Only the most anthropocentric among us would seriously argue that Earth, as part of a solar system, is a godsend.
For me, it always made sense intuitively that our solar system is one among many – just as our star is one among many, or indeed our planet is one among many just in our solar system.
We’ve known for a while that our Sun is one amongst, literally, billions in the Milky Way alone. Thousands of years ago though this concept was intuition, and postulation. A lot of ‘what if?’ type statements were made about our Sun, in comparison to the twinkling lights of the night.
“What if we’re just a lot closer to this one, than to others, so it looks bigger and brighter?”
“What if it’s actually not all that different from others?”
Though there was no way to confirm these ideas – even if intuitively they did make a world of sense.
Through the advent of technologies – namely telescopes, invented roughly 400 years ago – data would eventually be provided to confirm the intuition that our little Sun was in fact quite a bit like all those stars that surround us at night.
(Of course to be accurate, the Sun is also dissimilar from many stars in terms of size, temperature, age, and so on — just as Mercury and Jupiter hold some traits in common, they are of course dissimilar in others.)
As time marches on, we find that in our solar system there is also a diversity of worlds: planets, moons, asteroids, comets – whatever classification you choose, there’s a multitude of those other bodies out there.
Again through technology – and again, namely telescopes – we’re able to confirm ideas that intuitively made sense to people of ages past: what if those wondering stars are other worlds?
In fact the word ‘planet’ derives from the Greek ‘asteres planetai’ – wandering stars – as the paths of the planets appears separate against the backdrop of the star field in our night sky.
Around the same time that we confirm there are other worlds around our star, folks start to wonder ‘what if those stars have planets, like ours does?’
It makes sense intuitively – just as the concepts of other Suns in the galaxy and worlds in our solar system makes sense.
What’s been lacking though is the technology to confirm this intuition – since let’s be honest, intuition alone is a very lousy way to do science.
We need data to confirm the hypothesis.
The first exoplanet – or extra-solar planet, aka a planet orbiting a star other than the Sun – was discovered in 1992. That’s only 22 years ago.
And in fact that 1992 discovery was of planets orbiting a pulsar. The first discovery of an exoplanet orbiting a main-sequence star (something loosely like the Sun) was in 1995 – not even two decades ago!
So on one hand, it might have been forgivable for people to argue that our solar system is unique. There had been, after all, no data to argue otherwise.
On the other, since the mid-90′s, there have been different techniques to detect exoplanets.
Though it wasn’t until 2009 that the rock star took the stage: Kepler.
(if you want to read all about the Kepler mission, go here – those details aren’t what this article is about)
With the Kepler mission taking centre-stage in our planet-hunting endeavour, we were finally able to take the first steps in confirming something that makes sense intuitively: many (if not most) other stars have planets orbiting them, just as ours does.
Exactly how many planets each star has, exactly the nature of those planets orbits, exactly the composition of those planets – and many other details – continue to be open questions in most cases. Though it’s worthwhile to note that in some examples, perhaps a dozen, we have a pretty good understanding of the answers to those questions.
Should it be surprising that we don’t have all the answers? Of course not. We have only confirmed that these things exist in the first place in the last couple decades.
There are planets out there everywhere – and lots of them.
Their makeup is as diverse as the makeup of our solar system.
But now that we have data to confirm the exoplanet intuition, we need data for next big intuition: life.
And just has happened historically, we’ll start in our own solar system with Mars.
We have been investigating Mars from afar for hundreds of years. Over the last few decades we’ve been investigating it close-up. We’ve confirmed the presence of water. We’ve confirmed a hospitable environment (at least historically).
It’s time to go to Mars and search directly for life.
This search will primarily be one for ancient life, though it’s not out of the question that some microbes could exist underground near a water supply today.
Once again, this is an issue where it is intuitively plausible that Mars was home to life. We know the conditions were right, so why not?
But this is a big question, and again intuition isn’t enough – we need data.
I do, openly, speculate that this is another case where intuition will eventually be confirmed by data (whether it’s within the next few years or not though is harder to guess – Mars is a pretty inhospitable place now, and so evidence of past life might be hard to find – if it is there at all).
Speculation aside though, data can confirm for us that Earth is simply one planet amongst hundreds of billions – if not more.
This is a reality that may take some time to sink in, but it is an undeniable truth.
Just as it is equally true that the Earth is round, that we orbit the Sun, and that the Sun is but one amongst a vast ocean of stars.