The most brilliant astrophysicist of our age was Steven Hawking, who died about a year ago. Not surprisingly, he had a lifelong interest in the idea of life developing elsewhere in the universe.
Towards the end of his life, he expressed considerable reservation about the wisdom of advertising our own existence. given the uncertainty of whether an intelligent alien life form would be kindly disposed towards us or would even recognize that we were important. Near the end of his life, he expressed this unsettling thought:
"If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans."
More information about what Hawking thought? Look here:
Stephen Hawking takes a hard line on aliensBy Leo Hickman
The Guardian
Mon 26 Apr 2010 12.05 EDT
https://www.theguardian.com/commentisfree/2010/apr/26/stephen-hawking-issues-warning-on-aliensHawking believes we would be well-advised to keep the volume down on our intergalactic chatter and do all we can to prevent any "nomadic" aliens moseying our way to take a look-see. Should they find us here tucked away in the inner reaches of the solar system, chances are they'd zap us all and pillage any resources they could get their hands on. Our own history, says Hawking, proves that first encounters very rarely begin: "Do take a seat. I'll pop the kettle on. Milk? Sugar?"
"Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach," says the theoretical physicist in Into the Universe with Stephen Hawking. "To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is to work out what aliens might actually be like."