Time Escape

"Mars, do you receive it? Please reply to Earth if you receive it!" One million humans took a ride on Mars and left the solar system 10,000 years ago to explore the universe, but they mysteriously lost contact 1 light-year outside the solar system. Ten thousand years later, the earth embarks on a journey of search. Just where Mars lost contact, humans detected an object with a mass of 7×10^23 kilograms (exactly the same as the mass of Mars before leaving)! But there is nothing before humanity! …