What if the Earth was not a hot ball of gas?

If you go back to your lessons in science and geography, you are likely to remember your teacher telling you that our Earth was once a hot ball of gas that cooled down over millions of years to become what it is today. But what if your teacher was wrong, the text book was wrong and the earth was never a hot ball of gas? How was the Earth back then, you may ask. The answer to that would be, very much like how it is today!

The original Theory

Ancient Earth, called Hadean, was believed to be extremely hot by geologists. As per this theory, there was probably an ocean of magma that covered the entire surface and no life form would be able to survive such conditions.

The Discovery

Around 30 years ago, when geologists first came across Zircon, a mineral found in crystalline form, which contains trace amounts of uranium and thorium. Using radiometric dating techniques, geologists were able to determine the age of these crystals which turned out to be around 4 billion years.

Over the years, geologists have studied the zircon crystals and found more information about their shape, size, colour, how they are formed and what are their constituents are. This analysis has revealed that formation of zircon requires relatively cooler temperatures and most importantly, water. So, if the zircon crystals found were over 4 billion years old, there had to be some cooler surfaces on the Earth and cool enough for formation of water! This is completely contradictory to the original theory about Hadean and therefore, at least at some places, there existed water on the surface of the Earth. Or probably, the Earth was not a hot ball of gas as we were taught, it was just the way it is today (except the humans, of course!)

Testing New Hypothesis

In order to accept this new theory, geologists would have to find some proof to support their claim. But how do you prove that something happened 4 billion years ago? Luckily, we still have magma that is pouring out and cooling down to form more crust even today. The place is Iceland, which is undergoing a spurt of growth thanks to the volcanic eruptions that are a part of the islands daily routine. So, researcher Tamara Carley and her colleagues analysed the modern day zircons that are formed on Iceland.

What Dr. Carley found was even more interesting. Not only are zircons on Iceland formed out of hotter magma that was found during Hadean times, it is also cooled down by water that is warmer that what was found on the Hadean. So, to sum up, not only did Hadean have a cooler magma, it also had cooler water available in its oceans/ water bodies than what we have today.

In conclusion, geologists really need to come up with a much stronger theory of how our Earth was back in history and our textbooks need a change of content big time.