Billions of years ago the, Earth was younger. In fact, billions of years ago, a lot of stuff was younger than it is now. It seems an innocuous or even moronic statement, for sure, but it’s a statement at the heart of one of the planet’s long unanswered questions.
Why didn’t Earth freeze under a younger Sun?
Because, not only was Earth younger, but so was our Sun, and thus, it was cooler, less energy efficient, so to say. Thus it should have made Earth a very cold and formidable place; however evidence suggests that it was in fact the opposite.
The science suggests that those billions of years saw the Sun reduced to 25% of what it is today in terms of output, so atmospheric temperatures on Earth should have been colder by around 25°C. But ancient rocks show that liquid water existed, subsequently proving that temperatures must have been at the least, above freezing, for liquid water to exist.
An implausibly high concentration of carbon dioxide in the atmosphere would explain this, according to modeling, but...
Now, Philip von Paris of the German Aerospace Centre in Berlin and colleagues, have suggested a new idea. They have built a model that they believe better simulates the types, pressures and layering of atmospheric gases at the time.
Their model showed that the atmosphere at the time was actually a better insulator than we thought, and that C02 with a partial pressure of only 2.0 millibars would have kept temperatures above the freezing point between 2 and 2.5 billion years ago. That being said, their research still leaves the period of time between 2.5 and 4.6 billion years unanswered and a mystery.
In addition, there are those who simply do not believe the original research. "I don't trust the tuning of their model," says Jim Kasting of Pennsylvania State University at University Park.
Joshua Hill, a Geek’s-Geek from Melbourne, Australia, Josh is an aspiring author with dreams of publishing his epic fantasy, currently in the works, sometime in the next 5 years. A techie, nerd, sci-fi nut and bookworm.
