NASA scientists have recently discovered 1, 235 potential planets orbiting distant stars using the Kepler space telescope. These are of course potential planets, as they must been seen at least three times in order to confirm their existence.
Of these 1, 235, the NASA experts suggest that 54 of them may lie in habitable zones, where temperatures would allow water to exist in liquid form, which of course is required for life as we know it. The key here, is life as we know it.
NASA scientists have discovered systems that, prior to this, we had no idea could exist. For example, a cluster of 6 potential planets packed so tightly together that they influence each other's orbit around their respective sun. It seems like the more we know...the less we know?
But back to the point...life as we know it. Remember not too long ago when NASA had another big discovery? This one was about the bacteria that can use arsenic instead of phosphorus in its' DNA. (Remember your six key ingredients for life: carbon, oxygen, nitrogen, hydrogen, sulfur, and....phosphorus!) That's right, this little guy can replace one of the six major building blocks of life as we know it with a horribly poisonous compound called arsenic.
The point...what is life as we know it? Until this bacteria, we had a completely different view of life here on Earth, let alone on other planets. We have a poor definition of life...I remember arguing that viruses are alive in grade 11 biology...I still think they are, more or less, but that what we define as life only includes organisms that are similar enough to us- and wrongly excludes viruses. (Think about it- how can something have
DNA or RNA and not be alive...energy,waste, reproduction, etc- these are things that we like to associate with life because it includes most things- this makes it inclusive of the majority, but not necessarily correct).
This begs the question, if we saw life on another planet...would we recognize it?