For over 150 years, humans have been trying to communicate with extraterrestrial life. Despite no definitive proof that anyone has tried to call us back, there has been a number of unusual signals and sounds that researchers are still trying to explain.
10. The Mystery Roar
Space is a vacuum, so there’s no sound. However, radio waves can travel through it and many celestial objects give them off — the Milky Way, for example, emits a hiss. In July 2006, researchers launched a weather balloon from NASA’s Columbia Scientific Balloon Facility in Palestine, Texas. They were looking for signs of heat at the edge of the atmosphere where it changes into a vacuum at 120,000 feet. Instead, what they heard was a roar that was six times louder than they were expecting. The roar came from far out in the universe, and researchers are unsure of what caused it or where it came from.
9. The Chilled Out Sounds of Moon Miranda
Uranus has five moons, and the innermost is Miranda. Miranda, noted for its odd surface and shape, is called a “Frankenstein” moon because it looks like the pieces were shoved together. It’s about one-seventh the size of Earth’s moon, but has canyons that are 12 times deeper than the Grand Canyon. It’s also noted for giving off a relaxed ambient sound that was picked by Voyager 2. It was so interesting that NASA actually released an album of it.
8. The Eerie Sounds of Jupiter
Galileo is a NASA spacecraft that was launched on October 18, 1989, with the purpose of studying the solar system’s largest planet, Jupiter. On June 27, 1996, it did a flyby of one of Jupiter’s moons, Ganymede. While orbiting the moon, researchers gathered data and re-created the sound on Earth. They believe the sound comes from charged particles near the moon. Three other recordings were made byVoyager 1 (launched in September 1977) and Voyager 2 (launched in August 1977), which captured other sounds in the Magnetosphere, including lightning in the atmosphere.
7. Kepler Star Sounds
The Kepler space observatory was launched on March 7, 1999 with the goal of finding other, Earth-like planets that would hopefully be habitable. While on its journey, it has recorded data from the light curves of stars. These curves have frequencies of brightness variations that are very similar to sound frequencies. The frequencies are well out of human range, making it impossible for us to hear them, but by using a mathematical technique called Fourier analysis researchers scaled the frequencies to a level that humans can hear.
6. Radio Transmission SHGb02+14a
SETI@home is an Internet based project that takes information from the Arecibo Observatory and puts it on people’s computers. Released in 1999, it’s used as a screensaver that scans information while looking for possible signs of life.
The most promising signal found through the project is Radio Transmission SHGb02+14a, which came in March 2003. The source was observed three times, at 1420 megahertz (MHz). When first setting up the project, researchers decided to use 1420 MHz because chemicals emit signature electromagnetic frequencies and 1420 MHz is the frequency signature of hydrogen, the most common element in the universe.
The three signals came from an area between the constellations Pisces and Aries. However, the closest stars in that area are over1,000 light years away. If the signals did come from there, they travelled an incredibly long distance, which has led to some skepticism. Other people think it was just an equipment malfunction, because the transmissions were all weak. Another odd aspect of the transmissions is the way the signal drifted; it would mean they came from a planet that is rotating 40 times faster than the Earth. Researchers are still unsure what radio transmission SHGb02+14a is, but it’s the most famous signal from the SETI@home project.
5. The Strange Sounds of Saturn
Cassini–Huygens is an unmanned spacecraft that was sent to Saturn in 1997, and was the first to enter the ringed planet’s atmosphere. In April 2002, Cassini was about 234 million miles away from Saturn when it started detecting radio waves coming from auroras around the poles of Saturn. These auroras are similar to the southern and northern lights here on Earth. The eerie sounds are quite complex, with lots of rising and falling tones along with many changes in frequency and time.
4. The X-Ray Signal
Looking at a detailed study using NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton, another X-ray observatory, researchers discovered an unexplained x-ray signal in the Perseus galaxy cluster. It’s a mystery as to what caused the signal, but they believe it has something to do with dark matter. Dark matter is a theoretical type of matter that astrophysicists have only been able to infer exists from the way gravity is affected by visible matter. Astrophysicists believe dark matter makes up about 26% of the universe, while visible matter only makes up about 4%. The rest of the universe is thought to be dark energy.
When astrophysicists found the x-ray wave they believed it came from sterile neutrinos, which are a type of hypothetical neutrino that’s believed to interact with normal matter only via gravity. Some astrophysicists believe that these neutrinos could help explain dark matter. They’re currently looking at more clusters to see if they can find similar x-ray signals and confirm that the hypothetical sterile neutrinos exist.
3. The Unsettling Sound of a Black Hole
Want to hear one of the most unsettling sounds ever? Check out the sound a black hole makes. The sound was created by MIT’s Edward Morgan, from data he gathered from a black hole in the GRS 1915+105 star system. The star system, which was discovered in 1992, has both regular stars and a black hole. The black hole is the largest in the Milky Way, has a mass 10 to 18 times larger than the sun, and is about 250 million light years away from Earth.
If you were looking at this in terms of music, the noise from a black hole is in B flat, but there’s no way humans could normally detect it due to its octave and frequency. It’s 57 octaves lower than middle C, and people can only hear about 10 octaves. As for the frequency, it’sway out of human range, being a million billion times deeper than anything we can perceive. In fact, it’s the deepest note ever detected from any object in the universe.
2. The Parkes Radio Telescope Bursts
When doing sweeps of the sky between February 2011 and January 2012, the Parkes radio telescope in New South Wales, Australia found four bursts of radio signals. Each of them only lasted for milliseconds, but they were incredibly powerful — as powerful as 300,000 years worth of energy from our sun. There have been similar radio bursts in the past, but they were never sure if it originated in the Milky Wayor in a neighboring galaxy. However, these bursts appeared to have come from much, much further away.
There are a few theories as to what would cause these bursts, including neutron stars with super-strong magnetic fields called magnetars colliding with each other. Other ideas are that they’re black holes that are evaporating, and gamma ray bursts involving a supernova. It could even be some new type of astrophysical event we currently don’t know about.
1. Arecibo Telescope Radio Bursts
The signals in the above entry could have been written off as a problem with the Parkes telescope. It may have been malfunctioning, or picking up radio signals from Earth. However, on November 2, 2012 at the Arecibo radio telescope in Puerto Rico, they also picked up one of these fast radio bursts. Like the radio bursts detected by the Parkes telescope, these too traveled a great distance to get to Earth.
Researchers did calculations and believe these signals happen about10,000 times a day. Astrophysicists are currently building new telescopes, and using telescopes in Australia, South Africa and Canada, to try and understand why these radio signals are so frequent and what they represent.