Dwelling on Earth: Ep1 Transcript

Dwelling on Earth
Episode 1: "Earth as Home"

When you think about space, what comes to mind? Maybe you think about the space race, and

NASA putting a man on the moon. Or maybe you think about Elon Musk and the colonization of

Mars. Or your favorite TV show growing up? Or invaders from space? Or perhaps, like the

creators of this podcast, you are a Carl Sagan fan. But in fact, humankind was pondering what

lies beyond long before you, or me, or Carl Sagan.

“Humans on earth for as long as we have recorded history and quite possibly much further back

than that have always been fascinated with the idea of leaving the planet and traveling into the

sky, which they define variously as a heavenly place or a supernatural place or a physical

location filled with other bodies that human beings could visit and occupy, and potentially other

civilizations and other forms of life.”

That is Matthew Hersch, a Harvard Associate Professor of the history of science who focuses

on the history of aerospace, computer, and military technologies. We spoke to Dr. Hersch to

learn more about the history and reasoning behind humankind’s obsession with space.

“The motivations for people to travel into space varied very widely, some we might call scientific

interest in exploration, others had profound spiritual or religious interests in traveling into space.

Others saw space as a potential battleground in which future wars would be fought. Other

people were consumed by the idea of colonizing other planets of spreading humanity far and

wide, both because they just thought it would be a really neat thing to do and because they did

not think that Earth would be a habitable place for very long.”

Many of these motivations are still influential today. NASA, along with many other space

agencies around the world, has as its core mission the advancement of space science. The

search for life on planets other than our own has profound spiritual and religious implications.

And in 2019, the United States Space Force was added as the eighth branch of the US military.

But perhaps most intriguing is the idea that humans will eventually need to find a new home in

the cosmos.

“The idea which we still hear today is the notion that humanity can’t survive as a single planet

species, that if it is going to survive in the long term it needs to spread its wings and settle on

other nearby worlds. Our planet itself is a very interesting one but our star is very standard. It

has been alive for about 5 billion years, and the sun will likely expire or end its kind of main

sequence in another 5 billion years at which point if humans haven't masters the technology to

leave earth, they are probably not going to and humanity itself may go extinct as as just a

interesting flash in the history of the universe that arose, lived and then died. This notion is kind

of horrific to a lot of people who are fascinated by space flight and want to see the continued

development of the human organism and everything that comes with it.”

And the death of the sun isn’t the only reason humans might want to have a planet B. More

immediate threats like nuclear war, pollution, and climate change have been put forth as

existential threats to humanity that justify--and even necessitate--space colonization, the sooner

the better. This argument has garnered support from people like Elon Musk, Stephen Hawking,

and Jeff Bezos, along with a host of various organizations such as the Alliance to Rescue

Civilization, the National Space Society, and the Mars Society, just to name a few.

But many, including Neil Degrasse Tyson and Bill Nye, are skeptical that a self-sustaining

human settlement on another planet is going to be possible any time soon. The prime candidate

for such a settlement is our planetary neighbor of Mars. But the journey to Mars using current

technology takes about 7 months. Once humans arrived, they would be treated to a toxic

atmosphere, average temperatures of around minus 80 degrees fahrenheit, and dangerously

high levels of radiation. Not exactly a walk in the park.

In addition to the incredibly complex technical challenges of establishing a self sustaining

settlement on Mars, many have expressed concerns over the economics of the endeavour,

which may cost as much as $10 trillion dollars or more. Such a hefty price tag begs the

question, who will pay?

“This is a very interesting political question. One thing that people who work on space policy

have wrestled with particularly in the united states for the last 50 years or so is figuring out just

how interested the average american is in space exploration and how much they are willing to

spend on it. The latest data we have is that although people seem to think that it’s a neat idea,

the support for spending a lot of money for people to explore space has never actually been

there, and probably was never even there even during the height of the moon race of the

1960’s.”

Others have questioned whether we should be trying to leave Earth at all, positing that Earth is

the perfect place for life--and humans--to thrive.

“It is an interesting statement, I think there is something to the human exceptionalism

associated with it that you can think that things can possibly be better anywhere else. But if we

look very clearly at human life on earth, we see something very interesting. 80 percent of this

planet is covered with water and human beings aren't born knowing how to swim, so this is

actually a terrible planet for human beings to live on. It also has polar regions in the north and

south that are unihabilte, that will kill humans with exposed skin. And many of the equatorial

regions are far too hot to sustain a healthy human habitation for an extended period of time.

Um, the idea that life on earth is sort of perfectly suited to this environment is also something

that Charles Darwin really quite ably criticized . As far as he was concerned, when he saw

species around the world, when he saw animal and plant species that were actually fairly poorly

adapted to the environment in which they live. They had vestigial organs and limbs they didn't

need, there was very little indication of intelligent design rather random mutation. And his big

cognital leap, conceptual leap in creating his theory of natural selection was that organisms did

not have to be perfect to thrive on earth, they just had to be more perfect than other organisms.

So although we want to believe that earth is the perfect place for us, all we can really say is that

it is a place in which we have been able to live.”

In fact, a recently published study out of Washington State University identified 24 so-called

“superhabitable” planets that may be even better suited to supporting life than our own planet.

This finding comes with a few caveats though. Firstly, the study focused on factors that affect

the likelihood of finding extraterrestrial life on those planets, which does not necessarily equate

to improved turn-key livability for humans on that planet. In addition, all of the planets in the

study are over 100 light years away, meaning that even if we could travel at the speed of light,

they would take more than a century to reach.

With superhabitable planets laying beyond our reach for the foreseeable future, and Mars, our

closest bet in the solar system, having an atmosphere that is too thin and too cold to support

water in a liquid form, let’s turn our attention back to our own planet. By cosmic standards, our

home is pretty ordinary. It is a medium sized planet, orbiting an average star, in an

unremarkable solar system, located in one of about 200 billion galaxies.

But from the perspective of life as we know it, earth is quite special. For starters, earth’s orbital

distance from our particular star results in a temperate climate for most of the planet. This

particular climate lends itself to one of the most important features of earth: the presence of

liquid water, which covers about 71% of the planet's surface. Likewise, our atmosphere has a

chemical makeup that lends itself to supporting life. That atmosphere also has a dual role--along

with the electromagnetic field emitted by the earth’s core--in protecting the earth’s surface from

the constant bombardment of solar-radiation. Our planet’s only moon stabilizes the tilt of the

earth’s rotation, without which most regions of earth might see seasons ranging from hot

equatorial summers to harsh arctic winters. Even our planetary neighbors, Jupiter in particular,

contribute to the stable environment of earth by absorbing massive numbers of asteroid and

comet strikes that would otherwise be impacting earth. But earth is more than just the

biochemical ingredients for life and a stable environment for them to interact.

“What we can say about the earth is that when it's working, it works reasonably well, it's a

coherent ecosystem that has kept life alive for an extended period of time. In a way it's kinda

like a spaceship itself, and this is an idea that is closely related to Buckmen Fuller and others,

that what we have is a self contained, closed system that has to recycle the air and the water

upon it, that has to keep the very large population alive. And if not for the instabilities and

created by the people and other organisms that live on it, does reasonably well.”

It is this planetary system, and the ecosystem that has come to rely on it, that humans have

adapted to live with. Is the system perfect? It is hard to say, and there are signs that point to

“no.” But maybe that is not such a bad thing.

“The danger of course of saying that earth is a perfect place for life is that it leaves us to believe

that it is a resource that we can consume at will to any extent that we are able, without regard to

future generations and the planet’s ability to sustain that kind of use. And it think it's better to

say that it's a delicate and sensitive, in some cases though self regulating, that has managed to

support a great deal of life, but that requires a great deal of stewardship and responsibility to the

other creatures that upon it.”

For the foreseeable future, it is very unlikely that we will be able to find or engineer an

alternative planet that can substitute for this system. But for that same future, it is possible that

“spaceship earth” can continue to operate if we show it care and respect commensurate with its

value. Regardless of whether humans go on to colonize space, earth will always be our cosmic

equivalent of a “home”. And as was once pointed out--quite aptly in this case--”there is no place

like home.”

In 1990, the Voyager 1 space probe took a picture of earth as it prepared to breach the edge of

our solar system, nearly 4 billion miles from our home. This picture, depicting earth as a mere

speck of pale blue dot on an otherwise dark and empty canvas, was taken at the urging of Carl

Sagan to illustrate the importance of our speck. In a now famous speech on the photo, titled the

pale blue dot, Carl Sagan said this:

“ The Earth is the only world known so far to harbor life. There is nowhere else, at least in the

near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the

moment the Earth is where we make our stand… There is perhaps no better demonstration of

the folly of human conceits than this distant image of our tiny world. To me, it underscores our

responsibility to deal more kindly with one another, and to preserve and cherish the pale blue

dot, the only home we've ever known.”

In the next episode of this series, we’ll be diving into the topic of the homes we create on Earth.