In the past three decades, scientists have found more than 4,000 exoplanets. And the discoveries will keep rolling in; observations suggest that every star in the Milky Way galaxy hosts more than one planet on average.
Given a convergence of ground- and space-based capability, artificial intelligence/machine learning research and other tools, are we on the verge of identifying what is universally possible for life — or perhaps even confirming the existence of extraterrestrial intelligence?
Is 2020 the celestial payoff year, in which objects of interest are found to offer "technosignatures," indicators of technology developed by advanced civilizations?
Related: 13 Ways to Hunt Intelligent Aliens
Space.com asked top SETI (search for extraterrestrial intelligence) experts about what next year may signal regarding detecting other starfolk.
"Well, despite being the widely celebrated 100-year anniversary of the election of Warren G. Harding, 2020 will not likely gain fame as the year we first discover extraterrestrial life," said Seth Shostak, a senior astronomer at the SETI Institute in Mountain View, California.
The search for intelligent beings elsewhere, Shostak said, is largely conducted by checking out nearby star systems for either narrow-band radio signals or brief flashes of laser light. And those might succeed at any time, he told Space.com.
"But one should remember that this type of search is gaining speed in an exponential fashion, and that particular technical fact allows a crude estimate of when SETI might pay off. If we take — for lack of a better estimate — Frank Drake's opinion that there might be 10,000 broadcasting societies in the Milky Way, then we clearly have to examine at least one [million] – 10 million stellar systems to have a reasonable chance of tripping across one. That goal will be reached in the next two decades, but certainly not in 2020," Shostak said.
But there are still reasons for intelligent-alien hunters to be excited and optimistic about the coming year. Multiple existing projects will either be expanded or improved in 2020, Shostak said. For example, the SETI Institute will get new receivers for the Allen Telescope Array in northern California, and both the SETI Institute and the University of California, Berkeley, will conduct new searches for possible laser technosignatures.
"And, of course, there's always the unexpected," Shostak said. "In 1996, the biggest science story of the year was the claim that fossilized Martian microbes had been found in a meteorite. No one really saw that coming. So one can always hope to be taken by surprise."
Related: 5 Bold Claims of Alien Life
"I am skeptical about picking a specific year for the first discovery. Previous predictions of success have been wrong," said Michael Michaud, author of the thought-provoking book "Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials" (Copernicus, 2007).
"I and others have observed that the continued improvement of our search technologies and strategies could boost the odds for success," Michaud said, noting that the primary focus of SETI remains on radio signals. "However, we still don't cover all frequencies, all skies, all of the time. Other types of searches have failed, too, such as looking for laser signals or Dyson spheres [ET mega-engineering projects]. Those campaigns usually have limited funding and often don't last long."
A new possibility has arisen because of exoplanet discoveries, Michaud said: "In some cases, astronomers now can look for chemical evidence of life in planetary atmospheres. It is conceivable that we will find simple forms of life before we find signals from a technological civilization."
If astronomers do someday confirm a SETI detection, how should they announce the discovery? It is an old question that has been answered in several ways.
"The prevailing opinion among radio astronomers has been that the news will leak quickly. If that is correct, scientific and governmental authorities won't have much time for developing a public-affairs strategy," Michaud said.
"It remains possible that the sophisticated monitoring capabilities of intelligence agencies might be the first to detect hard evidence," Michaud said. "One might think that the government would have a plan to deal with such an event."
But, Michaud said that his own experience suggests that such plans are unlikely to be drawn up due to a "giggle factor" and would be forgotten as officials rotated out of their positions. He previously represented the U.S. Department of State in interagency discussions of national space policy.
"While I'm enthusiastic at the reinvigoration of technological-signatures work, and in particular the growth in looking across much of the electromagnetic spectrum, I think this is going to be a long-term project. I estimate a very small probability of success in any given year," said Pete Worden, executive director of the Breakthrough Initiatives. "But those chances are now orders of magnitude better than they were even a decade ago."
Breakthrough Initiatives is tackling the big question of life in the universe, the notable query about whether or not Earthkind is alone. Breakthrough Initiatives is a multifaceted group that's reinvigorating the search for extraterrestrial intelligence.
"The Breakthrough Initiatives is committed to full and immediate disclosure of any and all results," Worden said. "We would rely on the principal investigators of our projects, along with their home institutions, to prepare and release both scientific reports and public announcements."
Preparing for discovery
Despite the ongoing work by Breakthrough Listen, NASA's Transiting Exoplanet Survey Satellite (TESS) and research into the detection of promising biosignatures and technosignatures, there's no reason to think 2020 would be the year for discovery, said Steven Dick, a recognized astrobiology scholar and writer of the award-winning book "Astrobiology, Discovery, and Societal Impact" (Cambridge University Press, 2018).
"In my view, all these things combine to increase the chances over the next decade of finding extraterrestrial intelligence. I would caution, though, that any discovery will be an extended process, consisting of detection and interpretation before any understanding is achieved," Dick said. "This is clear from the history of discovery, even when we thought we had evidence in hand."
Like Shostak, he cited the Mars meteorite ALH 84001, which in 1996 generated excitement and debate that ancient, microscopic life existed on the Red Planet.
"One thing that is certain is that we are getting a better handle on the issues of societal impact, should such a discovery be made. Many more social sciences and humanities people are getting involved in astrobiology, which is all to the good. In other words, we are preparing for discovery," Dick said. "So, I see the search advancing incrementally next year, but with an accelerating possibility that life will be discovered in the near future."
Three-way horse race
"There's plenty of real estate where life could exist," said Douglas Vakoch, president of the nonprofit Messaging Extraterrestrial Intelligence (METI) in San Francisco.
"We are right now on the verge of finding out whether there is life elsewhere in the universe, and there are three ways we could find it. Think of it as a three-way horse race to find ET," Vakoch said.
But will any of the horses cross the finish line in 2020?
It all depends on the prevalence of life beyond Earth, Vakoch said, and the number of targets we can scan with available technologies — whether these instruments are located in Earth-based observatories, in space-based telescopes or in craft that travel to other planets and moons in our solar system, Vakoch told Space.com.
So, will scientists find intelligent alien life next year?
"It all depends on how plentiful intelligent extraterrestrials are. If one in 10,00 star systems is home to an advanced civilization trying to make contact, then we're behind schedule in making first contact, and the news we're not alone in the universe could well come in 2020," Vakoch said.
And there are expectations for microbial life, similar to Earth's bacteria, to be even more widely spread throughout space than intelligent life.
But bacteria can't send us radio signals. "We need to develop new technologies to discover them at a distance," Vakoch said. "As the next generation of space telescopes is launched, we will increase our chances of detecting signs of life through changes to the atmospheres of planets that orbit other stars, giving us millions of targets in our search for even simple life in the cosmos."
By the end of 2020, we'll be within a few months of the much-awaited launch of NASA's James Webb Space Telescope, Vakoch said, which will be able to study the atmospheres of exoplanets for potential signs of life. But it could take much longer, until after the launch of the European Space Agency's Atmospheric Remote-sensing Infrared Exoplanet Large-survey, or ARIEL, in 2028, before we have "definitive proof" of extraterrestrial microbes through telltale alterations in the atmospheres of exoplanets, Vakoch said.
Living with uncertainty
There are a number of spacecraft in the proposal stage that could conceivably detect extraterrestrial life within our solar system, "but don't hold your breath for discovery by 2020," Vakoch said. "But if we do someday find even microbial life elsewhere in our solar system that has an independent origin from terrestrial life, then we would know that the entire universe is chock-full of life."
Humans cannot control whether or not there is life elsewhere in the universe, of course.
"Either it's there or it's not," Vakoch said. "We may not be able to decide whether we'll find it in 2020, but we have a tremendous capacity to decide whether we will find it eventually, if it's out there to be discovered."
"To be human is to live with uncertainty," Vakoch concluded. "If we demand guarantees before we begin searching, then we are guaranteed to find nothing. But if we are willing to commit to the search in the coming year and long afterwards, even without knowing we will succeed, then we are sure to discover that there is at least one civilization in the universe that has the passion and the determination to understand its place in the cosmos — and that civilization is us."
- Greetings, Earthlings! 8 Ways Aliens Could Contact Us
- Electronic E.T.: Intelligent Aliens Are Likely Machines
- SETI: All About the Search for Extraterrestrial Intelligence (Infographic)
Leonard David is author of the recently released book, "Moon Rush: The New Space Race" published by National Geographic in May 2019. A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us on Twitter @Spacedotcom or Facebook.
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If we do, we had better be careful who we let contact them. The parlous state of intelligence on this planet at the moment, is a cause of concern.Reply
Currently, the JWST has the best outlook for utilising the onboard spectrometer to find those elements indicating the presence of possible life.Reply
JWST, with its powerful infrared-detection capabilities, is able to see through dense dust with more clarity and detail than any telescope that has come before. That's because infrared wavelengths of light don't scatter off dust particles the way shorter wavelengths do, which means instruments like JWST can effectively see through dust far better than optical instruments like Hubble's.
In a molecular cloud called Chamaeleon I, located some 500 light-years from Earth, data from the JWST has revealed the presence of frozen carbon, hydrogen, oxygen, nitrogen, and sulfur – elements vital to the formation of atmospheres and molecules such as amino acids, collectively known as CHONS*.
"These elements are important components of prebiotic molecules such as simple amino acids – and thus ingredients of life, so to speak," says astronomer Maria Drozdovskaya of the University of Bern in Germany.
In addition, an international team of researchers led by astronomer Melissa McClure of Leiden University in the Netherlands has also identified frozen forms of more complex molecules, such as water, methane, ammonia, carbonyl sulfide, and the organic molecule methanol.
Cold, dense clumps in molecular clouds are where stars and their planets are born. Scientists believe that CHONS and other molecules were present in the molecular cloud that birthed the Sun, some of which were later delivered to Earth via icy comet and asteroid impacts, the same impacts which brought the Earth water.
Although the elements and molecules detected in Chamaeleon I are quietly floating about right now, one day, they could be caught up in planet formation, delivering the ingredients necessary for the emergence of life to new baby planets.
"Our identification of complex organic molecules, like methanol and potentially ethanol, also suggests that the many star and planet systems developing in this particular cloud will inherit molecules in a fairly advanced chemical state," explains astronomer Will Rocha of Leiden Observatory.
"This could mean that the presence of prebiotic molecules in planetary systems is a common result of star formation rather than a unique feature of our own Solar System."
Chamaeleon I is cold and dense, a dark conglomeration of dust and ice that constitutes one of the nearest active star-forming regions to Earth. A census of its composition, therefore, can tell us quite a bit about the ingredients that go into star and planet formation and contribute to an understanding of how these ingredients are incorporated into newly forming worlds.
To determine the chemical composition of the dust in Chamaeleon I, scientists rely on absorption signatures. Starlight traveling through the cloud can be absorbed by elements and molecules therein. Different chemicals absorb different wavelengths. When the spectrum of the light that emerges is collected, these absorbed wavelengths are darker. Scientists can then analyze these absorption lines to determine which elements are present.
JWST peered deeper into Chamaeleon I for a census of its composition than we've ever seen before. It found silicate dust grains, the aforementioned CHONS and other molecules, and ices colder than any measured before in space, at around -263 degrees Celsius (-441 degrees Fahrenheit).
And they found that, for the density of the cloud, the amount of CHONS was lower than expected, including only around 1 percent of the expected sulfur. This suggests that the rest of the materials may be locked up in places that can't be measured – inside rocks and other minerals, for instance.
Without more information, it's difficult to gauge at this point, so more information is what the team intends to get. They hope to obtain more observations that will help them map out the evolution of these ices, from coating the dusty grains of a molecular cloud to their incorporation into comets and perhaps even to seeding planets.
"This is just the first of what we will obtain to see how the ices evolve from their initial synthesis to the comet-forming regions of protoplanetary discs," McClure says.
"This will tell us which mixture of ices – and therefore which elements – can eventually be delivered to the surfaces of terrestrial exoplanets or incorporated into the atmospheres of giant gas or ice planets."
The research has been published in Nature Astronomy.
* CHONS - is a mnemonic acronym for the four most common elements in living organisms: carbon, hydrogen, oxygen, and nitrogen .
While the acronym CHNOPS, which stands for c arbon, h ydrogen, n itrogen, o xygen, p hosphorus, s ulfur, represents the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.
The chemical elements most prominent in building the structures of the molecules of life are carbon, hydrogen, oxygen, nitrogen, phosphorous and sulfur, sometimes represented mnemonically as CHONPS. These elements combine in a vast number of molecules involved in life processes. Their fitness for making these compounds is related to their relative electronegativities which contribute to their ease of combination.
Although present in relatively small amounts, metal atoms also play a surprisingly important role in the chemistry of life. About a third of the enzymes in the body involve a metal ion as an essential participant. From the electron transport chain to the maintaining of membrane potentials of cells, metals play essential supporting roles for the atoms involved in the major structures of life.
Nucleic acids, the building blocks of life as we know it, are made of carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHON P). They are key components of DNA and RNA, wich carry the genetic information of cells. Nucleotides, the building blocks of nucleic acids, are composed of a pentose sugar, a nitrogenous base, and a phosphate group. Proteins, carbohydrates, and lipids are all made of the same elements: carbon, hydrogen, and oxygen. The difference between them is in the arrangement of those atoms. Proteins have a nitrogen atom in addition to the CHON elements, while carbohydrates and lipids do not. Nucleic acids such as DNA and RNA contain phosphorus in addition to the CHON elements. With JWST finding these elements the hunt for the telltale signs of life is on.