He knew he was now the only man in the universe. He had found out when his ship crossed Plutos orbit, from which vantage point the Sun looked like a dim star, no different from the one it had been thirty years before when he left the Solar System. But the ships computer had just finished running a parallax measurement that told him Plutos orbit had moved outwards by a considerable amount, from which it could be calculated that the Sun had lost 4.74% of its mass since his departure, and from this another conclusion could be drawn that made his heart first quiver and then freeze.
That has already happened.
Actually, by the time he set out humanity already knew it was going to happen, having launched tens of thousands of probes through the Sun, astrophysicists had determined that the Sun would undergo a brief energy flash and lose about 5% of its mass.
If the sun had memory, it would not be disturbed by this. In its long life of tens of billions of years, it has experienced much greater changes than this. When it was born from the swirling vortex of a star cloud, the transformation of its life was in milliseconds. At that brilliant moment, the collapse of gravity ignited the flame of nuclear fusion to illuminate the dark chaos of the star cloud... It knows that its life is a process, and although it is currently in the most stable period of this process, occasional small mutations are inevitable, just like the calm surface of the water occasionally has a small bubble floating up and bursting. The loss of energy and mass means nothing to it; it is still itself, a medium-sized star with a visual magnitude of -26.8. Even other parts of the solar system will not be greatly affected: Mercury may melt, Venuss dense atmosphere will be stripped away, and the outer planets will be even less affected. Mars color may change from red to black due to surface melting, while Earth will only experience a surface temperature increase to 4000 degrees Celsius for about 100 hours. The oceans will certainly evaporate, and the surface rocks of the continents will melt, but thats all. Afterwards, the sun will quickly return to its original state, but due to mass loss, the orbits of the planets will shift slightly outward, which is an even smaller effect. For example, on Earth, temperatures may drop slightly, averaging around -110 degrees Celsius, which would help the melted surface re-condense and retain some water and atmosphere.
At that time, people often talked about a joke, which was a conversation between a person and God: Oh God, ten thousand years is so short for you! God said: Just one second. Oh God, one hundred million yuan is so little for you! God said: Just one cent. Oh God, give me one cent! God said: Please wait for one second.
Now, the sun has kept humans waiting for "one second": the predicted time of energy flash is 18,000 years later.
This is indeed just one second for the sun, but it can make humans living on Earth today take a transcendent attitude towards what happens after "one second", even as a philosophical idea. The impact is not non-existent, human culture is becoming more and more decadent day by day, but at least humans still have 400-500 generations to think about ways to escape calmly.
Two centuries later, humanity took its first action: launching an interstellar spaceship to search for stars with potentially habitable planets within 100 light-years. The spaceship was named Ark and the astronauts were called Pioneers.
The Ark passed by sixty stars, and also sixty hells. Among them was a star with a satellite that was an iron water droplet in a white heat state with a diameter of 8,000 kilometers. Due to its liquid state, it constantly changed shape during operation... The only result of the Arks journey was further proof of humanitys loneliness.
The Ark had been traveling for twenty-three years, but this was "Ark time", as the ship had been moving at nearly lightspeed and two hundred fifty thousand years of Earth time had passed.
The Ark was originally supposed to return on schedule.
Due to the inability to communicate with Earth when approaching the speed of light, it is necessary to reduce the speed to below half the speed of light, which requires a lot of energy and time. Therefore, Ark generally decelerates once a month to receive information from Earth, but when it decelerates again next time, the received information will be sent out by Earth more than 100 years later. The time between Ark and Earth is like looking at a target through a high-magnification scope - if the scope moves slightly, the target in the scope jumps across a huge distance. The last message received by Ark was sent from Earth 17,000 years after its launch in "Ark time", but more than 10,000 years ago in Earth time. When Ark decelerated again a month later, it found that the direction of Earth had become silent. A slight error may have occurred in the calculation of the suns position over 10,000 years ago, and during this one month on Ark, something happened on Earth over 100 years ago.
The Ark had truly become an ark, but it was now an ark with only Noah on board. Of the other seven pioneers, four died from radiation from a supernova that suddenly exploded at 4 light-years from the spaceship, two died of illness, and one (a man) shot himself during the last deceleration communication, listening to the silence in the direction of Earth.
Later, this lone pioneer kept the Ark at communication speed for a long time. Later, he accelerated the spacecraft to the speed of light, and the faint fire of hope in his heart made him quickly slow down to listen. Due to the increasing frequency of deceleration, the return journey was prolonged.
The silence continues.
The Ark returned to the solar system 25,000 years after its departure from Earth, nine thousand years later than scheduled.
