How to effectively survey alien planet for complex lifeforms?

Question

Two approaches:

1. Using powerful scanner to detect unique heat signature on the surface while maintaining orbit.

2. Deploy probe to physically examine the world at ground level with motion detector and visual feedback.

Using the latest technology in existence or newest scientific discovery, how do I design a tool that any man-made spaceships can use to explore alien planets for extraterrestrial complex lifeforms? Mine are probably out dated and aren't reliable, I'm thinking of incorporating MRI scanning concept into a spaceship for both long range and close proximity scanning is it feasible?

Answer 1

You will use different approach:

Step 1: Discover a planet. You are going to use already existing telescopes. Example: Kepler-186f

Note: From now on I am using planet Earth as example

Step 2: Analyse planet position and its spectrum. You will realise that it is in habitable zone and can support life. From the spectral analysis you should be able to know, that such planet has water AND oxygen. Something funny can be going on!

Step 3: Listen and analyse even more. Ok, here I am going to assume you could not catch any signal. It can happen. But still, such planet looks promising

Step 4: Send probe. Possibly for fly-by. Problem with our grant system is, that you need results fast. So first probe will do just fly by and send even more promising pictures:

Image credit: Wikipedia

You will get a lots of data from that picture. You will know that there is definitely water and such planet has atmosphere. The scientists will have even good clue that such planet definitely supports some complex organisms: Plants.

From scope of your question, you are done here, but lets continue:

Step 4: Send orbiter. It will send a lot of pictures:

Image credit: Google Earth

Again, job done. Now you know that such planet definitely supports complex life. Also, from the orbiting devices you will also know where to search for them

Edit: Also, at this point, you should know if such planet has some intelligent life going on:

Image Credit: Google Earth

Step 5: Send rover device. The device will land and analyse the planet even more:

Image credit: Wikipedia, idea taken from What-If

Step 6: Back up! Yikes! The aliens are scary