Recently NASA has revealed that they have recorded the sound of Sun. They say that it produces a sound like "Om". I can't understand how they can hear it.
It's not that recent (it was 2010), it wasn't NASA (it was researchers at the University of Sheffield who used data from a NASA satellite), it wasn't sound per se (it was instead sonified data), and neither NASA nor those researchers said that the sound produced was "Om".
Data sonification is a scientific tool of growing importance. It is the sound equivalent of visualization techniques that have been used for centuries. (Graphs are a rather old visualization technique.)
In this case, researchers at the University of Sheffield used sonification techniques to translate imagery of solar coronal loops into sound. A faithful representation of that generated sound would not have been audible; the frequency would have been too low for a human to hear it. Those researchers had to speed up the playback to make the generated sound audible.
That's not to say that those sounds are a complete fiction. The surface of the Sun is not a vacuum, nor is its interior. There truly are low frequency sounds associated with events on the surface of the Sun. The Sun rings with sound (low frequency sound). Studying the sounds produced by the Sun gives scientists insights into what is happening inside the Sun.
There's a small downside in making scientific data public: Non-scientists who have a penchant to read/see/hear things into that scientific data will do just that. To me, the people who say that this is proof that the universe does indeed chant the sacred "Om" are no different that those who see cities on the Moon or Mars in NASA photography.