A NASA-affiliated scientist (reports the Guardian) and some colleagues at the University of Pennsylvania have been sketching out what might happen in the event that humanity and intelligent aliens make contact, something, it should be stressed, that they consider to be unlikely.

The team has come up with various outcomes.

Some are beneficial:

Beneficial encounters ranged from the mere detection of extraterrestrial intelligence (ETI), for example through the interception of alien broadcasts, to contact with cooperative organisms that help us advance our knowledge and solve global problems such as hunger, poverty and disease.

Some are meh:

The extraterrestrials may be too different from us to communicate with usefully. They might invite humanity to join the “Galactic Club” only for the entry requirements to be too bureaucratic and tedious for humans to bother with.

Some are grim:

While aliens may arrive to eat, enslave or attack us, the report adds that people might also suffer from being physically crushed or by contracting diseases carried by the visitors.

Caution is called for:

To bolster humanity’s chances of survival, the researchers call for caution in sending signals into space, and in particular warn against broadcasting information about our biological make-up, which could be used to manufacture weapons that target humans. Instead, any contact with ETs should be limited to mathematical discourse “until we have a better idea of the type of ETI we are dealing with.”

I can see something to that argument, but this (emphasis added), well no:

“A preemptive strike would be particularly likely in the early phases of our expansion because a civilisation may become increasingly difficult to destroy as it continues to expand. Humanity may just now be entering the period in which its rapid civilisational expansion could be detected by an ETI because our expansion is changing the composition of the Earth’s atmosphere, via greenhouse gas emissions,” the report states.

I suspect that our radio transmissions may have already done that job. According to the team behind Lightyear FM quoted in a 2015 account from Wired, the Beatles had already made it some 40-50 light years from Earth by then.

And then there’s the danger posed by all the alien Gores and Gretas:

“Green” aliens might object to the environmental damage humans have caused on Earth and wipe us out to save the planet. “These scenarios give us reason to limit our growth and reduce our impact on global ecosystems. It would be particularly important for us to limit our emissions of greenhouse gases, since atmospheric composition can be observed from other planets,” the authors write.

Whatever the question, it’s always the same answer . . .