What constitutes being "Outside" our Solar System?

A tweet-investigation about what it means for any man-made object to be considered as being "outside" our solar system.


  1. It started innocently enough. A single tweet on a monday morning to start my day. 

  2. Well, it was actually a re-tweet about Pioneer leaving our star system. But of course everyone knows what i care about...anything outside our star system. Anything and all things "Exo"!

  3. So i gave it some more thought...Hey wait a minute! Passing Pluto's orbit constitutes being outside our solar system? Something's weird about that. So i had to tap the hive mind to confirm and bring that into focus.

  4. There were responses to my query, with varying angles. Implying that historically speaking, it initially included Neptune, Pluto and the Heliopause. 

  5. Of course, there is a fuzzy boundary which was starting to become apparent in the oncoming responding tweets. I wondered if there was a boundary considered in terms of Science, and if there's a boundary considered in terms of humanity's culture and history.

  6. But the boundary that overlaps between that "edge" considered by Science, Culture and History is where it gets tricky.

  7. Suddenly, we have all other objects that can be considered as boundaries and markers for the definitive outer "edge" of our solar system. The Kuiper belt, the Oort cloud and Sedna and so on...

  8. And then comes the issue about how the media treats it.
  9. But one thing is for sure. It does not depend on Pluto's orbit (or perhaps any object for that matter) And that which I agree with.

  10. It seemed that the sequence of tweets mirrored what happened in history as our knowledge of the solar system expanded. What we considered as the "edge" of our solar system gradually began to be extended outwards.
    The markers, boundary and the edge of our solar system are moving further outwards as we discover new things at the edge...