It has been argued that the greatest reason our species should explore space and colonize other planets is so that a cataclysmic fate won’t be able to claim all of humanity. That is the driving force behind Elon Musk’s plan to colonize Mars. And it has certainly been the driving point behind Stephen Hawking’s belief that humanity should become an interplanetary-species.
And according to Hawking, becoming interplanetary is something of a time-sensitive issue. During a recent speech presented at the Oxford Union Society (Oxford University’s prestigious debating society) Hawking laid it out plainly for the audience. Humanity has 1000 years to locate and colonize new planets, he claimed, or we will likely go extinct.
For almost 200 years, the Oxford Union Society has been a forum for intellectual debate. In the past, it has also hosted such speakers as the Dalai Lama, Stephen Fry, Morgan Freeman, Richard Dawkins, and Buzz Aldrin. On this occasion, Hawking addressed a crowd of students and professors about space exploration and humanity’s future – two subjects he’s well versed in!
As Hawking made clear, humanity faces a number of existential threats, many of which are going to become a serious problem during the 21 century century. These include, but are not limited to, the threat of Climate Change, nuclear holocaust, terrorism, and the rise of artificial intelligence. The solution, Hawking argued, is to get into space and establish colonies as soon as possible.
“Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next 1,000 or 10,000 years. By that time we should have spread out into space, and to other stars, so a disaster on Earth would not mean the end of the human race.”
This was not the first time Hawking has expressed concerns about the future. In January of 2015, Hawking joined Elon Musk and many other AI experts to pen the “Research Priorities for Robust and Beneficial Artificial Intelligence” – aka. the “Open Letter on Artificial Intelligence”. In this letter, he and the other signatories raised concerns about the short-term and long-term implications of AI, and urged that steps be taken to address them.
In addition, back in January of 2016, Hawking warned that humanity’s technological progress has the power to outstrip us. This occurred during his speech at the 2016 Leith Lectures, where Hawking spoke about black holes and why they are fascinating. During the Q&A period that followed, Hawking turned to the much more dour subject of whether or not humanity has a future. As he said at the time:
“We face a number of threats to our survival, from nuclear war, catastrophic global warming, and genetically engineered viruses. The number is likely to increase in the future, with the development of new technologies, and new ways things can go wrong. However, we will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period. Most of the threats we face come from the progress we have made in science and technology. We are not going to stop making progress, or reverse it, so we have to recognize the dangers and control them. I am an optimist, and I believe we can.”
Similarly, Hawking indicated back in 2010 that humanity’s survival beyond the next century would require that we become a space-faring race. In an interview with Big Think, Hawking claimed the odds of humanity making it to the 22nd century was bad enough for a single-planet species, let alone the 31st:
“I believe that the long-term future of the human race must be in space. It will be difficult enough to avoid disaster on planet Earth in the next hundred years, let alone the next thousand, or million. The human race shouldn’t have all its eggs in one basket, or on one planet. Let’s hope we can avoid dropping the basket until we have spread the load.”
But before anyone gets all gloomy, it should be noted that between our plans to colonize Mars, and the success of the Kepler mission, we have found hundreds of planets that could serve as potential homes for humanity. But as Hawking has stated in the past, we will need at least 100 years to develop all the necessary technologies to build colonies on even the closest of these planets (Mars).
Beyond our survival as a species, Professor Hawking also advocates space travel as a way of improving humanity’s understanding of itself. This was made evident in a direct quote that the Union live-tweeted during the speech, in which he said: “We must continue exploring space in order to improve our knowledge of humanity. We must go beyond our humble planet.”
And as he has done so often before, Hawking ended his speech on an optimistic note. According to the Independent, he wrapped up his Oxford lecture with the following words of advice:
“Remember to look up at the stars and not down at your feet. Try to make sense of what you see, wonder about what makes the universe exist. Be curious. However difficult life may seem, there is always something you can do and succeed at. It matters that you don’t just give up.”
It seems we have our work cut out for us. Extra-terrestrial and/or extra-solar colonies by 3016… or bust!
Welcome back to our series on Colonizing the Solar System! Today, we take a look at Earth’s “sister planet”, the hellish, yet strangely similar planet Venus. Enjoy!
Since humans first began looking up at the skies, they have been aware of Venus. In ancient times, it was known as both the “Morning Star” and the “Evening Star”, due to its bright appearance in the sky at sunrise and sunset. Eventually, astronomers realized that it was in fact a planet, and that like Earth, it too orbited the Sun. And thanks to the Space Age and numerous missions to the planet, we have learned exactly what kind of environment Venus has.
With an atmosphere so dense that it makes regular surface imaging impossible, heat so intense it can melt lead, and sulfuric acid rain, there seems little reason to go there. But as we’ve learned in recent years, Venus was once a very different place, complete with oceans and continents. And with the right technology, colonies could be built above the clouds, where they would be safe.
So what would it take to colonize Venus? As with other proposals for colonizing the Solar System, it all comes down to having the right kinds of methods and technologies, and how much are we willing to spend.
Examples in Fiction:
Since the early 20th century, the idea of colonizing Venus has been explored in science fiction, mainly in the form of terraforming it. The earliest known example is Olaf Stapleton’sLast And First Men(1930), two chapters of which are dedicated to describing how humanity’s descendants terraform Venus after Earth becomes uninhabitable; and in the process, commit genocide against the native aquatic life.
By the 1950s and 60s, terraforming began to appear in many works of science fiction. Poul Anderson also wrote extensively about terraforming in the 1950s. In his 1954 novel, The Big Rain, Venus is altered through planetary engineering techniques over a very long period of time. The book was so influential that the term term “Big Rain” has since come to be synonymous with the terraforming of Venus.
In 1991, author G. David Nordley suggested in his short story (“The Snows of Venus”) that Venus might be spun-up to a day-length of 30 Earth days by exporting its atmosphere of Venus via mass drivers. Author Kim Stanley Robinson became famous for his realistic depiction of terraforming in the Mars Trilogy – which included Red Mars, Green Mars and Blue Mars.
In 2012, he followed this series up with the release of 2312, a science fiction novel that dealt with the colonization of the entire Solar System – which includes Venus. The novel also explored the many ways in which Venus could be terraformed, ranging from global cooling to carbon sequestration, all of which were based on scholarly studies and proposals.
All told, most proposed methods for colonizing Venus emphasize ecological engineering (aka. terraforming) to make the planet habitable. However, there have also been suggestions as to how human beings could live on Venus without altering the environment substantially.
“[T]he atmosphere of Venus is the most earthlike environment (other than Earth itself) in the solar system. It is proposed here that in the near term, human exploration of Venus could take place from aerostat vehicles in the atmosphere, and that in the long term, permanent settlements could be made in the form of cities designed to float at about fifty kilometer altitude in the atmosphere of Venus.”
At an altitude of 50 km above the surface, the environment has a pressure of approximately 100,000 Pa, which is slightly less than Earth’s at sea level (101,325 Pa). Temperatures in this regions also range from 0 to 50 °C (273 to 323 K; 32 to 122 °F), and protection against cosmic radiation would be provided by the atmosphere above, with a shielding mass equivalent to Earth’s.
The Venusian habitats, according to Landis’ proposal, would initially consists of aerostats filled with breathable air (a 21:79 oxygen-nitrogen mix). This is based on the concept that air would be a lifting gas in the dense carbon dioxide atmosphere, possessing over 60% of the lifting power that helium has on Earth.
These would provide initial living spaces for colonists, and could act as terraformers, gradually converting Venus’ atmosphere into something livable so the colonists could migrate to the surface. One way to do this would be to use these very cities as solar shades, since their presence in the clouds would prevent solar radiation from reaching the surface.
This would work particularly well if the floating cities were made of low-albedo materials. Alternately, reflective balloons and/or reflecting sheets of carbon nanotubes or graphene could be deployed from these. This offers the advance of in-situ resource allocation, since atmospheric reflectors could be built using locally-sourced carbon.
In addition, these colonies could serve as platforms where chemical elements were introduced into the atmosphere in large amounts. This could take the form of calcium and magnesium dust (which would sequester carbon in the form of calcium and magnesium carbonates), or a hydrogen aerosol (producing graphite and water, the latter of which would fall to the surface and cover roughly 80% of the surface in oceans).
NASA has begun exploring the possibility of mounting crewed missions to Venus as part of their High Altitude Venus Operational Concept (HAVOC), which was proposed in 2015. As outlined by Dale Arney and Chris Jones from NASA’s Langley Research Center, this mission concept calls for all crewed portions of the missions to be conducted from lighter than air craft or from orbit.
The benefits of colonizing Venus are many. For starters, Venus it the closest planet to Earth, which means it would take less time and money and send missions there, compared to other planets in the Solar System. For example, the Venus Express probe took just over five months to travel from Earth to Venus, whereas the Mars Express probe took nearly six months to get from Earth to Mars.
In addition, launch windows to Venus occur more often, every 584 days when Earth and Venus experience an inferior conjunction. This is compared to the 780 days it takes for Earth and Mars to achieve opposition (i.e. the point in their orbits when they make their closest approach).
Compared to a mission to Mars, a mission to Venus’ atmosphere would also subject astronauts to less in the way of harmful radiation. This is due in part to Venus’ greater proximity, but also from Venus’ induced magnetosphere – which comes from the interaction of its thick atmosphere with solar wind.
Also, for floating settlements established in Venus’ atmosphere, there would be less risk of explosive decompression, since there would not be a significant pressure difference between the inside and outside of the habitats. As such, punctures would pose a lesser risk, and repairs would be easier to mount.
In addition, humans would not require pressurized suits to venture outside, as they would on Mars or other planets. Though they would still need oxygen tanks and protection against the acid rain when working outside their habitats, work crews would find the environment far more hospitable.
Venus is also close in size and mass to the Earth, resulting in a surface gravity that would be much easier to adapt to (0.904 g). Compared to gravity on the Moon, Mercury or Mars (0.165 and 0.38 g), this would likely mean that the health effects associated with weightlessness or microgravity would be negligible.
In addition, a settlement there would have access to abundant materials with which to grow food and manufacture materials. Since Venus’ atmosphere is made mostly out of carbon dioxide, nitrogen and sulfur dioxide, these could be sequestered to create fertilizers and other chemical compounds.
CO² could also be chemically separated to create oxygen gas, and the resulting carbon could be used to manufacture graphene, carbon nanotubes and other super-materials. In addition to being used for possible solar shields, they could also be exported off-world as part of the local economy.
Naturally, colonizing a planet like Venus also comes with its share of difficulties. For instance, while floating colonies would be removed from the extreme heat and pressure of the surface, there would still be the hazard posed by sulfuric acid rain. So addition to the need for protective shielding in the colony, work crews and airships would also need protection.
Second, water is virtually non-existent on Venus, and the composition of the atmosphere would not allow for synthetic production. As a result, water would have to be transported to Venus until it be produced onsite (i.e. bringing in hydrogen gas to create water form the atmosphere), and extremely strict recycling protocols would need to be instituted.
And of course, there is the matter of the cost involved. Even with launch windows occurring more often, and a shorter transit time of about five months, it would still require a very heavy investment to transport all the necessary materials – not to mention the robot workers needed to assemble them – to build even a single floating colony in Venus’ atmosphere.
Still, if we find ourselves in a position to do so, Venus could very become the home of “Cloud Cities”, where carbon dioxide gas is processed and turned into super-materials for export. And these cities could serve as a base for slowly introducing “The Big Rain” to Venus, eventually turning into the kind of world that could truly live up to the name “Earth’s sister planet”.
Welcome back to the first in our series on Colonizing the Solar System! First up, we take a look at that hot, hellish place located closest to the Sun – the planet Mercury!
Humanity has long dreamed of establishing itself on other worlds, even before we started going into space. We’ve talked about colonizing the Moon, Mars, and even establishing ourselves on exoplanets in distant star systems. But what about the other planets in our own backyard? When it comes to the Solar System, there is a lot of potential real estate out there that we don’t really consider.
Well consider Mercury. While most people wouldn’t suspect it, the closest planet to our Sun is actually a potential candidate for settlement. Whereas it experiences extremes in temperature – gravitating between heat that could instantly cook a human being to cold that could flash-freeze flesh in seconds – it actually has potential as a starter colony.
Examples in Fiction:
The idea of colonizing Mercury been explored by science fiction writers for almost a century. However, it has only been since the the mid-20th century that colonization has been dealt with in a scientific fashion. Some of the earliest known examples of this include the short stories of Leigh Brackett and Isaac Asimov during the 1940s and 50s.
In the former’s work, Mercury is a tidally-locked planet (which was what astronomers believed at the time) that has a “Twilight Belt” characterized by extremes in heat, cold, and solar storms. Some of Asimov’s early work included short stories where a similarly tidally-locked Mercury was the setting, or characters came from a colony located on the planet.
These included “Runaround” (written in 1942, and later included in I, Robot), which centers on a robot that is specifically designed to cope with the intense radiation of Mercury. In Asimov’s murder-mystery story “The Dying Night” (1956) – in which the three suspects hail from Mercury, the Moon and Ceres – the conditions of each location are key to finding out who the murderer is.
In 1946, Ray Bradbury published “Frost and Fire”, a short story that takes place on a planet described as being next to the sun. The conditions on this world allude to Mercury, where the days are extremely hot, the nights extremely cold, and humans live for only eight days. Arthur C. Clarke’s Islands in the Sky (1952) contains a description of a creature that lives on what was believed at the time to Mercury’s permanently dark side and occasionally visits the twilight region.
In his later novel, Rendezvous with Rama (1973), Clarke describes a colonized Solar System which includes the Hermians, a toughened branch of humanity that lives on Mercury and thrives off the export of metals and energy. The same setting and planetary identities is used in his 1976 novel Imperial Earth.
In Kurt Vonnegut’s novel The Sirens of Titan (1959), a section of the story is set in caves located on the dark side of the planet. Larry Niven’s short story “The Coldest Place” (1964) teases the reader by presenting a world that is said to be the coldest location in the Solar System, only to reveal that it is the dark side of Mercury (and not Pluto, as is generally assumed).
Mercury also serves as a location in many of Kim Stanley Robinson’s novels and short stories. These include The Memory of Whiteness (1985), Blue Mars (1996), and 2312 (2012), in which Mercury is the home to a vast city called Terminator. To avoid the harmful radiation and heat, the city rolls around the planet’s equator on tracks, keeping pace with the planet’s rotation so that it stays ahead of the Sun.
In 2005, Ben Bova published Mercury (part of his Grand Tour series) that deals with the exploration of Mercury and colonizing it for the sake of harnessing solar energy. Charles Stross’ 2008 novel Saturn’s Children involves a similar concept to Robinson’s 2312, where a city called Terminator traverses the surface on rails, keeping pace with the planet’s rotation.
A number of possibilities exist for a colony on Mercury, owing to its the nature of its rotation, orbit, composition and geological history. For example, Mercury’s slow rotational period means that one side of the planet is facing towards the Sun for extended periods of time – reaching temperatures highs of up to 427 °C (800 °F) – while the side facing away experiences extreme cold (-193 °C; -315 °F).
In addition, the planet’s rapid orbital period of 88 days, combined with its sidereal rotation period of 58.6 days, means that it takes roughly 176 Earth days for the Sun to return to the same place in the sky (i.e. a solar day). Essentially, this means that a single day on Mercury lasts as long as two of its years. So if a city were placed on the night-side, and had tracks wheels so it could keep moving to stay ahead of the Sun, people could live without fear of burning up.
In addition, Mercury’s very low axial tilt (0.034°) means that its polar regions are permanently shaded and cold enough to contain water ice. In the northern region, a number of craters were observed by NASA’s MESSENGER probe in 2012 which confirmed the existence of water ice and organic molecules. Scientists believe that Mercury’s southern pole may also have ice, and claim that an estimated 100 billion to 1 trillion tons of water ice could exist at both poles, which could be up to 20 meters thick in places.
In these regions, a colony could be built using a process called “paraterraforming” – a concept invented by British mathematician Richard Taylor in 1992. In a paper titled “Paraterraforming – The Worldhouse Concept”, Taylor described how a pressurized enclosure could be placed over the usable area of a planet to create a self-contained atmosphere. Over time, the ecology inside this dome could be altered to meet human needs.
In the case of Mercury, this would include pumping in a breathable atmosphere, and then melting the ice to create water vapor and natural irrigation. Eventually, the region inside the dome would become a livable habitat, complete with its own water cycle and carbon cycle. Alternately, the water could be evaporated, and oxygen gas created by subjecting it to solar radiation (a process known as photolysis).
Another possibility would be to build underground. For years, NASA has been toying with the idea of building colonies in stable, underground lava tubes that are known to exist on the Moon. And geological data obtained by the MESSENGER probe during flybys it conducted between 2008 and 2012 led to speculation that stable lava tubes might exist on Mercury as well.
This includes information obtained during the probe’s 2009 flyby of Mercury, which revealed that the planet was a lot more geologically active in the past than previously thought. In addition, MESSENGER began spotting strange Swiss cheese-like features on the surface in 2011. These holes, which are known as “hollows”, could be an indication that underground tubes exist on Mercury as well.
Colonies built inside stable lava tubes would be naturally shielded to cosmic and solar radiation, extremes in temperature, and could be pressurized to create breathable atmospheres. In addition, at this depth, Mercury experiences far less in the way of temperature variations and would be warm enough to be habitable.
At a glance, Mercury looks similar to the Earth’s Moon, so settling it would rely on many of the same strategies for establishing a moon base. It also has abundant minerals to offer, which could help move humanity towards a post-scarcity economy. Like Earth, it is a terrestrial planet, which means it is made up of silicate rocks and metals that are differentiated between a iron core and silicate crust and mantle.
However, Mercury is composed of 70% metals whereas’ Earth’s composition is 40% metal. What’s more, Mercury has a particular large core of iron and nickel, and which accounts for 42% of its volume. By comparison, Earth’s core accounts for only 17% of its volume. As a result, if Mercury were to be mined, enough minerals could be produced to last humanity indefinitely.
Its proximity to the Sun also means that it could harness a tremendous amount of energy. This could be gathered by orbital solar arrays, which would be able to harness energy constantly and beam it to the surface. This energy could then be beamed to other planets in the Solar System using a series of transfer stations positioned at Lagrange Points.
Also, there’s the matter of Mercury’s gravity, which is 38% percent of Earth normal. This is over twice what the Moon experiences, which means colonists would have an easier time adjusting to it. At the same time, it is also low enough to present benefits as far as exporting minerals is concerned, since ships departing from its surface would need less energy to achieve escape velocity.
Lastly, there is the distance to Mercury itself. At an average distance of about 93 million km (58 million mi), Mercury ranges between being 77.3 million km (48 million mi) to 222 million km (138 million mi) away from the Earth. This puts it a lot closer than other possible resource-rich areas like the Asteroid Belt (329 – 478 million km distant), Jupiter and its system of moons (628.7 – 928 million km), or Saturn’s (1.2 – 1.67 billion km).
Also, Mercury achieves an inferior conjunction – the point where it is at its closest point to Earth – every 116 days, which is significantly shorter than either Venus’ or Mars’. Basically, missions destined for Mercury could launch almost every four months, whereas launch windows to Venus and Mars would have to take place every 1.6 years and 26 months, respectively.
In terms of travel time, several missions have been mounted to Mercury that can give us a ballpark estimate of how long it might takes. For instance, the first spacecraft to travel to Mercury, NASA’s Mariner 10 spacecraft (which launched in 1973), took about 147 days to get there.
More recently, NASA’s MESSENGER spacecraft launched on August 3th, 2004 to study Mercury in orbit, and made its first flyby on January 14th, 2008. That’s a total of 1,260 days to get from Earth to Mercury. The extended travel time was due to engineers seeking to place the probe in orbit around the planet, so it needed to proceed at a slower velocity.
Of course, a colony on Mercury would still be a huge challenge, both economically and technologically. The cost of establishing a colony anywhere on the planet would be tremendous, and would require abundant materials to be shipped from Earth, or mined on site. Either way, such an operation would require a large fleet of spaceships capable of making the journey in a respectable amount of time.
Such a fleet does not yet exist, and the cost of developing it (and the associated infrastructure for getting all the necessary resources and supplies to Mercury) would be tremendous. Relying on robots and in-situ resource utilization (ISRU) would certainly cut costs and reduce the amount of materials that would need to be shipped. But these robots and their operations would need to be shielded from radiation and solar flares until they got the job done.
Basically, the situation is like trying to establish a shelter in the middle of a thunderstorm. Once it is complete, you can take shelter. But in the meantime, you’re likely to get wet and dirty! And even once the colony was complete, the colonists themselves would have to deal with the ever-present hazards of radiation exposure, decompression, and extremes in heat and cold.
As such, if a colony were established on Mercury, it would be heavily dependent on its technology (which would have to be rather advanced). Also, until such time as the colony became self-sufficient, those living there would be dependent on supply shipments that would have to come regularly from Earth (again, shipping costs!)
Still, once the necessary technology was developed, and we could figure out a cost-effective way to create one or more settlements and ship to Mercury, we could look forward to having a colony that could provide us with limitless energy and minerals. And we would have a group of human neighbors known as Hermians!
As with everything else pertaining to colonization and terraforming, once we’ve established that it is in fact possible, the only remaining question is “how much are we willing to spend?”
One day – and it really is only matter of time – humans will set foot on the surfaces of other far-flung worlds in our Solar System, leaving the Earth and Moon far behind to wander the valleys of Mars, trek across the ice of Europa, and perhaps even soar through the skies of Titan like winged creatures from ancient legends. But until then we must rely on the exploration of our robotic emissaries and our own boundless imagination and curiosity to picture what such voyages would be like. Here in “Wanderers,” video artist Erik Wernquist has used both resources in abundance to visualize fascinating off-world adventures yet to be undertaken by generations to come. Continue reading “This Short Film is a Stunning Preview of Human Space Exploration”