In the hypothetical case where we were able to build NASA’s prototype spacecraft, capable of moving at relativistic speeds, and gathering the indecent amount of energy needed to propel them, the journey would not be as pleasant as it appeared to be aboard the Millennium Falcon . And the main impediment to interstellar travel is not the technological part, which we could master in a matter of centuries, but the dangerous space environment, as astronauts well know, which once again highlights the fragility of the human body.
If we were moving at the speed of light (300,000 kilometers per second) through outer space, we would die in a matter of seconds . Although the density of particles is very low in a vacuum, at high speed, the few hydrogen atoms per cubic centimeter would hit the prow of the vehicle with an acceleration similar to that achieved in the Large Hadron Collider (LHC), thus acquiring an energy of 10,000 sieverts per second. Taking into account that the fatal dose for a human being is about 6 sieverts, this beam of radiation would damage the ship and destroy all traces of life inside.
According to the measurements of scientists at Johns Hopkins University, no frontal shielding would be able to rid us of ionizing radiation . A 10-centimeter-thick aluminum partition would absorb less than 1 percent of the energy, and its size could not be infinitely increased without compromising the power needs of the powertrain. In addition to atomic hydrogen, the spacecraft would have to resist the erosion of interstellar dust, increasing the chances of seeing its pulverized structure considerably. As a solution, we would have to settle for reaching speeds of only 10 percent the speed of light, which would hardly allow us to travel to the nearest star, Proxima Centauri, within a human lifetime, since 4.22 years light away would become in 40 years of travel.
Cosmic radiation is, therefore, an insurmountable obstacle to travel at the speed of light , which, if overcome in the distant future, would allow us to attend the most incredible spectacle of our lives. At that speed, time would expand and we would age more slowly (ISS astronauts age 0.007 seconds less every 6 months than people on Earth) and our field of vision would curve like a tunnel, and we would move towards a flash of white light, without a trace of stars, as we leave the most absolute darkness behind.
