This is question is similar to this, but that question has already been voted to be closed. I will add though that I joined this website today, so I am still learning how to write a good question here. And I was guided by @uhoh (thank you) to modify my question and repost it.
When scientists explore other planets such as Mars, it seems that
- they generally look for life derived from water, oxygen and carbon, and
- that they do this with a purpose to see whether that planet is habitable for humans or not.
Please correct me if I am wrong on either of these.
But here I would like to ask something different and that is, have there been any searches for extraterrestrial life which doesn't require water, oxygen and carbon? If not, does that mean that with today's science and technology we would not be able to detect such life forms?
I did find the following two questions, but they and their answers focus on why carbon and water are essential for life.