A new study has found an intriguing new method to find candidate planets that could be harboring fusion-capable alien lifeforms.
Artist’s impression of an Earth-like planet from space.
Anew study published in the journal Astrophysical has outlined a novel method that could be used to detect advanced alien civilizations remotely. The premise is to look for signs of nuclear fusion on distant planets.
The secret behind the new technique is something called a planet’s deuterium-to-hydrogen (D-T) ratio. This ratio on Earth is about ten times higher than can be detected in the Milky Way’s interstellar medium.
Moreover, it is also known that rocky planets tend to have higher D-H ratios than this medium. So, the researchers postulate that if a distant planet’s D-H ratio is lower than the interstellar medium’s “baseline,” it could indicate something fishy going on.
This is further reinforced by the fact that no known natural process would reduce the D-H ratio on an exoplanet. This presents an intriguing possibility for finding potential candidate planets that harbor advanced alien life.
What’s all this about deuterium?
Deuterium is a naturally occurring isotope of hydrogen present across the known universe. It is very stable, meaning it has a long lifespan. Deuterium contains one neutron and one proton, unlike regular hydrogen, which only has a proton.
This extra neutron makes deuterium heavier than regular hydrogen, making it easily distinguishable when analyzing atoms from afar. It also happens to be a promising fuel for nuclear fusion.
Given its larger mass and higher relative reactivity, deuterium could, at least in theory, make nuclear fusion more plausible if appropriately harnessed. If used as the primary fuel for a nuclear fusion reactor, deuterium should enable the release of more significant amounts of energy when compared to “regular” hydrogen.
For reference, the lion’s share of energy released from our sun comes from the fusion of hydrogen atoms in its core. On Earth, the idea is that this process could be replicated by fusing deuterium with another isotope of hydrogen called tritium.
Tritium has an even larger isotope, consisting of one proton and two neutrons in its atomic nucleus. When deuterium and tritium are combined, they release around 17.6 megaelectron volts (MeV) of energy per fusion reaction.
That works to be around 2.8 watts-per-second (or 2.8 joules) per atomic fusion event. In other words, the process has a relatively very high energy yield. Even a slightly more advanced alien civilization, the paper proposes, could have mastered nuclear fusion, which would alter a planet’s chemical nature.
A potential smoking gun?
The researchers propose that should an alien civilization master nuclear fusion, they would be looking for potential naturally occurring sources of deuterium (and tritium) as a raw material. To this end, it would be likely that if a planet harboring alien life had oceans, it follows that deuterium could be harvested from them.
Tritium would be a giveaway if detected, as this doesn’t occur naturally and generally needs to be synthesized. However, with only a 12-year half-life, detecting it in large quantities would be challenging.
But if an advanced civilization could achieve deuterium-to-deuterium nuclear fusion, this would provide abundant energy for their needs, from daily life to powering advanced technologies.
The researchers propose this could catalyze the astronomy community to develop new spectrometers to analyze the atmospheres and oceans of Earth-like planets.
Even if their proposals don’t yield signs of advanced alien civilizations, it will be interesting to understand the history of water on those planets.
