Reviewer Kristine Morris Interviews Joseph Silk, Author of Back to the Moon: The Next Giant Leap for Humankind
Mother, mother moon is a little miffed with us: After all I do to make Earth a fertile, enchanting place for mankind, you barely pay me any attention. Only one brief visit in more than fifty years … you ought to be ashamed. Perhaps, one day soon, you’ll see my true dark side.
Joseph Silk has never taken the moon for granted and can’t understand why the rest of the world can’t see the extraordinary benefits of earthlings making a permanent home there. The author of 
Back to the Moon, Joseph acknowledges the high cost but says the moon’s rare-earth mineral wealth will offset much of that expense. An astrophysicist, James also salivates at the thought of building a mega-telescope on the lunar surface, noting that with its “thousandfold improvement or more on [the James] Webb’s sensitivity, we’ll unravel the deepest mysteries of the universe.”
Our intrepid Kristine Morris reviewed Back to the Moon for Foreword’s September/October issue and soon after found the time to launch a few sky-is-the-limit questions at James via email. Enjoy!
Your book, Back to the Moon, brings forward some very important arguments for the many ways that a science-focused return to the moon could both benefit further space exploration and answer some intriguing questions about the nature of the universe, human origins, and whether or not we are alone in the vast reaches of space. Why was this a particularly good time for your book to be published?
Half a century ago, the Apollo project succeeded in placing the first men on the moon. We haven’t been back since 1972. There is now great interest in going back to the moon, and this time, it will be a diverse set of astronauts that does it. Leading the way is NASA’s ARTEMIS project. Named after Apollo’s twin sister, the project plans to launch a new generation of rockets that will transport humans to the moon. Preparation is underway. We’ll be back, most likely by 2024.
What initially sparked your interest in astrophysics?
There I was, pacing the hallways of my university, trying out different lectures and seeking something inspiring before I was scheduled to move out into the real world. Totally by chance, I stumbled into a packed auditorium where the most charismatic of lecturers was explaining the meaning of inertia in the universe. I was inspired. And I never looked back.
It appears that there are currently two main drivers of lunar exploration and development: science and economics. How would each of these differ in their approach to safeguarding the lunar environment, and what might be the possible areas of cooperation or conflict between the two?
It will be incredibly expensive to explore the moon—vastly more expensive than the Apollo program, but comparable in relative terms. NASA’s budget peaked at about four percent of the federal budget. Now it’s down to about a third of a percent, and just a few percent of NASA’s current budget goes to space exploration. For comparison, US military spending is some ten percent of the federal budget. So, there’s room to expand.
I expect that lunar exploration will eventually require an Apollo-like effort. It’ll be costly. But if the lunar program is funded, a few percent of the funds would suffice for all the science we can imagine. Other countries will participate, and that will help. Much of the slack will be taken up by commercial sponsors with dreams of mining for rare earth elements and developing tourism. People are already queuing up for the first commercial circumlunar flights.
One major component of resource development on the moon will be establishing supplies of rocket fuel. That means liquefying oxygen and hydrogen, using the water and ice that are abundant on the moon. The fuel will be used for return flights to Earth, transport of needed supplies to the moon, and interplanetary exploration.
Which nations are most advanced in lunar exploration?
The US is leading the way in crewed exploration of the moon. But China is not far behind. Other nations, including Russia and India, are focusing on mapping the lunar terrain for prime mining sites in order to establish a basis for commercial development.
Now that the James Webb telescope is sending its amazing images back to Earth, do you still believe that large telescopes on the moon are essential? What would they provide that telescopes such as the Webb cannot?
The Webb is a relatively tiny instrument. Its mirror is just six meters across. Imagine a much larger telescope. It would be far too large and far too expensive to launch into space from Earth. But building a mega-telescope on the moon offers a new direction. Gravity is low, there are no winds. Construction is feasible and would bring revolutionary light-gathering power. It’s a relatively inexpensive component of the huge lunar infrastructure that we’ll build. With a thousandfold improvement or more on Webb’s sensitivity, we’ll unravel the deepest mysteries of the universe.
What discoveries about the origins of humanity might we hope for from telescopes located in craters at the Moon’s poles?
Here’s where the difference in size counts most. If we can build giant telescopes with unprecedented light-gathering power on the moon, the prospects for probing the origins of life will greatly increase as vast numbers of exoplanets are discovered. But without the power of large, lunar-based telescopes, the chances of discovering biological tracers on any of them are extremely small, and finding more complex indicators of life will have even smaller odds.
What type of evidence would resolve the question of whether the universe is finite or infinite? Is there currently any evidence that might lead to an answer to this question, and do you see it being answered in the foreseeable future?
It is going to be difficult to get a definitive answer as to whether the universe is finite or infinite. The universe is finely balanced according to our observations. If it has a slight extra component of dark mass, then it would collapse in the future. But this lies within the current observational uncertainties. Future observations will have the sensitivity to address this question.
What are your thoughts on NASA’s Artemis program and its plans to construct a base camp at the south pole of the moon?
Full speed to the moon! Artemis will build base camps with one main mission: to extract hydrogen and oxygen from the lunar regolith to create abundant rocket fuel. The craters at the south pole are in near permanent darkness, and have icy floors. They also have high rims with near permanent solar illumination that will supply solar power. And, by exploiting the low gravity of the moon for launch sites, we’ll dramatically lower the costs of space travel. Interplanetary travel will begin in earnest—the first stop for crewed travel may be Mars, decades from now.
What are some of the challenges that would be faced by those seeking to create lunar bases for scientific exploration of the cosmos? Are any of them currently surmountable with available knowledge and technology?
Strolling on the lunar surface will be easy, but living there will have its challenges. It’s not advisable to stay outside too long because of radiation hazards from solar flares. Creating a local atmosphere in vast inflatable domes should be straightforward, but the greatest risk comes from mini-asteroid impacts. One could build self-repairing structures. And with advance warning of any giant and potentially dangerous solar flare, one could shelter deep under the surface. There are lunar caves large enough to host an entire city.
How does lunar exploration benefit planet Earth and its inhabitants? How can the expense of lunar and space exploration be justified when we are facing massive multiple crises here on Earth?
Rare earth elements and semiconductor resources are limited on the Earth. We may only have thousands of years left of resources for mining some rare earths that are crucial to computer technology. And the mining is highly toxic. Lunar resources are thousands of times larger than terrestrial supplies. And we can ship the toxic waste to the Sun, the ultimate dump site.
With humanity still addicted to solving its differences by engaging in warfare, how can we be sure that any one nation would not establish a military base on the moon from which to control Earth? What types of agreements would have to be in place to prevent such an occurrence? Who is currently discussing this issue?
There is an international agreement signed at the United Nations that agrees to demilitarization of the moon. It also limits environmental pollution. However, the means of enforcement is unclear. There could be something akin to a police force, at least as envisaged by the US.
Do you have hope that mutually-honored agreements are a possibility, given the state of international affairs today?
NASA’s Artemis program envisages international collaboration. A number of countries have signed up. But some major space powers, notably China and Russia, are going their own way. We can look forward to serious competition for lunar resources.
How might conflicts over access to the moon’s resources be avoided?
The Antarctic region is an area of abundant resources where many countries have territorial claims. Via international agreements, we have succeeded in controlling resource extraction and pollution. We will do something similar for the moon. The 1967 Outer Space Treaty was ratified by 104 parties. It’s not too precise, but does provide guidance on military activities, resource extraction, and pollution. Enforcement is another matter. The moon is still a pristine environment. I am optimistic that the international space powers will unite to preserve its special status.
What types of rare elements might be mined on the moon, and which industries would benefit most?
Rare earth elements like europium and neodynium are critical for modern technologies. They are essential for products ranging from electric cars to computer hard disks, flat screen monitors, wind turbines, and cell phones. China has some sixty percent of the global reserves, compared to the US’s one percent, and it dominates world production. At anticipated extraction rates, terrestrial resources of some rare earths will be exhausted in thousands of years. And the price will rise astronomically as supplies run low. There will be intense commercial pressure to mine the moon as well as the nearest asteroids. Lunar resources of rare earths are a thousand times more abundant than terrestrial reserves. That’s the only long-term solution.
What is the likelihood that samples of water (ice), rocks, minerals, etc., brought back from the moon, could be dangerous to life on Earth?
The moon is a dead environment. It suffers extremes of temperatures that have rendered the lunar surface completely sterile. There shouldn’t be any risk in bringing lunar rocks to Earth.
How do you view the ideas of moon “colonization” and lunar tourism? What might be the consequences, and what does the timeline for such developments look like?
Lunar mining may begin in a decade. Lunar tourism, too. Let’s hope it will be done with careful regulation to control the lunar environment. The price of transport to the moon will eventually drop as competition steps up. Right now, a return ticket would set you back some fifty million USD, according to some estimates. And this is for a flight five years from now. But the moon will eventually open up to something more accessible, in much the same way as Antarctic cruises have become affordable, or a century earlier, flying. The ticket price will surely come down.
In a perfect world, what would be your vision of science-oriented lunar exploration?
Let’s build telescopes, there’s so much more we can see! The moon’s lack of atmosphere means that the entire electromagnetic spectrum is available. And stellar images won’t twinkle and be blurred. We’ll resolve more and more as we build larger telescopes. We expect to revolutionize the search for exoplanets and any signs of remote extraterrestrial life.
Can we expect another book? If so, what is its topic?
Another book is in the works. It will be about current fashions in cosmology.
What would you say to others who are considering a career path similar to yours?
My advice to those considering a career in astrophysics is to choose your topic carefully. The new telescopes are so complex that much of the preparatory work is done in large collaborations. So, you need to choose carefully. Select an emerging project that is exciting and at the forefront of our knowledge, or lack of knowledge, where most of its discoveries will be far in the future. Its potential accomplishments should be decades away, and they should be capable of addressing the ultimate questions, such as where did we come from, and are we alone in the universe. That way, you will have time to rise to an important role in a project that may change our perspective on the cosmos.
Kristine Morris
