New Podcast: Humanity’s 3 Hopes For Alien Life
There are three very different ways humanity is searching for alien life beyond Earth. We can directly search the various planets and moons in our Solar System for past or present biological signatures simply by sending decontaminated probes, and looking for the evidence in situ. We can indirectly look at distant worlds around other stars, searching for the characteristic changes to the atmosphere and surface that life would bring. And, most optimistically, we can search for intelligent signatures created, perhaps willfully, by a technologically advanced alien species. These are our three hopes for finding alien life, and we’re actively pursuing all three.
Here’s how the different searches work, along with some speculation about what we’re likely to find, and what motivates us to look!
Aliens In The Multiverse? Here’s Why Dark Energy Doesn’t Tell You Anything
“It’s important to recognize that there are a wide variety of possible values that dark energy could have, including significantly larger values, that would still lead to a Universe very much like our own. Until we understand where these values come from, and what makes one set of values more likely than another, it’s grossly unfair to claim that we won the cosmic lottery in having a Universe with the values ours possesses. Unless you know the rules that govern the game you’re playing, you have no idea how likely or unlikely the one result you see actually was.”
There are a series of interesting results that have just emerged from the EAGLE collaboration, which has been simulating the Universe to learn what types of stars and galaxies form within it. They varied the value of dark energy in it tremendously, and found that even if you increased the amount by five, ten, or fifty times as much, you’d still form plenty of stars and galaxies: enough to give you chances at life like we have here. This surprised them, since they assumed the value of dark energy we have is finely-tuned to allow life. But it appears that things may not be as finely-tuned as we had thought! The simulation results are interesting, but this doesn’t really tell you anything about aliens in the Multiverse, since we have no idea what causes dark energy to have the values that it does.
Until we know the rules that govern this, we can’t really say what dark energy tells us about aliens in Universes other than our own. Here’s why.
Humanity’s 3 Hopes For Finding Alien Life
“Although it’s just conjecture at this point, scientists speculate that life in the Universe is probably common, with the ingredients and opportunities for it to arise appearing practically everywhere. Life that thrives and sustains itself on a world, to the point where it can change its atmospheric and/or surface properties, may need to get lucky, and is likely more uncommon. Evolving to become complex, differentiated, multicellular creatures is likely even rarer. And as far as becoming what we would consider an intelligent, technologically advanced civilization, it could be so exceedingly remarkable that in all the Universe, it might just be us. Yet despite how different these outcomes are, we’re actively searching for all three types of life in very different ways. When the first sign of alien life finally is discovered, which one shall emerge victorious?
No matter which method pays dividends first, it will be among the greatest day in the history of life on Earth.”
There are three very different ways humanity is searching for alien life beyond Earth. We can directly search the various planets and moons in our Solar System for past or present biological signatures simply by sending decontaminated probes, and looking for the evidence in situ. We can indirectly look at distant worlds around other stars, searching for the characteristic changes to the atmosphere and surface that life would bring. And, most optimistically, we can search for intelligent signatures created, perhaps willfully, by a technologically advanced alien species.
These are our three hopes for finding alien life, and we’re actively pursuing all three. Which one, if any, do you think has the best chance of paying off?
Ask Ethan: How Close Could Two Alien Civilizations Get To One Another?
“What’s [the] closest two, independent intelligent civilizations could be, ignoring interstellar travel and assuming they develop in different star systems and follow roughly what we know as ‘life’? Globular clusters can have a high density of stars, but does too high a density rule out habitability? An astrophysicist in a dense cluster would have a much different view of the universe and the search for exoplanets.”
Okay, so you have a planet that has the right ingredients for life, and everything has worked out according to your wildest dreams. We’ve developed life, it’s thrived for billions of years, and now we’ve reached the point where we’ve got an intelligent, technologically advanced civilization, just like we do here on Earth. Let’s imagine we’ve got multiples, now, throughout the Universe. What’s the closest two independent ones could possibly be? Should we look in the same solar system? In a globular cluster? In the galactic center? In a spiral arm? In an open star cluster? Or should we just wait for another one to pass close by in interstellar space?
The science is open to all of these possibilities, but some of them are strongly disfavored based on the evidence we have. Come find out how close two alien civilizations could get to one another on this edition of Ask Ethan!
The Drake Equation Is Broken; Here’s How To Fix It
“Knowing how many worlds there are out there in the Milky Way with life on them, and finding even one, would have tremendous implications for our existence, and for understanding our place in the Universe. Taking even the next step, and learning that there were complex, differentiated, large organisms on a world, like we have with the fungal, animal, and plant kingdoms on Earth, would revolutionize what’s possible. And finally, the chance we’d have to have communication, visitation, and a knowledge exchange with a scientifically or technologically advanced alien species would forever alter the course of humanity. It’s all possible, but there’s so much more we need to know if we ever want to find out. We must take these steps; the rewards are too great if there’s even a chance of learning these answers.”
Put forth in 1961, the Drake equation was a brilliant step towards estimating the number of intelligent, technologically-advanced civilizations out there. But it was full of flaws: huge unknowns, assumed incorrect priors like the Steady-State model of the Universe, and thought only of its application to radio contact between worlds. Here in 2018, we’ve surveyed huge sections of the Milky Way, understand stars and extra-solar planets as never before, and have only a few major unknowns about life in the Universe left. All told, there are likely some 100 billion planets that could develop life on them, and only three big uncertain steps remain: the development of life from non-life, the evolution of life into complex, differentiated organisms, and the development into a technologically and scientifically advanced civilization.
Based on what we know and what we hope to find, we can do better than Drake ever did. Here’s where we are, and what’s left to learn.
Do Earth-Sized Planets Around Other Stars Have Atmospheres? James Webb Will Find Out!
“Even so, because of its ability to measure light to high sensitivity far into the infrared, there’s a remarkable hope for determining whether these worlds have atmosphere regardless of any other measurements. As planets orbit their star, we see different phases: a full phase when it’s on the far side of the star; a new phase when it’s on the near side, and everything in between. Based on the temperature of the world at night, we’ll receive different amounts of infrared light from the "dark” side that faces away from the Sun. Even without a transit, James Webb should be able to measure this.“
The overwhelming majority of Earth-sized, potentially habitable planets that Kepler found are in orbit around red dwarf stars. In many ways, this is great: red dwarf stars are stable, temperature-wise, for longer than our Sun. Their planets are easier to detect, and they will be the first Earth-sized ones we can measure the atmospheres of directly. But even if we can’t make those measurements with James Webb, we’ll be able to learn whether they have atmospheres or not via a different method: by measuring the infrared radiation coming from the planets themselves in various phases. Just as we can measure the presence of Venus’ atmosphere from the hot, infrared radiation emanating from it even on the night side, we can make those same measurements with James Webb of other Solar Systems. By time the early 2020s roll around, we’ll have our first answers to this longstanding debate.
Many scientists think that Earth-sized planets around M-class stars will have no atmospheres left; others think there’s a chance they survive. Here’s how James Webb will find out!
Are Human Beings The Only Technologically Advanced Civilization In The Universe?
“There may never have been another intelligent, technologically advanced alien species in the entire history of the Universe. When you take into account that there may be 400 billion stars in the Milky Way, up to three potentially habitable worlds in many of these star systems, and some two trillion galaxies in the entire Universe, it seems like intelligent life is an inevitability. But our intuition can often lead us astray; what we feel is no substitute for science. The magnitude of the unknowns that abiogenesis, evolution, long-term habitability and other factors bring into the equation throws many of our assumptions about life into doubt. It’s true that there are an astronomical number of possibilities for intelligent, technologically advanced lifeforms, but the huge uncertainties make it a very real possibility that humans are the only spacefaring aliens our Universe has ever known.”
Given the huge number of stars, planets, and chances at life that the galaxy and the Universe has given us, it seems paradoxical that we haven’t yet encountered any form of alien intelligence or even life. The discoveries make in the field of exoplanet studies, particularly by the Kepler mission, make this an even bigger problem than we anticipated: more than 10^22 planets with Earth-like conditions are expected to exist in our Universe. But having so many chances, even with an astronomically large number like that, doesn’t necessarily mean we aren’t alone. The origin of life, the sustainability and development of complex, intelligent life, and the odds of technological success and ambition of a species that makes it are complete unknowns. We might enjoy thinking about these questions and exploring the Universe to hunt for answers, but the fact is that we don’t know.
Until we find out, it’s worth looking at all that’s possible, but we have to remain grounded. The truth may be out there, but we don’t have the solution yet.
Five reasons why the signals from Stephen Hawking’s Breakthrough Initiative aren’t aliens
“In 2012, a series of nine bursts were observed by both the Very Large Array and Arecibo, four of which were seen simultaneously. For the first time, this allowed us to pinpoint the location of a FRB’s source: a dwarf galaxy 3 billion light years away. Last month’s reinvestigation discovered a series of 15 repeating FRBs from the same source, each lasting under 300 microseconds. Is it advanced, powerful aliens? There are five reasons why that’s likely untrue.”
Whenever we detect a signal that we can’t immediately explain, it’s a very human trait to ascribe our greatest hopes (or fears) to it. In the case of a peculiar radio signal originating from deep space, that means the wildest speculations will involve intelligent aliens. But as much as many of us would hope that such a thing would be true, the physical properties of these fast radio bursts, even though they’re repeating, tell us otherwise. With an estimated 10,000 of them occurring on a daily basis, and with power some 10^19 times as great as the strongest radio signal ever generated by humanity, and with known astrophysical sources that can naturally generate signals of this magnitude and frequency, it’s completely unreasonable to think this has anything to do with aliens. Still, the science alone is interesting enough to warrant not only investigation, but a remarkable sense of wonder.
Here are the five top reasons why we can be very certain that the signals from Stephen Hawking’s Breakthrough Initiative aren’t aliens!
Afraid Of Aliens? The Science Doesn’t Back You Up
“The possible benefits to humanity of making contact are immeasurable. It would be like receiving a great galactic teacher, advanced thousands of years beyond our own scientific and technological capabilities. It would be the ultimate cultural exchange ever experienced on Earth. But the fears we have, that consume us, that lead to us eschewing the greatest cosmic achievement humanity’s ever dreamed of? They’re simply not based in science, logic, or reason. Thankfully, our fears don’t have to control our destinies. We can choose to use our minds instead.”
One of the questions that’s fascinated humanity since we first began looking up at the night sky is whether or not we’re alone in the Universe. Although we now know of other stars, other planets, and potentially inhabited worlds, we have yet to make contact with another intelligent species. Despite our curiosity, a great many people live in fear that if we did begin communicating with extraterrestrials, it would serve only to announce our presence to a potentially hostile (and more advanced) civilization. No one wants humanity wiped out, of course, but no one wants to bury our heads in the sand and to cease the search for one of the ultimate truths about our Universe. If you take a detailed, logical look at the problem, three possibilities for aliens emerge: they’re uninterested in us, they’re interested and benign, or they’re interested and malevolent. But even if they’re malevolent, they likely pose no danger to us, which you only learn if you put your fears aside and view the situation rationally.
There’s so much to potentially gain and so little to use, yet some of our greatest minds succumb to fear on this topic. Come take a look for yourself and see what you think!