Life on Earth began more than 3 billion years ago, evolving from the most basic of microbes into a dazzling array of complexity over time. But how did the first organisms on the only known home to life in the universe develop from the primordial soup?
One theory involved a "shocking" start. Another idea is utterly chilling. And one theory is out of this world!
Inside you'll learn just how mysterious this all is, as we reveal the different scientific theories on the origins of life on Earth.
It started with an electric spark
Lightning may have provided the spark needed for life to begin.
Electric sparks can generate amino acids and sugars from an atmosphere loaded with water, methane, ammonia and hydrogen, as was shown in the famous Miller-Urey experiment reported in 1953, suggesting that lightning might have helped create the key building blocks of life on Earth in its early days. Over millions of years, larger and more complex molecules could form. Although research since then has revealed the early atmosphere of Earth was actually hydrogen-poor, scientists have suggested that volcanic clouds in the early atmosphere might have held methane, ammonia and hydrogen and been filled with lightning as well.
Or could simple clay have fueled life’s beginning? Read on to find out.