NASA Chief Scientist Ellen Stofan staked out her position clearly on Tuesday: "I think we're going to have strong indications of life beyond Earth within a decade, and I think we're going to have definitive evidence within 20 to 30 years,” she said during a live webcast from a panel discussion on recent discoveries of extensive evidence of water and organics on other planets in the solar system.
Stofan is not a "lone voice in the wilderness," either; Jeffery Newmark, another panel participant from the agency, chimed in to say of the pronouncement, “It’s definitely not an if, it’s a when."
Other panel participants included astronaut John Grunsfeld, Director of Planetary Science James Green, and Director of Astrophysics Paul Hertz. None of them were shaking their heads or frowning as Stofan and Newmark spoke.
All this optimism from America’s space agency is not new or unusual. NASA has been searching for signs of life both within the solar system and further afield in the cosmos for years.
The difference here is the specificity of the timeline.
That horizon, within the lifetimes of most people alive on Earth today, is no accident or wild guess. Instead, it flows from the recent evidence uncovered of the existence of water over long periods of time on Mars, Europa, Ganymede, and Enceladus, and the fact that in-depth investigative missions are due to explore many of those areas within that window of time.
According to our best understandings of the evolution of multicellular organisms here on Earth, water is a key component in the formation of life. Given the breadth and scope of lifeforms which have developed under the right conditions here on our own planet — even quite extreme conditions — there appears to be little reason why they will not have formed on other planets with similar conditions as well.
Indeed, the real difficulty might not be discovering life on other moons or planets, but recognizing it. Evolutionary processes may operate identically on other planets, but the organisms they produce might be radically different from what human scientists are accustomed to viewing as “life.” There is some concern that apparent cellular evidence may be inconclusive.
“Is this life, is it not, how do those cells compare to cells here on Earth?” Stofan describes the process of comparison.
Stofan has been NASA’s chief scientist since 2013, having previously worked for the agency at the prestigious Jet Propulsion Laboratory in Pasadena throughout the 1990s. She is not of the opinion that machines are going to make these discoveries, however. She believes it will take humans to investigate and explore the evidence directly. NASA hopes to launch a manned mission to Mars in the 2030s to make that engagement possible.
NASA’s next scheduled Mars mission is the InSight lander, which will focus more on geophysical matters than biological. But the recently budgeted Europa mission to study Europa’s oceans and search for life there could launch as early as 2022. ESA also plans to launch a mission to study Europa, Ganymede, and Callisto in 2022. A probe mission to Enceladus to directly investigate the water plumes spraying from that moon is also under discussion.
The combination of increasing scrutiny and additional scientific evidence of a long-term presence of water dramatically increases the likelihood of some sort of life being detected, and relatively soon.