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Colonizing Planets or Moons for Human Habitation

Podcast by Dr. Bjorn Mercer, DMA, Department Chair, Communication and World Languages and
Dr. Gary L. Deel, Ph.D., J.D.Faculty Member, School of Business

Are there habitable planets or moons that could sustain human life? In this episode, Dr. Bjorn Mercer talks to professor Dr. Gary Deel about space exploration and the effort to find celestial bodies where humans could potentially live. Learn about overcoming challenges like differences in gravity, temperature, atmosphere as well as some of the possibilities like Mars, Venus and various moons.

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Dr. Bjorn Mercer: Hello. My name is Dr. Bjorn Mercer and today we’re talking to Dr. Gary Deel, full-time faculty in the School of Business. And, today we’re talking about the obstacles of living on other planets. Welcome, Gary.

Dr. Gary Deel: Bjorn, thanks for having me again. It’s always good to talk to you.

[Podcast: Next Manned Space Mission: Moon, Mars or Venus?]

Dr. Bjorn Mercer: I love this topic, talking about space and the, I guess you can say incomprehensibility of space is always just fascinating.

Dr. Gary Deel: Yeah. That’s what originally drew me to it, and I find it interesting as well and it’s fun to think about where we might be in the future, in terms of visiting, hopefully, for the first time and then eventually colonizing other celestial bodies.

Dr. Bjorn Mercer: Exactly. And so, my first question is, to put it plainly, Earth is perfect. It’s perfect for humans. So, what are the obstacles of living on other planets? And, when I say planets, I mean planets and moons.

Dr. Gary Deel: Sure. Well, I don’t know that I’d say Earth is perfect. There’s plenty of things that are desperately trying to kill us here. But, we’ve evolved to cohabitate in a certain sense with them on our own planet, so we’ve reached something of a symbiotic relationship with most of the life that exists here. We are nearing the two-year mark on the COVID pandemic in the U.S., so that’s just one example of ways in which Planet Earth isn’t necessarily perfect for us. But, it’s the best we can do, by far, for now.

In terms of the obstacles to colonizing or even visiting other moons and planets, they’re myriad. The most obvious one, of course, is gravity, and it’s important to note at the forefront that within the laws of physics and speaking practically, none of the obstacles that I’ll share with you today are beyond the scope of being solved or overcome or at least mitigated with science and technology. But, some come with far more difficulty than others.

Gravity’s one of those things that is difficult in some ways. We know from research looking at astronauts in space and the weightless or near zero G environment of orbital free fall around the Earth, that long term habitation in a weightless environment or near weightless environment results in muscle atrophy and bone atrophy and it’s not good for us when the body realizes that we don’t need certain muscles and our skeletal structure. It starts to metabolize that and it basically eats itself, which is not great. It’s dangerous for our organs and our long term health. So, really, for humans to go anywhere, we need to have gravity that as closely simulates what we call one G on Planet Earth as we can, which is just the gravity that we feel here on Planet Earth.

Now, you can find that if you happen to go someplace that has similar mass to the Earth. For example, Venus is often referred to as our sister planet. It’s very close in mass, within 10% of the mass of the Earth. So, Venus has got its own problems, which we may discuss here on our podcast, but, if you could stand on the surface of Venus without burning up or suffering other quick deaths, you’d feel a gravity that is pretty similar to that here on Earth. So, gravity issues would not be that much of a problem at a place like Venus.

Now, I could talk about a place like Mars. The gravity on Mars is about 40% that of the Earth. So, if you weighed 200 pounds here on Earth, you’d weigh 80 pounds on Mars, which is great because you’d be able to jump really far at first. But again, that significant difference in gravity would mean that there would be some atrophy. It wouldn’t be as much as being in a weightless environment, but you would have to worry about at least some long-term health complications.

On the moon, it’s far worse. It’s something on the order of maybe 15% [CORRECTION: Gravity on the Moon is 18% of Earth’s gravity]. This is why if you watch the old videos from the Apollo missions, you see the astronauts sort of seeming to float around and just bounce from place to place, because the gravity is so low. So, can we go to the moon? Yeah. We’ve done it and we probably will again in the near future. But, long-term habitation there could be dangerous for that reason.

We can also simulate gravity through a number of different options. One of them is centrifugal force, so if you rotate something. If you’ve ever been on that carnival ride where you stand with your back against the wall and then the ride starts to spin really fast and you feel the pressure being applied outward, basically you’re trying to fly out but the ride is keeping you in. That same effect can be used to create gravity with a spinning type of a spaceship or a spacecraft. And so, that’s one way we could simulate the same gravity that we feel here on Earth. All you need to do is calculate the proper rotation energy to create that G.

Another way you could do that is with acceleration and deceleration. So, we feel this every day when you ride in your car. When you drive down the road, as you accelerate from, say, a stop sign or a traffic light, you feel a pressure as you’re pushed back into your seat and when you apply the brakes, you feel a pressure in the other direction. It’s trying to propel you forward and out of the front of the car.

So, you could easily simulate gravity as long as your spacecraft was able to accelerate at the right acceleration, and in our case here on Earth, it’s 9.8 meters per second squared is the force of gravity. And then, you decelerate in the opposite direction as you’re approaching your destination.

So, you’d spend essentially half of your voyage between where you start and where you’re going on acceleration and the half of it on deceleration. Now, your spacecraft would have to sort of invert itself so that you’re not standing on the ceiling, so to speak. But, that really wouldn’t be a difficult problem in the weightlessness of space and you just re-orient yourself. But, you could simulate a gravity that would feel no different than you have here on Earth.

That’s a very long-winded explanation of the problem of gravity. And, I know you asked about all the obstacles. We haven’t talked about life support, circadian rhythms, radiation exposure, psychological issues. So, there’s a number of them and I’m happy to parse them with you here. But, it’s definitely a difficult challenge to explore space and to habitate other planets.

Dr. Bjorn Mercer: For sure. I love science fiction because in science fiction, we’re already out there, going from system to system. But, some of the fundamental things that we would have to figure out is gravity and atmosphere.

And, when you look at Venus, extraordinarily hot, and just that by itself is an obstacle for colonization. Just like you said, it’s a pretty good size for Earth and a pretty good gravity, but the intense heat and I’m assuming radiation exposure because it’s so much closer to the sun. And then, at the same time, Mars being farther away. It’s so cold and just like you said, the gravity and the atmosphere is so different that you’d have to figure out how to make sure that people don’t freeze.

And so, can you talk a little bit about why Mars is a good candidate but what would have to be overcome setting up shop in Mars versus Venus, which is so hot that it’s really beyond our technology today?

Dr. Gary Deel: Yeah, absolutely. I actually gave a lecture recently at the Mensa annual gathering in Houston in the summer of 2021 on this very subject. My personal opinion or perhaps just a pet project of mine is that I think that Venus doesn’t get enough attention. I hear Mars seems to be the obvious candidate. I think that’s largely a product of pop culture and the media and television and movies. We have many, many more space missions going to explore Mars for a number of reasons, but not the least of which is it’s a little bit easier to overcome the environmental challenges, although it’s further away.

So, to your point, Mars has some obvious advantages as we think about colonizing different bodies in the solar system. It is our next door neighbor further out from the sun, so that’s not really saying much. We’re still talking about a minimum six month voyage and 13 million miles and it’s quite a ways away. And so, the prospect is there and we figured out how to solve issues related to, for example, entry descent and landing, or what would be known in the space community as EDL.

This is difficult on any planet because you’re going from space varying speeds where you’ve got to make transfer orbits and this is very high velocity stuff to effectively zero. You’ve got to land on whatever you’re trying to get to and not explode when you get there, because you could land as a kinetic impactor at 17,000 miles an hour. It would be a successful landing, but you’d be in about a billion pieces and your spacecraft would be of no use to you after the fact.

So, you have to figure out how to land on the surface in a safe way. And, we figured out through sort of many different prototypes and experiments and trial and error what works and what doesn’t. We’ve done big bouncy airbag balls. We’ve done traditional types of landers. And then, the most recent and perhaps most widely covered ones are the Curiosity and Perseverance rovers that have a very complicated EDL sequence stemming heat shields and parachutes and retro rockets and sky cranes.

And, when you look at it in the simulation, it seems like it would be impossible for all of that to work, especially automatically, and I say that in the sense that Mars is too far away for us to be able to have any intervention live. We can’t steer it in. We can’t control it by remote because it takes roughly 13 minutes for a light signal, a radio signal, to transmit between Mars and Earth. So, we’re always at least 13 minutes removed from even seeing what’s going on and then another 13 minutes back to send a command to do anything, which is not enough time to allow for us to have any influence on the EDL sequence. So, everything has to go perfectly robotically on its own, and the good news is we’ve done that successfully and we’re getting better at it every day.

But, those two rovers that were extremely expensive and complicated projects, the fact that they made it and they’re both functional and working and there was no damage and the EDL sequences seemed to be perfect is a testament to how good we’ve gotten at that.

Mars has minimal atmosphere, 1% of Earth’s. That’s one of the problems with EDL, is that you have nothing to slow you down when you get there. That problem for humans is also a problem in the sense that there’s nothing for us to breathe. The minimal atmosphere that is there is mostly carbon dioxide, so even if it was more robust, it wouldn’t obviously be oxygen or nitrogen such as what we’re used to breathing here on the Earth.

And that presents two problems. One is, of course, our life support. We can’t breathe it. Number two is pressure, atmospheric pressure. We need that to survive. We’re used to one atmospheric pressure, which is similar to what we described earlier with one G of gravity. That’s what we’re evolved for and if we deviate from that significantly, we suffer health risks.

Divers know this when they go deep in the ocean because they have to slowly rehabilitate back to the surface. Otherwise, the experience, what we refer to as “the bends,” that bubbling of gases in the blood which can kill you if you return to one atmospheric pressure too quickly. So, there’s these sort of recovery chambers that divers have to come up slowly in stages that often take several hours just for their blood levels to rebalance themselves before they’re exposed to one atmospheric pressure again.

The same is true on Mars, but we’d be going in the other direction. Instead of more pressure, we’d be going to less, so much so that if you went to Mars without a spacesuit, your blood would start to boil from the lack of pressure and you’d be dead very quickly. If you didn’t suffocate from the lack of oxygen first, that would kill you. Or, as you mentioned, the cold temperatures.

You know, Mars is not as cold in certain areas at certain times of year as some people might think. People think that Mars might be hundreds of degrees below zero and at some times of the year and in some places, it is, so that’s not untrue. But, on the equator in the summer, the Martian summer, you can find temperatures that are above the freezing point, 50 degrees, 60 degrees Fahrenheit. So, it’s possible. But, I mean, daytime optimal temperatures, cloudless sky that allows for optimal sunlight. I mean, this is not an everyday thing. And, at night, it’s dropping considerably. I mean, to levels that humans could not survive without some type of insulation. So, that’s really a problem, for all intents and purposes, because the balmy temperatures are so limited.

[Note from Dr. Deel: This is not to imply that there are ever “clouds” on Mars. There are not. However, there are dust storms and other “weather” that could affect sunlight levels.]

So, if you go to Mars, you need absolutely some type of habitat and insulation. You need pressurized spacesuits. You need something to breathe. And, obviously, you’ve got to bring all of your food and water with you. There’s none of that there. So, these are some of the challenges that you’re going to find almost anywhere.

Now, the reason I said at the onset that I think Venus is more attractive than people might think. As you mentioned earlier, it’s really hot there. So, on the surface, it’s about 900 degrees Fahrenheit. It’s a pizza oven. The pressure is also so high than it would literally crush you to death. So, you probably wouldn’t be killed by the temperature first. You’d probably be crushed by the sheer weight of the atmosphere above you because Venus is sort of a demonstration of what can happen if you have a severe runaway greenhouse effect.

Now, just to ease minds, I don’t think that even the worst estimates for global warming here on the Earth could predict that we would ever end up like Venus. That’s kind of the worst of all scenarios. But, Venus is extremely thick carbon dioxide atmosphere. It’s also got sulfuric acid rain, which is a big problem.

So, you may be wondering why in the world would I think that it would ever be a candidate for habitation? Well, on the surface, it’s not, and that’s pretty much a non sequitur. But, it turns out, if you look at the data closely, and what I mean is the data from the missions that we’ve sent to Venus where we’ve sent landers to plunge through the atmospheric surface, measure the composition and the density and the temperature as they go down. We’ve done this, the former Soviet Union, now Russia, has done this. And, we’ve captured some really good data that allows us to get a sense of what things are like at different layers.

And, it turns out almost serendipitously that there is a layer in the Venusian atmosphere, I don’t have my data in front of me, but I want to say it’s about 50 kilometers above the surface, where the atmospheric pressure and the temperature are such that humans could survive in a situation without a pressurized insulated spacesuit. So, we would not need that sort of artificial apparatus.

Now, there are other problems. Of course, as I mentioned, there’s sulfuric acid rain or at least some of that vapor in the atmosphere. There’s reason to think that the levels, the parts per million at that altitude, would potentially not be too deadly for humans, probably wouldn’t be something you’d want to spend an awful lot of time in.

But, the point being that you could potentially go outside if you were to imagine yourself floating in a hot air balloon at 50 kilometers above the surface of Venus and stand outside with nothing more than an oxygen mask because you couldn’t breathe the atmosphere. That’s for sure. Again, it’s mostly carbon dioxide and sulfur dioxide. But, you’d eliminate those challenges and then you’re just left with some of the other ones, which are, again, what you have everywhere. You’ve got food and water.

[Correction from Dr. Deel: Venusian atmosphere is mostly carbon dioxide and molecular nitrogen.]

You mentioned radiation earlier and that’s a big problem on Mars because of the lack of atmosphere. So, you have nothing to protect you like we do here on Earth. We have the ozone layer and we have our thick atmosphere, relatively thick, that protects us from most of the cosmic and solar radiation that we experience.

But even so, if you think about it, when we go to the beach, we wear sunblock. Why? Because, we don’t want to be exposed to all that UV radiation, which in addition to causing painful sunburns, can cause melanoma and cancer. Radiation destroys DNA, so this is how you end up with cancerous cells and tumors and that kind of thing. This is why people who have too much sun exposure can be at risk for things like skin cancer. On Mars, that would be a huge problem, meaning you’d have to be protected by some type of shield on the surface or dig in a subterranean way so that the soil itself protects you.

Now, on Venus, as you mentioned earlier, it is closer to the sun, so you have some issue with greater density and intensity of radiation exposure. However, you have this tremendously thick atmosphere, and so, you have some protection, some insulation there. It’s unclear how much protection that would afford you and whether or not you would still need additional layers because, again, we just don’t have as much data on Venus as we do.

But, at that 50-kilometer mark, the question would be, or sort of the $64,000 question would be: would the radiation level with all the atmosphere still above you at that altitude be dangerous enough to be concerning? Or would it be something where you could spend short stints outside your spaceship or your floating sort of hot air balloon, if you will, without having to worry about immediately contracting some deadly radiation damage? That’s still to be known. But, again, the atmosphere itself is a plus in that sense because it does block out and shield a lot of that exposure.

They don’t have an ozone layer and Venus is not geologically active, which means it does not have a magnetosphere. That’s something that the Earth has which protects us largely because we have the Van Allen radiation belts that trap a lot of the solar radiation. But, that’s also true with Mars. Mars is not geologically active, either. So, both of these planets have a problem in that they have no magnetosphere.

There have been talks by engineers, STEM engineers and astronomical engineers, about potentially synthesizing a magnetic field of sorts. We’re talking a huge undertaking to do that. Could you artificially create a magnetic shield that would protect you on a planet? Potentially. But, this is on the order of like a Dyson sphere project. This is an enormous undertaking.

So, those are some of the sort of pros and cons and a very long-winded answer to your Mars versus Venus questions. But, I think Venus deserves more attention and there was a NASA project that was shelved that originated, I think, back in the 80s or 90s called HAVOC. It’s an acronym that stands for High Altitude Vehicle Operational Concept. And, you can look this up on Google. There are some sort of artist renderings and they look like hot air balloons or blimps, dirigibles that could potentially float around in the Venusian atmosphere and carry people around.

[Correction from Dr. Deel: “HAVOC” stands for High Altitude Venus Operational Concept]

The really cool thing is that on the subject of a dirigible on Venus, oxygen and nitrogen, the composition of air that we breathe here on Earth, is actually lighter than the carbon dioxide that comprises the Venusian atmosphere, which means that you could fill your blimp with the same stuff that you breathe. You wouldn’t need to fill it with helium or hydrogen like we use for our blimps here on Earth. You could actually fill it with the oxygen that you need to breathe and then live inside the buoyancy compartment. So, you wouldn’t need something hanging below that is your sort of life module. You could actually live inside the balloon itself. And, obviously, that also presents some safety benefits because you don’t have to worry about the thing springing a leak and exploding or anything of that nature.

[Note from Dr. Deel: Oxygen is still highly combustible, but pressurization needs would vary based on payload and crew weight and vehicle size.]

So, number of benefits in that regard and things to think about. But, it’s not at all clear which we’ll go to first. I think Mars will probably be the obvious one, given the attention and the pressure there, and that’s fine. I don’t think we should dismiss Venus altogether because I think there’s a viability model there in the atmosphere. Certainly not on the surface, but in the atmosphere.

Dr. Bjorn Mercer: For sure. It is interesting because, yeah, Mars has always gotten more attention. Maybe it’s because the science fiction that comes from Mars. For Venus, I think of the floating cities in Star Wars. Obviously, if you could figure out how to float a city, that could be possible. But, for both of these options, you need to have some sort of ability for humans to survive, just like you said. And then, at the same time, you need to be able to then extract minerals and resources from the planets you’re at, to self-sustain yourself because you can’t have all the resources coming from Earth. That would be too expensive and really, really impractical.

With Mars or Venus, how would you get? I mean, the oxygen, like you said of Venus, is potentially there, which is great. Now, with Mars, there’s no seemingly oxygen. Like, I guess you could mine for oxygen, which could be a possibility in which you have these big domes on Mars which creates everything. But then, that also creates this issue where if there’s any sort of, if it fails, potentially everybody dies. And, just imagining how things might occur in the future, a big dome makes sense on the moon, also.

Dr. Gary Deel: I think you’re right. You need to think about if you’re going to have a dome on the moon or on Mars, again, that radiation exposure. So, whatever the dome is comprised of needs to be radiation reflective, and you can resolve that with engineering. The oxygen could be chemically manufactured from carbon dioxide, so the fact that you have some carbon dioxide on Mars would give you a potential source for at least a limited amount of oxygen, especially if you’re only supplying it for a very small habitation dome. Same is true on Venus. So, you could manufacture your oxygen there. But, yeah. The question of how to support yourself with things like food and water are a bit more difficult.

Dr. Bjorn Mercer: Besides all the engineering obstacles, which, honestly, engineers can figure it out. Given enough time and technology advances, engineers can figure it out. Is just how do you then create the food. And, I’m not even talking about animals. Think if we went to Mars, most things would be plant-based or eventually just grow protein in the lab, like they’re really starting to do now. So, beyond the two planets we’re used to, Mars and Venus, are there any moons besides our moon which might be suitable habitats, which might be suitable places for humans to go and colonize?

Dr. Gary Deel: Yeah, potentially. Our moon’s not great because, again, very low gravity, low atmosphere, no atmosphere essentially. So, you’re starting with a situation that’s arguably worse than Mars, definitely worse in terms of the gravity, worse by a little bit in terms of the radiation because, again, you’re closer and you have zero atmosphere as opposed to 1% of Earth’s on Mars. But, they’re about the same in that respect, so the moon is not a great, it would be a great outpost for future missions and so that’s been proposed and may in fact be where we go first, is back to the moon to set up some type of permanent springboard that our Earth missions leave Earth, rendezvous with the moon, and then head off to wherever they’re headed as their final destination.

There are some moons in the outer solar system that have been attractive to researchers and just thinkers about what might be out there. We’ve sent missions like Cassini–Huygens and the Juno probe to Jupiter and Saturn, respectively, and so these missions have investigated the moons around the outer gas giants and found some interesting things.

[Correction from Dr. Deel: Ordered is reversed here. Cassini studied Jupiter and Saturn. Juno studied Jupiter.]

We’ve got terrestrial surfaces, solid landing points: rocky outcroppings on the surface that we could potentially build on. And, we’ve even found liquid pools of substances. It’s not water because water would be long past frozen at these distances from the sun. It’s super cold out there. But, we found, for example, liquid methane on the moon Titan, which is one of the moons of Saturn.

So, that’s interesting because prior to that, in fact, we were under the impression or we had no evidence to suggest that the Earth was not the only place anywhere that had liquid anything on its surface. And again, we go to Titan and we find that there’s lakes of methane. So, at that temperature, again, and those pressures, something like methane which is clearly a gas here on Earth under our conditions is a liquid out there. And so, you have phase changes, of course, that are accompanied by changes in pressure and changes in temperature.

So, these are places that we could potentially land on. The surface doesn’t provide a very attractive place to stay for any length of time for a number of reasons. One, it’s super cold. Two, you’d have potentially gravity issues to think about. Number three is radiation and that’s huge. With these outer gas giants, the radiation from the sun directly is lower because you’re farther away, but the, for example, Jupiter has such intense radiation belts around it that your exposure for just a few minutes on the surface of a moon that is orbiting Jupiter would be tremendously dangerous because, again, Jupiter traps so much of that radiation around it. Its gravitational pull is so strong and the magnetosphere around Jupiter is so strong that that radioactive environment becomes extremely harmful.

Where the prospect is, potentially, among those who think that that could be a viable model is actually beneath the surface because a lot of these moons are comprised not necessarily of rock or iron, but of ice and specifically water ice. And so, we find that there are moons around Jupiter that have an icy, a water ice surface.

And, because Jupiter has such a strong tidal influence on these moons, its gravity is so strong, it pulls and stretches these moons just like the moon that orbits the Earth pulls and stretches the ocean, and this is where our tides come from. But here, Jupiter’s gravity is so strong that it’s actually stretching and cracking these moons like you would squeeze a tennis ball and deform its shape from a sphere into an obloit spheroid or an oval and back again. And, it’s doing this with every orbit.

And so, what happens as a result of that, is you generate heat from the friction. So, we can look at these moons and we’ve seen from our space probes that there are cracks on the surface, indicating that there’s movement in the, if you want to call them, plates of ice as they experience these tidal forces.

There’s actually geysers that shoot up of water, which tells us that there’s probably a subsurface ocean beneath some of these moons. And, how does water exist in a liquid form beneath the icy surface? It’s the heat that’s generated in the core of these moons by that constant pulling and tugging and torquing. It’s just like if you squeeze a tennis ball over and over and over and over again repeatedly. If you do it long enough, that tennis ball’s going to heat up. It’s going to get hot because of the friction of it resisting your forces and you applying that force. Well, the same thing happens to the moon.

And so, these experts believe, some experts believe, that there are subsurface oceans of water beneath the icy surfaces. Now, these icy surfaces could be several kilometers thick, for all we know. So, getting through the ice is not just as easy as drilling a little hole. It would be a tremendous effort to do that. The question then becomes, though, if you could get through the icy surface to whatever subsurface ocean exists beneath, what would you find?

Because everywhere we find liquid water on Earth, we find life. In puddles and in what we used to think of as the Dead Sea, which turns out is teeming with microbial life. In the deepest depths of the Marianas Trench where there’s no sunlight whatsoever, we find bioluminescent organisms that are feeding off the geothermal activity of the Earth, these volcanic vents at the bottom of the ocean floor.

So, we used to think that in those deep, dark places there was nothing there because what could possibly exist where there’s no sunlight? But, we’ve been down there in recent years with technology and we’ve found that life is everywhere where we have water, liquid water specifically.

So, the question becomes when we eventually, if we go to these moons and we find a way through the surface ice into those subsurface oceans, will something be swimming around down there? Will we find life? Or, might we be the first life there and could we habitate those moons beneath the surface where the ice would protect us from radiation and we could float around in a submarine of sorts? Interesting questions.

Dr. Bjorn Mercer: They are. They are. You know, and one of the great things about talking about space exploration and habitating other celestial bodies is all the potentials. There’s so many wonderful potentials about the Venus, Mars, the various moons around Jupiter and Saturn. And, I’m glad you brought up the radiation around Jupiter. I don’t think a lot of people realize that Jupiter by itself creates so much radiation that it’s a deterrent.

Right now, with our technology, obviously, our technology is limited. In a lot of way, we’re still dreaming. We’re still dreaming of what can be, which is great because it really makes us think of what can be, but it really makes us realize what we have to do here on Earth.

So, this leads us to the last question, is: Why should humans be good stewards of the Earth since establishing a habitable planet is so difficult? And, I ask this because, you know, there’s a lot of buzz about Bezos, people wanting to go to Mars and colonize and all these different things, which is great. But, at the end of the day, Earth is perfect for humans. Not perfect in the sense that Earth can still kill us five times over. We evolved to live here. It’s good for our bodies. The Earth is a great place to grow and to really sustain humans. And so, why should we really be better at actually taking care of the Earth?

Dr. Gary Deel: Yeah. It’s a great question and I think people under-appreciate how nice the Earth is relative to, it takes some intense study into space and celestial bodies outside of our own planet within our solar system and then beyond, to realize that it’s few and far between. In fact, we don’t know of any other place that is as nice for human habitation as the Earth, even outside of our solar system. We’re exploring exoplanets and there’s possibilities out there, but we’ve yet to discover anything that is even close to approximating how comfortable it is relatively for us to live here on the Earth, and that’s given all of the things that we discussed: viruses and diseases. And again, these are just parts of our trees of life that have evolved to, in some ways, be adverse to our existence. Volcanic eruptions. Right? That could easily do us in. Earthquakes and tornadoes and hurricanes and storms from our weather patterns.

So, for all of these things that we wish were better, the Earth is still by far a better place to be than anywhere else you could transplant yourself right now if you wanted to. And, I think that’s the point here. I think that preserving our Earth and taking care to maintain the favorable conditions that we do have and to not make them worse is extremely important.

The subject of climate change and global warming comes to mind for obvious reasons. And again, I mentioned earlier that the worst estimates don’t predict that we would ever end up with a 900-degree surface temperature and the complete eradication of the human race like you would see if we instantly transported ourselves to Venus right now.

[Podcast: A Conversation about Climate Change (and What to Do at the Local Level)]

But, it could be a lot worse in terms of just incremental temperature changes, sea-level rise, increasing frequency and intensity of storms in the climate. I live in Florida, so we are that hurricane alley and we’re seeing them already. And so, we have to take this seriously and we have to appreciate the damage, the irreparable damage to some extent, that we could do.

I’m reminded of something that Dr. Neil deGrasse Tyson, author and director of the Hayden Planetarium at the Natural History Museum in New York, often says, and that is that if we have the capacity technologically to inhabit other planets and to terraform them into Earth-like or at least tolerable environments for human habitation, then we certainly have the capacity to protect Earth and to turn Earth back into Earth, and if we do damage, to repair it and to care about the planet that we inhabit now. And, I think that that’s absolutely true and it would be far easier, less expensive, less painful, to just preserve what we have here, at least for the time being.

And, I’m certainly not opposed in any way, shape or form to habitation of other celestial bodies. I think that’s really important for survival purposes and for the exploratory spirit that I think is part of the human condition.

But, the very fact that even if we do our best here on Earth and even if we abated climate change immediately, we still have things to worry about, like the fact that every once in a couple hundred million years we get hit by a giant asteroid that threatens to wipe out all life on the planet like that which, you know, the Chicxulub crater was created by and wiped out the dinosaurs.

So, there’s absolutely no reason to think that that couldn’t happen again. We have no way of predicting, at least with today’s technology, exactly when or where, and there’s, to be clear, there’s no immediate threat that it’s going to happen tomorrow. But, we don’t know.

And so, for that reason alone, if we care about the continuation of this human project, it would be to our advantage to have a multi-planetary species where all of our literal eggs are not in one basket. But, that being said, there’s no reason why we need to trash the planet that we live on now. And it just takes some education, some awareness, and some consideration for the impact that we have.

And I think one of the first steps is getting past the denial from people that are resistant to this idea that humans are a part of this equation. The science is conclusive now. You will never have 100% consensus wherever humans are corruptible or manipulable or simply fallible in any way, shape or form. But, you have something like 98% or 99% consensus among climatologists that humans have a significant role to play in the global warming effect that we’re seeing in recent years.

So, the jury’s not out. The verdict is in. It’s quite clear and we need to move beyond that to real policy initiatives and the international community is at least congregating to address this issue. I wish there were more concerted efforts at this point. But, it’s nice that we’re not doing nothing, but we still need to do more.

So, public awareness around this and a resistance to anyone who wants to continue to dig up the old conspiracy theories that this is not a human-influenced problem. We simply have to move on and that’s really important to the continued survival of our species and the comfort that we enjoy on this planet because it could be very different if we don’t take care and appreciate what we have.

Dr. Bjorn Mercer: Exactly. As far as the Earth goes, even if we mess it up and we kill ourselves as a species, the Earth will live on and there will probably be animals that live on and different things that live on past us and we will have killed ourselves, which is hard to imagine because from a very narcissistic perspective, the universe revolves around us as humans.

So, from my perspective, it’s not as easy as, “Oh, we need to start going out there because the Earth, may be a limited shelf life.”

Dr. Gary Deel: Yeah, absolutely. I think people under-appreciate the challenges associated with something like interstellar travel, let alone just within our own solar system.

When you think about interstellar travel, I mean, you can no longer measure in miles because you’re just in hundreds of trillions and quadrillions. You have to measure in light years, which is the distance that it takes light to travel in one year. Light, of course, which travels at this incredible speed that the universal constant, as we call it, that limit, nothing travels faster.

And, at our current technological speeds, I mean, the fastest spacecraft that we’ve ever developed would take tens of thousands of years to travel there.

In fact, for those space enthusiasts who may know this, recently we had news from the 70s. Carl Sagan’s Pioneer One and their Voyager One and Two rather, these space probes that we sent, some of the first to go to the outer solar system and photograph the gas giant planets for the first time. We’re still in touch with them. They’re powered by nuclear reactor batteries of sorts and they’re still moving out. We just sent them off on a mission to never return and they’re just traveling through space.

And, in recent years, in the last, I want to say five or so, both reported back that they have finally left what we refer to as the heliosphere, which is just the point at which the pressure from what we call the solar wind, the electrons that are emitted from the sun, meets that deep space equilibrium. So, at the edge, if you want to call it an edge, of our solar system. They just finally reported from their sensors that they got there and these space probes were sent out in the 70s. I mean, we’re talking 50 years of travel, give or take.

And so, it’s tremendously interesting to see that now we know where the edge of our solar system is. But, they haven’t even begun to step off the porch of our solar system and head out toward anywhere. So, it’s exciting to think and to look with our telescopes so that we can see what’s out there, but the prospect of going is quite a ways away. There’s ways to do it, but none of them are easy and we’re still within the realm of science fiction. So, for the time being, we need to care about the planet that we live on because we don’t have a planet B at the moment.

Dr. Bjorn Mercer: And, very well said. And, today we’re speaking with Dr. Gary Deel about the obstacles of living on other planets. My name is Dr. Bjorn Mercer and thank you for listening.

Dr. Bjorn Mercer is a Program Director at American Public University. He holds a bachelor’s degree in music from Missouri State University, a master’s and doctorate in music from the University of Arizona, and an M.B.A. from the University of Phoenix. Dr. Mercer also writes children’s music in his spare time.

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