SETI isn’t Science: Why the Search for Aliens is a Waste of Resources

Posted on April 27, 2019 by jpeilbert
the_search
xkcd comic 638: smart ants decide to redirect their resources to real scientific projects

The Search for Extraterrestrial Intelligence (SETI) has been ongoing for about 60 years now, and it’s time to reconsider if it’s worth the millions of dollars and hours it burns every year.

To start off, I want to make the case that SETI isn’t real science. It’s a faith-based effort that isn’t falsifiable. An article published in Nature pointed out:

“…no matter how scientifically rigorous its practitioners try to be, SETI can’t escape an association with UFO believers and other such crackpots. But it is also because SETI is arguably not a falsifiable experiment. Regardless of how exhaustively the Galaxy is searched, the null result of radio silence doesn’t rule out the existence of alien civilizations. It means only that those civilizations might not be using radio to communicate. Indeed, SETI is marked by a hope, bordering on faith, that not only are there civilizations broadcasting out there, but that they are somehow intent on beaming their signals at Earth.”

And now you’re thinking: SETI may not be a science by some standards, but imagine if it worked! To that I respond: if. I would never play the lottery just because it would be great if I won, and at least I can know the odds of winning the lottery. The only way to guess at the odds of SETI finding something is by plugging in un-testable, made-up values into the Drake equation until it spits out an answer you like.

If you’re interested in hearing more anti-SETI rhetoric and discussion, I encourage you to check out this blog post and this reddit thread.

Don’t get me wrong: pop science is a great way to get people interested in funding and doing science. But something that has been described by one scholar as “uncomfortably close to the status of pseudoscience” is a waste of funding end energy, not to mention the unrealistic view it gives people of what real science is.

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The Drake Equation

Posted on April 27, 2019 by anna_h

We hear about aliens all the time, whether in books or movies or tv shows, and this leads us to ponder our own existence. Are we alone, or is there other life out there? This is a question that has plagued mankind since begun exploring interstellar space, and started looking for life in our own Solar System. If it turns out that life is actually out there, it is natural to wonder if there is other intelligent life in the universe. Would there be other human civilizations, or is Earth the only planet in the entire universe that harbors intelligent life, and we really are all alone. And even if there are other human civilizations out there, how would we find them? Scientists now speculate that we might be able to detect other civilizations simply by listening for signals that they are sending into interstellar space. By this method, efforts to search for extraterrestrial intelligence can only succeed if advanced civilizations are broadcasting signals right now.

The astronomer Frank Drake wrote a simple equation that summarizes factors that would determine the number of civilizations we might be able to contact. This equation, known formally as the Drake equation, gives us a simple way to calculate the number of civilizations in our galaxy that are sending signals into outer space. The Drake equation relates the number of possibly habitable planets in our galaxy, fraction of habitable planets that actually have life, fraction of life-bearing planets on which a civilization capable of interstellar communication has arisen at some time, and the fraction of life-bearing planets that are communicating now. In short, the Drake equation tells us how many civilizations we could possibly contact right now. Because we do not actually know how many possibly habitable planets there are in our galaxy, we cannot accurately calculate the number of civilizations that are communicating right now. However, the Drake equation is still useful as it relates all of the factors necessary for us to determine the number of communicating civilizations, and we can therefore make a general estimate of the number of civilizations we could possibly contact today.

The Drake Equation
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Finale – Culminate Post

Posted on April 27, 2019 by luanaisaac1125
An artist’s concept of our Solar System. The lines emanating from Earth represent the missions we’ve sent out.
Source: NASA/Jenny Mottar

I learned much more than I thought I would in this course. Before taking this class, all I really knew about our solar system was that there are 8 planets (and Earth is the third one), the asteroid belt is a thing, Jupiter is big, and Saturn is the planet with pretty rings. I didn’t know everything in space was so far apart (even our moon is much farther than I thought it was). I had no idea Venus was such a hot, cloudy, and fascinating hellscape. I didn’t know the asteroid belt was so much calmer than how it’s portrayed in movies. I wasn’t aware that the Kuiper Belt and the Oort Cloud even existed. I didn’t know Jupiter and Saturn were basically the same size/radius (I always thought Jupiter was bigger). I didn’t know comets had two tails. I didn’t know Jupiter has a volcanic moon that spews sulphurous gas into space. I didn’t know Saturn had a moon that spouts geysers of ice into space. There was just so many interesting things this class taught me about all the worlds and objects in our solar system and throughout the rest of space. It all made me excited about the possibility of expanding/improving space travel so we can learn even more about the things farther away from us.

The only reason I regret taking this class this semester is because I liked it so much. I sincerely wish I had more time here to take more astronomy classes and learn more and more about what we know of space and everything in it. At the same time, I’m glad to have taken this class my last semester as an undergraduate because it’s been one of my favorite classes I’ve taken here. I actually learned a lot of interesting things, and this class was fun. It felt like a great way to finish up my time here.

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What’s in a Black Hole?

Posted on April 27, 2019 by Aaron Molotsky

There are few things in the entire Universe that are as terrifyingly awesome as a black hole. To have a region of space exist that contains gravitational forces so strong that literally nothing can escape it (whether it’s a particle, light, or any electromagnetic radiation for that matter) seems like a concept straight out of a sci-fi novel or scary space movie. The general idea is that a ton of matter is compressed and compacted into such a small space, generating a gravitational field that nothing can escape from it.

These regions of spacetime, known commonly as black holes, were first theorized back in the early 1900s based on Einstein’s theory of general relativity. In essence, his explanation demonstrates two important principles (listed below):

  1. Moving things follow curves in space (which are created by mass).
  2. Light travels at a constant speed, but it is affected gravity (meaning that if light changes speed, it’s traveling along a curve in spacetime).

From these two fundamental ideas behind general relativity, physicists and astronomers were able to conjecture that black holes can exist (Schwarzschild). With that in mind, they were also able to conclude that when massive stars die (as a result of running out of nuclear fuel), they leave behind small yet super dense cores. Depending on the composition of that core (whether or not it has enough mass), gravitational forces can overwhelm everything else acting on the core, producing a black hole.

What’s even crazier than the idea of a black hole is the fact that humans currently can’t even directly observe black holes (with any sort of telescope, no matter the type of electromagnetic radiation it looks for). Because black holes are inherently empty space, there’s “nothing” to actually observe. Instead, we’re able to determine the presence of black holes by monitoring their effects on space objects nearby. By looking at the effects that black holes have on different celestial objects (whether it’s interstellar matter, stars, etc.), physicists are able to make conclusions about black holes’ behavior and thereby learn more about them. More information can be found at the following link.

And lastly, it’d be remiss to not mention the recent photograph scientists were able to take of a black hole. Using the Event Horizon Telescope, scientists were able to image the supermassive black hole at the center of galaxy M87. The actual picture taken can be seen below!

black_hole
A picture of the supermassive black hole located in galaxy M87. The picture can be found at the following link.

 

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The Fermi Paradox and The Great Filter

Posted on April 26, 2019 by luanaisaac1125
A ~6 minute video about the Fermi Paradox. Posted to YouTube by “Kurzgesagt – In a Nutshell”

Simply stated, the Fermi Paradox asks the question, “Where Are All The Aliens?” The life-projecting equations we’ve discussed in class, such as the Drake and Seager Equations, all seem to suggest that thousands, millions, or billions of other forms of life should be out there in the universe. But if that’s the case, why haven’t we found them yet? The Great Filter is a potential solution to this paradox; it suggests that there is some obstacle standing in the way of life reaching out, colonizing, or coming into contact with the rest of the galaxy.

Where it gets interesting to me is the discussion of whether or not humans are past the Great Filter. A lot of the time, people seem to think humans are really special, so it would be easy to assume that we’re ‘the lucky ones,’ and are thus far the only living species that have overcome the Great Filter. On the other hand, there’s the possibility that the Great Filter lies ahead of us, and humans are hurtling headfirst into their own extinction. The Kurzgesagt (a mouthful, I know) video linked above, as well as a few others I will link to below discuss the Fermi Paradox and the Great Filter in a simple, straightforward way using some cutesy visuals and calming background music. I think they provide an easy-to-swallow way of thinking about a looming existential problem.

The Great Filter is honestly a bit scary to think about, but it’s an important thing to consider all the same. Do you think we’re past the filter, or is it still something we’ll have to try and overcome in the future? If it does lie in front of us, will we be able to slip through and survive, or are we heading towards extinction?

Some other Kurzgesagt videos that may be worth checking out if the Fermi Paradox/Great Filter interests you: Fermi Paradox (2/2) and The Great Filter. Also, you could look into the text of the original ‘Great Filter’ essay, written by economist Robin Hanson.

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Are We Alone?

Posted on April 26, 2019 by Aaron Molotsky

As we’ve seen over the past few generations, our ability to harness technology to accomplish things never before seen or done has only increased exponentially. As a race, we’ve been able to photograph a black hole, we’ve been able to send probes to places in space that were thought to be unreachable, and we’ve just overall been able to further explore the Cosmos as a whole. However, with this rapid increase in explorational manpower, we beg the question — are we the only organic beings out there? How is it that we have not found evidence yet of any galactic civilization?

This is the exact question that the Fermi Paradox concerns itself with. Enrico Fermi, a Nobel-Prize winning physicist, created the paradox to encompass the idea of how we have yet to detect an alien civilization even though we know that there are billions of different stars, planets, and other places in space that aren’t our Solar System. As we know, there are several different solutions that attempt to explain Fermi’s Paradox. They include the following list of different explanations:

  1. We could be alone in the entire Universe. Galactic civilizations are so rare that we’re seemingly just an anomaly (i.e. we’re the first).
  2. We could be one of many different civilizations, but nobody’s colonized the galaxy we’re in. This could be a result of costly interstellar travel, space exploration being boring, or that most galaxies are colonized and ours just isn’t overly important or relevant. It could also be that all civilizations in the past that have had the ability to colonize the Cosmos have destroyed themselves before actually colonizing anything.
  3. There are galactic civilizations out there, but they have yet to reveal themselves to us yet (for whatever reason).

It’s important to note that Drake’s Equation readily ties into the ideas that Fermi’s Paradox discusses. As we know, his equation represents a probability that estimates the number of different extraterrestrial civilizations in our galaxy. All in all, it seems like most of these theories and equations are largely conjecture — we really don’t know what’s out there, at all. The moment we learn about another civilization existing in space, there will be a large turning point in history. It would be crazy to find out that there exists civilizations other than ours!

The picture below explains Drake’s Equation, which summarizes the different factors that represent how likely we may come into contact with alien civilizations (which is super relevant to the Fermi Paradox!).

drake-eqn.png
A visual representation of the different factors involved in Drake’s Equation (as found at the following link.

 

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The Rare Earth Hypothesis

Posted on April 25, 2019 by epiphany9

I was inspired by Victoria’s post to think more about the Fermi Paradox, and specifically, explanations of the uniqueness of intelligent life on Earth. The Rare Earth Hypothesis is one such explanation; it postulates that conditions favorable to life (and particularly intelligent life) are incredibly rare in the universe. It is in opposition to hypotheses that suggest intelligent life is (or has been) abundant but that we haven’t yet detected it for various reasons.

The Rare Earth Hypothesis mentions a number of characteristics that make Earth special. One particularly notable characteristic is our large moon. Of the four terrestrial planets in our Solar System, Earth is the only one that has a moon of decent size, and this moon has shaped Earth life in a multitude of ways. For one, the Moon creates large tides (twice the size of those the Sun creates), and the resultant tidal pools might have been crucial to the evolution of complex life, as these areas are only sometimes submerged in water. The Moon’s tidal forces also could have led to plate tectonics and the formation of oceanic crust. We do not currently know how rare a moon like ours is in the universe, as we have not yet detected any exomoons with certainty.

In addition, the Moon was likely formed due to a giant impact event (Theia, a Mars-sized object, crashed into a very young Earth). This chance event gave the Earth its axial tilt, leading to seasons, which were an impetus for organisms to adapt to different climates. The giant impact also led to the Earth’s rapid rotation, stabilizing daily temperatures and facilitating photosynthesis.

Artist’s rendition of a giant impact between two worlds

Image credit: NASA/JPL-Caltech

If complex life can only form on a planet that is within its habitable zone and has undergone such a giant impact, then it makes sense that we have not yet detected other intelligent life – it is simply that rare.

However, a common criticism of the hypothesis is that life on other worlds need not take the form of life on Earth, meaning that the exact same conditions are not necessary. This counterargument holds that Earthly conditions were just one of the many ways life could arise. We do not currently have sufficient technology to test the Rare Earth Hypothesis, as we are unable to detect moons, plate tectonics, surface water, or even signs of simple life on planets beyond our Solar System. Perhaps, then, time will tell why we are alone…or reveal that we are not.

Do you agree with the Rare Earth Hypothesis? Do you think there is an alternate explanation for the lack of intelligent life, or do you think there is currently intelligent life we haven’t found yet?

Sources:

“Rare Earth Hypothesis.” The Center for Planetary Science. Web.

“Rare Earth Hypothesis.” Wikipedia, Wikimedia Foundation, 9 Apr. 2019. Web.

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Are Extremophiles Our Roommates?

Posted on April 25, 2019 by Campbell Flower

Extremophiles are microorganisms that can survive in extreme conditions, such as high temperatures or great acidity. A recent study has found extremophiles in a location much more familiar to us, and it’s actually in the homes of humans.

Thermus Scotoductus cells, found in the water heaters of homes. Image courtesy of Science Daily

The study took samples from water heaters across all 50 states. Around 50% of the tested samples found evidence of microbes, with Thermus scotoductus being the most dominate species in all positive samples. The extremophiles pose no health risks to humans, making water containing the microbes still completely safe to consume. Thermus scotoductus has previously been found in hot springs, hydrothermal waters, and deep in a gold mine. Scientists are surprised to see such a large presence of this species in water heaters even in places with such a large abundance of other microbes, such as near Yellowstone. Even though we traditionally think of extreme conditions as “weird” or “inaccessible” parts of nature, our perception is shifting with this discovery.

And why do extremophiles colonize in water heaters? Scientists say the high temperatures and low levels of organic matter make the heaters an ideal environment for microbes. They can even survive being transported between water heaters because they can survive cooler temperatures as well. There is a correlation between colder temperatures outside and a greater presence of microbes, possibly because colder weather results in increased water heater temperatures. Scientists are still working to understand how the microbes enter our homes.

To read more, visit this article.

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The Twins Study

Posted on April 25, 2019 by Campbell Flower

NASA has conducted a study that looks at the effects of being in space on the human body, and they are calling it the “Twins Study”. The two test subjects are identical twin astronauts Mark and Scott Kelly. Mark and Scott are the only twins to have traveled to space. The information collected can be extremely valuable now, as we consider sending people to Mars.

Mark Kelly (left) and Scott Kelly (right). Photo courtesy of NASA

The premise of the study is to examine the differences in twins who were originally genetically identical after one spends time in space. Scott Kelly spent 340 days in space from 2015-2016, but Mark stayed on Earth during this time (making him the control group). Each twin provided NASA will different biological samples before, while, and after Scott was in space. The findings showed various differences in Scott’s DNA compared to Mark’s. Such changes included an increase in genes related to the immune system, DNA repair, and stress. Scott also lost weight, had a decrease in blood pressure, had worsened eyesight due to a thickening of the optic nerve. Positive changes in his motor function and spatial awareness were found. None of the changes the study found were life-threatening, and most returned to normal after Scott was back on Earth for about 6 months.

Historically, astronauts have experienced a variety of health challenges while in space. These include headaches, nausea, insomnia, a decrease in muscle mass, a decrease in bone density, a lower red blood cell count, and a worsening of vision. Astronomers are hoping that by studying the specific genetic changes found in Scott Kelly, they can create medicine to help minimize the symptoms of space travel by specifically looking at the biochemistry of astronauts. This study could be instrumental in being able to send people into space on the long journey to Mars.

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Adaptive Archaea

Posted on April 25, 2019 by epiphany9

Discovered in 1970, Archaea might be the least well-known of the three domains of life (the others being Bacteria and Eukaryota), but it is a fascinating and diverse group of organisms and quite possibly the first on Earth. Like bacteria, archaea are unicellular, prokaryotic organisms, meaning that they lack nuclei and other membrane-bound organelles in their cells. However, archaea are more closely related to eukaryotes (including us!), than to bacteria. According to the Theory of Endosymbiosis, the line of descent from the Last Universal Common Ancestor first split into Bacteria and Archaea.

The Tree of Life showing that Archaea and Eukaryota are more closely related to each other than to bacteria.
Image credit: John D. Croft via Wikimedia Commons

Archaea are particularly interesting to astronomers because this domain contains a large portion of extremophiles, organisms that can thrive in extreme conditions. Some of the first archaea were discovered in the hot springs of Yellowstone National Park. Others have been discovered within the digestive tracts of various organisms, in underground petroleum deposits, or in waters with extreme pH (in either direction). It is notable that archaea developed in the much harsher conditions of the early Earth, which lacked “features” such as the ozone layer to keep out ultraviolet radiation.

One of the most interesting and best-studied groups of archaea is the Halobacterium (a bit of a misnomer, as it is not a bacterium at all!), which thrives in extremely salty water. This property opens up the possibility that they might survive on Mars, where liquid salt reservoirs have been discovered just last year. Experiments have already demonstrated that two types of halobacterium (Halococcus dombrowskii and Halobacterium sp. NRC-1) can survive conditions similar to those on Mars, including an atmosphere made almost completely (98%) of carbon dioxide, and an average temperature of -60˚C. In addition, Halobacterium salinarum NRC-1 can survive environments of high radiation because it has an unusual adaptation: multiple copies of its genes, spread out across different chromosomes. This way, if radiation damages one gene copy (or even two), the cell survives off the remaining copy(s), while it repairs the damage. Thus, the Halobacterium are a wonderful model for the types of organisms that might be found on Mars if we continue to explore! 

Sources:

“Archaea – The Most Ancient Life.” The Virtual Fossil Museum. Web.

Fox-Skelly, Jasmin. “Earth – The Microbes so Extreme They Might Survive on Mars.” BBC, 21 Dec. 2015. Web.

Hallsworth, John E. “What on Earth Could Live in a Salt Water Lake on Mars? An Expert Explains.” Phys.org, 6 Sept. 2018. Web

“Introduction to the Archaea.” UC Museum of Paleontology, University of California, Berkeley. Web.

Rampelotto, Pabulo Henrique. “Extremophiles and Extreme Environments.” Life (Basel), 7 Aug. 2013. Web.

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