Word that water may well flow on Mars (periodically) was met with great excitement by many people. Water makes it easier to land and live there, as well as dramatically increasing the potential for life on Mars.
However, a few people were dismayed by the hugely significant discovery, which seems a little odd. Until you learn about the Fermi Paradox and the Great Filter [before yesterday, I knew of the former but not the latter].
Concisely, the Fermi Paradox wonders why we haven’t encountered any other aliens (yes, space is enormous, but species could have been developing for billions of years more than us, so where are they?). The Great Filter is a reference to a theoretical barrier that is very difficult to surpass, and prevents species reaching a certain technological height (hence why we haven’t encountered any).
A very interesting and lengthier explanation is available here [some fruity language so perhaps NSFW]: http://waitbutwhy.com/2014/05/fermi-paradox.html
The issue with the Great Filter, as well as potentially not existing, is that nobody knows where it is. It might be an extremely early evolutionary barrier, at the unicellular level, or it could be in our distant (or immediate) future.
The human race is inherently unstable, to some degree. It might be that high intelligence (which, on an individual level, has high co-morbidity with many psychological conditions) in a species naturally coincides with instability. It’s not hard to think of the numerous wars we’ve made on ourselves. If we keep doing that, the chances of nukes or biological agents (or weapons yet undeveloped) getting used on a global level will shorten (perhaps to a terminal extent).
We’re also very near the Singularity, a moment when artificial intelligence will exceed that of ourselves. This is significant because we could create a machine, which then designs a more intelligent machine, and so on. As this moment approaches, we’re also developing ever more effective robotic forms of death, which has led scientists to call for laws governing autonomous killing machines.
Inventing autonomous killer robots with superior intelligence to our own would be a very human way to commit species-wide suicide.
Drifting back to Mars and the Martians: if there is life on Mars, then that removes the earliest instances of the Great Filter, and makes it a bit more likely the Great Filter (which may well be an apocalypse of some variety) lies in our future, rather than our past.
Cheery thought. And all because some salty deposits were found several million miles away.