Above photo: From Channel 4.
Since 1970, people have celebrated Earth Day every year during April. It is a day to reflect on how lucky we are to be on this planet. Unfortunately, it’s not a national holiday. All of us, all over the world, both adults and schoolchildren, should be given the day off filled with festivities and programs on all types of media that explain and emphasize how fortunate we are to be here. I’ve come to think of our intimate relationship with the Earth similar to that between two people, a two-way street with give and take. Ancient peoples thought of the Earth as a goddess; for the Greeks, it was Gaia, the personification of the Earth. Even in modern times, there is the Gaia hypothesis by British scientist James Lovelock that views the Earth as a living organism. Think of the marriage between a woman and a man where divorce is not an option. One part of the relationship, the Earth, gives us sustenance and a place to survive and live long-term. In return, the other partner, we, as a dominant species, have the responsibility not to abuse that relationship. But this does not seem to be happening. Before discussing this, let us consider, with a broad brush, what our planet gives us.
First, Earth’s distance from the Sun together with the greenhouse gases it produces keeps water in a liquid state. In other words, we live in a habitable zone, where carbon-based life exists, as far as we know, only because of the presence of liquid water. Second, this planet provides plate tectonics, landmasses that slide over and under, basically colliding with each other around our planet’s surface. This allows the important greenhouse gas CO2 to be cycled. Under normal circumstances, Earth gives us a balance of CO2, between production and removal. Production is mainly both natural and human sources of carbon dioxide emissions. Natural sources include decomposition, ocean release, and animal respiration. Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil, and gas. Removal of CO2 comes from plant respiration, plankton in the seas, and minerals that capture the gas in chemical reactions and return it into the Earth’s mantle through plate tectonics.
Next, the Earth gives us a protective blanket, our atmosphere, against lethal solar and cosmic radiation. Its ozone layer is part of this protection. Earth produces a magnetic field due to rotational processes in the Earth’s core made up of a solid iron ball and a layer of liquid nickel-iron alloy surrounding it. It deflects highly-energetic charged particles. Furthermore, if not for Earth’s magnetic field, our atmosphere would have been blown away eons ago by the solar winds as has happened on Mars, which has no magnetic field. The Earth with ‘symbiotic’ help of our moon gives us stability. That is, our planet’s tilt stays practically constant and any wobble is reduced to prevent dramatic swings in climate, which would have adversely affected the evolution of life here. The Earth provides us lands with wonderful landscapes, freshwater rivers and lakes, and wide-open clean oceans, diverse animals and fish for food and the former for companionship, all in an environment in which we thrive. Earth’s contribution to our relationship has been substantial and indispensable for our existence.
On the other hand, it’s clear that over the past few centuries, our contribution to this important relationship with the Earth is becoming increasingly problematic, bordering on abusive. This is the anthropogenic (i.e., man-made) attack on the environment by our modern society. Our environments, both large and microscopic, living and non-living are under attack. We now threaten biodiversity, the variety of life that keeps a balance in ecological systems. We are depleting natural resources such as clean water, clean air, and many living organisms that have been around for millennia. Today’s minimal efforts in taking care of Earth may not be enough to maintain a decent life for future generations. Do most people take the serious threats climate change, environmental degradation, ocean acidification, mass species extinction, ecological collapse, overexploitation, pollution, deforestation, as a call to action? Are these simple alarmist’s rants? I think not. They are a call to action.
So what can be done? Can we simply find a better planet somewhere once Earth becomes uninhabitable? Lately, there has been much hype in the media about sending astronauts back to the Moon and even to Mars. News articles enthusiastically proclaim that a Moon colony is in our not too distant future followed by one on Mars, a colony with millions of happy ‘Martians’. It is curious, how little one reads in the news media about the health risks new explorers face when they leave the protective blanket of Mother Earth and venture into space for long periods. What is being done to protect the lives of those we send into space.
One of the few recent books that discuss these issues is “Beyond Earth”1 by Charles Wolfforth and Amada Hendrix, the latter a planetary scientist who for twelve years worked at NASA’s Jet propulsion Laboratory on such projects as the Galileo and Lunar Reconnaissance mission, the Hubble telescope, and the Cassini mission to Saturn. The authors discuss how serious are the health issues facing spacefarers. After reading about the risks, one cannot watch sci-fi movies about space travel and think people can simply jump on a rocket and head out to live on the Moon and Mars or other places without recognizing the consequences to human health. This is in addition to living in extreme and altered gravity environments. What early explorers like Columbus did in venturing into the vast ocean to discover new places is ‘a stroll in the park’ compared to what spacefarers will face. Columbus and his crew always had a sea-breeze, water to drink, and an atmosphere over their heads to protect against serious radiation. If anyone on Earth ever thinks that it’s OK to mistreat this planet, as is now happening, because we will have an out by going to other worlds and have a good life, he or she should think again.
To understand what spacefarers face, scientists and doctors who study space medicine refer to tissue damage by various forms of radiation. For this damage, they use a unit called a Rem, the higher the dose of radiation in Rems for a short time like seconds or minutes, the greater the damage. What are some effects of exposure in terms of Rems? A dose of less than 100 Rems, little or no effects scientists tell us. 100 – 200 Rem and above things start to get bad, including increasing doses, vomiting, diarrhea, hair loss, hemorrhaging, internal bleeding, delirium, and death. This is familiar to anyone who knows what happened to the people of Hiroshima and Nagasaki during World War II. The bottom line is that without some form of protection or shielding against radiation coming from our Sun and outer space, we’d be burnt to a crisp or we’d forever be living deep underground.
What is sufficient shielding, especially for future space travelers? Scientists measure the shielding property of materials as the amount of matter one puts between the radiation source and the person in its path. Scientists measure this as the mass per surface area or grams/per square centimeter (gm/cm2.). Let’s compare some shielding numbers of a few familiar things. Luckily, our somewhat dense atmosphere offers good radiation protection coming in at around a whopping 1000 gm/cm2 (yes, still use UV cream with a high SPF number). What about the International Space Station (ISS), it comes in at 5 gm/cm2. A radiation dose for a 6-month stay is 5-20 Rems, not much of a problem because it’s spread out over time. A powerful solar flare of Jan 20, 2005, bathed the ISS in substantial proton radiation. For an astronaut wearing a space suit, 0.3 gm/cm2, and working outside of the ISS, he or she would have gotten radiation poisoning. Inside the bulkhead was a relatively safe spot. There the occupants received about 1 Rem same as people on Earth receive in 2 years, but they received this amount in 2 days. The quicker a dose comes, i.e. Rems per sec, min, etc, the less time the body has to repair cell damage.
What about our trips to the Moon? In August 1972, between Apollo 16 returning from the Moon and Apollo 17 leaving, a potentially dangerous situation arose. A large solar ejection blasted the Moon with a proton storm of lethal intensity. If astronauts had been walking on the Moon then, they would have received a lethal dose of radiation of over 500 Rems. Inside the orbiting lunar module, the astronaut would have received a non-lethal dose, but that amount of radiation would have led to radiation sickness, vomiting, fatigue, reduced red blood cells, and later, a high risk of cancer. And let’s not forget about Moondust, which might be construed as pixie dust sprinkled on couples to make them fall in love. Bu this ubiquitous dust can be deadly. Lunar dust contains fine silica shards that can cut like glass. On Apollo missions, the dust clung to astronaut’s suits, scratched their visors, made their eyes water, and their throats sore. Recent studies reveal that prolonged exposure to this dust could lead to serious effects like bronchitis or cancer. In all likelihood, future Moonians will live underground in a highly filtered air and water environment with a closely regulated 24-hours night-day cycle.
What about a trip to Mars? It seems this is several orders of magnitude worse. Astronauts will spend months in the depths of space in a crowded habitat, which further entails mental, physical, and emotional problems3.
Besides solar flares or solar winds, travelers will be exposed to galactic cosmic rays mainly in the form of what is called HZE particles, “space monsters that make Earth an island that is difficult to leave.”1 HZEs are the nuclei of heavy elements like carbon, oxygen, silicon, and iron formed deep inside stars, violently ejected, and now traveling the universe with great energies. Imagine an atomic particle carrying as much energy as a major league fastball. Even with a present-day spaceship’s shielding, HZE are particularly dangerous because of secondary radiation. This radiation comes about because when HZEs hit the shielding, hundreds of particles are released from collisions with the shielding and become a new source of radiation. A double whammy.
One scientist who knows more about this than most in space medicine today is Prof. Francis Cucinotta, a former NASA employee, who is now at the University of Nevada. He specializes in the hard mathematics of risk modeling. His many papers paint a picture that HZEs present an increased cancer risk and damage to the central nervous system, potentially affecting the mental abilities of future astronauts undertaking such a trip. Prof. Cucinotta has stated that the actual risks are unknown and warned that much more work needs to be done. Unfortunately, his and others works are now more than two decades old and it appears that NASA leaders still haven’t gotten the message. One rarely encounters news items addressing any of this.
Regarding a manned mission to Mars, a 2013 study by the National Academy of Science concluded: if the objective is critically important, if time is of the essence, if a hero or heroine steps forward willingly and with full knowledge, and if there is no other way, then a sacrifice may be ethically justified, like running into a burning building or leading a suicide mission in battle. And that’s just for starters, once on Mars, brave people will be faced with no magnetic field, lethal radiation, little atmosphere high in life-threatening nitrogen and CO2, no oxygen to speak of, and a ground toxic with perchlorates to name just a few dangers. Living underground will not be their first choice, it may be their only choice. Mars’ 1/3 the gravity of Earth most likely will have its dangers to human health. Lastly, because of these extreme environmental hazards, completely safe shielding on the surface will most likely never be enough given the financial costs or even the enormous costs in establishing colonies in space, any commercial monies to be made will depend on the cost versus benefit. And what would be the benefit? Future operations to recover water to make rocket fuel or mining rare earth minerals or isotopes like He-3 on places like the Moon, Mars, or even asteroids will best be carried out by self-sustaining ‘colonies’ of artificially intelligent robots or even human-like androids. They would not be susceptible to most dangers facing people in the same environment, easily repairable with 3D sophisticated printers, and couldn’t care less about the inconveniences of living in space. It is reasonable to assume that such ‘colonies’ would, in the long run, be a lot cheaper. Eventually, on long trips to close stars harboring habitable earth-like planets, super intelligent androids could clone humans on or close to arrival.
No doubt, the relationship between the Earth and us is becoming more and more lopsided and abusive. We take and give very little back to ensure a pristine Earth is in our future for generations to come. We are in an emergency. If this were a nuclear alert, we’d be close to Defcon 1. Catastrophes in the past like mega-volcanic eruptions and massive asteroids hitting Earth have led to mass extinctions of plant and animal life on the planet. Now we are becoming the next catastrophe. We must keep constantly reminding ourselves through all forms of education and media that this is our home, our only home. The vast majority of people on Earth are going nowhere in spite of all the hype of space travel, which does not bode well for those few who manage to leave Earth and adapt, if ever, to living in a radiation-rich and extremely inhospitable environment, possibly living underground for the rest of their lives. Not an inviting future.
We know how to treat the Earth better. While on the International Space Station and looking down at the Earth, the astronaut Mike Massimino said,” I thought at one point, if you could be up in heaven, this is how you would see the planet. And then I dwelled on that and said, no, it’s more beautiful than that. This is what heaven must look like. I think of our planet as a paradise. We are very lucky to be here.” Time is now running out in paradise.
Footnote 1 – C. Wolfforth and A. Hendrix, Beyond Earth, Pantheon Books New York, 2016
Footnote 2 – Among the problems include disruption in sleep patterns, a compromised immune system, a loss of fluid volume, anemia, neurological changes, muscle atrophy, loss of aerobatic fitness, bone loss, veins, and arteries become more permeable, fluid leaks into tissues, the spleen breaks down red blood cells, organs float up in the chest to new positions. Astronauts get taller, their waist contracts, and their chest expands. Many of these changes appear to reverse, some taking longer than others, but the long-term effects are not known. See also the recent twin studies on the astronauts Mark and Scott Kelly for some microbiological changes: https://www.nasa.gov/twins-study
Footnote 3 – Earth simulation experiments in cramped quarters for prolonged periods can lead to depression and mental problems that can interfere with carrying out astronaut-like duties.