Depends who got to the top first. If the most advanced was peaceful but eliminated threats. I’d assume they could create a collective empire.
Apex ruthless only gets you so far verses a collective.
Apex ruthless only gets you so far verses a collective.
If aliens did come here they'd have to be very brave, powerful enough not to worry about what we'd do, or unaware of what we are.
I'm not too worried they'd kill us to protect themselves though. At the rate we're going, we'll kill ourselves off along with every other living thing on the planet long before we get out of our own solar system.
However, humans were aware of this possibility and had spent centuries reorganizing the solar system to have a measure of resilience to it. So, to humanity's great credit, he had to go get permission from his supervisor for to deploy a next-tier solution.
"Why would anyone travel across town (i.e., the galaxy) just to step on an anthill?" We have a whole industry dedicated to exterminating any other life that invades "our" living space. It's considered an unremarkable necessity.
If aliens had the technology to visit us right now, the latter is a given.
You don't have to assume anything crazy. You can create a planet killer by simply accelerating a decently massive object at relativistic speeds and firing it at earth.