Killer asteroids created continents on Earth, helped birth LIFE, paved way for Humanity
Asteroids have a pretty bad track record when it comes to Earth. They have caused massive destruction, brought about ice ages, were the reason behind the extinction of dinosaurs and continue to spread panic even today. Asteroids are a big concern for scientists to the point that both NASA and China are testing independent mechanisms to protect the planet from their onslaught. But what if we said that the same asteroids which pose a threat to the existence of humanity were also the ones which enabled humanity to exist in the first place. How? By creating continents on Earth. In effect, in their destructive power also lies the power of creation. Read on to know more.
According to a new study published in the Nature journal, a group of researchers have found evidence that asteroids might be behind the creation of continental plates on Earth. But, why do we even question the creation of continents? It is because no other planet, that we know of, has continents. And these continental plates played an important role in evolution of life outside oceans and creating the first mammals. So, what has this study found which confirms that asteroid strikes to Earth helped humanity?
In a post written by the lead author of the study Tim Johnson on The Conversation, he said, “we studied ancient minerals from Western Australia and found tantalising clues suggesting the giant impact hypothesis might be right”.
Asteroids could have given birth to continents on Earth
While the technical geography is harder to understand, in simple words, the Earth is divided into three layers — the crust, mantle and the core. Among them, the crust contains lithosphere which includes the ocean floor and continents. And right underneath is this almost-molten mantle which contains lava-like structure. The theory has been that the mantle gave birth to crust. But for that, the mantle which is kept in a high-pressure, high-temperature surrounding, needs to be able to release that and solidify to become crust. And this is where asteroids come in.
Massive city-killing asteroids would blast huge volumes of mantle and throw them in a radius of hundreds of kilometers, which would then cool and form crust after undergoing some intermediate stages.
The researchers found two pieces of evidence of this. First was to measure the proportion of oxygen isotopes in Zircon, the oldest known crustal material. The proportions in young Zircon grains revealed deep melting of the mineral, which is similar to the state mantle is found in.
There is one more piece of evidence. “The zircons from the Pilbara Craton (western Australia) appear to have been formed in a handful of distinct periods, rather than continuously over time….Spherule beds (of Pilbara Craton) are deposits of droplets of material “splashed out” by meteorite impacts on Earth. The fact the zircons have the same age suggests they may have been formed by the same events”.