Today, Felisa Wolfe-Simon and scientists at NASA announced the discovery of a new form of bacteria that uses arsenic as part of its basic biology, something previously thought impossible. The bacteria appears to use the arsenic to replace phosphorous — possibly even in its DNA. Phosphorous was considered to be essential for all life, and so if confirmed, this discovery is a stunning affirmation of the idea that life can exist in forms wildly different from those normally found on Earth, and that in turn has enormous implications for how we should look for life elsewhere in the cosmos.
To help understand the science, and the excitement, here are five TED talks on how, and why, we might search for such life.
Starting close to home, Penelope Boston shows how the study of life in extreme conditions on Earth is related to the search for extraterrestrial life, and exactly how the lessons from caves can be applied on Mars and beyond.
In another exciting possibility nearby, Carolyn Porco gives a quick update showing tantalizing hints that Saturn’s moon Enceladus might harbor life.
Going beyond the solar system, Dimitar Sasselov explains how his team has found hundreds of Earth-like planets, many of which might harbor life.
But how do you look for life hundreds or thousands of light-years away? Garik Israelian demonstrates how spectroscopy could find signs of life, and even intelligence over astronomical distances.
And why should we do this? Jill Tarter, in her 2009 TED Prize wish, makes the case that searches for extraterrestrial life can give us a profound sense of our common humanity, and so not only can we search for them, but we must do so.