The Origins of Life

Astrobiology

In this course, Professor Ian Crawford (Birkbeck College, University of London) introduces astrobiology, which is the search for life in the universe. To begin, we: (i) address the three things necessary for life to survive, as well as how life might have originated on Earth; then (ii) the history of life on Earth is explored, which can inform what kind of extraterrestrial life we might expect to find elsewhere; and (iii) discuss how extreme life on Earth can provide insights into the possibility of life on other planets; before (iv) talking about the possibility of life on Mars and explore the evidence for water on the planet; and (v) discuss potential habitable environments in the solar system besides Mars, particularly the icy moons of the giant planets; and (vi) about the prospects of finding life on planets orbiting stars other than the Sun; before (vii) thinking about how often communicative intelligent life could form in the universe using the Drake Equation; and finally (viii) the eighth mini-lecture is about optimistic and pessimistic solutions to the Drake Equation.

The Origins of Life

In the first mini-lecture, we discuss astrobiology as the search for life in the universe. Life needs at least three things to survive: a source of raw materials, a liquid medium, and a source of energy. Our planet Earth fulfils all of these, but the question remains about how life originated in the first place. Charles Darwin speculated that life may have begun in a "warm little pond," and hydrothermal vents in the deep ocean have also been postulated as possible places where life may have originated on Earth. It is unknown if either of these environments was where life originated on Earth. It is also unknown if life on Earth was inevitable, as there may have been something in the early Earth's environment that made the origin of life inevitable, but we cannot know for sure.