Hawke did not visit Uranus, which was orbiting just on the other side of the Sun. However, it is estimated that after another two billion kilometres of flight, Hawke's fleet will pass Neptune when it reaches its orbit, giving it a rare opportunity to observe Neptune up close.
At this moment, Hawke's fleet has reached a speed of 500 kilometres per second relative to the Sun.
During the long journey, Hawke had lined up his fleet in the shape of a sphere. At the core of the sphere were three county-class ships, beyond that were seventy country-class ships surrounding them, and beyond that, a thousand village ships, like stars in the moon, defending the county-class and country-class ships in the centre.
Each ship was spaced at least five hundred kilometres apart from each other, and the thousand or so ships formed a large sphere 10,000 kilometres in diameter, with Hawke sitting in the centre of the sphere, commanding the huge fleet as it raced through space.
In front of the fleet, the village class ships, on guard duty, sent out lasers from time to time, vaporising any asteroids in their path. Like crabs, Hawke's fleet rampaged through the solar system.
Up ahead, the blue, ocean-like Neptune had come into Hawke's view. Here, Hawke saw the spectacular large black spot on Neptune and observed Triton up close.
Once a Kuiper Belt object, Triton has been captured by Neptune's powerful gravity, so Triton's orbit is retrograde, and it is slowly approaching Neptune. When its distance from Neptune exceeds the Losch limit, it will be torn apart by Neptune's powerful gravity, and then the pieces of Triton will hit Neptune.
It is foreseeable that this will be another huge impact event no less than the Jupiter-Moon collision. But it will not affect the inner planets too much because it is so far away.
Hawke did not slow his fleet down. Now that he had made up his mind to leave the solar system, no scenery, no matter what it was, could keep Hawke in place any longer.
The encounter with Neptune had been a fleeting one. Instead of stopping for Neptune, Hawke used its gravity to accelerate his fleet to a speed of 520 kilometres per second.
A month later, Hawke's fleet reached Pluto's orbit. After expressing his sympathy through the telescope for Pluto, which was 300 million kilometres away, Hawke continued his flight towards the outer solar system.
Here, already, was the territory of the Kuiper Belt. The Kuiper Belt, the main source of short-period comets in the solar system, from which, for example, the famous Halley's Comet is thought to have come. But Hawke wasn't so lucky as to happen to encounter it. Now Halley's Comet is still hanging out in some nook or cranny of the solar system.
Here, it was six billion kilometres from the Sun. Looking towards the Sun from here is only a little brighter than looking at Venus from Earth. She has turned into a point of light, losing all her detailed features. But even at such a distance, she still dominates everything here. Yes, in the Kuiper Belt, Pluto, Zina, Sedna and other celestial bodies are still orbiting around that bright spot in the distance, along with countless other icy rocks.
Here, it is cold and dark. Solitude is the eternal melody of the universe; light is a rare sight in it.
There were at least a hundred million celestial bodies scattered within this vast space. But Hawke could see nothing. The density of matter, compared to this vast space, was too thin.
Hawke still went on without a trace. In space, because of the loss of reference, it was not possible to perceive that one was moving. Hawke's huge fleet of ships hovered silently in space, not moving at all.
Hawke had been observing the strength of the solar wind. During this long journey of nine months, Hawke saw that the speed of the solar wind was slowly decreasing, which meant that the sun's influence on this place was getting weaker and weaker.
Gradually, gradually, the speed of the solar wind, from several hundred kilometres per second, decreased to below the speed of sound of three hundred and forty metres per second. Hawke knew that he, himself, had come to the edge of the solar system.
Outwards, there would be an endless world of interstellar medium. The sun, with its powerful energy and the solar wind, had carved out a world of its own in the interstellar medium, and where Hawke was, would be the borderline between the solar empire and the interstellar medium.
Here, at the top of the heliosphere. Here, eighteen billion kilometres from the Sun.
Under the influence of the interstellar medium, the speed of the solar wind, at last, has dropped below the speed of sound. Here, the solar wind will engage the interstellar medium in a fierce encounter, there will be countless particles colliding fiercely where Hawke cannot see them, where the temperature is several thousand degrees Celsius.
Yes, it is cold, it is dark, and humans would be frozen to ice in an instant here, but the temperature here is, indeed, several thousand degrees Celsius.
Temperature, is simply a physical measure of the intensity of the thermal movement of the molecules of an object. There is so little matter here, so thin, that the temperature, though high, can have no effect on Hawke. It's like the Earth's ionosphere, where the temperature is over a thousand degrees, and yet there are still several artificial objects flying freely there.
This is the ultimate battleground. The solar wind had been defeated in the battle with the interstellar medium. Hawke knew that after crossing here, the sun would have no other means of influencing it than gravity.
It took Hawke two days to cross here, through the top of the heliosphere. As he watched the number of energetic charged particles from the Sun slowly diminish and eventually disappear from the probe, he looked at the bright spot in the distance, which had dimmed somewhat and was no longer very different from the rest of the stars in the universe, and felt an indescribable feeling in his heart.
"Mother, dear mother, goodbye, goodbye." Hawke muttered, with an urge to cry.
Moving on, it would be the domain of the interstellar medium, that is, the hydrogen and helium from the galaxy. The matter here was unimaginably thin, not even reaching the point of one atom per cubic centimetre. Such a density would be equivalent to taking a drop of water and spreading it evenly over five million cubic kilometres of space.
What lay ahead to greet Hawke would be a solitary journey through such space, for more than six thousand years.
After leaving the top of the heliosphere, Hawke remained in a state of trance for a year, leaving all the daily operations of the fleet to automatic programs, and looking through his telescope at the direction of the sun every day, lost in his memories. Fortunately, the course had already been set, and there was no need to worry about asteroid attacks here, so Hawke's fleet was safe from accidents.
Here, at a distance of thirty-five billion kilometres from the sun, it would take thirty-two hours for the sun's light to reach here. But here, at such a distance, Hawke had made a major discovery.
He had discovered a planet.
Yes, reaching hydrostatic equilibrium and possessing enough mass to clear the rest of the small bodies in orbit, this planet, by all accounts, met the astronomer's definition of a planet.
Its mass, which reached one and a half times that of the Earth, was that of a rocky planet that orbited the Sun at an extremely slow speed, with a period of seven hundred and thirty-two years.
Looking at the planet, Hawke's mind was enlightened and he understood many things.
Before, mankind had always wondered if there was another large planet beyond Pluto's orbit, otherwise there would be no explanation for the strange orbits of many small bodies in the Kuiper Belt. Now, Hawke had finally found the answer.
Here, indeed, there was a large planet. But because it is so small and it is so dark here, humans have not been able to discover it.
Hawke named the planet "The Lost Star". It is a lost land, never before recorded in human writing.
Hawke devoted a great deal of energy to the Lost Star. He even made an emergency probe satellite and launched it into orbit around the Lost Star. This way, even if Hawke's fleet continued to leave, Hawke could keep observing the Lost Star.
The Lost Star has no atmosphere, but on its surface Hawke has observed what appears to be liquid nitrogen and a white, water-ice like solid. This suggests that if the temperature is right for the water ice to melt and the liquid nitrogen to sublimate, it could have an atmosphere like Earth.
Above the Lost Star, there are mountains, proof that it once had crustal movement, and crustal movement, proof that it has a liquid, fiery core. Perhaps it would also have had volcanic eruptions, hot springs caused by geothermal heat, and at the hot springs, life might have existed.
Thoughts ran through Hawke's mind.
Hawke's observations of the Lost Star continued for a year, until no more signals could be received from the satellites, and Hawke had to regretfully give up his study of it.
The discovery of the Lost Star saved Hawke from his slump, and Hawke regained his spirit and possessed a desire to explore.
Work on the compilation of the Ultramarine Vault was resumed, and research on projects such as hyper-range communication, anti-gravity technology, and a new generation of spaceship engines was on the agenda. Physical theory research is also in full swing, even as the sheer volume of science** calculations has pushed the main computer's computing schedule to three hundred years from now.
In other words, there was enough data to calculate to keep the main computer at full capacity for a full three hundred years. This result made Hawke smile bitterly. But there was plenty of time in the journey, and Hawke was in no hurry at all.
Time, in this lonely, but fulfilling state, slipped away. Since his encounter with the Lost Star, Hawke had not encountered any more matter. This situation lasted for six hundred years.
After six hundred years, Hawke reached a place.
Here, the Oort Cloud, here, one light year from the sun.