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article imageAnother Earth is found — but will we ever be able to reach it?

By Daniel Woods     Jul 24, 2015 in Science
NASA's announcement on Thursday of its discovery of a cousin planet to Earth was historic, breathtaking but are we destined to merely be admirers from afar, or will we ever be able to visit?
Yesterday was a remarkable day - for the first time, we had some solid evidence of a world just like our own. Before Thursday, it was reasonable to speculate about the likelihood of other planets such as ours existing out there, but speculation and knowledge are worlds apart.
We can now say with a good degree of certainty, that we have found another world apart from Earth that stands a very good chance of bearing the fundamental features, the prerequisites for life. Kepler 452B is the right distance from it’s sun for there to be a hospitable atmosphere and conditions that could host organics, the chemical building blocks of life.
NASA comparison of Earth and Kepler 452B
NASA comparison of Earth and Kepler 452B
NASA
It is a similar size, taken in the context of the broad scale of planet sizes, it has a similar length of year, and similar size sun as we do here. A world with just one of these characteristics would be cause for excitement, but to find all of them in one planet and one star system is stunning – the science community must have felt as if they had hit the jackpot.
Kepler 452B ticks a lot of boxes - but perhaps the most compelling element of this discovery is the age of the planet, and the length of time it has existed in the 'habitable zone' - much longer than our world has. Six billion years longer.
Diagram of the habitable zones that both Earth and Kepler 452B inhabit
Diagram of the habitable zones that both Earth and Kepler 452B inhabit
nasa
The significance of this is that Kepler 452B has had a huge time frame for any potential life to have developed and evolved. Yesterday was the day when our hierarchy of plausibility, what we understand and rank as possible, was reordered. The odds of life existing elsewhere away from Earth dropped like a stone, and the probability of us finding a second home, went through the roof.
Comparative timeline of Earth and Kepler 452B s age
Comparative timeline of Earth and Kepler 452B's age
NASA
Scenarios that had hitherto been the preserve of dreams, fantasy and fiction edged a little bit closer to crossing into the realms of reality. Once the sense of amazement, profundity and wonder subsides, certain possibilities that would not have been entertained before, come into sharper focus, possibilities that can now be discussed with greater reverence sobriety and gravity. Possibilities such as could we ever actually make that momentous next step in human evolution, probably rivalled only by conquering mortality, and actually leave Earth?
The Blue Marble Earth image Nasa released earlier this week – the home we may have to one day leav...
The Blue Marble Earth image Nasa released earlier this week – the home we may have to one day leave.
NASA
It is a scenario that fascinates us for a number of reasons - philosophically, it appeals to our instincts as a species to explore, perpetuate, survive and progress, but also on a more pragmatic level as we may soon find ourselves in the situation whereby we have to leave Earth, either due to our plundering of its finite resources or a broader threat of extinction events.
But here comes the reality check - Kepler is just too far away for us to get there.
And this is the unavoidable problem we face if we ever want to leave Earth, to take up residence on another planet as biologically rich and atmospherically perfect as ours. We might indeed find habitable worlds much closer than Kepler 452B, but until we do the problem of travelling light year distances is one that will remain constant and implacable.
According to the laws of physics, as we currently understand them, nothing can travel faster than the speed of light - and this is the precise rate of speed we would have to equal or surpass in order to get to Kepler 452B. So as things stand, it is just not physically possible for us to reach these worlds.
Or is it?
When testing a new form of electromagnetic propulsion, known as EmDrive, researchers at NASA fired lasers into a resonance chamber. They observed some unexpected, unintended and perhaps, what the more romantic of us would say, serendipitous results. By accident, the team found they had accelerated particles to faster than light speeds. 
The pattern produced by the EmDrive tests resembled what some physicists tentatively refer to as a warp bubble - they found that the mathematical models which predict a warp bubble, matched the patterns found in the EmDrive experiments. 
So what exactly is a warp bubble? A warp bubble is the effect of a theoretical model, which predicts a loophole in general relativity, a manipulation of the structure and energy of space-time, that would allow objects - potentially us or a vehicle - to travel light year distances in weeks or months, distances that would otherwise take centuries.
Harold G White, NASA mechanical engineer, aerospace engineer and applied physicist explains:
"In terms of engine mechanics, a spheroid object would be placed between two regions of space-time: one expanding and one contracting. A warp bubble would then be generated that moves space-time around the object, effectively repositioning it — the end result being faster than light travel without the spheroid (or spacecraft) having to move with respect to its local frame of reference. Nothing locally exceeds the speed of light, but space can expand and contract at any speed. Mathematically, the field equations predict that this is possible, but it remains to be seen if we could ever reduce this to practice. Space-time is really stiff, so to create the expansion and contraction effect in order for us to reach interstellar destinations, in reasonable time periods would require a lot of energy.”
Visual modelling of a warp bubble
Visual modelling of a warp bubble
Howard G Davies
The other theoretically possible option, to travel light-year distances is going through a wormhole. Wormholes are familiar to most people, due to popularisation of the concept in science fiction and fantasy books, films and art - the notion of travelling across or perhaps between universes is a very convenient and attractive plot device.
The basic theory was proposed by the German mathematician Hermann Weyl in 1921, and in 1935 Albert Einstein and Nathan Rosen used the theory of general relativity to reason the possibility and existence of bridges through space-time, a compaction which allowed the connection of two different points in space-time. In other words a shortcut that would drastically reduce distances and travel times. 
Concept diagram of a wormhole
Concept diagram of a wormhole
http://project-quasar.wikia.com
So how would this be possible if we are to accept that faster than light travel is not feasible?
The impossibility of faster than light relative speed only applies locally. Wormholes could allow faster than light travel, because the speed of light would not be exceeded locally at any point. Traveling through a wormhole would be at slower than light speeds. So if two points are connected by a wormhole, the length of which is shorter than the distance between them, outside the wormhole, the time taken to go through it could be less than the time it would take light to make the journey, if it took a path through space outside of the wormhole.
But despite being possible within the framework of general relativity, wormholes have never been observed in nature, and there are no known natural processes predicted whereby a wormhole could form naturally. In addition, for one to be of utility to us, it would have to allow travel in both directions, from one part of the universe to another. It would have to be traversable.
The possibility of traversable wormholes was demonstrated by Kip Thorne and Mike Morris in 1988. Quantum field theory allows the existence of states where energy can be negative at a given point, and this effect may mean it is possible to stabilize a wormhole, such that it becomes traversable. If a wormhole contained sufficient exotic matter, dark matter, whether naturally occurring or artificially added, it could be held open by a spherical shell, and used as a method of sending information or travelers through space. Dark matter could very well be the fuel needed for constructing and sustaining a wormhole.
But again, reality bites. The technology we have at our disposal today is nowhere near that needed to enlarge or stabilize wormholes. Of course that doesn't mean the technology won't arise in the future, and scientists continue to research the subject as a potentially viable means of travel.
So when we look at the next step, the available options of how we could get there, it becomes pretty apparent that for now, we are not going anywhere, and especially not to Kepler 452B.
But the question also arises, what if we had to leave Earth in order to continue our existence?
We would probably face a choice between accepting the end of our species, or existing in limbo, set adrift for an indefinite period, on some form of human made habitat, a space ark, until we eventually find and reach another world.
This course of action would obviously require a lot of advance preparation. And guess what? Scientists have been working on this eventuality for the last 40 years.
Exterior of Kalpana One
Exterior of Kalpana One
Bryan Versteeg
Project Persephone, is a newly formed team of international scientists, set up to investigate living technologies that could function on a habitable starship architecture. Their aim is to work towards building a craft that would be self-sustaining, and house an ecosystem which could replicate the processes on Earth for generating light, air, water, food and gravity, while accommodating a few thousand individuals for multiple generations, while travelling to a habitable planet.
Circular interior of Kalpana One
Circular interior of Kalpana One
Bryan Versteeg
One of the most complete designs of a space settlement station articulated to date is Kalpana One, the culmination of a study that set out to build on earlier plans drawn up since the 1970's, that had inherent problems with rotational instability – any settlement would need to rotate in a stable fashion to create a functional gravity environment onboard – and efficient use of volume and structure.
Interior of light source Kalpana One
Interior of light source Kalpana One
Bryan Versteeg
The purpose of Kalpana One was to find a design that could create a 1G (Earth–level gravity) living space, and the most habitable station for volume per shielding and structural mass. The project concluded that an elongated can shape would be the most effective design for achieving these goals.
Exterior full view of Kalpana One
Exterior full view of Kalpana One
Bryan Versteeg
With a population target of 3,000 residents, the Kalpana One station has a central hub which floats on magnetic bearings, so it can remain motionless while the rest of the structure rotates, and with a radius of 250m and depth of 325m, it can spin at a rate of 2 revolutions per minute, giving the feeling of 1G earth gravity on the areas where passengers will live.
If humans are to endure as a species, these scenarios are all ones our future descendants will be pushed into facing eventually. Luckily for us it probably won't be our generation or our children's generation, and we can still embrace these amazing discoveries with wonder, awe, romance and a sense of innocence. The discovery of Kepler 452B is a cause for hope and optimism - it has expanded not only our knowledge, but also our sense of possibility, and whether we are ever able to visit the world in person or not, being human has felt ever so slightly different since Thursday.
More about kepler 452b, Earth, NASA, Evolution, general relativity
 
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