The things that exist beyond our galaxy are unimaginable. Yes, the life-giving air we breathe in the earth’s atmosphere, does not exist in space for sure, but there are so many other things that do exist out there. The interstellar space for instance, is filled with something called the interstellar medium (ISM) that consists of interstellar gases and much more. NASA’s Voyager 1 has recently detected this interstellar medium’s humming, as per a study published in Nature Astronomy on May 10.
The faint, persistent hum, caught by the explorer spacecraft, is coming from plasma waves of the interstellar medium. “It’s very faint and monotone because it is in a narrow frequency bandwidth," said Stella Koch Ocker, one of the researchers at Cornell University that conducted the study. Interstellar Medium consists of ionized, atomic and molecular gases, stardust and cosmic rays.
Cosmic rays are high-energy atomic nuclei and protons that travel everywhere through space. Cosmic rays, among other materials from the interstellar medium, can cause serious damage to our DNA that can result in our cells developing cancer, and in the case of being unable to repair the damage, dying. Our star Sun tries to protect our solar system from these harmful rays by forming a heliosphere, a bubble around our solar system where the pressure of the solar winds, charged particles coming from the sun, exceeds that of cosmic rays.
However, the sun is not able to completely modulate them, and the cosmic rays infiltrate the heliosphere. At this point, the earth’s magnetic shield and its atmosphere come to our rescue by deflecting and neutralizing the space radiation.
Now that the Voyager 1 is off the edge of the sun’s heliosphere, it has encountered the interstellar medium. The space probe, launched by NASA in 1977, had crossed the edge of our solar system in 2012. Sent for the exploration of the solar system and if possible beyond, Voyager 1 has travelled more than 38 billion kilometres, which is more than 150 times the distance from the earth to the sun.