Common knowledge - and the famous Alien theatrical poster - dictates that in space "no one can hear you scream," suggesting the vacuum of space is a massive, silent void. However, that's not entirely true.
Take for example, this new recording obtained by a NASA student balloon experiment. They recently uncovered some strange sounds from the edge of space, 22 miles above the Earth. The odd hissing and whistles certainly sound rather out of this world, but could they be alien? Have a listen below:
The High Altitude Student Platform (HASP) project, which captured these sounds, aims to send various helium balloons high into the atmosphere of the Earth - just below the stratosphere - and dangle a series of infrared microphones to record atmospheric infrasound. This type of research was originally conducted in the 1960s to detect evidence of nuclear explosions, but now the HASP team is interested in listening to those sounds the human ear was never supposed to hear.
Infrasound is essentially sound which has a frequency lower than 20 hertz, making it inaudible to human ears. These signals are then sped up to bring them into the human hearing spectrum. They can be caused by a vast array of natural and manmade occurrences, and some have even linked these low frequency sounds to ghost sightings.
Currently, the HASP project is not entirely sure what the sounds they recorded are, but that doesn't mean they were provided by little green men. Instead, they have too many possible answers. They could be signals from a wind farm under the flight path of the balloon, crashing ocean waves, wind turbulence, gravity waves, clear air turbulence, or maybe even the balloon itself. For his part, the student who found the sounds, Daniel Bowman of the University of North Carolina, told LiveScience:
"It sounds kind of like The X-Files."
However, sound isn't just limited to our atmosphere, 'sounds' can be recorded in space, although clearly they are not transmitted through vibrations in the air like on Earth. Instead, pressure - such as that caused by explosions or solar eruptions - can cause plasma and gasses in space to vibrate, essentially creating sound that can be recorded by sophisticated equipment. Let's listen to some of the more 'out there' (figuratively and literally speaking) space recordings.
Voyager 1 Records Interstellar Space
Voyager 1 is furthest manmade object to ever be sent from Earth. The probe, which has been on the job for 37 years, is currently around 12,200,000,000 miles from Earth and is hurtling through interstellar space at a rate of 38,000 miles per hour. In April 2013, it recorded the sounds created by a massive solar eruption that had occurred a year earlier. Have a listen below:
The Sounds of Saturn
When NASA's Cassini spacecraft passed nearby Saturn, it detected intense radio transmissions coming from the planet's poles. The signals were recorded and then compressed into the human auditory range. Listen below:
The radio signals originate from the planet's auroras and are similar to those also recorded with Earth's own northern and southern lights. However, conspiracy theorists suggest the rising and dropping tone are indicative of intelligent life.
The 'Predator' Comet
Late last year, the European Space Agency conducted the first ever landing on a comet - 67P Churyumov–Gerasimenko - with their Rosetta lander. However, before touching down on the spinning rock, they also recorded electromagnetic radiation emanating from its magnetic field. The strange clicking and warbling sounds have frequently been compared to those made by the Arnie's alien nemesis in Predator:
The 'Sounds' of a Black Hole
One of the oddest arrangements currently known in the universe is the binary star system GRS 1915+105. This system features a blackhole which is being continually fed by a nearby star. This results is a strange situation in which the pair create a space geyser of massive power. Essentially, the blackhole rips matter away from the star and then fires out the resulting accretion disk, which is essentially equivalent to flinging a mass equal to the size of a 100 trillion ton asteroid across space at a speed nearing that of light. It does this every half an hour.
No, I don't really understand what that means either, but luckily the guys in charge of NASA's Rossi X-Ray Timing Explorer Satellite do. They were able to capture the readings from GRS 1915+105 and convert them into sound. Listen below: