Sometimes people question the value of science, like whether it matters we now have confirmation of liquid water on Mars. I often question the value of celebrity gossip, so it’s not a sufficient answer to simply reply, ‘Because, science.’ What would a possible future benefit from knowing more about space and other planets look like?
To answer the celebrity issue, maybe if you learn about a celebrity’s allergies you could stop them from eating something they shouldn’t and going into anaphylactic shock. But good luck with that.
In the case of water on Mars, it helps with planning for future missions to Mars, but can also let us learn about the types of worlds that can exist. Down the long road of the future, we might be quicker to figure out a similar planet is similar if we know more about Mars, just like if you know a lot about one actor, you might extrapolate information about another.
But more than that, a lot of the science and engineering from studying space are in figuring out “how do we figure out X?” We have some scientific question and we can’t just scratch off a lottery ticket and see what the answer is. We have to feel our way to the answer through a lot of obstacles.
In the case of water on Mars, we could have just sent a giant bomb full of color-changing-when-wet tablets to mars and blown it up, dispersing them all over the planet. But that would have put a bunch of those chemicals all over the planet, potentially ruining future explorations, and it might still not have given us the real answer, depending on when and how the water flows.
Instead, they sent a vehicle with a decent number of tools and sensors, including cameras, to look around, feel around. That meant doing a lot of work, including designing and building the rovers, which includes how to power them, how to get them to Mars, and how to get them onto the surface. A lot of those issues being solved helps build the next one better, and it also tells us where we need better technology.
Okay, okay, a lot of boring science stuff. Who cares? People on earth have other stuff to worry about.
But if and when we find out a big rock is on a collision course with earth, you’ll probably care, right? They’ve hit us before, and sooner or later we will probably have to deal with the prospect of an impact coming our way. Space exploration is an insurance policy. The more we know about space and getting up there and working up there, the better our chances at dealing with something that could make us all have a really, really bad time.