Is there really a universal hum?
Yes, scientists have discovered a background “hum” of gravitational waves stretching across the universe—a constant vibration caused by massive objects like supermassive black holes colliding and merging. We can’t hear it, but it’s giving us a whole new way to explore the cosmos.
What is the hum?
It’s the collective ripple of low-frequency gravitational waves—tiny distortions in spacetime created when supermassive black holes spiral together and merge. Think of it as the universe quietly vibrating in the background.
How was it detected?
Astronomers turned to pulsars—rapidly spinning neutron stars that act like cosmic metronomes. By tracking minute variations in the timing of their pulses over years, they spotted patterns revealing gravitational waves.
What does the hum tell us?
This hum opens a new window into the universe. It helps scientists understand how galaxies evolve and how supermassive black holes form, dance, and eventually collide.
Why can't we hear it?
The hum is far too low for human ears. Only highly sensitive instruments can pick up these subtle vibrations rippling through space and time.
Does the earth hum too?
Yes. Heard as a low, rumbling, or droning sound, similar to a truck or engine idling, only 2% of the population report hearing it.
What could it be?
Environmental and geological sources:
Ocean waves: In 2015, French scientists proposed that ocean waves colliding with continental shelves could cause the Earth to vibrate, creating a low hum.
Seismic activity: Natural seismic activity, including volcanic eruptions and microseisms, can produce low-frequency vibrations.
Atmospheric resonance: Electrical charges from lightning strikes have been proposed as a source of atmospheric resonance.
Physiological and internal factors:
Hyperacusis: This condition, an oversensitivity to certain frequencies, could make individuals more aware of innocuous background noises that most people filter out.
Spontaneous otoacoustic emissions (SOAE): Some people's ears naturally produce faint sounds, which could be confused with an external hum.
There is no evidence to support that extraterrestrials are producing the hum, that remains in the realm of speculation and conspiracy theory.
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