By Jhanvee Khanna
It’s been more than 4 decades since Voyager 1 has been navigating through the darkness of space all alone. Like a faithful soldier who has served more than what was needed. And for 3 more years, before it rests, it will continue to provide us with valuable information about deep space. Currently, at 15 billion miles away from us, Voyager 1 has successfully crossed the solar system’s edge.
But how exactly do we define this edge? One way is to define heliopause as the boundary of the solar system. The heliopause is where the solar wind (streams of charged particles continuously thrown off by the Sun) is too weak. Back in 1977, when the probe was launched, it was thought that the heliopause was at around 5-10 Au¹. However, in reality, it stands at an astounding 120 Au (truly out of the world).
There is an endless interstellar medium out there, but you won’t see much of it. A cube of air at sea level on Earth has more than a trillion times the number of molecules as an equal-sized cube of the densest portions of the interstellar medium. The region that Voyager 1 is travelling through is far more barren. And for most of the part, the silence is deafening.
Apart from being an invaluable source of information, Voyager 1 is priceless for humanity. Why must you ask? Because it carries a message, evidence of our existence – The Golden Record, a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life. Amongst the sets of the messages written in many languages, the one in English says- ‘”Hello from the children of planet Earth.” Voyager 1 is not only a hope for humanity but also for our friends in distant stars who’ll know someday that they, like us, are not alone.