This article is the second of a two-part series by physicist Eric Hedin and is reprinted with permission from Evolution News. Part 1 is here.
Simply reducing the mass of the spacecraft won't solve the problem. Imagine replacing your 747-sized spacecraft with a much smaller 4,500 kg economy model, about the size of a Winnebago camper trailer, that's 1/89th the mass of the original spacecraft. Unfortunately, this means that the energy needed to get there is 54 times the total energy consumption of the United States for one year.
Yes, we need a lot of energy, and apparently what we currently use to generate energy is nowhere near what we need for interstellar space travel. But is it possible to develop a super-high energy source? The gold standard for generating energy from mass is to completely annihilate matter and convert it 100% into energy, according to Einstein's famous equation: E=mc2So how much mass would need to be converted into pure energy to reach the original estimate of 1.4 quadrillion kWh? The answer turns out to be a little over 5.6 million kg, roughly 14 times the mass of a fully loaded 747-sized spacecraft.
It gets more complicated, but we can be sure that we would need more than 5.6 million kg of material to convert to energy, since we would need even more energy to accelerate the extra material that would have to be carried as fuel for the spacecraft. A rough estimate is that the mass of fuel needed to accelerate the spacecraft, plus the mass of that fuel, would be close to 1,400 times the original mass of the spacecraft. This seems unrealistic, but maybe not impossible.
However, according to known physics, the only way to convert matter into pure energy is to combine it with an equal amount of antimatter, so space travelers would also need to carry an equal amount of antimatter with them. A better solution would be to find a way to easily convert matter into antimatter, but we can't do that directly. The bottom line is that it takes an enormous amount of energy to accelerate matter and move it through space at such a high speed.
Do you move with the universe?
Perhaps instead of trying to move Through If there is space, we can find a way to move. and The Universe. Here we refer to the results of Einstein's general theory of relativity. In this model, space itself flows into a mass at a speed proportional to the strength of the gravitational field around the mass. In the limit of a black hole, as you approach the event horizon, the boundary of the black hole, the speed at which space flows into the black hole is equal to the speed of light. Nothing can travel faster than the speed of light through space, so nothing can escape from within the event horizon of a black hole.
How can we use the flow of space to travel in space? One useful concept is that space travel is possible by falling into a black hole: by flowing with space toward the black hole's event horizon, you can travel at the speed of light without consuming external energy.
While falling into a black hole is a one-way, “rock bottom” experience, physicists have been mathematically studying the concept of a wormhole, a theoretical construct of spacetime that connects two different points in spacetime. It is theorized that under certain conditions, matter could pass through a wormhole, effectively creating a shortcut through hyperspace to facilitate travel to distant points in the universe (or even to another universe). But while they serve a purpose as plot props in science fiction stories, wormholes remain a long way from scientific reality.
First of all, despite the many existing descriptions of constructing a traversable wormhole, we are far from actually creating one – at least, we cannot even imagine an experiment that, if carried out, would bring such an object into existence – and furthermore, no wormholes have been observed in the universe so far.
In the science fiction imagination, one of the most intriguing possibilities for interstellar travel is to make the entire spacecraft have zero inertia. From a physics perspective, we don't know how this can be achieved, but if it were possible and relativistic limitations somehow did not apply, the results would be amazing. Since an inertia-free spacecraft would have effectively zero mass, its cruising speed would be limited only by the balance between the rocket thrust and the friction the spacecraft encounters as it moves through the near-vacuum of the interstellar medium. In this ingenious technology-based science fiction series, the science-savvy author estimated that the cruising speed of the spacecraft would be about 300 light years per hour. In this fictional world, the trip from Earth to Gliese 12b would take only about 8 minutes.
Children of Light
The dream of interstellar space travel is a reality because, according to the physics we know, the distances that separate us from other stars are almost immeasurable. To put it simply, the furthest distance humans have traveled from Earth is to the Moon. Our distance to the Sun is 400 times that of the Moon, and the star system, 40 light years away, is more than 2.5 million times farther away than the Sun.
Human inquisitiveness finds it difficult to accept that traveling to the stars may not be physically possible. However, our gazes on the unreachable heavens lead us to look up and stretch our imaginations to envision a world much larger than our own. Traveling to the stars may be intriguing and fascinating because we were originally created with the destiny of accessing this world.
In the Bible story, God is spirit and light, and we are called “children of light.” (Ephesians 5:8) To make the impossible possible, we may need to become beings of light ourselves. Light does not need an external source of energy to travel between stars, and in light's reference time frame, it does not require time to travel, even from one side of the universe to the other.
This is part one of a two-part series: Interstellar Travel: Fantasy or Fate?
