Aliens Think Humans Are Disgusting?

Anyone hoping that the first spaceman to land on Earth is as friendly as ET could be in for a shock. In the latest bid to get us to cut greenhouse gases, scientists have decided that eco-conscious aliens disgusted by mankind's emissions could destroy our planet in disgust. When observed from afar, the changes in Earth's atmosphere could label us as a civilisation that has grown out of control.

ET: "Your planet is disgusting and dirty."

Anyone hoping for a friendly form of alien life landing on Earth, like ET, could be disappointed. Nasa scientists have decided that aliens looking down on our planet will be less than pleased with our greenhouse gas emissions. Aliens reaching that conclusion may then launch a pre-emptive attack to protect this perceived threat to their own way of life.

But that is only one possibility. Scientists are also considering other unwelcome - and far-fetched - outcomes, such as aggressive extra-terrestrials who eat or enslave us, or perhaps they are industrial types who want to improve their own technological infrastructure and so pillage ours.

Lead researcher Shawn Domagal-Goldman and his team compiled a list of hypothetical situations to help us should we come into contact with other life forms. The report, a joint effort between Nasa and Pennsylvania State University, answered the question 'Would Contact With Extraterrestrials Benefit Or Harm Humanity?' Providing beneficial, neutral and harmful outcomes, the report is designed to prepare mankind for the possibility of an alien encounter on Earth.

HYPOTHETICAL SCENARIOS OF CONTACT BETWEEN MAN AND ET

BENEFICIAL

• Mere detection - this would have philosophical implications
• Cooperative extraterrestrials - discussion of science and maths; advice in avoiding global catastrophe; solutions to problems on Earth
• Uncooperative extraterrestrials - humanity successfully overcomes a threat

NEUTRAL

• Invisible to us - intentionally hiding; unintentionally escape our notice (different form of existence, no desire to communicate, too far away)
• Noticeable but different - uninteresting and non-useful; mild nuisance

HARMFUL

• Intentional harm - selfish ET that eat, enslave or attack us; universalist ET that want to improve their infrastructure, use our resources or see us as a threat
• Unintentional harm - physical hazard caused by disease, invasive species, mechanical harm, act of incompetence, computer virus, biological hazard or demoralising cultural impact

In the best case scenarios put forward, the scientists claim that mankind could swap information to overcome hunger, poverty and disease. An alternative scenario could see man triumph over an alien force and learn from their technology.

The report says: 'In these scenarios, humanity benefits not only from the major moral victory of having defeated a daunting rival, but also from the opportunity to reverse-engineer extraterrestrial intelligent (ETI) technology.'

In the neutral category, it suggests man could feel indifferent towards any alien invaders because useful communication is not possible. There is even the possibility that aliens are too bureaucratic and tedious for us to join the 'Galactic Club'. Echoing the situation in the film District 9, in which aliens are put into a refugee camp in South Africa, they could even become a nuisance to Earthlings.

The most harmful outcomes are also suggestions that would fit well in an apocalyptic Hollywood film script, with Independence Day-style attacks, accidental destruction of our planet or diseases wiping out the entire population. Their suggestions to help with our survival against such events include the issuing of warnings against broadcasts that might help aliens from learning about our biological make-up. The first part of our contact, they add, should be limited to maths 'until we have a better idea of the type of ETI we are dealing with'. The report adds: 'A pre-emptive strike (by aliens) 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.

Aliens: "Surrender, earthlings."

'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 Earth's atmosphere, via greenhouse gas emissions... 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.'