NASA hosted a panel discussion with many of its high-ranking scientists on April 7th regarding the possibility of discovering signs of alien life within the 21st century. The consensus the NASA officials put forth was overwhelmingly optimistic in this regard: Not only will we discover alien life in this century, but we’ll discover it in the next 20 years.
Meaning… my theoretical grandchildren could grow up in a world where alien life is a historical fact.
What makes NASA so sure of this time frame? Three reasons. Or rather, three missions that will launch in the next 10 years that will bridge the gap between theories of alien life and evidence of alien life.
Mars in 2020
The more that we explore Mars the more circumstantial evidence we find that life could have developed on the red planet. Although humanity now has several vehicles on the ground and in orbit of Mars, none have been constructed specifically to explore for signs of life beneath the Martian surface, where it is believed that direct confirmation of previous life is most likely to be discovered.
In 2016, a Mars lander mission called InSight will launch to take the first look into the deep interior of Mars and a currently unnamed Mars rover will be launched in 2020 to directly search for signs of previous life, fitted with instruments that will be able to detect the presence of organic compounds in rocks from a distance through chemical spectrometry, high resolution ground-penetrating radar, and x-rays. This rover will also carry MOXIE, a preliminary terraforming tool designed to test whether oxygen can be manufactured from the carbon dioxide abundant on Mars.
Not only that, but the 2020 rover will save samples of its evidence to be retrieved by a manned NASA mission to Mars currently planned for the 2030s.
If we find life on Mars, it will most likely be bacterial or similarly unicellular. Still, it will have been generated wholly separately from Earth and will be the first truly alien life we’ve ever found! It may also give us clues as to why Martian life never made the leap into multicellular forms, which is one of the greatest mysteries surrounding the development of life on Earth.
Europa in 2022
Our solar system is lousy with moons, just lousy*, and it’s only been relatively recently that we’ve thought to poke at them for signs of life. Hence the 2022(ish) launch of the Europa Clipper!
*Actually, half the planets in our system have fewer moons than they probably should. Weird!
Saturn’s moon Titan usually gets top billing for being the only moon in the solar system with its own weather, but recent examinations of Jupiter’s moons have revealed not one but several moons that may harbor warm liquid ocean environments underneath their icy, radiation-reflective shells. Of these, Europa is the most likely candidate to harbor life. Not only have we confirmed the existence of oceans under Europa’s icy surface, but the moon contains more water than there is in Earth’s oceans.
The Europa Clipper satellite, although not designed to scan the moon for life, is now being refocused on doing so indirectly by flying through the periodic ejections of internal seawater that occur on Europa’s surface and studying it for microbial life.
That might not be all that we find. Plumes of water vapor powerful enough to crack through Europa’s surface could carry a lot of organic material, from microbes to plant leavings to eggs to material from the decayed bodies of deceased animal life. That’s right. The Europa Clipper could catch space fish.
Alien Civilizations in the 2020s
This project is my absolute favorite. It’s so simple and so clever!
In 2018 the James Webb Space Telescope will be launched into orbit and once it begins looking at the hundreds of exoplanets that we’ve already found then discovering the presence of complex alien life on distant worlds will stop being a question of if and become a question of when.
And it all comes down to the gas that life leaves behind.
The James Webb Telescope will be able to conduct “transit spectroscopy,” which will read the starlight filtering through the atmospheres of exoplanets as they transit (cross in front of) their parent star. Stars are overwhelmingly bright—so bright that you can’t see tiny planets that transit in front of them—but we’ve gotten very practiced at this in the last 30 years, to the point where we can scan the starlight that passes through the air of super-Earths, which are more massive than our own planet but significantly less so than gaseous worlds such as Uranus and Neptune.
For the first time we will be able to see the emission spectrum i.e. colors of the atmosphere of an alien world, and that is very important. Why? Let’s refresh on some simple science:
A color is basically a wavelength of light. The longer the wavelength, the more red the color, the shorter the wavelength, the more blue it is. This wavelength is also a measure of energy. A short wavelength is a more energetic photon than a long wavelength.
This energy/wavelength futzes with the electrons of other particles. And if you recall, a particle with electrons is also known as an element, i.e. the kind you find on the periodic table. This exact process is complicated, but what it means is: You can tell what elements are present in a light source by the emission spectrum/colors of the light. This is how we know what the sun is made of. This is what’s known as “spectroscopy,” and it is rad.
Soon we will be able to determine the color of exoplanet atmospheres, which means we’ll be able to determine their elemental make-up. Does the emission spectrum match of Kepler-423-b consist mostly of hydrogen? Phooey. No life there. Does the emission spectrum of Pictoris-b match iron? Wow, no life and no atmosphere! Does the emission spectrum of EPIC-201505350-c match oxygen? YES! Wait, how much? 35%? That’s a lot. There’s life on this world alright, but it probably all consists of plants that undergo photosynthesis, along with insects and ocean creatures. There’s no large or ubiquitous presence of carbon-based life there to exhale carbon dioxide, and maybe not enough tectonic activity to release CO2 and methane, either. Unless the trees are intelligent beyond our understanding of trees, there’s no one there to contact. (Except maybe the Na’vi. But ugh, so boring.)
Our search won’t end there, however. One of the dubious silver linings of our current global warming trend is that it has given us mountains and mountains of hard data on how industrial processes affect large systems like the Earth’s atmosphere. Humanity knows more about the chemical make-up of the air it breathes than it ever has, and one of the benefits of this is that we can use that information to not only find civilized life elsewhere in the universe, but to determine what stage of civilization that life is in.
Finding an exoplanet atmosphere that matches Earth’s can mean a lot. It means for sure that intelligent complex life has developed on that planet, but that doesn’t mean civilization has developed along with it. Life existed on Earth for hundreds of millions of years before a civilization grew out of it, and until we find evidence otherwise, we have to assume that it takes at least this long elsewhere.
The only way we can know for sure that an exoplanet’s intelligent life has developed into a civilization is by measuring the pollutants present in their atmosphere. Coal and gas power produce quite a lot of gas after being processed, regardless of how purified the exhaust is, and only half a century of regular use is enough to be detectable on a global scale. Even if a civilization shifts to non-polluting sources of energy early in their development, they’ll most likely need to use burnable energy sources for a generation or two in order to develop the communication systems, transit mechanisms, and technologies necessary to make renewable energy development possible.
And that’s just thinking about the tech that would be in play. Carbon-based life itself shifts the make-up of an atmosphere to even greater extent through expulsion of waste gases and decay. This process is slow, taking millions and millions of years, but in the end it can be the greater indicator of civilized life. Regardless of how it happens, one thing is certain: the atmosphere of a life-friendly planet looks different than the atmosphere of a life-friendly planet undergoing an Industrial Revolution.
And in the end, that’s how we’ll know we’re not alone. Because some alien civilization somewhere out there has been workin’ on their railroad, all the livelong day.
Chris Lough wants to know when that alien civilization spotted Earth. They’re probably only 100 light years away if they have!
