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We calmly trace the reasons why humanity has yet to achieve interstellar travel—the furthest dream of space journeys, specifically the journey to stars other than the Sun. From the position of Voyager 1, which has been flying between stars for half a century, we examine how vast distances, the human body and a single lifetime, infinitely growing energy, and the seemingly empty space between stars block our path. We also meet guests who have crossed the path we have yet to traverse in reverse: 'Oumuamua, Comet Borisov, and the 3i-Atlas. At the end, we explore the Golden Record carried by the two Voyagers and examine the unanswered questions surrounding interstellar travel. 📌 Content Covered in This Video Voyager 1 is the first man-made object to enter interstellar space, crossing the heliosphere boundary where the winds blowing from the Sun end, and it takes nearly a day for commands from Earth to reach it. - If we reduce the distance between Earth and the Sun to about one meter, our nearest neighbor, Proxima Centauri, is located just short of the distance between Seoul and Busan, and its neighbor, Alpha Centauri, does not rise above the horizon from anywhere in Korea. Even if we maintain the speed of the fastest spacecraft, Parker Solar Probe, it takes over 6,000 years to reach a neighboring star, and even traveling at 1 percent of light, it takes over four centuries. In the weightless universe, bone density decreases by just over 1 percent per month, and based on the cosmic radiation measured by Curiosity, flying for about a year would reach the lifetime limit for an astronaut. Pushing a ship weighing about 100 tons to half the speed of light requires two and a half years' worth of the energy humanity uses in one year, and the same cost must be paid again to stop upon arrival. If traveling at 10 percent of light, every single atom between stars strikes the front of the ship with energy roughly equivalent to a beam particle fired by a hospital's radiation therapy machine, and the space thought to be empty becomes a solid wall. - Oumuamua, captured by the Pan-STARS telescope in Hawaii in 2017, is the first interstellar object recognized by humans, and opinions are still divided on why it was pushed further away without a tail. The second visitor, found by a telescope designed and built by amateur astronomer Gennady Borisov, contained an unusually high amount of carbon monoxide. The Three Eyes Atlas, found by the Atlas network in Chile in 2025, was the earliest of the three, and model estimates suggest it may be over 7.5 billion years old. Each of the two Voyagers carries a Golden Record selected by a committee led by Carl Sagan, and Voyager 1 will pass by a star in the constellation Ursa Minor at a distance of over one and a half light-years in about 40,000 years. ⏱ Chapter 00:00 A probe flying for half a century 03:51 Even with the fastest 05:47 The slow path, one life with the body 08:47 The fast path, an infinitely growing price 11:08 An empty-looking wall 14:00 The first guest caught on a mountaintop in Hawaii 17:59 A handmade telescope 19:53 The third guest from the skies of Chile 22:33 The guest we sent 24:50 Things we still don't know 🔗 Source List NASA — Voyager Frequently Asked Questions Astronomy.com — Radiation measured by Curiosity on voyage to Mars has implications for future human missions The Astrophysical Journal — The Interaction of Relativistic Spacecrafts with the Interstellar Medium (Hoang et al., 2017) NASA — 'Oumuamua NASA — Comet 3I/ATLAS Facts and FAQs 🔔 Before falling asleep We continue to create space stories that are great to keep playing in the background. #SpaceTravel #InterstellarTravel #Voyager #Oumuamua #SpaceDocumentary #SleepDocumentary #ScienceDocumentary