With our current understanding of the cosmos, the number of planets that we discover, and especially the number of potentially viable or habitable planets that can be found in the huge expanse of space, it testifies gradually from myopic pretension to assume that we are the only life form that would be. Also the possibility that there may be intelligent life elsewhere becomes more accepted.

There are literally billions of galaxies with billions of stars, many of which have planets. With billions of planets which are, according to the Drake Equation hundreds of millions of which life is possible.

Following the claimed discovery of an arsenic -eating bacteria (Halomonadaceae) in the Californian salt lake Mono Lake introduced NASA in 2010, that this the estimation of extraterrestrial life totally changed.
Previously, it was assumed that 6 elements in the DNA are necessary for life. In the above case is phosphorus replaced by arsenic. Other shapes and compositions may therefore also be life. And that increases the chances of alien life considerably.

Space Probes delve into our solar system to life. Outside our solar system in the SETI project with radio telescopes searching for signals from an intelligent source.

Scientists keep potentially habitable planets in an index. At present, 47 planets (and counting) and moons are found that fit into the picture, such as Gliese 581g and Kepler 22 -b.

A practical opportunity to make contact we have not (yet).
But they might have.
Suppose we get early or late visit of (higher) intelligences, how would that go?

If we are going to confess to ourselves, take a deep look into our own hearts, it promises no good. As white Westerners we've visited the most remote and almost inaccessible chunks of country on our own globe, and colonized them.

We went there out of curiosity, and to accumulate wealth.
We took what we found useful and valuable, crops and animals, gold and commodities. Sometimes temporary or only initially in exchange for worthless beads and mirrors, or booze and guns. And else we took it by force. Of easy targets like the dodo (apparently tasty flightless bird on Mauritius) we would have eaten the last just to taste him.
Original owners, occupants or users were expelled as they competed for the same goods.

Or murdered.
We brought faith and diseases, and took what came to us, even the soil. Where in and on we forced the natives to work for us. Whether we shipped them thousands of miles to work for us, at least those who survived the trip.

What will be left of the original culture of Indians, Negroes, Aborigines?

Fundamentalists and suicide bombers now still kill because of an ideology or belief. We still murder each other because of raw materials, territory, oil. Even for the sake of another religion or orientation people are tortured in the most gruesome manner and slain.

Will aliens who have the knowledge and the technology to travel light years far have more respect for our primitive life form that they are going to find here? Kilo's science fiction stories about alien invasions serve various options.
Some believe that centuries ago already aliens (gods) came to the earth.
Others are convinced that secretly unrecognizable people are disguised aliens or reptilians that live among us. Or that governments have for a long time contact or cooperate with ETs and ufonauts.

But that's about beliefs, not about knowing. Let's just say that the possibility exists that they could (ever) come.

Perhaps unintentionally are traveling with ET, as with us, viruses and bacteria that does not harm them, but for other life forms are disastrous. Or maybe our astronauts bring something unconsciously from a space trip. Whether they are traveling in a meteorite to here.

Maybe aliens want, like our own white ancestors, also just simply commodities. Or food, hemoglobin, fat,... Or cheap miners? Converts?
Why would in this they be different or better than us?

Maybe their ethical awareness is with their technology developed?

Let us hope that they are wiser than men, and above all humane.

Extraterrestrial danger, lies and nonsense are not censored. (Hugo Tresinie)