Our solar system is currently located inside a region of space called the Local Interstellar Cloud (LIC). The temperature in that region outside the solar system is approximately 10,340 degrees Fahrenheit — as hot as the surface of the Sun.
The intensity of the radiation in our solar neighborhood is going to be a big problem for manned missions to even the nearest star systems, like Alpha Centauri 4.4 light years away. The only reason humans aren’t now being bombarded with that deadly radiation is that the Sun’s heliosphere, its magnetic field and solar wind, are keeping it at bay.
Could even inorganic explorers, like robotic space probes, survive outside the heliosphere? That’s one question we may some day have an answer to. The two Voyager probes are currently racing to the border between the heliosphere and the interstellar medium beyond.
The Local Interstellar Cloud is not the only one of its kind. In fact our solar system, which travels in orbit around the Milky Way galaxy, entered it between 44,000 and 150,000 years ago and is expected to exit it in another 10,000 to 20,000 years. But in the Orion-Cygnus spur of the Milky Way’s Perseus arm along which our solar system’s orbit takes us, there are many such highly radioactive areas.
After reading about this recently, I began to wonder if it won’t force our descendants to use some kind of “warp” or wormhole transport, rather than a brute force force sub-light approach if they want to travel between the stars. Warping space or travel within a wormhole might allow them to avoid the interstellar medium between star systems altogether.
Of course high levels of radiation in the interplanetary space within the Sun’s heliosphere has for some time been acknowledged to be perhaps the major challenge in the way of the manned exploration of deep space. It’s sobering to consider that the interstellar medium is even more hostile to life.