Let’s imagine another life form entering this star system, what features would be considered good enough to talk about once he’s back home at a barbecue under five shining moons in his star system? Well let’s see where to start? How about starting from the outer reaches of the system? OK here we go.
1) Heliosphere. This intrepid explorer would first realize that he’s entering a star system the moment he gets the gentle nudge from incoming shock waves at the end of the heliosphere.That’s where the influence of the sun cease and interstellar space begins. Fluctuations in the gravity and magnetic fields will tell him that he’s entering a region dominated by a main sequence yellow star and he;s already getting excited, he’s coming from a similar star system and he just hope that he’ll be the first one to spot a new civilization in this quadrant of space. By his calculations he’ll be able to see the first rock of this system in about 15 minutes, after all it’ll be only a couple hundreds billions miles to the core of the system, he’ll better slow down a bit.
2) Oort cloud and Kuiper belt. The calculations were right on the spot and he’s now traveling through a massive reservoir of loose rocks and ice followed by a few millions miles of nearly empty space and then more rocky bodies and some more ice. If this is anything like the place he comes from this is the part of system where comets and asteroids are more likely to originate. He wonders if those icy bodies had the same big influence in shaping the fate of countless animal species that must have existed before any intelligent civilization can develop. On his world comets have been the culprit for almost any big extinction event in history. So far this system is remarkably similar to his own and he’s fairly confident about what to expect next.
3) Gas Giants.He’s not surprised to see Uranus and it’s moons as he’s expecting to see huge balls of gas surrounded by a variable number of moons. Wait there’s something you don’t see every day, this planet whatever it’s called (Uranus) it’s tilted almost 90 degrees on it’s side, the poles are where you would expect the equator to be. This seasoned explorer knows that the only possible explanation for this is a massive collision with another colossal body that forced this planet into this interesting position. Other than that the only feature he expect to see is one or more giant storms fast moving around the upper atmosphere. No big surprise there. The next gas giant he’ll encounter is called Saturn,main features are it’s fantastic rings visible from millions of miles away and one very interesting moon surrounded by an orange atmosphere. Oh dam, this is not a new star system, someone already beat him to the punch. According to his computer he already missed a planet during the entry phase, the 2 expeditions that have been here before encounter a blue seemingly peaceful planet before the one that rotates on it’s wrong axis. He now knows that the orangy moon is not really a good place for life yet and it won’t be for millions of years, the moon has lakes and rivers but those are made of hydrocarbons not water so let’s no waste time with it and instead let’s try to explore the part closer to the sun. He’ll know when he’ll be inside the inner system because the last planet the expeditions before him visited was a gas giants with a big red storm on it’s surface. He knows there’s a moon in the red spot planet system where life could exist, (Europa) but he can’t stay here for long so that will have to wait for the next expedition. He now passes Jupiter and notes that the red spot is still there, last expedition was more than 300 years ago so the spot must be older than that. Cool. It’s so big it’s own planet would fit in it and have space to spare, you definitely don’t want to drive into it regardless of your starship size. The cool thing is, between here and the star he can name anything he’ll encounter.
4) Asteroid belt. Dam pieces of rock! Not you again, you just a waste of his time, just a bunch of loose rocks orbiting around the central star. He’ll be out of here in a couple of minutes.
5) Rocky planets. Now we are talking! A new planet, cold, almost no atmosphere here, it has ice caps but those are mainly CO2 not water. However there are huge river basins and canyons, one of them as big as a continent on his planet, and there’s a big volcano that seems to be dormant (mount Olympus is 3 times higher than Everest). Water once flowed here but now is probably trapped in the soil as permafrost. He’ll call this place Mars. Next is a blue planet, there’s liquid water on the surface, a lot of it. The planet axis is tilted by a few degrees, enough to have seasons, lifeforms could definitely survive there. Another stability boost is the fact the this planet has a big enough moon to stabilise the climate even further. He’ll call this one Earth. This is a place that needs further exploration. Closer to the star there’s an almost identical planet but the atmosphere is not blue, more yellow/brownish, according to the instruments it’s mainly composed by CO2, there’s plenty of acid rain falling down but oddly enough that rain never touches the surface of the planet. It’s also too hot for any living thing to survive, so hot that most metals would not be staying solid for long. He’ll call this place Venus. He’s about to turn around when he noticed a little rock orbiting very close to the star. It’s just few miles long, no atmosphere, a lot of impact craters and a very dense core but that’s it. He’ll call this rock Mercury.
Time to head back home where he surely is going to be famous, after all he just discovered four more planets and possibly one where life and intelligence can be found. Wouldn’t that be cool?