 It feels like every week someone tries to propose a new definition of what should and shouldn't a planet be. But there's a new definition that's being proposed, and in addition to that it's actually starting to gain some traction. But will it be enough to bring Pluto back from its minor planet status? Well, this is your space pod for Thursday, February 1st, 2018. Here we go again, and everyone's going to be upset about it too, and are we going to be able to revive Pluto? Well, actually this new proposed definition is sort of looking at the largest planets that we know of. John Hopkins University Astrophysicist Kevin Schloffman has proposed setting an upper boundary for the size of a planet. The proposal is based on uniform data that we've gotten from observations of 146 planetary systems around other stars. Now one of the most important parts of the proposal is setting an upper limit for the mass of a planet. And this is going to be placed somewhere between four to ten times the mass of Jupiter. At that point, processes different from planets begin to occur, and you end up with what's called a brown dwarf. This is a kind of substellar object that's often been described as a failed star. It's too large to act like a planet, but it's too small to generate the needed nuclear fusion in its core like a star. Now chemical makeup becomes key in differentiating from extremely high mass planets and brown dwarf stars. A planet like Jupiter starts out as a rocky core, and then it accretes or has gas come on to it, and it builds up a thick atmosphere over time. Now something like a brown dwarf is created by a completely different process. It does so under gravitational collapse, so material comes together under gravity and forms the brown dwarf. Now this means that stars that are metal rich would be expected to have more objects with rocky cores accreting gas as opposed to metal pore stars, which will most likely have gas around them, which will then form brown dwarfs under gravitational collapse. Now Shlothlin's models have found that right at about ten times the mass of Jupiter, the object being formed could go either way into a planet or a brown dwarf, and thusly at ten times the mass of the planet Jupiter, you have an upper limit being born for you to actually go with. Now as for a lower limit, it seems like no one is willing to touch that one, not even Hades himself is willing to tread into that kind of contentious territory. Now don't forget to check out our previous live show where we have a round table discussion about Falcon Heavy and its upcoming launch. It's something that you're definitely going to want to tune in and listen to. In addition to that, we have our regular live shows every Saturday at 1,800 coordinated universal time, and you definitely want to watch live because there's things that happen that don't end up in our on-demand version on YouTube. And if you like us a lot, don't forget to like the videos and subscribe to us and share them to everyone that you can. So until the next space pod, keep exploring.