There have never been any guidelines worked out on how you find out whether aliens drop down on earth and how you speak to them. That is because most of us didn't know that they have, and would be put on the spot if we learn that they do. But now that President Obama is on the brink of revealing that aliens are frequent callers on earth, here's what you could try.

Let's start at the very beginning.

Be an expert - maybe a scientist, researcher or seeker - with SETI (Search for Extraterrestrial Aliens) Institute, a US-based research group that has dedicated radio telescopes to scan the skies for messages from alien space.

Or befriend someone who is an expert.

If you are working in SETI, or happen to get some records if you aren't, then look through their logs.

If you find a message, you might find anything from out there. Perhaps another how-to: It might be a manual to build a portal or cook a strange dish.

Secondly, check out whether it isn't just some kind of fake message, or only a natural phenomena - perhaps a bird, an insect or an optical illusion - as the skeptics claim all the time.

Thirdly, if you do feel that it could be an alien signal, then get into the act of telling the International Astronomical Union, the United Nations, Committee on Space Research or any other global body.

Fourthly, you can then tell the media about it. It can come out in the open. So that would begin a virtual invasion - of the virtual and human kind, of course. The whole world will be freaking out and sending excited messages about the alien visitors on earth.

Fifthly, do not immediately send back any messages to the ETs, or build the rocket or dish based on their instruction for a while. Instead, let the global experts break their wise, grey - or dyed - hair over it for a while.

Sixthly, just collect stocks and supplies - if you find any - and store them in a secret alien-proof bunker in the desert.

Seventhly, you need to figure out what you want to tell the Aliens. Are you going to become good friends with them? Will you take their help in building up a technological revolution on earth? Or will it be "insult them by accident" and create enemies?

Eighthly, find out how you will speak to them. You can move on from SETI, or Search for Extraterrestrial Aliens to CETI, or Communications with Extraterrestrial Aliens. SETI's lifespan will be over, anyway.

It would be easy to find out about the aliens' intentions, and you will, soon. There are two options:

Option one - the aliens will attack you and gobble you up. In which case, you wouldn't have to do anything further.

Option two: They might be friendly and try to use sign language

After that, you can work out the whole thing in your own way.

The Rio Scale

The guidelines explained above are based on the Rio Scale. It was in 2000 that SETI researchers, which included the well-known Jill Tarter, designed the Rio Scale, with an online calculator.

This is how it works:

Step 1: What is the class of phenomenon? Is it a direct message sent to Earth? Do they expect a reply to the question? Or is it just an alien artifact or sphere nearby?

Step 2: Can the finding be verified? Can the signals by SETI researchers hint at some old data that cannot be confirmed?

Step 3: Are we talking to somebody within or outside the solar system?

Step 4: Are you completely sure of what you spotted? Does everyone believe you or are you going to be sent to a loony bin?

You can now get ranked on The Rio Scale between 0 and 10. While Level 0 is "no importance" or "you're a crank", level 10 is "extraordinary importance", or "now would be a good time to panic".

How to communicate - and should you, anyway

So now that it's done, what are you going to say to those aliens?

How do you communicate with them? Some attempts have been made, and a number of messages and mails have been sent over the years to any that exist. For instance, in 1999 and 2003, a series of signals were sent to contact various stars with images of Earth and different mathematical principles that could be used by aliens.

But is it really a good idea to send messages of our existence into space? Seth Shostak felt that it would be useful to send the entire internet, which would give aliens a whole perspective of our earth.

However, he was refuted by the science fiction author David Brin, who felt that we should keep quiet about the existence of life on the earth.

Still, what really will happen when we do touch base with the aliens? Will we go berserk or will we just settle down and accept it?

Both. For a while, humans will go on a rampage and try to get some idea of the amazing phenomena. But once they get used to it, they will simply settle down in their new world, perhaps even getting bored and yearning for old times.

What would you do? There is no how-to book - yet - for that.