Originally published March, 2023 in The Astronomy Cafe.
Thinking ahead to the 22nd seems no more of a challenge than what we had in the 1960s when we considered the mythical 21st century. But one thing is for certain, we had no idea that the socially transformative impacts of computers, smartphones and the internet would be on the horizon. We also had no idea that Stanley Kubrick’s 2001: A Space Odyssey would be way too imaginative even after Neil Armstrong walked on the moon. In the 1950s, we thought we would be driving atomic-powered cars by the 1960s. And of course, we had no idea that global warming was going to be such a problem only 40 years after the first Earth Day. One thing we do know for sure is that on April 27, 2109 Rutgers University will be opening a Time Capsule!
This essay covers some ideas in space exploration and travel. A future essay will cover climate change and other issues.
Space Travel
Historically before 2025 CE, NASA’s budget was locked at about 0.5% of the federal discretionary budget and human spaceflight was allotted from this $10 billion (0.17% of federal budget). At this sustained pace, there should be an accumulated minimum of $770 billion invested in manned activities in space by 2100 CE – the lions share going to lunar and Martian bases. You can buy a lot of infrastructure for that amount of money even with expensive billion-dollar launch vehicles!
A stable population of over 50 researchers and engineers would be a conservative estimate. This requires only an annual off-world population growth rate of 2% by 2100 CE. They would be operating inside habitats protected from radiation exposure, have sophisticated medical and surgical facilities, and the low gravity of the moon (0.2 g’s), would not be an issue impacting astronaut (Lunites?) health. The location of this base would be near the shadowed craters in the South Pole where water ice would be mined for fuel and atmosphere. The buildings would be robotically built using 3D printing techniques developed in the 2020s. They would also be covered by radiation-proof lunar regolith. Better yet, find a lava tube and seal off its ends, then erect a pair of pressurized bulkheads and build ordinary habitats at low cost. Using 3D printing, this process can be automated.
By the start of the 22nd century, if the first human expedition to Mars occurred in 2050 CE, then 50 years have now elapsed. While a lunar base at this time may have 50-100 people, the level of difficulty in transporting material and people to Mars may not allow a Martian base with more than a dozen ‘Martians’ on a 2-year rotation back to Earth. The Planetary Society thinks there could be over 1,000 people living in a sustained way on Mars by 2070, but the devil is in the details as they say. At an off-world sustained growth rate of 2% per year, we only get to about 200 people by then including the lunar base. Of course, the rapid commercialization of space may well create its own demand for people to visit the moon and Mars, and so extra capacity will have to be built by private companies.
Aside from billionaires, it is not known how much a trip will cost and if ordinary people being chased by climate change issues, will have the spare cash. The truth of the matter is that on Mars, there is simply nothing for a non-scientist to do to occupy their time. You will always live inside a cramped ‘dome’ and only venture outside in a spacesuit. You could hike or drive to a new destination, but you would always see essentially the same rust-red landscape unless you visited the ice-covered poles, which would be hazardous. Psychologists say that we have limited coping skills to deal with this kind of monotony,
However, if any traces of life are discovered either as fossils or as living systems, this will entirely change the game. It is not unlikely that with indigenous Martian life, Mars will be under extreme quarantine to prevent humans from contaminating the Martian biosphere with terrestrial DNA, or coming into contact with potentially lethal viruses.
As for the rest of the solar system, we have had tremendous success deploying robotic explorers to the moon and Mars. This technology will continue to be used with even more advanced systems that have sophisticated artificial intelligence and can operate autonomously for long periods. By the end of the 22nd century, these systems will have been placed on the surfaces of Mercury, Venus, the large moons of Jupiter and Saturn, and even a few of the distant moons of Uranus, Neptune and some asteroids too. The Curiosity rover cost $2.5 billion and has lasted over 10 years, so this technology is extremely cost-effective for the science returned. Making them fully autonomous using AI will eliminate the need for long time delays to Earth to operate them telerobotically. These systems will return to Earth high-def video that will be immediately incorporated into fully immersive Virtual Reality experiences for the general public not just a few lucky scientists.
Astronomy
Meanwhile, astronomers will continue to have no problems forecasting eclipses and unusual planetary alignments with enormous accuracy to the day, hour and minute across the centuries. We are still going to have two or three solar eclipses every year, but the one on June 25, 2150, will be the longest one since 1973 at 7 minutes and 14 seconds. It will be followed on July 16, 2186, by the longest total solar eclipse in 10,000 years at 7 minutes and 29 seconds. Most eclipses last only 2-5 minutes so these will be truly exceptional.
The first transit of Venus across the face of the sun since 2012 will occur on December 11, 2117. The previous one was a major media event observed by billons of people. Its companion event will occur 8 years later on December 8, 2125.
Then on September 14, 2123, from Earth, Venus transits across the disk of Jupiter. The last time this happened was on November 22, 2065, and it will no doubt still be a public spectacle of some interest.
Mars gets into the act three years later as it ducks behind the planet Mercury on July 29, 2126. Then on November 15, 2163, Mars colonists will see Earth pass across the face of the sun. This Earth transit will be repeated on May 10, 2189. Some lucky ‘Martians’ may actually get to see both events.
From Neptune, there will also be a transit of Jupiter across the sun on August 8, 2188, so if you were clever, you could see the Jupiter transit first and then travel to Mars to see the Earth transit a few years later.
And among the other astronomical events, the nerds among us will wait patiently for the astronomical ‘Julian Day’ calendar to roll over to 2500000 on August 18, 2132. We also get to celebrate the return of Halley’s Comet on March 27, 2134. Forty years later in 2178, Pluto returns to the same place in its orbit where it was discovered in 1930. But one astronomical activity will continue its essential work.
Killer Asteroids
Earth orbits the sun in a veritable shooting gallery of asteroids that share nearly the same orbit, and comets that arrive unexpectedly from the far reaches of the solar system.
By 2023 CE, the orbits of 20,000 ‘Near Earth Objects’ had been calculated. Hundreds of these NEOs have been placed on a Potentially Hazardous Object watch list because they are larger than 100 meters and could be ‘City Killers’ or worse if they impacted a populated area. The highest risk of impact for a known asteroid is a 1 in 714 chance by an asteroid designated 2009 FD in 2185, meaning that the possibility that it could impact then is less than 0.2 percent. The Sentry Risk Table only lists 2017WT28, about 8 meters in diameter, as an impact risk for the year 2104. Its odds are about one-in-100. A 2021 survey estimates that there are over 4 million NEOs larger than 10 meters yet to be found. However, current surveys are estimated to be more than 95% complete for objects bigger than 200 meters. This means that there are no Dinosaur Killer events of the 6km-class anytime soon.
By the end of the 22nd century, we will have had at least one if not two more events like Tunguska in 2009 and Chelyabinsk in 2013. If we are unlucky, a city or town may be obliterated, but chances are we will be able to divert its orbit to avoid impacts using the DART technology from 2021.
New Physics
Among physicists and astronomers, the search for the nature of dark matter and clues on how to go beyond the so-called Standard Model will inevitably be helped by new instruments. Current designs already have 100 TeV available by the end of the 21st Century, and likely 1,000 TeV by the 22nd century. Along the way, we may even discover new approaches to achieving these high energies, perhaps by harnessing free cosmic ray protons. These are known to have energies above 300,000,000 TeV, but they are unfortunately few and far between. You get one or two of these during the lifetime of a typical physicist.
Although no ‘new physics’ has been detected by 2023 CE, it is almost certain that the Standard Model will start to show its incompleteness somewhere above 20 TeV. Hopefully, the missing ingredients we discover will explain both the nature of dark matter and the origin of dark energy, which were discovered by astronomers in the 20th century.
The really good news is that even with these mysterious ‘dark’ ingredients to the universe, there are almost no examples in history where some new scientific observation did not have a complete explanation within a century of its discovery.
Exoplanets and the Search for Life
Astronomers will also be very busy studying exoplanets and discovering ones with signs of a biosphere, leading to a surge of innovative techniques for trying to actually image the surfaces of these worlds and detect artificial illumination on their dark hemispheres or signs of industrial pollution. Beyond the ‘baked-in’ mysteries of our dark universe, the search for extraterrestrial life will have matured in some fascinating directions by now. In our solar system, we will have explored the deep oceans of Europa, Titan, probed the crust of Mars, and settled the question of whether in our solar system any other abode than Earth ever experienced life.
Beyond our solar system, our catalog of over 500,000 exoplanets by then, and a thousand nearby habitable worlds discovered, will have been followed by an equally intense period of searching for biomarkers in their atmospheres, or illumination on their nighttime hemispheres. This isn’t to say that it is a certainty we will find extraterrestrial life by the 22nd century, but we will have certainly studied all the ‘low hanging fruit’ exoplanets for signs of it. Within 500 light years of the sun, we will know what planetary systems to avoid if we chose to visit them with AI-enabled spacecraft. If we don’t find any exoplanets with biosignatures in the solar neighborhood by this time, humans may never take the next step and conduct interstellar travel, at a cost of trillions of dollars per mission. What would be the point?
Meanwhile, another search-for-life pursuit will have started to mature so that it can inform us about an even bigger picture.
Intelligent Life in the Universe
Since the late-20th century, a small cadre of intrepid and patient astronomers have been using radio telescopes to search for signs of intelligent life. On Earth, a biosphere in existence for 3.8 billion years led to beings with radio technology only in the last 100 years. The goal of these radio searches is to detect the ‘spillover’ radiation from other civilizations across the Milky Way, far outside the 1,000 light year limits we are searching for viable biospheres. Every year that goes by, and every negative result that turns up, only reinforces the statistical assessment that intelligent life capable of, or interested in, radio technology are dismally few and far between in our Milky Way.
Science fiction author Arthur C Clarke once remarked, “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” I don’t find the prospects of extraterrestrial life ‘terrifying’ and am more inclined to agree with what Ted Arroway said in the movie Contact, “I don’t know Sparks. But I guess I’d say if it was just us…seems like an awful waste of space”.
Gravity Astronomy
The discovery of gravity waves in 2015 will lead to far more sensitive instruments by the 22nd century that will lay-bare the details of the Big Bang event itself along with actual hard data on the origin of time and space. Cosmology should largely become a closed textbook with all of the essential physical details worked out and covered by newer Big Bang theories. This, of course, depends on whether the issue of dark matter and dark energy are also resolved. Stay tuned!
Science Fiction
Recognizing the futility of creating interesting science fiction stories that begin only a few decades out, some writers have moved their stories to 2050 and beyond. Only a few Old School stories written in the mid to late-20th century still find the first decades of the 21st century interesting, and with the right technology twists to make entertaining reading. None of them were very good at predicting what the end of the 20th century would look like, so we take any fictional prognostication with grain (ton?) of salt. Still…
2100 The Ring of Charon. Earth accidentally destroyed by a Graduate Student (Allen)
2101 Babylon 5. First Martian base established (TV).
2115 Childhood’s End. Adult humans extinct. Killed by their own mutated children (Clark)
2119 Orphans of the Sky. The first Centauri expedition (Heinlein)
2123 Starwings. Earth Holocaust; Interstellar travel begins. (Proctor)
2125 Methusela’s Children – Interstellar colonies (Heinlein)
2125 Childhood’s End. The Earth is destroyed by its evolved children (Clark)
2130 Rama Revealed. Alien artifact found (Clark)
2140 New York 2140. Major flooding (Robinson)
2144 Aliens. Movie events. Need I say more?
2149 The Seeds of Aril. Interstellar Expeditions in 1-person pods (Robertson)
2150 Dr Who. Earth overrun by the Daleks. (TV)
2150 The Expanse – Mars population 100 million (TV)
2156 Babylon 5 – The Centauri civilization contacts Earth.
2171 Moving Mars – Major Mars colony established (Bear)
2190 Seetee Ship – Story events (Williamson)
2195 Ender’s Game – Interstellar war with aliens (Card)
