I have been a supporter of the Search for Extraterrestrial Intelligence (SETI) since I learned of its existence. Essentially, SETI is a search for technosignatures of alien origin, specifically using radio astronomy. However, I occasionally encounter skepticism toward SETI, and I love to engage with fellow skeptics on topic about which we disagree. I recently received an e-mail with a fairly typical skeptical perspective:

“I am sure we will eventually find signs or evidence of life outside our solar system but the likelihood of finding a life form that can communicate on a level that we can understand seems so unlikely as to be not worth pursuing from an economic point of view.”

His basic argument is that, in order for us to communicate with an alien technological species they would have to be very similar to us. This would require a degree of “parallel evolution” that is fantastically unlikely. Even given the vastness of the universe, he feels the probably is simply too close to zero to justify any investment. I disagree, however, with his core premise.

First let me say that we simply have no idea how common life, intelligent life, and technological civilizations are in the universe. That is one of the questions SETI is attempting to answer. We suffer from the so-called “N of 1” problem – we have only one example of life and a technological species. He agrees life is likely common, which I think is likely, but feels technological species are exceedingly rare, but we simply have no basis for this conclusion. The evolution of greater intelligence occurred in many clades on Earth. Many, of course, like insects, will never achieve technological status, but that doesn’t matter. Greater intelligence is a massive evolutionary advantage, and is likely to occur in many lines.

Continue Reading »

This weekend I was at the AAAS (American Association for the Advancement of Science) meeting in Seattle talking about science communication. The meeting often creates a pulse of science-news reporting, base on all the presentations and lectures there. One talk I didn’t get to see was by Dr. Anthony Beasley, director of the US National Radio Astronomy Observatory in Charlottesville, Virginia. He argued that the search for extraterrestrial intelligence (SETI) should “come in from the cold” and be incorporated into every aspect of astronomy. Let me go over the reasons why I completely agree.

First, doing so would be a great boost to SETI itself. For example, private funding has recently allowed a SETI project using the VLA (Very Large Array) which the project managers argue will increase the power of SETI by 10-100 fold. Taking SETI from an isolated project here and there to the mainstream of astronomy would certainly greatly magnify the power of SETI searches, and therefore increase the probability of achieving a positive result.

Further, as Seth Shostak has pointed out to us during interviews on the SGU, SETI research does a lot of non-SETI astronomy. Of you are scanning the skies with radio telescopes looking for signals that may be intelligent in origin, you are also gathering a lot of information that can be used for other purposes. So even if SETI never detects such a signal, the effort will not have been wasted. A lot of non-SETI astronomy will still have been done. The broader point is that, by combining SETI with other projects, astronomers are efficiently using equipment and data. What this means is that the question of SETI vs other projects is a false dichotomy. We can do both.

But the biggest question in all of this is – is SETI itself valuable? There are two criteria that are usually brought to bear in answering this question. Mostly people focus on the probability of detecting an ET signal, with critics of SETI arguing that it is probably too small to be worth the effort of searching. Defenders of SETI often focus on the other criterion – the value to humanity if we did detect a signal. In essence SETI is like playing the lottery – the probability of winning is low but the potential benefits are high. How do we balance these two things out?

Continue Reading »

I recently receive the following e-mail question:

Got a question for you: do you consider the Search for Extraterrestrial Intelligence to be science or pseudoscience? I recently got into an online debate and found myself in the minority because I maintained that the central thesis — that if intelligent life exists somewhere out there in the greater universe, we would be able to recognize it based upon patterns in radio waves — is not falsifiable.

It would seem to me that the only way to truly falsify SETI, we’d need to map quite literally every body in the universe and rule them out one by one and say that they don’t have anything there in terms of extraterrestrial intelligence.  Unlike other complex hypotheses that are limited by available technologies, I’m not convinced that the task of mapping the universe is even possible, even with a sufficiently advanced technology.

I have received some version of this question many times over the years, always by people who are trying to be skeptical and apply what they have learned about the differences between science and pseudoscience.  It therefore seems like an excellent opportunity to explore this important issue.

Continue Reading »

Blogging for the Discovery Institute, Michael Egnor repeats the already debunked canard that the Search for Extraterrestrial Intelligence (SETI) is analogous to the search for Intelligent Design (ID) in nature. This time he is responding to a recent blog entry of mine on SETI. He doesn’t actually respond to any of my points – he is just using my entry as an excuse to repeat the SETI false-analogy.

Egnor writes:

One is struck by SETI supporters’ speculative extravagance. The most cogent critique of SETI, in my view, is that it is akin to an article of faith. There is absolutely no evidence for the existence of extraterrestrial life. SETI is surely a shot in the dark, perhaps literally, but I do believe that it is a worthwhile scientific venture. Methodologically it is certainly science, even good science. The reception of signals with specified complexity or the discovery of artifacts apparently crafted by intelligent non-human agency would be clear evidence for extraterrestrial intelligent agency. Carl Sagan’s example in “Contact” is entirely valid. The reception of a signal repeating prime numbers would be very unlikely to have a non-intelligent natural source, and the most reasonable scientific inference would be that it was generated by extraterrestrial intelligent life.

Continue Reading »

I am a strong supporter of SETI – the search for extraterrestrial intelligence. To me this is a fascinating scientific endeavor with a potentially huge payoff. And yet, I find that even within skeptical circles I hear grumblings that SETI is not real science.

The primary complaint stems from the misapplication of an important scientific principle – that a necessary criterion for any scientific hypothesis is that it needs to be falsifiable. If you cannot make an observation or conduct an experiment to prove an idea wrong, then that idea is not useful to science.

SETI critics argue that the notion of extraterrestrial intelligence is inherently unfalsifiable. No matter how much you look with negative results, one could always argue that it is not enough, we have to look deeper into space, for fainter signals, in more EM frequencies.

Continue Reading »

Last year the inner solar system had an interstellar visitor – 3I/Atlas (which stands for the third interstellar object which was discovered by the Atlas telescope). The third ever of anything is by definition a rare event, and so this was scientifically exciting. The comet came into the inner solar system, passing close to Jupiter and Mars, but not to the Earth, went behind the sun, then emerged on its path away from the sun. It is now headed for the orbit of Jupiter and out of the solar system. At first 3I/Atlas displayed a number of minor anomalies. It was behaving sort of like a comet, but with some differences. This fits well, however, with the main hypothesis that it is an interstellar comet – so it’s a comet, but may have a different composition from comets that were formed in our own solar system. This is not almost certainly the case – the comet comes from the thick disc of the galaxy, likely from a low metallicity star system, and has likely been travelling through interstellar space for billions of years, possibly being even older than our own star.

Now that it is passing out of the solar system we can look at all the data that NASA collected and make some fairly confident conclusions. There are a lot of sources of information, but Wikipedia actually has a pretty good summary and list of references. In the end, 3I/Atlas behaved mostly like a typical comet. It formed a tail heading away from the sun, brightened as it got close, then faded away as it moved away from the sun. Spectral analysis found that the comet was unusually rich in carbon dioxide (CO2), with small amounts of water ice, water vapor, carbon monoxide (CO), and carbonyl sulfide (OCS). It also had small amounts of cyanide and nickel gas, which is common in comets from our own solar system. In other words – it is a comet. It did originate from a part of the sky that we had previously calculated would have fewer such interstellar objects, which either makes it especially rare or means that our calculations are off.

Every time we encounter a new interstellar object we gather more data about such objects – how frequent are they, where do they come from, and what is their nature. Right now we have just three data points. After the first one, Oumuamua, we had not idea how common they were because we had just one data point. Now we have enough instruments surveying the sky that we are better able to detect such objects, which are very fleeting. The question was – was Oumuamua a one-off, and we just got lucky to detect something that happens very rarely, or are such objects common. We now have three data points and can conclude that they are fairly common, and we should detect one every few years or so, perhaps even more often if we start looking more.

Continue Reading »

Construction begins this week on what will be the largest radio telescope in the world – the Square Kilometer Array (SKA). This project began more than 30 years ago, in 1991, as an idea, with an international working group forming in 1993. It took three decades to flesh out the concept, create a detailed design, secure the land rights, and secure government funding. The first antennas will go online by 2024 with more added through 2028 (which will complete the first phase – about 10% of the total planned project). This will result in a radio telescope array with a total area of one square kilometer.

There are actually two components to the total array. One is being built in Australia, the SKA-Low, for low frequency. These will use antennas that look like two-meter tall metal Christmas trees. There will be 500 arrays of 256 antennas for a total of 131,000 antennas. This will be the low frequency array, able to detect radio waves between 50 megahertz and 350 megahertz. There will also be SKA-Mid in South Africa, which will be an array of 197 dishes sensitive between 350 megahertz and 15.4 gigahertz. The whole thing will be connected together, with the bulk of the computing power located in the UK.

Why do astronomers connect radio receivers together? This has to do with interferometry – the ability to combine two signals so that they can simulate a single receiver with a diameter equal to the distance between the two receivers.  It’s not the same as having one giant dish, however. An array increases the resolution of the received image, but the sensitivity is still a function of the total receiving area (not the distance). The Very Large Array (VLA) in New Mexico has radio dishes on rails, so that they can be moved into different configuration. By moving the dishes apart you can achieve greater resolution, but by moving them closer together you get greater precision – so there is a trade-off from moving receivers farther apart. There is no substitute for total collecting area, which is why the SKA will have so many individual receivers.

Continue Reading »

Recently experts gathered online for a digital conference in which they discussed possibilities for detecting signs of alien technological civilizations – so called “technosignatures”. Being an enthusiast, I have heard of many of these before, but there were a lot of new ideas coming out of that meeting as well. Here is the preprint, with all the technical information. I think collectively this is a compelling case for NASA and other agencies to include the search for technosignatures as a part of their mission.

The most obvious technosignature is radio signals, most likely deliberately broadcast, either out into the universe or even directed at Earth (if they have detected our own technosignatures). This is the object of SETI (The Search for Extraterrestrial Intelligence). NASA briefly funded a SETI project, but then pulled funding. The effort continues, however, with other funding. I have interviewed Seth Shostak from SETI several times and he makes a couple of points worth emphasizing here. One is that SETI is simultaneously doing a lot of non-SETI astronomy. They are essentially doing radio astronomy but looking at any data in such a way that it could detect an alien signal.

The members of the recent meeting also considered what they call “synergies” or ancillary benefits for each of the techniques they discuss. This is critical, I think, because it means even if we never detect an alien technosignature, the effort would not have been wasted. We will have accomplished a lot of meaningful astronomy in the meantime. I would argue it wouldn’t be wasted in any case – negative results from an experiment are still results. We would have gathered lots of data about how rare technological civilizations are in the universe. But if you look at the table of discussed techniques in the paper, each one has a listed potential synergy. In fact, they also list existing astronomical data that can be searched for technosignatures.

Seth also pointed out that if we did detect an alien message hiding in radio signals, we would very likely not be able to read it. This is because radio signals get weaker with distance, and at some point they would be lost in the background radio noise. The more powerful the initial radio signal, the greater its range. The current authors call this the “cosmic footprint” of each technosignature, and coin the term “ichnoscale” to measure it. For example, they give radio astronomy a 10 kpc (kiloparsec) ichnoscale for detecting alien signals.

Continue Reading »

A new paper published in Nature Astronomy presents further evidence for significant water near the surface of the Moon. This is exciting news for the prospects of a lunar base, especially since NASA is planning on returning permanently to the Moon by 20204.

The Artemis program (Artemis is the twin sister of Apollo) plans to put the first woman and the next man on the lunar surface by 2024. Even if they don’t meet this ambitious timeframe, they will likely succeed sometime this decade. Unlike the “flags and footprint” mission design of Apollo, Artemis is designed for sustained exploration of the Moon. Artemis will use the space launch system, which will be the most powerful rocket in the world. In fact, the most powerful configuration of the SLS will be more powerful than the Saturn V rocket. This is because the SLS was designed no only to return to the Moon, but to be powerful enough to get to Mars, which is the ultimate goal.

On top of the SLS will be the Orion capsule, NASA’s deep space capsule. Orion can accommodate up to four astronauts, and is designed for multi-week missions. It will have exercise equipment, radiation shielding, and on board waste disposal. When they get to the Moon they will have a new lunar lander, currently in development. But unlike Apollo, NASA also plans on building the Gateway – a lunar orbiting platform for long term occupation and exploration of the Moon.

After the initial Artemis missions, NASA plans to create a basecamp near the south-pole of the Moon for long term occupation and exploration of the Moon. Why the south pole? In NASA-speak the poles, “may contain mission-enhancing volatiles.”  In addition “These sites may also offer long-duration access to sunlight, direct-to-Earth communication, surface slope and roughness that will be less challenging for landers and astronauts.”

Continue Reading »

The next NASA rover to Mars, the Mars 2020 Rover (final name to be determined), launches next July. It will arrive at Mars in February 2021. This is the next iteration of rover design and has some interesting new features, include a drone that can fly around to survey more of the Martian surface.

But perhaps the feature that is getting the most attention is the drill. For the first time a Mars rover will have the ability to drill down into the rock and dirt. Why is this so important? If Mars ever contained life, then it is likely the remnants of that life can be found down in the rocks, rather than on the surface. This is the first rover specifically designed to look for signs of life.

There is even the remote possibility of finding signs of recent, or even current life. The mission will be looking for life signatures, such as certain forms of carbon, or signs of sustained water presence in the past. Once the rover lands and is operational, it should only take a few months for answers to start beaming to life. We may know by the middle of 2021 if life ever existed on Mars.

Finding signs of life on Mars will have profound scientific implications. However, CNN, when reporting about this, chose to go with this headline: “When — or if — NASA finds life on Mars, the world may not be ready for the discovery, the agency chief says.” They quotes NASA chief scientist, Jim Green:

“It will be revolutionary,” Green told the Telegraph. “It will start a whole new line of thinking. I don’t think we’re prepared for the results. We’re not.”

Continue Reading »