Physicist Michio Kaku, Ph. D. personally believes that a possible alien contact could happen within the century. The outcome of which could vary depending on a couple of factors such as their intent and level of technology.
Interest In Space
Early on in 2018, it was clear that space and its alien inhabitants would be on many people's minds. As early as January, the so-called first alien sighting of 2018 caught the interest of many, and by February, SpaceX's launch of the Falcon Heavy with a Tesla Roadster really had a lot of people excited for its prospects for future space travel.
Even in movies, it is clear that there is a lot of interest in the idea of possibly communicating with alien civilizations. Recently, researchers found humans are likely to have a positive reaction at the idea of discovering alien life, but there's also the question of how they might react to humans.
Reddit AMA With Michio Kaku, Ph. D.
In a Reddit AMA last Thursday, esteemed physicist Michio Kaku answered many fans' questions about varying topics including the threat of artificial intelligence and robots. Naturally, he was also asked about his thought on a possible alien contact in the future and what the prospects of such a contact may be.
Kaku stated that he personally believes that an alien contact could happen within this century by radio communications. However, there are the constraints of language, level of technology, and perhaps their intentions. Furthermore, there is also the question of whether they are Type I, II, or even III in the Kardashev Scale.
Generally, he believes that the aliens might be peaceful if they have had more years of resolving fundamental questions. However, he believes that if they don't care much for the human race, humans could be harmed simply because we are in their way, in the same way that forest animals are threatened by a developer because they are "in the way."
"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," said Kaku.
The Kardashev Scale
The Kardashev Scale was developed by Russian astrophysicist Nikolai Kardashev in 1964 as a means to classify civilizations into Type I, Type II, or Type III based on their level of technological advancement. The human race is not yet qualified to be classified in the scale.
Type I (planetary) describes a civilization that has already used and harnessed all the available energy from its neighboring star to meet the needs of its people, whereas Type II (stellar) is quite similar except that a Type II civilization has control of the entire star, instead of just harvesting the energy from it. This means that this civilization has control of the entirety of the power of their star.
A Type III (galactic) civilization is a highly advanced society that has already mastered energy on a galactic scale, practically turning them into a master race. With regard to its people, this society may be quite different in that they could already be an advanced mixture of man and machine.