from the International Space Station. Credit: NASA/Chris Hadfield.

In Tasmania, an island south of Australia, rescue officials are still trying to locate around 100 residents who have been missing after a fire tore through a village, destroying dozens of homes. You can see images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite that were taken on January 7, 2013 at the Earth Observatory website.

Follow Chris Hadfield on Twitter to see more images.

Additional information on the bush fires from Voice of America

Wildfire Smoke is Visible Even at Night from Space

The Whitewater-Baldy fire is the largest wildfire in New Mexico’s history and has charred more than 465 square miles of the Gila National Forest since it started back on May 16, 2012 after several lightning strikes in the area. This wildfire produced so much smoke that it was visible even at night to the astronaut photographers on the International Space Station. This image was taken on June 2, 2012 by the crew of Expedition 31 on the ISS, with a Nikon D3S digital camera. A Russian spacecraft docked to the station is visible on the left side of the image.

Credit: NASA Earth Observatory website.

Smoking Wildfires Seen From Space

Wildfires continue to rage across the western United States, burning forests and property alike, and even the most remote have sent up enormous plumes of smoke that are plainly visible to astronauts aboard the Space Station.

The photo above was taken by an Expedition 31 crew member on June 27, showing thick smoke drifting northeast from the Fontenelle fire currently burning in Wyoming. More plumes can be seen to the north.

Utah’s Great Salt Lake can be seen at the bottom right of the image. Its two-tone coloration is due to different species of algae that live in the lake, which is split by the physical barrier of a railroad causeway.

You can watch a video of the wildfires in the west taken from the ISS here, and see more “fire and smoke” news and images from space here.

Image: NASA