A comet that struck the earth in ancient times probably caused global warming way back then.
55 million years ago, the earth experienced some events that triggered a spate of global warming. This is known as the Paleocene-Eocene Thermal Maximum (PETM).
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Although very scant evidence exists as to the reasons behind this occurrence, some clues have been found recently. A comet underwent impact with the earth during this era. What is yet to be determined is whether this was the exact cause of the ensuing global warming.
PETM has become a real topic of interest for scientists all over the world. It is the only geological marker in the past to compare the present global warming with.
Yet it all remains an enigma. The carbon dioxide in the atmosphere underwent a sharp rise during PETM. The concomitant spikes in global temperatures remained extant for 150,000 years, according to DailyMail.
Although researchers feel sure that the temperature rise was due to the carbon dioxide injection in the atmosphere, they do not know why this happened in the first place.
The only theories that have been formulated point to volcanoes bursting and extraterrestrial phenomena that had an effect on the earth.
Sections of the marine shelf were examined by oceanographers recently. The regions were associated with the Paleocene-Eocene boundary. It underwent formation due to the movement of huge glaciers between the two periods.
Small glass spheres were found in the vicinity. They had unique patterns. Also there were craters in the loci. The presence of these spherules shows that glasses and crystallites were extant and that they had singular shapes.
The fast cooling of these crystallites from a molten state was something which was new for the experts.
The crystallites also had microcraters. This gave away their speed as they were falling and hitting the ground. They had soon solidified. The final conclusion that has been reached is that these crystallites were terrestrial flotsam and jetsam that had been ejected when a meteorite hit the earth.
The comet had hit the earth close to the Paleocene-Eocene boundary. The cause of the global warming was thus an extraterrestrial impact.
This finding will motivate scientists to carry our further research into the matter. They will discover even more clues which might lead to novel discoveries in geology and climate science.
The findings of this study got published in the journal Science.