Steven Greer is the founder of The Disclosure Project and CSETI. The aim of these projects is to bring forth credible witness testimony from high-ranking officials from around the world, especially the US, concerning the topic of what the World knows as the UFOs. He has many hours of recorded interviews, which are accessible from his websites, which i will enlist below.
CSETI means "Center For The Study of Extraterrestrial Intelligence" and one of their aims is to develop diplomatic contact between other intelligent races in the Universe and human beings. They claim they have had contact for a long while now - something around 20 years.
Now what has this got to do with Mantras?
During the contact sessions that Dr. Steven Greer hosts in various areas around the world, especially in the US, they use different techniques to change their level of awareness and perception, one of them being mantras. The changing is necessary in order to begin to sense the presence of the visitors, who they invite from outer space. Allegedly, they exist in another dimension/phase and oftentimes shift from the visible spectrum to the invisible.
The way to invite the beings to come and "mingle" is to step into the Unbounded Mind - they use a mantra to achieve that. It clears the mind and focuses it lightly on the mantra, until suddenly, you realize that all consciousness is one and manifesting throughout the wole Universe through different beings. Your awareness changes and you will be able to Remote View extraterrestrials and their craft and call them in this state of Unbounded Mind, to visit us. Greer says that ETs are constantly scanning the field of consciousness for such occurrences and so your contact attempt won't go in vain.
The concept of clearing the mind, stopping the inner dialogue, mind becoming aware of the mind itself and achieving a different state of consciousness is not unordinary(Castaneda, Indian traditions, ...). What probably seems unordinary is the use of this state to contact ET Intelligence, but this is exactly what Greer has been doing for a long time now, according to his own claims.
Your experiences regarding this topic?
http://www.disclosureproject.org/
http://cseti.org/
