The 18 Month Winter Caused by the Asteroid that Wiped Out Dinosaurs


66 million years ago an asteroid, the Chicxulub asteroid, hit the world and changed history forever. Today, research is still being carried out into this event and scientists are still finding out new information, creating a much clearer picture of the climate catastrophe.

The Chicxulub Asteroid

The Chicxulub asteroid was 6-9 miles in diameter and struck earth in the location known today as the Yucatan Peninsula of Mexico. The asteroid wiped out dinosaurs’ reign over earth and set off earthquakes, giant tsunamis and volcanoes as well as creating an endless night and an 18-month winter.

The initial hole which punched into the Earth was estimated 30km deep and 80-100km wide. Due to it being unstable and under the pull of gravity, the sides of this depression meant it would have collapsed inwards.

After the asteroid struck, the sun disappeared behind a huge cloud of smoke that encircled the planet, turning day into night and causing temperatures to plummet as fire fell down from above.

The Effects

Research conducted at the end of last year (2017) indicated just how cold Earth became after the asteroid struck the planet. In fact, Earth likely experienced a number of years with an average of minus degree temperatures.

It was already well known prior to research that there was a large increase in dust from vaporised rocks, sulphur, and carbon dioxide during that time. However, the asteroid sent dust into the Earth’s atmosphere which blocked out the Sun, causing both the Earth to cool and less sunlight for plants to photosynthesize.

The release of carbon dioxide into the atmosphere caused the Sun’s heat to be trapped, which is a very similar scenario that we find ourselves in today, and sulphur gas also contributed to the blocking of sunlight, which added to the freezing temperature.

Estimates were made which determined that Earth’s temperature was on average 12°F for at least three years after the asteroid hit our planet. This abrupt and long change in temperature explains why so many species struggled to survive and why some did not make it.

After the Dust Settled

Chemical Reactions

Even once the dust finally cleared nearly two years after the asteroid struck the earth, the chemical reactions in the upper atmosphere would have wrecked the protective layer of ozone, meaning the sun’s rays would have irradiated anything left alive by the strong ultraviolet light.

The Extinction of Species

As a result of this event, it was estimated that over three-quarters of all species on Earth, including most of the dinosaurs, were now extinct.

The Layer of Spherules

Finally, as a result of the asteroid strike, the vaporised rock in the air was condensed into small particles known as spherules. As these fell to the ground, the friction would have made them so hot that they would have started fires on the ground, causing a fire-like rain.

Interestingly, a thin layer of spherules can be found all over the world, even after all of this time.

Following on from this. We will be investigating the Paleocene–Eocene Thermal Maximum and how it compares to the today’s climate.

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