Planet earth is overdue for another catastrophe. It may not occur for thousands or even millions of years, but there have been five mass extinction moments in earth’s history, and another is inevitable. Whether it’s man-made or natural, terrestrial or from the deep reaches of space, we must pursue alternative living situations beyond earth while there’s still time. Theoretical physicist and futurist Michio Kaku shows us where things stand with space exploration and the hurdles that humans must clear to become a multiplanetary species.

The eruption of supervolcano Toba in modern-day Indonesia sent millions of tons of dirt, smoke, and rock hurtling miles into the atmosphere and across continents. Debris covered Malaysia and India with a coat of ash and rock up to 30 feet thick. Populations as remote as South Africa’s were decimated. Wherever this toxic cloud reached, it spelled destruction for the plants and animals residing there. They were buried in the ash, burned in the blistering heat, choked in the poisonous smog, or frozen in the winter that set in when the dust settled. Somehow, a handful of humans survived, eeking out an existence on whatever scraps of edible matter remained. Imagine that: a remnant of humanity small enough to fit in a small concert hall.

The ocean spray or majestic mountain vistas might lull us into a sense of security, but the laws of physics dictate that we are not immune to another disaster of super volcanic proportion. The gaps between these mass extinction events are thousands or even millions of years. There have been five so far in Earth’s history. The sixth could be due to man-made climate change. It could be natural, like another Ice Age or the eruption of the monstrous volcano currently dormant under Yosemite. It could be an extraterrestrial threat, a meteor crashing into our atmosphere and ending us like one did 65 million years ago. Carl Sagan rightly described our planet as a “cosmic shooting gallery.” Should we manage to evade all these dangers, the ultimate danger is the exhaustion of our Sun, which will be the most decisive end to life on earth.

Cataclysmic events like this are rare, but shaping. Barring humans—and only recently in their case—no species could predict catastrophes. They merely react as the crises loom large. Animals either emigrate from inhospitable places, adapt to the new conditions, or die. Homo sapiens is the only species capable of shaping its destiny. We don’t have to wait around to become part of the latest mass extinction.

There are a number of historic waves of science and technology that have laid the groundwork for space travel and settlement. The nineteenth century witnessed the first wave, as physicists made foundational discoveries in thermodynamics and mechanics. This was the era of steam engines, locomotion, and factories.

The second wave began in the twentieth century as physicists gained a better grasp of electricity and magnetism. This made the Age of Electricity a reality, and its tendrils took firm hold of homes and businesses across the world, in the form of radio, television, generators, and radar.

In the twenty-first century, quantum physicists have brought in the third technological wave, building on developments in laser and transistor technology. From these accomplishments have come the super computer, telecommunications, GPS, and the internet.

At least two more waves of science need further amplifying in order for interplanetary and interstellar life to be feasible. The fourth wave already underway involves AI, nanotechnology, and biotechnology. Terraforming Mars will be unlikely until the twenty-second century, but it will be built on the technologies we develop now, like self-replicating robots, ultra tough nanotech, and crops engineered to handle life on Mars—or Jupiter or Saturn. A fifth wave will be needed if we hope to traverse the solar system itself, like nanoships, laser sails, and engines that run on antimatter.

Astronomers have discovered over 4,000 planets in the Milky Way, and estimate that there might be as many as twenty billion earth-sized planets in our galaxy. Our corner of the universe is brimming with potentially inhabitable locations.

The prospect of extraterrestrial civilizations and the possibility of cultivating life on new planets is a remarkable notion. As science progresses, we ourselves are becoming the gods our ancestors feared and revered, capable of shaping not just earth but galaxies. The path forward is a difficult one, but we don’t have another option. Humanity’s time on earth is limited. Posterity will thank us for our preparation.

Until recently, there had been a decades-long hiatus in space program development in the United States. The wheels of NASA bureaucracy were painfully slow and there was not a clear heading until 2105: return to the moon, and then land astronauts on Mars.

Contemporary space exploration projects are no longer the exclusive domain of governments. There is significant private interest as well.

Jeff Bezos and Elon Musk—among others—are leading the charge in what some are already calling the battle of the billionaires. Bezos wants to get a man on the moon again whereas Musk wants to get to, and eventually terraform, Mars. Bezos’ Blue Origin space program developed the first rocket to return to its original launch pad without a hitch. Musk’s SpaceX program has engineered the first rocket to develop multiple payloads. Both are remarkable feats, and the competition will only expedite tech development.

Blue Origin recently released a VR simulation of the experience that they are almost ready to offer tourists: a rocket shot to the edge of earth’s atmosphere. His line of rockets, New Shepard (a nod to the astronaut, Alan Shepard), is shy of the 18,000 mile-per-hour launch speed required to get a rocket into orbit. The simulation shows a spacious cabin, where every seat is a window seat, offering a view of the 68,000 mile-long, 11-minute journey to a suborbital position. The sky changes from light blue to deep violet to jet black. At the edge of the atmosphere, passengers can unbuckle and experience the sensation of weightlessness. Leaps,  somersaults, and walking on the ceiling are possible during this venture, giving new meaning to “moving freely about the cabin.” Blue Origin has not listed a specific cost yet, but many people estimate the price will be about $200,000 per person.

Moon landings raise important political questions. Can a country claim territory on the moon? There was an Outer Space Treaty that the United States, Soviet Union, United Kingdom, and a number of countries signed, declaring that they would abstain from seizing lunar territory; but with the battle of the billionaires heating up, we must now ask questions about how private ownership should be handled.

It will be imperative to work some of these questions out, but the prospect of residence on the moon is an exciting one to ponder. So far, sci-fi writers and Hollywood artists have given us the clearest glimpse of what that could entail, but scientists are right behind them. China announced its intentions of landing on the moon by 2025. Obama held out 2030 as a date, but under the Trump administration, that timeline has been pushed up.

Now, all these initiatives cost an arm and a leg, but there are new possible revenue streams that those at Silicon’s cutting edge are looking to make a reality. Scientists and entrepreneurs are having serious discussions about mining space for minerals and natural resources. Among the most promising interplanetary possibilities are asteroids.

To quickly recap 6th grade science, a meteor is a chunk of rock that immolates as it encounters earth’s atmosphere; a meteorite is a specimen that manages to break into the atmosphere and makes it to earth; a comet is like a meteor, but the direction of the tail is driven by solar winds rather than the rock’s trajectory; finally, asteroids are bits of rock in space that form a belt between Mars and Jupiter. Astronomers believe these asteroids are the remains of a collapsed planet.

The asteroid belt is no place for a colony—maybe not even for a space station—but it is prime for mining valuable minerals. Many contain iron, nickel, and cobalt, as well as far rarer materials like platinum, palladium and osmium. These resources are rare and, thus, extremely valuable. In the summer of 2015, for instance, one asteroid was spotted that was about 3,000 feet long and contained approximately 90 million tons of platinum. That’s a price tag of over 5 trillion dollars! The 16,000 asteroids near earth are much smaller (about 10 feet across) and can be readily corralled into earth’s or the moon’s atmosphere.

It sounds like science fiction, but some of the most powerful people in the the tech industries, like Eric Schmidt and Larry Page as well as celebrities like James Cameron, are rallying around the cause. Their recent start-up, Planetary Resources, is dedicated to extraterrestrial mining endeavors. Earth’s resources are limited and dwindling, and it could be asteroids that provide the most lucrative revenue streams for centuries to come.

The 2015 blockbuster The Martian starring Matt Damon depicts and predicts the challenges of colonizing Mars. The protagonist is left on Mars and has to devise methods for maintaining an oxygen supply and growing crops on a frozen planet until a rescue shuttle lands in nine months. The film exposes the lay person to the difficulties inherent in such an enterprise.

Because Mars is frozen, you'd need to find ways to convert the ice into drinkable water as well as extract oxygen for breathing and hydrogen for energy sources. Then there’s the dust storms, radiation, air so thin that Mount Everest’s summit would be a refuge, and a climate so volatile that temperatures can plummet to almost -200o F after sunset. Because Mars’ gravity is about a third of earth’s, a consistent, rigorous athletic regimen is paramount. Gravity is a natural stressor that engages muscles and retards atrophy. Less gravity means more exercise.

Of course, less gravity also means new opportunities for theatrics in sports. Once the life-threatening conditions have been neutralized, there will be opportunities for tourism and then colonization. Theoretically, a third of earth’s gravity means athletes will be able to jump and throw three times as high. Instead of a triple axle on ice, it will take a triple triple axle to win a figure skating competition. This will necessitate larger courts and stadiums and entirely new dynamics to sporting events.

The terraforming of Mars will be our biggest challenge. It will require creating means to raise the Red Planet’s atmospheric temperature to above freezing. The channels and grooves in Mars's surface tells us that Mars had bodies of water, probably about three billion years ago. There’s a basin that, if liquefied, would become an ocean the size of the United States, creating sources of water for drinking and growing crops.

Scientists have a few ideas about how we could terraform Mars. One would be to introduce water vapor and methane into the atmosphere, creating a greenhouse that would raise the surface and air temperature and melt the planet’s ice caps. We could also build several colossal satellites that could direct sunlight toward the ice caps. The goal of these proposals is to force an ecological tipping point, so that the warming process would continue on its own. There’s plenty of carbon dioxide on the planet, so plants would be able to thrive. There are already vital nutrients in Martian soil as well. Studies have revealed that certain lichen, algae, and bacteria specimens can survive Martian conditions for a time.

As some critics have pointed out, there is a chance that these conditions could be reversed, but that could take as long as a century, so there would be plenty of time to devise creative solutions, like installing an enormous copper coil around the planet’s equator to help conduct heat. In any case, these are developments that will likely take place in the twenty-second century.

Hopes of more lengthy odysseys to planets and stars beyond our solar system have prompted debates about the best way to keep people alive for the duration of the journey. Three common proposals are multigenerational star craft, suspended animation, and extending longevity.

Let’s say there’s a planet a mere 100 light years away with conditions similar to those of earth’s, and NASA makes plans to explore it. Assuming the antimatter engines have been developed which would dramatically increase the speed of a star craft, it could still take 200 years. That’s about 10 generations of space travelers, only one of which has signed up for the venture. There are a lot of variables to be considered here: what do we do about the boredom that would inevitably ensue? How would the voyagers feel a sense of purpose? The first generation has consented to the experiment, but what about the generations born while en route? What would happen in the event of an interstellar coup?

A way to bypass the questions of progeny, purpose, and politics would be to put humans in a state of hibernation for the duration of the flight. This would save on costs of food and subverted voyages. Scientists have looked into the process of freezing human beings, known as vitrification, but results have been disappointing thus far. Unlike fish and frogs, which can be frozen solid but thaw out with the spring, human beings can’t withstand the same conditions. The glucose required to lower the freezing point of blood would kill us. The other antifreeze-like solutions that scientists are developing would irreparably harm the human body.

There remain significant challenges to vitrification and intergenerational travel. A third option is immortality. Eternal life has been a perennial human longing. For most of our history, it’s been the stuff of myth and folklore, but recently scientists and Silicon Valley’s best have wanted to bring it to life. Google cofounder Sergey Brin has been very explicit about his intention to “cure death,” and he’s in conversation with pharmaceutical companies about how best to approach the problem. Other high-profile entrepreneurs are brimming with optimism about increased or infinite longevity. Peter Thiel hopes for a modest 120 years. Russian tech giant, Dmitry Itskov, wants 10,000.

As geneticists hone in on the sequences responsible for aging, the age-old question of how to age without getting old might be solved soon. This will make space exploration a less daunting prospect. And who knows what might be possible beyond longevity? Advances in science open up possibilities of changing not just human life expectancy but the human body itself. Brain-computer interface (BCI) and bioengineering integrate improvements in human performance via computer chips and DNA splices. Could we be nearing a post-human era as we prepare to colonize the cosmos? With government funding and substantial private interest, the future has never been brighter.