Leaving aside the Sun, the closest star to the Earth is Proxima Centauri. This star belongs to a stellar system named Alpha Centauri, formed by 3 stars that orbit the ones around the others. Of all of them, Proxima Centauri is the closest to the Earth, which lies at a distance of about 4.24 light-years. The other two stars of the system are 4.37 light-years away from the Earth.
So, the light of Proxima Centauri takes 4.24 years to reach our planet. Theoretically, this is the minimum time in which we can get to Proxima Centauri, because anything can go faster than light. (According to some, projects, faster speeds higher than that of light could be reached, but it isn’t known for sure if they could work). So, how much time would it take to travel to the closest star?
Currently, The technology used in rockets is based on the combustion of two chemical elements, that release the necessary energy to propel the rocket. Using this technology we can reach speeds of about 40,000 kilometres per hour.
At this speed, a spacecraft would take more than 100,000 years to reach the closest star (Proxima Centauri). The Voyager 1 probe, the furthest man-made object that has ever been created (it is found 14.7 billion miles away from Earth) travels at a speed of about 38,000 miles per hour (61,000 km/h). The probe acquired this speed using the gravitational field of Jupiter and Saturn to gain more speed. If Voyager 1 maintains its current speed, it is calculated that it will get to Proxima Centauri in about 80,000 years.
For the moment we have only talked about reaching the closest star. However, if we were to get much further away, the amount of time necessary to accomplish it would be gigantic. It is for this reason that, through the years, many proposals and projects have been developed to create much more powerful rockets than the ones that exist nowadays.
Other alternative motors
With the current technology, other types of engines could also be built, such as nuclear thermal engines, or EM (electromagnetic) drives. Unfortunately, these engines would take at least 1,000 years to cover the distance between the Earth and Proxima Centauri. Even if it is a great improvement in comparison to the previous situation, it is still an unviable time period for our epoch.
Finally, the two types of motors that would enable us to travel to the closest star at more elevated speeds are nuclear fusion rockets and antimatter rockets. Using these technologies, the journey could take 36 years in the case of nuclear fusion, and 8 years using antimatter. However, the technological challenges for the manufacturing of these spacecrafts are countless. To mention some of them: the necessary spaceships would have a gigantic size, the manufacturing price would be very elevated, and, currently, the necessary production of antimatter for the journey would be almost impossible. Moreover, they are technologies that are still in development.
In future posts, I will talk in detail about every one of the named systems, as well as others that I haven’t mentioned here.