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Honestly, jus about any study could be related to astrobiology in some way, but there are definitely connections between space medicine and astrobiology. Understanding how the space environment effects the health of humans and other organisms and how biology can overcome the effects of the space environment falls into better knowing how life may spread through the universe once biospheres become able to either shed their living material in some way (planetary impacts, massive eruptions, etc.) or when intelligent organisms set out into the space environment of their own accord.

I worked for JPL/NASA for 40 years and I spent a lot of time at JSC.  I did some work on microgravity experiments both at JSC and at Edwards AFB. One of the concerns we had was micromusculature atrophy in an extended microgravity environment. Atrophy of the arterial walls in the lower extremities due to a lack of gravity induced hydrostatic pressure was of particular concern. Inappropriate soft tissue remodeling appeared to be a serious problem. What is the status of this now?  It would seem to be a problem for a Mars mission.

Hello all,

I got to know about this website through professor Sara Imari Walker's interview on Sean Carroll's podcast, and was really excited to hear from scientists exploring a broader definition of what life is in the way she laid it. It seemed to me you guys operate in the general field of Object Oriented Ontology, among other schools of thought, is that correct?

I apologize if those are noob questions, I'm not a trained scientist; just very curious and an avid reader of philosophical and scientific works. I do have the goal of developing a thesis on the field of the ethics of space exploration (astroethics? Is that or could that be a thing?), but, unfortunately, that's a nonexistant program in my country as of now. Do you know of any course or program in that line in academia today?

Questions that intrigue me and that I'd like to investigate from a philosophical POV, for instance, are the impacts of space mining and other operations in which biological processes (meaning "intelligent" "life") actuate in the rate of matter and energy exchange from planets to the cosmos and vice-versa. Is this a valid scope of scientific investigation in your opinion, or have I just been watching way too much Trek?

Thanks in advance for you attention,

Hi Gina, 

     I recently graduated with my undergrad in Natural Sciences with a concentration in Biology from Excelsior, and on March 2nd, I will begin my graduate education via American Military University (AMU), in Space Studies.


     I'm in need of a bit of guidance, being that I'm not actively working in any field of science, some of the requirements and/or expectancies can be a bit foreign to me. 


     My curriculum at Excelsior didn’t include a chemistry, physics, or geology, so along the way I decided to try and take these courses when and wherever I could if I had an open elective to support it. I recently voiced my concerns to Excelsior after the fact about how I thought that these courses are usually considered core courses at most other colleges, including AMU.

     So, what I want to know is this. 


Q1. From a big picture perspective do not having these courses on my transcript matter?


     In any case, I was able to take both an Earth Science, and Chemistry course in seat, but sadly, no physics. 


Q2. I guess what I really would like to know if whether or not, NOT having exposure to all of the sciences (being B,E,C,A,P; Biology, Earth Science, Chemistry, Astronomy & Physics) would be looked down on?


Q3. If so, what are some alternatives to traditional college courses?


     I would really like to take a physics and another chemistry class prior to the start of my space studies graduate but then again I’d like to be certain that the motions that I’m going through will be recognized and accounted for.


Q4. Could MOOCs, ACE credits or classes provided by outlets such as Coursera , EdX, or www.study.com be used to supplant those traditional colleges or to serve as proof of understanding of the topics to a potential employer or team?

Q5. Or should I not worry about this and just spend all additional efforts going forward knocking out Astrobiology course work online via NASA?




Again, any help or guidance would be greatly appreciated. 



Hi Jerry,

These are really important questions for you to consider! I'm going to offer some brief responses here:

Q1 - It sounds like you've already been accepted to a graduate program in space studies. So, for the short-term having a physics course likely won't effect you. Of course, you'll be benefitted in your studies by learning some physics, but you can do that on the cheap with some textbooks and online resources. As for the longer-term, most employers don't care what classes you took in college nearly as much as they care about your acquired skills and work ethic.

Q2 - You definitely don't need exposure to all of the sciences to gain a job in the sciences or to pursue more advanced learning. If you're speaking directly to being involved in astrobiology, then taking a look at those of us in the field and our backgrounds will quickly show that we come from many different disciplines and only a very small number of us have even taken degrees in multiple fields. 

Q3- There are lots of ways to catch yourself up in physics and other studies. I honestly have always been that kind of nerd who loves to read old textbooks because there's so much good information in them. If you really want to have a certificate or other verification to show that you've studied in a certain area, then Coursera and other MOOCs are a great place to spend a small amount of money.

Q4 - As above, these online courses can be a great way to learn and you can put a certificate on your CV, but none of us can really speak to how much it may matter to an institution, employer, or team. That would be very case-dependent.

Q5 - For becoming an astrobiologist, you actually don't need to take any courses that are specifically titled "astrobiology". However, it certainly couldn't hurt and may help guide you a bit more in figuring out where in the realm of astrobiology you want to work. Since you are a little uncertain of your future direction right now, I think what might help the most right now is figuring out where you want to be in your career, finding others who are there, figuring out how they got there, and then figuring out how much of their paths are the same and how much is different. But, as always, take that with a grain of salt - there certainly is not single track or path to get where you want to go. 

I hope some of this helps.




       Thank you so much!

       This helps me tremendously and a thousand apologies if I came across a bit pushy, that wasn't my intent, but thank you nonetheless!


I keep wondering if the amphoteric nature of water, it being acidic and alkali at the same time, is what allows life to develop after nucleosynthetic evolution of the chemical elements in this universe?
All life on Earth is ultimately powered by electrons you see http://www.bbc.com/earth/story/20160613-there-are-microbes-that-eat...

Andrew, water is essential for life, but as a professional chemist, I can assure you the amphoteric nature is not really that significant. The key is hydrogen bonding, without which reproduction would be impossible. Reproduction requires the accurate transfer of information (although evolution requires the transfer to be capable of error!) and given the mass of information required for any complexity, this can only be done by mapping one polymer onto another. The information must be imparted by units that are different (e.g. 1 or 0) and for reasons outside the scope of a simple reply, only nucleobases work. These have to be attracted to their complementary base without external help during biogenesis, and they do that through forming either two hydrogen bonds (net attraction about 26 kJ/mol) or three (about 40 kJ.mol) and they are cleverly designed so they can't get this accidentally wrong. Now when you form polymers, the energy of linking between two strands is the sum of the interaction energies, and the force driving towards dissolution, entropy, is roughly proportional to the number of molecules. This is a bit oversimplified, but the key is, if you wish to separate the strands, the hydrogen bond energy linking them has to be overcome, and this can be done from water, which also forms hydrogen bonds and will replace all the ones that did the linking, so the separation is approximately neutral in energy, and the nucleic acids can reproduce.

So, here is the first of eight questions from an ‘Arrival’ fan (I promise it’s not an exam question I've been set - I'm just writing a book and trying to make it as authentic as possible - I will try to ask the question during the 'Ask an Astrobiologist' on April 14, 2020): It’s the 'digits of a cephalopod-like-descended humanoid' question! Assume a cephalopod-like-descended air-breathing tool-using bipedal humanoid with two arms and an aragonite skeletal structure which transitioned from a marine to a land habitat approximately 25 million years ago. Assume it evolved on a similar planet to Earth, but with less arboreal cover, and in a similar solar system. The cephalopod remote ancestor resembled a cuttlefish-squid-octopus cross and had eight arms. How many fingers would the humanoid have (note biological symmetry holds)?

I think it would be hard to say. There aren't really any laws of biology that we know of (yet) that could tell us if there is a most likely answer. Maybe some creature with so many appendages wouldn't have much evolutionary pressure for the adaptation of multiple digits on each appendage. Or maybe their biology and evolutionary adaptability would allow them to evolve having many digits. There's no a lot that we know of that might limit it, especially if they could form digits without having to co-opt bones for digits. That's one thing I love about the potential for alien life - there are lots of possibilities. I really enjoyed Arrival and Ted Chiang's short story on which it's based. He has a newer book out (came out last year) that I've been meaning to pick up. 

I am unhappy with the assumption of an aragonite skeleton. Aragonite crystallises out o shellfish from calcium bicarbonate in seawater when it is at a pH where calcium bicarbonate is out of equilibrium. If the pH falls so there is more of it, the aragonite dissolves (which is why the rising CO2 levels in the oceans is really bad for shellfish. Much more and those that depend on aragonite will not be able to form shells). So aragonite is usually exterior. Given the potential pH differences when the animal is exerting, I think aragonite would be a bad choice for an internal skeleton, and why would something choose it when phosphate is much better, and the animal needs phosphate anyway?

Another interesting question is why the squid/octopus type creatures did not develop a skeleton? The answer, for the octopus at least, is the absence of a skeleton gives it clear advantages in being able to squeeze into tight spaces. So the question is, once the animal forms that sort of structure, what advantage would a skeleton give? Evolution cannot plan for the future - it advances in small steps and every step must be adequate in the niche for reproduction. Fish developed a skeleton because it gave them advantages in speed and manoeuvrability but I cannot see the advantage for an octopus.  There are also serious disadvantages for coming onto land - the entity has to see its tentacles, which means it cannot see behind it, and it cannot really develop a neck. My guess is this proposed species would be an evolutionary failure.

Graham and Ian,

Thanks for these replies. So, because of the framing of the book, I am envisaging a species that transitioned from a marine habitat to land because of the same evolutionary pressures that drove fish out of water. For a multi-million-year period, they developed as a coastal species, escaping predators in the sea due to falling sea levels, benefiting from food resources in plentiful archipelagoes, and as they utlized these more effectively an spread into the ecological niche, so they became ambulatory, with arms to assist movement, and hands to assist with grasping prey. The 'skeleton' developed from the remote ancestor's aragonite cuttlefish-like backbone in that multi-million-year period, to support movement.

What I am looking for is a skeleton which, while functional, is significantly weaker compared to a human's in the book, due to less evolutionary competition to build for strength and no arboreal phase. This is important to the interspecies politics I am working on, e.g., they view competitive contact sport differently. So, an aragonite skeleton is basically untenable? I guess a phosphate skeleton could evolve from aragonite and just not be as strong as ours?

For the purposes of the book, the species is humanoid and has hands. I am just wondering, for advanced tool use, why five digits? Would four do? Humans with only four fingers due to e.g., amputation, seem to do fine, especially if it is just a little finger. Also, I envisage their index fingers being longer than their middle fingers. Is there any functional reason that an index finger might, millions of years ago, have developed from an index tentacle? Why are human's middle fingers the longest? Is there an overwhelming evolutionary reason for this? I guess atsrobiologists get the digits question a lot.



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