(Space) – Humans will make contact with aliens by the end of the century, theoretical physicist and futurist Michio Kaku told Redditers last week. However, Kaku said he wasn’t sure whether we’d be able to communicate directly with this unknown extraterrestrial society — one that could run the gamut from hostile to pacifist, according to Kaku.

In his AMA on Reddit, Kaku responded to a question about alien civilizations, saying, “Let me stick my neck out. I personally feel that within this century, we will make contact with an alien civilization, by listening in on their radio communications. But talking to them will be difficult, since they could be tens of light years away. So, in the meantime, we must decipher their language to understand their level of technology. Are they Type I, II, or III??? [These represent three categories in the Kardashev scale, measuring technological achievement in civilizations based on their level of energy use for communication.] And what are their intentions. Are they expansive and aggressive, or peaceful.”

Kaku added, “Another possibility is that they land on the White House lawn and announce their existence. But I think that is unlikely, since we would be like forest animals to them, i.e. not worth communicating with.”

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