This is something known as "object permanence," and we can see this in children even up to 24 months. But, since the participants are so small (and rather difficult to communicate with) how are we able to actually measure object permanence?
Speaking of object permanence, can we talk about Pluto for a moment? Because, as anyone who knows anything about Pluto will tell you, this little world is anything but permanent.
The small rocky body was discovered in 1930 by Clyde W. Tombaugh. The scientific community quickly heralded it as the 9th planet in our solar system. However, because it has such an elliptical orbit, Pluto swings about the solar system wildly, careening in for a moment and then shooting back off into the outer reaches of the solar system. As a result, from 1979 to 1999, Pluto was actually the 8th planet in our solar system. The in 1999, it once again became the 9th planet, and it was to be the 9th planet for another 200 years (until bout 2199), at which point it would again become the 8th planet…and so on and so on.
But of course, things changed, because in 2006 Pluto was reclassified as a dwarf planet (to the dismay of most Earthlings). Why this sudden change? Why isn't it this little world a fully fledged planet?
We are collaborating with scientists from the Rochester Institute of Technology (RIT) to bring you a weekly podcast hosted by astrophysicist Brian Koberlein (One Universe at a Time). In this week’s episode, Dr. Grant Gutheil, Associate Professor of Psychology at Nazareth College in Rochester NY, and RIT astrophysicist Brian talk about object permanence and what makes a planet a planet (and why Pluto isn't one).
The ‘One Universe at a Time’ Podcast is produced at the Rochester Institute of Technology with support from the RIT College of Science.