Does humanity have a future beyond Earth?

by Corey P | Jun 3, 2020 | Does humanity have a future beyond earth, The Future

“Nuclear war. Runaway climate change. A global pandemic. Today our world faces all manner of existential threats. But scary possibilities like these are nothing compared to what astronomers say lies in store for Earth. Our planet’s ultimate destiny is to be baked, blasted, and eventually disintegrated.

There’s nothing we can do to prevent this cataclysm. Yet according to scientists who study the far future, including Yale University astronomer Gregory Laughlin, the prospect for life is, oddly, rather bright. Given technological advances and the continuing evolution of our species, humans should be able to survive — in some form — long after Earth has ceased to exist.

But our distant descendants are going to have to do some planet-hopping.

The Multi-Planet Era:

The first major cosmic crisis will strike in about 1.5 billion years. At that point, according to projections by environmental scientist Andrew J. Rushby at the University of East Anglia in England, the brightening sun will set off what might be termed “super-global” warming. Earth will be heated until the oceans boil.

By then, though, will we care? We already have the technology to establish bases on the moon and Mars. So a billion and a half years from now, we’ll likely have colonized the whole solar system — and perhaps other star systems in our Milky Way galaxy.

As the sun grows hotter, other planets will become more appealing. Just as Earth becomes too toasty to sustain life, Mars will reach a temperature that makes it habitable. Cornell University astronomer Lisa Kaltenegger has run models showing that the Red Planet could then stay pleasant for another 5 billion years.

About 7.5 billion years from now, the sun will exhaust its hydrogen fuel and switch to helium. That will cause it to balloon into an enormous red giant. Mars as well as Earth will be fried. On the other hand, the once icy moons of Jupiter and Saturn will have become tropical water worlds — prime real estate for human colonies. We could live there for a few hundred million years.

The Starhopping Era:

Fortunately, Laughlin points out, there are 200 billion other stars in the Milky Way, most with planets of their own. Perhaps our descendants will have mastered near-light-speed travel. Even with current technology, however, interstellar travel is conceivable on the kind of timescales we’re talking about.

The fastest spacecraft built to date, Voyager 1, is racing away from the sun at 38,027 miles per hour. At that speed, it would take 70,000 years to reach the nearest star. But future humans might build interstellar arks, giant ships on which generations of travelers would live and die before delivering colonists to a new destination. Such star-hopping colonists could spread across our entire galaxy before Earth overheats, even assuming no advances in rocketry.

At first, those voyagers might choose to set sail for planets around midsize, yellow stars similar to our own. That will take care of us for quite a while, since sunlike stars last 12 billion years before they fizzle. As one star ages and dies, we can move on to the next. We’ve got time.

Fifty billion to 100 billion years from now, though, all of the raw material for new stars will be used up. The last generation of sunlike stars will burn out, and humans will need a new kind of place to live.

It turns out that we have better options than yellow stars like our sun. The Milky Way is dotted with red dwarfs, cooler and dimmer than our sun but built to last. “For the next 10 trillion years, the red dwarfs are just coming into their own,” Laughlin says.

And so planets around red dwarf stars may be our homes until about 15 trillion years from now, when they too will expire.

The Gravitational Era:

Red dwarfs will be the last generation of stars. Once they die, the universe will go dark — literally. Even so, Laughlin doesn’t see this as the end of the line for life. Instead, we will enter what he calls “the gravitational era.”

In this dark future, we might build enormous space power plants around black holes, lowering masses toward them to harvest their gravitational pull “like the weights pulling down in a grandfather’s clock,” says Princeton physicist J. Richard Gott. Or we might tap the internal heat of planets to generate energy: The gravitational interaction between celestial bodies creates friction, which can keep planets hot inside even without any starshine.

Don’t picture cave dwellers huddling around geothermal heaters. Trillions of years of evolution will have long since transformed us, Laughlin says. Perhaps we will have merged with our computers. Perhaps we won’t even have a physical form. The only thing our descendants will definitely have in common with us is the essential spark of life: not flesh and blood necessarily but information.

“That’s the most important lesson from thinking about the far future universe,” Laughlin says. “We’re being naïve when we think of life only in terms of Earthlike planets and carbon-based life.”

Information-based life can keep going almost forever. The gravitational era that begins around 15 trillion years from now could continue for quintillion years and beyond, Laughlin estimates. A quintillion is a 1 followed by 18 zeroes. It is trillion times as long as the entire history of our hominid line on Earth.Will the universe die before we do?

Still, even this near-eternity is not the same as eternity. At some point, life runs into the physical limits of matter itself.

Physics theories suggest that sometime between 10^34 (1 decillion) and 10^64 (1 vigintillion) years from now, the protons found in the nuclei of all atoms will decay. That means black holes will be the only organized form of matter in the universe. Future humanity can’t have any physical form at this point.

At 10^100 years — 10 duotrigintillion years A.D. — even black holes will evaporate. There will be no energy or structures of any kind — just a cold, eternal mist of farflung particles. This really is the end point for life.

Or maybe not. Paul Steinhardt of Princeton University, one of the founders of modern cosmological theory, is exploring a model in which the universe goes through endless cycles of creation. His latest version, developed with Anna Ijjas of Columbia University, suggests that the universe could experience a new Big Bang well before the final black hole apocalypse.

If it does come, a new Big Bang would wipe away all traces of this universe — unless we can find a way to leapfrog into the next cosmic cycle. Current physics offers no guidance here.

Then again, we have quite a while to ponder the problem.”

Does humanity have a future beyond Earth?

by Kiran S | Jun 3, 2020 | Does humanity have a future beyond earth, The Future

“Life in a distant future as imagined by Amazon founder Jeff Bezos will be, in many ways, like life today. People will socialise, commute to work and have weekends to rest. The only difference is that we will be living in huge spinning cylinders that closely mimic our planet, but are actually in orbit around it. The world’s richest man, according to Forbes, is one of several prominent people who are thinking seriously about what humans might do if they ever have to develop habitats beyond Earth.

Mr Bezos’s vision is based on ideas first put forward in the 1970s by the Princeton scientist Gerard O’Neill. He proposed that humans could live in a set of twin cylinders, each measuring four miles in diameter and 16 miles in length. The cylinders counter-rotate so they keep facing the sun. At a recent event for his space company Blue Origin, Mr Bezos suggested that a series of these colonies could be designed for specific uses: some residential, others for industry and leisure. He even proposed that some cylinders could have a lower gravitational pull so residents could “go flying with your own wings”. The weather, he said, will be “like Maui on its best day, all year round”, referring to the picturesque Hawaiian island. “Imagine what architecture would be like if it did not have to fulfil its primary purpose of shelter,” he told the event in Washington, DC, in May this year. Mr Bezos is not the only person exploring the idea of living in space.

As the effects of climate change become more apparent, governments, scientists and entrepreneurs across the world have started looking more seriously at concepts that were once considered more within the realm of science fiction. Space exploration: Blue Origin’s orbital rocket “People have always shown they will do what is necessary to survive,” says Therese Griebel, deputy associate administrator for programmes at Nasa’s Space Technology Mission Directorate. “If the Earth becomes unsustainable, there will be a reason to go somewhere else.” Other plans to live in space take various forms. Ms Griebel predicts humans could live sustainably on the moon by 2028, if Nasa can find a way for us to survive the freezing lunar night. SpaceX founder Elon Musk, meanwhile, prefers the longer-haul option of Mars. The main challenge for any proposal is to find a way to extract resources from wherever humans choose to live.

On the moon, this is likely to mean using the ice found recently at its poles and converting it into water, oxygen and hydrogen for fuel. ISpace is just one of a handful of companies which thinks that such an opportunity could be turned into profit. The Japanese company says it has raised nearly $100m in its quest to get to the moon and start mining it. Its founder and chief executive, Takeshi Hakamada, says this will be the first step towards setting up a permanent colony there. Moon walk: ISpace’s Hakuto-R lunar lander and rover “The biggest hurdle to living in space is finding the resources needed to fuel your transportation needs,” says Mr Hakamada. “You need a lot of propellant, so mining the moon is the best way to get that.” The company plans to land on the moon in 2021: Mr Hakamada predicts there will be a community of at least 1,000 people living and working there by 2040.

Mining the moon is also a crucial part of Mr Bezos’s plan. He has promised to sell $1bn worth of his stock in Amazon every year to help fund Blue Origin, which is planning to land on the moon by 2024. Even among space enthusiasts, however, there is some scepticism that moon mining could ever work. Al Globus, a former contractor at Nasa, is a proponent of O’Neill colonies, but believes the materials will have to come from Earth rather than another planetary body. “Mines fail on earth all the time,” he says. “I don’t think we are going to get it right on the moon, especially not first time.” Some think that neither the moon nor purpose-built colonies will ever be big enough to house humanity should Earth’s resources run out.

Mr Musk could counter this with his plan to fly humans to Mars in the next five years as the first step in the planet’s slow colonisation. The red planet: Elon Musk, chief executive of SpaceX, is exploring how humans might colonise Mars © Bloomberg He says he can overcome Mars’ cold conditions by setting off nuclear explosions in its atmosphere — a plan he has referred to as “nuke Mars”. Critics say these schemes are the idle fantasies of middle-aged men, which threaten to distract from attempts to solve climate change on Earth.

Emily Cunningham, an Amazon employee, told Mr Bezos at the company’s annual shareholder meeting this year: “Our home planet Earth, not far-off places in space, desperately needs bold leadership.” ISpace predicts it is likely to cost up to $10bn just to start producing fuel from the ice on the moon, making heavy government investment a necessity — something that seems unlikely given the more immediate domestic problems most developed countries are trying to solve.

Some involved in space research, however, predict that as early experimental missions start to yield results, public and governmental interest in interplanetary living will grow, giving it the impetus it needs. Ms Griebel says: “Once you start building the infrastructure to extract resources from the moon, you will be able to sustain people for longer and longer. It becomes more real as you start to do it.”