10 Mysteries of Titan

The excellent as always Mr John Michael Godier has come out with a new video, I suggest giving it a watch. Mr Godier here explains ten mysteries of Titan, the only moon in our solar system with a substantial atmosphere, and the only other terrestrial body in our solar system with surface liquids, specifically lakes and rivers of liquid methane. It’s also becoming more and more evident that prebiotic chemistry of sorts is occurring on Titan, and what’s happening their may hold clues for the origin of life here on earth as well, as the early earth is believed to have been very similar to Titan.

It’s even possible we may find life there, however such life would be totally alien to our own, utilizing an entirely different, and also entirely hypothetical, biochemistry than the water based one that is used on earth. Titan also quite likely has a subsurface ocean of liquid water, and that subsurface ocean may very well have hydrothermal vents, meaning that it’s quite likely that even if no life is found on Titan’s surface, that life may still be found on Titan irregardless of its surface conditions.

10 unsettling astronomical incidents and phenomena

https://www.youtube.com/watch?v=pul9r0jfbug&list=PL1WRbGpKFCAJMfdKHM-zwe5qecY3r910n&index=11

This is a video by the excellent as always Mr John Michael Godier listing, and explaining, some unsolved astronomical phenomena. While the general rule is that “it is never aliens, until it is,” some of the phenomena listed are so strange that aliens remain a serious possibility. One of these is the Wow signal, which to this day defies explanation, it was recently proposed it may have been due to comet emissions, but this was shot down by the scientific community because if comets were emitting at the hydrogen line radio astronomers would have noticed it by now.

I recommend giving it a watch, it’s a good reminder there’s lots we still don’t know about our universe.

Remembering Carl Sagan

If only Sagan were around today to learn of the fascinating insights we have discovered since his untimely death. Since his death we have discovered more than 4,000 exoplanets, we have discovered numerous candidates for harboring extraterrestrial life in our solar system alone (*cough* Europa *cough*), coinciding with that we have discovered that numerous minor planetary bodies have oceans of liquid water inside them, with some (*cough* Europa *cough*) even possessing the right chemical mix for complex life to occur on them, not merely simple life, but complex life, I`d be willing to bet that there are fully fledged animals inside Europa’s oceans.

Sagan would be amazed by what we have discovered since his death. He would be 83 years old today. The work he had done in popularizing science to the masses remains uncontested, he inspired millions of future scientists with his works, he was truly a gift from the gods. Rest in peace, Carl, you have earned it.

A more nuanced version of the rare earth hypothesis

The tweaked version of the rare earth hypothesis I present is this: We all know that the odds of life existing elsewhere in the universe is greater than ever before, and it is conceivable, perhaps even likely, that life can be found pretty much anywhere where there is a terrestrial body with liquid water present on it in some way (note: I`m restricting the notion of “life” to carbon and water based life like that found here on earth for obvious reasons), such as the moons of the outer solar system, perhaps even rogue planetary bodies or rogue moons as well, assuming they had oceans of liquid water present in their subsurface regions.

But I find it likely that while life may indeed be common in the universe, most of that life is going to be microbial, even on earth-like terrestrial planets orbiting stars not too different from our own. Look at it this way, for pretty much most of the history of life on earth (three and a half billion years, from the Hadean to the late Proterozoic), *all* of the biosphere was comprised of microbes, even today most of the biomass is again made up of microbes, multicellular eukaryotes make up a pithy fraction of the rest.

In the absence of necessary selective factors that are a prerequisite for multicellularity to arise in previously unicellular organisms, it can be assumed that the vast majority of life in the universe is microbial. There are about 10 or so billion earth like planets in our galaxy alone, and I’d wager that the number of those planets containing complex life on them is low, if we assume life is found everywhere where it can develop, then pretty much *all* of those planets would have life on them in some way, albeit being *microbial* life, so, using my generous assumption, there’d probably be a few hundred thousand to a few million planets with complex, multicellular life on them, that may seem like a big number but we’re dealing with 10 *billion* earth like planets out there, that’s a *pathetic* number indeed in comparison to ten *billion*.

Now how many years did it take for sapience to arise on earth (“sapience” in this context meaning “human-level intelligence,” obviously other animals are sapient as well but they probably *aren’t* human-level sapients, your pet cat or dog, while hardly idiots, don’t count, and for the sake of argument neither do dolphins or elephants)? It took roughly four billion years for the first members of the genus Homo to arise, for most of which our history we were nothing but hunter-gatherers, we’ve only been practicing agriculture for a mere ten millennia, we’ve only been recording history for about half of that, and we have only had an advanced technological civilization capable of radio astronomy for about a century now.

I think it obvious that the number of those planets with complex life on them *also* bearing sapient life at the same time we do to be *ridiculously* low, possibly even in the single digits, and most of those planets with sapient life on them odds are the sapients never left their stone age, because the development of civilization here on earth was dependent upon a number of *highly specific* circumstances that are probably, given how long we went without even developing agriculture, not that common among sapients, it was never a given *we* would develop civilization, and it is hardly a given *they* will either.

So assuming what I wrote above is true, the Fermi Paradox is hardly a paradox at all, everyone else as intelligent as we are are still stuck in the stone age and therefore have no hopes of becoming a spacefaring civilization, we’re the lucky ones, and I hope we live long enough to make us of our lucky status before climate change does us in.

The Strange History and Stranger Planet of Barnard’s Star

https://www.youtube.com/watch?v=WqHpOKJ8u0s

The above video, made by a certain “ParallaxNick”, describes the history of Barnard’s Star beginning with its discoverer, the eponymous E.E. Barnard, himself a noted astronomer of the late 19th and early 20th centuries. While some aspects of the Barnard’s Star itself are interesting, such as the fact that Barnard’s Star is potentially a halo star, and is as old as our galaxy is, at twelve billion years of age, what I found most interesting were the aspects concerning the potential planet orbiting Barnard’s Star.

This planet, according to its discoverers, has a 99% chance of existing, so we can be reasonably certain that this planet does indeed exist. Furthermore, while this planet is nowhere near the habitable zone of Barnard’s Star, specifically being beyond the Snow Line, even though its distance from its homestar is comparable to the distance of Mercury from our own Sun, but it isn’t a gas giant. Gas giants can’t exist around Barnard’s Star, according to the video anyways, because Barnard’s Star is too low in metals to permit such a planet from forming.

This planet is a super earth, at around two to three times the size and mass of Earth, and yet this planet may still be capable of allowing life to flourish on it. To compare this planet to any of the inner planets within our own solar system would be wrong, this planet is more comparable to Titan, the famous moon of Saturn known for possessing lakes and rivers of methane and ethane.

While it is unlikely that methanogenic based life exists, as far as we know anyways, it is not impossible as far as the laws of physics allow it, and so Barnard’s Star b, as the potential planet has been dubbed, may be home to a thriving biosphere like Earth is, although any methane-based biosphere would be incapable of allowing complex, multicellular life to form in reasons outlined in another ParallaxNick’s videos, the one on Titan linked to in the video above.

Explaining the Great Filter

http://mason.gmu.edu/~rhanson/greatfilter.html

The cited paper describes the hypothesis of “The Great Filter,” a
proposed explanation to Fermi’s Paradox, and the explanation I find the
most compelling. According to a hypothesis there is a Filter causing
potential civilizations to never attain interstellar colonization, but
where exactly this Filter lies is unknown.

If the Filter lies past us, if say, the Filter is the chance for life to originate then we’ve long
since past the Filter and have nothing to worry about, but if life is
common in the universe (this is the reason why some scientists dread
discovering alien life on Mars and Europa) then we haven’t reached the
Filter yet, and therefore have reason to fear.

In line with this hypothesis any positive result we get from SETI would be bad news, for
it means that since life is common, especially intelligent life, that
the Filter therefore lies ahead of us, and any negative results we get
from SETI are good news, for the Filter is long behind us.

Given the likelihood that we are not alone in the universe, what this means is that we have reason to fear for our future, and given that we are currently bombarding ourselves with a number of different threats (nuclear Armageddon and global warming being the two foremost threats we are currently subjecting ourselves to), the Great Filter may not lay that far off in our future.

 

Life on Venus

https://www.youtube.com/watch?v=hnGwblw54z8

Some compelling content from Mr John Michael Godier, this time he covers “10 Unsettling Solar System Possibilities.” Personally the one I found the most compelling concerned the possibility of life in the atmosphere of Venus, which I will elaborate on below:

It is known for a fact that Venus once had liquid water on its surface, like how Mars used to and how Earth currently does, and it is a fact that Venus has long since lost that water, with the surface of Venus now being a “hellish, heated wasteland” unsuitable for life. But in the atmosphere of Venus there exists a place suitable enough for extremophiles to exist, being at roughly the same atmospheric pressure as the surface of the Earth currently is.

It is possible that some life survived to call this portion of the Venusian atmosphere home, after all, microbes have been found living high up in the atmosphere of Earth as well, what’s to prevent some extremophiles from living in the atmosphere of Venus?

And as the old saying goes, life always finds a way. I once brought up an argument based off of simple thermodynamics that abiogenesis is inevitable.[1] So even though we don’t know for certain that life developed on Venus, this argument further bolsters my case.

We may have even detected possible evidence of microbial life in the atmosphere of Venus, when NASA was undergoing its usual scanning of Venus they detected small blots wherein UV was prevented from reaching the surface of Venus, and UV-absorbing microbes have been offered up as a possible explanation for this anomaly, and would also explain where these hypothetical microbes get their food, they metabolize UV radiation as an energy source.

[1] For a link to the cited paper proposing that argument in question, seeĀ here.