What would happen if we found out that we are not alone in the universe? Or, on the flip side, what would happen if we decided that we really were alone? Experts provided updated answers to those age-old questions, from a scientific as well as a religious angle, during a Sunday session at the American Association for the Advancement of Science's annual meeting. But one of the most intriguing questions had more of a personal spin: What would you ask E.T. if you had the chance?

First, here's some background:

Questions surrounding the possibility of life beyond Earth might get more serious sometime in the next quarter-century or so. Wesley Traub, chief scientist for NASA's Exoplanet Exploration Program, predicted that by 2030, five Earth-scale planets would be identified among the 100 closest star systems as worthy of being studied for signs of life. He based that prediction on the most recent lineup of candidates from NASA's planet-hunting Kepler probe.

"About a third of all planets are planets that could have life on them," he said — that is, Earth-size worlds or super-Earths.

Looking for alien life
What would scientists look for when it comes to life detection? Traub speculated that future spacecraft could analyze the atmospheres of alien worlds for signs of high oxygen levels and water vapor. Spectral analysis of the light reflected by those planets might even turn up the chemical signature of chlorophyll or other chemicals indicative of life. But it'd be almost impossible to tell whether the alien organisms are one-celled creatures, six-legged dinosaurs or intelligent species. If they're smart enough to communicate with us, the only way we'd know is through well-known means such as radio signals or laser bursts (or maybe orchestrated blasts from a stellar beacon).

Seth Shostak, senior astronomer at the SETI Institute, has said that evidence of alien life — either through such direct contact or through long-distance chemical analysis — could become available in a time frame ranging from 2025 to 2035. And he bet his listeners at Sunday's talk that he'd buy them a cup of coffee if E.T. wasn't found in their lifetime. (Will that bet ever pay off? Think about it: You can't take your Starbucks with you.)

So what would society do if life is detected? At Sunday's talk, science historian Owen Gingerich said the first scientific claims for E.T.'s existence would likely be hotly contested, just as the Mars meteorite microfossils have been for the past 15 years. Even if the findings are confirmed, it would take years for the implications to sink in.

Most of the leaders of the world's religions say extraterrestrial life wouldn't shake their faith. But 16th-century theologian Giordano Bruno was burned at the stake after saying so, and even today some believers say E.T.'s existence would make a "mockery" of Christianity. Like it or not, religious institutions and other pillars of society would have to accept (or deny) a paradigm shift at least as big as the shifts sparked by astronomy and biology. 

Misanthropic principle
What if life is not detected? It's pretty hard to prove a negative, but suppose future probes analyze the atmospheres of scores of Earth-size planets ... and find nothing worthy of note. Suppose the search for extraterrestrial intelligence continues for a century ... and no messages are received. Howard Smith, a senior astrophysicist at the Harvard-Smithsonian Center for Astrophysics, said the evidence already suggests that intelligent life is extremely rare in the universe, and we're the only sentient beings within a 1,250-light-year radius. (Smith chose that figure because it's about as far as humans could possibly travel during a 100-generation round trip at the speed of light.)

"We are probably alone and will have to solve our own problems," he said at Sunday's talk.

Smith calls this the "misanthropic principle." That term plays off the widely cited anthropic principle — the idea that Earth appears to be so suited for life as we know it not necessarily because God made it that way, but simply because we wouldn't be around to see it if it wasn't.

The way Smith sees it, the misanthropic principle is a good thing. The view that we alone are responsible for our zone of the cosmos should make us feel "blessed," and more careful about not spoiling the good thing we've got here.

"The misanthropic principle is joyous," Smith said. "We should rejoice in our good fortune."

Is it depressing or liberating to think that we're truly the best the universe has to offer, at least in this celestial neck of the woods? Feel free to add your comments below.

Oh, and about the question we started out with: What would you ask E.T. if you had the chance? This came up during the question-and-answer session, and one of the suggestions was along the lines of "Dear E.T.: Do you have a religion?" (That led science writer David Despain to quip in a Twitter comment: "Hello, I'm a Jatravartid. Let me share with you the message of the Great Green Arkleseizure's white handkerchief.")

Personally speaking, I'd rather ask: "How did you do it? How did you survive long enough to get to this point of contact?" If E.T. responds by raising its ray gun, I'd probably have the answer I wasn't hoping to get.

But what would you ask? 

More about the search for aliens:

• How would alien life change your life? 
• What to do if we find alien life
• Calculate the odds of finding E.T.
• Hawking: Aliens may pose risks to Earth
• Still more about the search from msnbc.com

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about Alan Boyle's book on Pluto and the search for planets, check out the website for "The Case for Pluto." 

NASA

In 1977 NASA's Voyager 1 and 2 spacecraft launched into space carrying phonographs called the Golden Records containing pictures and sounds meant to show extraterrestrials a glimpse of life on Earth. The records were engraved with pictures explaining how to play them. Click on the picture for an explanation of the code.

When E.T. sends us Earthlings a message, what should we say in response? Three alien hunters suggest in the journal Space Policy that we should develop an international protocol for sending effective, intelligible communications. A website could be set up for people around the world to leave messages, following the protocol, so that we can then figure out what messages are best-suited for cross-cultural communication.

"An effective message to extraterrestrials should at least be understandable by humans," Dimitra Atri of the University of Kansas, Julia DeMarines of the International Space University, and Jacob Haqq-Misra of Penn State University write in their paper.

The concept of creating and testing such a protocol fits with the thinking of other space experts, according to Douglas Vakoch, director of interstellar message composition at the California-based SETI Institute.

Cornell

This graphic was transmitted in coded form in 1974, using the Arecibo radio telescope. Click on the picture for an explanation of the code.

The proposal from the three researchers "is on target in really wanting to encourage an open, transparent process for engaging the world community in thinking about how we would want to represent ourselves, and how we would create a message that stands a chance of being understood," Vakoch told me today.

Talking to E.T.
Unless E.T. comes to Earth in a spaceship and gets out for a meet-and-greet, the chances of a face-to-face encounter anytime soon are close to nil. Instead, cross-civilization communication will have to span vast distances, using technology such as radio waves and pulses of light.

Astronomers on the lookout for these types of communications have already established protocols for making sure a communication received isn't just a natural noise or interference from a satellite. They've also established first-order steps to decipher the message, such as determining the basic units of the information sent.

This same community of researchers has also spent the past 50 years chewing on the question of what to say to E.T. The trick, noted Vakoch, is finding something that is universal.

"Some have focused on pictures, with the idea that vision has been very helpful here on Earth and so too might be helpful on another world," Vakoch said. "You might expect intelligent creatures on another world to be visual creatures as well."

But what may be a meaningful picture to a person from a Western culture may be gibberish to the indigenous Maori people in New Zealand, for example.

"Similarly, a Westerner may look at some ceremonial carving from the Maori and say, 'You know, that's a beautiful geometrical shape,' but a Westerner may miss the fact that there's a human body being depicted in that message," Vakoch said.

Another idea is to use basic math and science. After all, if alien beings are able to communicate with us, they must have the engineering and technical know-how required to send messages across interstellar distances.

"I think the key to creating a message that has a reasonable chance of being understood is to send as many distinct messages as you can, with the hope that at least one of them might be understood," Vakoch said. "Anyone who claims they have one message that will undoubtedly be understood is overly optimistic."

Sharing ideas
The Space Policy paper calls for setting up a website where users around the world can submit messages that fit the protocol. This will allow the discovery of "the types of messages better suited for cross-cultural communication," the authors write.

The SETI Institute's Earth Speaks project is built along these lines, notes Vakoch. The website solicits suggestions for the most important things that people want E.T. to know about life on Earth at the beginning of the 21st century.

Vakoch said the idea proposed in the Space Policy paper is complementary and attracts another audience to mull the questions surrounding what to say to E.T. "We need more people involved in space policy to be thinking about these issues," he said.

More on the alien quest:

• E.T. calling? Here's what to do
• How should we 'talk' to aliens?
• What to do if we find alien life 
• Are we missing E.T.'s call?
• Calculate the odds of finding E.T.
• Stephen Hawking worries about the aliens
• Too risky to phone E.T.? Too late — NASA's tried
• Six frontiers for extraterrestrial life

Tip o' the Log to Lisa Grossman at Wired.com.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Henry Bortman / 2010

Astrobiology researcher Felisa Wolfe-Simon works with samples at California's Mono Lake.

The controversy over findings that suggest life can grow using arsenic entered a new phase today: The researchers behind the radical claim issued a statement responding to their critics — and said the comments and responses generated by their experiments would be reviewed and published in a future issue of the journal Science.

In their original study, published online by the journal Science on Dec. 2, the researchers suggested that salt-loving bacteria gathered from California's Mono Lake could be coaxed to substitute atoms of arsenic, which is toxic to life on Earth, in place of the usual phosphorus atoms in DNA and other parts of their cellular machinery.

Since that study was published, a number of microbiologists and chemists have questioned whether the experiments actually proved the researchers' point. The critics said inadequate care was taken in purifying DNA samples from the bacteria in the arsenic-rich medium, and that the arsenic found in the DNA was merely contamination. They said that the bacteria might have been using trace amounts of phosphorus left as impurities in the growth medium, and that arsenic bonds in the DNA could not have stood up to exposure to water.

For the past couple of weeks, members of the Mono Lake research team have declined to respond in detail to the criticisms, saying that they preferred to address questions through a peer-reviewed process. But today, team leaders Felisa Wolfe-Simon and Ron Oremland of the U.S. Geological Survey said they were providing additional information about the experiments "as a public service ... while more formal review of their responses to comments sent to Science continues."

In a preliminary Q&A, Wolfe-Simon and Oremland recapped the procedures they went through to purify arsenic-laden DNA and said they felt the critics' concerns about the procedures were not valid. They also said "it is conceivable" that DNA containing arsenic is more resilient to water exposure than previously thought, although they acknowledged that "more research is warranted" on this question.

They pointed out that the Mono Lake bacteria could not grow unless either arsenic or phosphorus was added to the medium. Such data "clearly demonstrate" that the trace amounts of phosphorus left in the medium were insufficient to support further growth, they said.

In their conclusion, the research team reflected on what they've gone through and what lies ahead:

"For all of us, our entire team, what this was like was unimaginable. We are a group of scientists that came together to tackle a really interesting problem. We each used our talents, from technical prowess to intellectual discussion, to objectively determine what exactly was happening in our experiments. We freely admitted in the paper and in the press that there was much, much more work to do by us and a whole host of other scientists. The press conference even included a technical expert, Dr. Steven Benner, who voiced some of the concerns we responded to above. Part of our reason for bringing this work to the community was to make the intellectual and technical connections for more collaborations to answer many of the lingering questions. We were transparent with our data and showed every datum and interesting result. Our paper’s conclusions are based on what we felt was the most parsimonious way to interpret a series of experiments where no single experiment would be able to answer the big question. 'Could a microbe use arsenic in place of phosphorus to sustain its growth?' The best science opens up new questions for us as a community and sparks the interest and imagination of the general public. As communicators and representative of science, we feel that support of new ideas with data is critical but also to generate new ideas for others to think about and bring their talents to bear on.

"We look forward to working with other scientists, either directly or by making the cells freely available and providing DNA samples to appropriate experts for their analyses, in an effort to provide more insight into this intriguing finding."

Science is making the original study as well as its news article about the research available for free online with registration. If you're interested in this issue, be sure to read today's full statement — and feel free to comment below.

Update for 11:55 p.m. ET: Rosie Redfield, a microbiologist at the University of British Columbia who was a prominent critic of the original "arsenic life" research, has posted her critique of the today's statement.

Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Did UFOs interfere with nuclear missile systems in the 1960s? Has the U.N. appointed an ambassador to the aliens? Due to a grand convergence, such questions have been generating fresh waves of headlines over the past few days — and that provides a ripe opportunity for a reality check.

The nuke-test angle was today's highlight, due to a much publicized news conference at the National Press Club in Washington. Eyewitness accounts about funny business at and around military bases have been circulating for years, and in fact are among the main themes of Leslie Kean's recently published book "UFOs: Generals, Pilots and Government Officials Go On the Record."

Several retired military men discussed their recollections of an incident that took place at Malmstrom Air Force Base in Montana in March 1967, relating to reported missile system malfunctions at two locations known as Echo Flight and Oscar Flight. The recollections were mostly secondhand: Robert Salas, Dwynne Arneson and Robert Jamieson, three retired military officers who played a part in the Malmstrom incident, said they were told that UFOs had been sighted around the time of the malfunctions. Salas said he was told that a "red, glowing object," about 30 feet in diameter, hovered just outside the silo facility when the weapon systems went offline.

You can hear the two men tell their stories in the video clip above, recorded by the NECN news network, or watch the full news conference here. "I've studied UFOs for over 60 years, believe it or not," Arneson said, "and I am convinced that somebody out there is trying to send us a message. If I knew who they were, I probably would not be here."

Another retired U.S. military officer, Charles Halt, discussed the well-known 1980 Bentwaters incident. Halt was deputy base commander at the Bentwaters air base in England when sentries reported seeing strange lights in the surrounding Rendlesham Forest. A few weeks later, there were renewed reports about the lights — and when he went out with a couple of policemen to take a look for himself, he saw a "bright glowing object like an eye" that exploded right in front of them.

"I have no idea what we saw that night, but I do know it was under intelligent control," Britain's Mail Online quoted Halt as saying. "My theory is that it was from another dimension or extraterrestrial."

UFO researcher Robert Hastings said the men at today's news conference were among more than 100 former or retired U.S. Air Force personnel who "have come forward and revealed ongoing UFO surveillance of, and occasional interference with, our nuclear weapons. ... The fact that the Pentagon and CIA have successfully kept the truth from public view for so long is in itself mind-boggling."

Actually, the tales have long served as grist for an inconclusive debate over the nature of unidentified flying objects. Skeptics have said the fact that Cold War weapons systems sometimes malfunctioned should not be surprising, and that it's too much of a stretch to link such malfunctions with lights that may have been seen in the sky. Over at the Reality Uncovered website, the debate over what was seen (or not seen) is raging anew in the wake of today's news briefing.

Our roundup of eight UFO cases that generate buzz includes the Malmstrom incident — and for the full background on the Rendelsham Forest sightings, you can check out this story as well as the declassified X-Files from Britain's National Archives. To get the flavor of the UFO debate in general, take a look at our recently published pair of commentaries by NBC News space analyst James Oberg and "UFOs" author Leslie Kean.

Ambassador to the aliens?
Could it be that U.N. officials know something we don't know? Over the weekend, Britain's Telegraph and other news outlets suggested that Malaysian astrophysicist Mazlan Othman may be campaigning for the role of official greeter in the event that aliens make contact. Othman, who set up Malaysia's space agency several years ago, now serves as head of the U.N. Office for Outer Space Affairs in Vienna.

She was quoted as telling scientists during a recent talk that the search for alien signals "sustains the hope that someday humankind will receive signals from extraterrestrials." If contact is made, "we should have in place a coordinated response that takes into account all the sensitivities related to the subject," she said. "The U.N. is a ready-made mechanism for such coordination."

The Telegraph reported that a plan to make Othman's office the coordinating body for alien encounters would be debated by U.N. scientific advisory committees and would eventually be considered by the U.N. General Assembly. It said Othman would lay out the role for the U.N. and herself at a Royal Society conference in Buckinghamshire next week.

The only problem with all this is, there's already an international group designated to address the issue of potential alien contact.

"We consider it our job, and have for many years, to cover this topic," said Arizona State University astrobiologist Paul Davies, who cjairs the SETI Post-Detection Taskgroup. "We have no idea who this person is or where the U.N.'s coming from, but they don't seem to follow through very well."

The task group, operating under the aegis of the U.N.-recognized International Academy of Astronautics, is charged with developing a protocol for dealing with the discovery of signals or other evidence of the existence of an extraterrestrial civilization. Davies and his colleagues are considering this very topic during the International Astronautical Congress this week in Prague, the Czech capital.

During a phone call from Prague, Davies told me that the protocol is in draft form. The current version suggests a number of organizations that could be involved in planning a response to alien signals, including the U.N. Committee on the Peaceful Uses of Outer Space. If there is a confirmed detection, the U.N. secretary-general would be among the first to know. But there's nary a mention of the U.N. Office of Outer Space Affairs, the place where Othman is in charge.

There's always the chance that Othman's intentions were misunderstood. And in fact, Othman herself reportedly knocked down the idea that she was seeking the U.N.'s appointment to be ambassador to the aliens. "It sounds really cool but I have to deny it," she told The Guardian in an e-mail.

Davies told me that the idea of having an "official greeter" for a visiting alien delegation is ridiculous in any case.

 

Space.com

What are the odds for alien life? Use our Drake Equation calculator to get an estimate.

"No serious scientist working in this field ever thinks this is a remote possibility," he said. "The best we can hope for is that we can pick up some kind of signal, or perhaps some semblance of alien technology. ... Nobody in this field expects flesh-and-blood beings to be traveling across vast distances of time and space to receive some ceremonial greeting from Earth."

In a book titled "The Eerie Silence," Davies delves into the decades-long search for alien signals and lays out the scenarios for future extraterrestrial contact.

Davies doubts there will be a clear-cut "take me to your leader" message. Instead, scientists may well have to puzzle over ambiguous indications: Is a particular series of blips a coded transmission from E.T., or is it a natural phenomenon ... or could it even be blowback from our own space communication systems? Might scientists discover a planetary system with activity strange enough to be classified as the result of life at work?

Scientists are pretty good at sorting out those kinds of questions, Davies said. "What we're not so good at is figuring out how, in the event of some putative signal, it would play out," he added. So on that score, maybe it's a good sign that U.N. officials — and news media outlets as well — are taking more of an interest in the question of what happens after we get a signal from E.T.

"We do welcome the interest of the U.N., as we welcome the interest of any major diplomatic organization," Davies said. "If they knew what they were doing, I would be slightly more confident."

What would you do if E.T. came up to you and said, "Take me to your leader"? Or, for that matter, neutralized our nukes? How seriously should we be taking UFO reports? Feel free to weigh in with your comments below.

Update for 1:45 a.m. ET Sept. 28: Seth Shostak, senior astronomer at the SETI Institute, sent these observations about the first-contact issue via e-mail from Prague, where he's also attending the International Astronautical Congress (and attending task group meetings):

"Any signal would likely come from hundreds to thousands of light-years away. Our reply would take centuries to get there, and be to a society that had already advanced centuries or millennia beyond their original query.

"Most important: Any society that's targeting us with a strong signal is more technically advanced than we are. Ergo, they already have the receiving capability to pick up our leakage — the radio and TV we've been inadvertently sending into space for 70 years. Since those signals are out there, they are our de facto envoys."

More about UFOs and the alien search:

• Share your stories about UFOs
• The best places to spot UFOs
• Timeline for the SETI quest
• 2060: Will contact come by then?

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