Yes but the solar system is a biased sample: life evolved in it. Maybe it was helped by Jupiter shielding us from asteroids that could wipe out life on the planet? If it's statistically more likely that intelligent life evolves in a system with large planets then we would expect to see a difference between our solar system and others that we observe.

All asteroid crashes aren't equal. Earth got most of its water from an asteroid crash.

Basically a huge of range of things have to work on large timescales for intelligent life to evolve on a planet.

Which is why intelligent life apart from us could just be absent or very very rare and far away.

The article discusses an "oligarch" model of planet formation, where there are roughly early sized and spaced oligarchs early on in planet development.

Because our solar system didn't end up with the "peas in a pod" pattern, planet formation they also posited a period of violent collisions that stirred things up. Wild, uneducated, and necessarily oversimplifying speculation: perhaps all these early collisions brought water which helped encourage development of life, and led to the formation of Jupiter, which then protected that life's development.

My point is that a large planet in the system reduces the probability of large asteroid impacts later in a star system's history. I didn't mean that it immediately removes all asteroids from a star system after forming.

True, but you need water rich asteroids to crash in the immediate phases after planet formation, and then you need life to develop. After which you need asteroids to not crash into the planet. Of course in the meanwhile, you need a lot of other things like formation of atmosphere, plate tectonics, volcanic eruptions, lakes sitting on geysers etc etc.

Basically things have to (not) happen in a series of steps for life to form, even if other things like a rocky planet being situated in the goldilock zone come true. This is apart from a lot of other factors, like not having a big sun etc etc.

All this suggests even if we consider 'Terrestrial mediocrity' to be true. Life could just very very rare across the universe, if not totally absent.

The "Jupiter as a shield" hypothesis has been questioned recently: https://phys.org/news/2016-02-jupiter-role-planetary-shield-...

That's fair enough, the point I tried to make is: Statistically, we would expect our solar system to be average among solar systems that can support intelligent life, not among all solar systems (following the Anthropic Principle). Therefore, the difference we see between our solar system and the average star system might imply something about what kind of conditions make intelligent life more probable in a star system.

If we see that in all star systems we know that evolved intelligent life (even if there's only 1 we know of) there is a large Jupiter-like planet, and that's very atypical among star systems, that suggests that Jupiter might have increased the probability that intelligent life evolved here.

How do you know the statistic probability of life evolving in a solar system? We don't have an observation technique to definitively observe this.

Again, we've only ever observed a single solar system up close.

Yet, life here on earth has happened more than one way. Seems like its pretty hardy if one planet gets more than one start on life? Isn't that a statistic of sorts?

There are currently no evidence that life on earth happened more than once.

How about the multiple principles of life observable in what we see? Not just plants vs animals or fungi, Sulphur-based life chemistry, iron vs copper blood in higher orders and so on?

Currently, all life we know of fits into a single tree of life. All known lifeforms for instance agree on using RNA for something, hence the RNA world hypothesis. I would also be interested in a study which points to the opposite.

Thats not true is it? life on earth started more than once, source pls!!!

Keep in mind that this isn't true for every system they've detected, it's just more likely than not given current examples - 909 planets in 355 systems according to the abstract: http://iopscience.iop.org/article/10.3847/1538-3881/aa9ff6/m...

There's plenty of differences from our own solar system out there that also don't fit that pattern. Gas Dwarfs are a planetary type that we don't have in our own solar system, for example: https://en.wikipedia.org/wiki/Gas_dwarf

I always thought something so far away would appear to us as Pixels.

Its kind of mind blowing, we have techniques both theoretical and practical to only see pixels and yet come up with their exact dimensions.

We don't usually detect them directly. We observe a star dimming (planetary transit) or wobble and infer the planet's location, speed, and mass from that. We are only just developing techniques to observe very large planets close to their sun directly by efficiently cancelling out the sun's light.

That is precisely what is so interesting.

Even a star wouldn't be anything more than a fat pixel, and the planet would be more like a thin pixel. Plus the star dimming, given the orbit would also be a long drawn phenomenon, like in case of earth(1 year).

I understand we ideally decide these things based on color of the light we see. And light waves stretch as the distance increases, and it can all be figured out by doppler effect.

But its still kind of mind blowing how much we can infer from just these things.