And now what? If we look behind us, the Sun has shrunken to a small brilliant point in the black sky. Looking ahead, we face the eternal night of cosmic space. A cold and desolate darkness, barely pierced by a myriad of incredibly far-away lights. If we continued traveling at the speed of light towards the closest of those lights, a star called Proxima Centauri, we would certainly need lots of patience: in fact, we will need more than four years to travel the forty thousand billion kilometers that separate us from the star. As we approach, we discover that this celestial body is part of a very strange triple system: it rotates around two other stars which are revolving about each other. This is a surprise, but not very unusual: many stars are part of multiple systems and our solitary Sun is sort of an exception. If we wanted to continue our journey towards other stars, years and years would pass by before reaching the next one, and with time, we would understand that not even our grandchildren's grandchildren would reach the edges of that gigantic spiral called the Galaxy, which contains from one hundred to two hundred fifty billion stars. At the speed of light, it would take no less than 100 000 years to cross from one end of the galaxy to the other. But even if our lifespan could be extended and we could cross such an enormous distance, we would still have to say that we had not seen very much of the universe. In fact, beyond our Galaxy, past an even greater abyss of emptiness, there are still other star systems scattered throughout the cosmos. Astronomers estimate that the universe contains at least one billion galaxies which are similar to ours, the farthest of which are ten to fifteen billion light years away!
And now what? If we look behind us, the Sun has shrunken to a small brilliant point in the black sky. Looking ahead, we face the eternal night of cosmic space. A cold and desolate darkness, barely pierced by a myriad of incredibly far-away lights. If we continued traveling at the speed of light towards the closest of those lights, a star called Proxima Centauri, we would certainly need lots of patience: in fact, we will need more than four years to travel the forty thousand billion kilometers that separate us from the star. As we approach, we discover that this celestial body is part of a very strange triple system: it rotates around two other stars which are revolving about each other. This is a surprise, but not very unusual: many stars are part of multiple systems and our solitary Sun is sort of an exception. If we wanted to continue our journey towards other stars, years and years would pass by before reaching the next one, and with time, we would understand that not even our grandchildren's grandchildren would reach the edges of that gigantic spiral called the Galaxy, which contains from one hundred to two hundred fifty billion stars. At the speed of light, it would take no less than 100 000 years to cross from one end of the galaxy to the other. But even if our lifespan could be extended and we could cross such an enormous distance, we would still have to say that we had not seen very much of the universe. In fact, beyond our Galaxy, past an even greater abyss of emptiness, there are still other star systems scattered throughout the cosmos. Astronomers estimate that the universe contains at least one billion galaxies which are similar to ours, the farthest of which are ten to fifteen billion light years away!
