For centuries, physicists have believed that there is no limit to how quickly an object can move. The speed of light, which is 300,000 kilometers per second (186,000 miles per second), is the fastest that anything can travel. The closest star to Earth, Proxima Centauri, is located 4.25 light-years away, or about 25 trillion miles (40 trillion km). The fastest spacecraft ever launched is the Parker Solar Probe, which is currently in space.
It has a maximum speed of 450,000 miles per hour. That means it would take only 20 seconds to get from Los Angeles to New York City at that speed. However, it would take 6,633 years for the solar probe to reach Proxima Centauri. The speed required to orbit Earth is 4.9 miles per second, or approximately 17,600 miles per hour.
To escape Earth's gravity and travel to another moon or planet, a speed of at least 7 miles per second or about 25,000 miles per hour is necessary. But even if we manage to build faster spaceships, our bodies will have to face new dangers posed by traveling at such high speeds. Marc Millis, a propulsion physicist and former director of NASA's Innovative Propulsion Physics Program, warns that this possible speed limit for human travel remains a distant concern. In the Isaac Asimov Foundation series, humans can travel from one planet to another, from one star to another, or across the universe using jumping motors.
Some characters in movies like “Interstellar” and “Thor” use wormholes to travel between solar systems in seconds. Scientists are also investigating other ways to go fast, including faster-than-light trips popularized by Star Trek. The Orion spacecraft is expected to take astronauts to a low Earth orbit and could break the 46-year record for being the fastest we've ever traveled. But even if we manage to build faster spaceships, our bodies will have to face new dangers posed by traveling at such high speeds.