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Welcome back to SciShow Breaking News; I'm Hank Green. Now I don't want to freak you out, because I know that some of you are pretty much in a constant state of alarm these days, but every now and then something comes along in the world of science that sets off the crazy.

And such a thing happened recently because scientists say they discovered the first ever Rogue Planet. A planet that's not part of any stellar system, no star to orbit, no curfew to stick to, no respect for authority.

In today's issue of the Journal Astronomy and Astrophysics, a group of French and Canadian astronomers have observed a free-floating objects with a planetary mass about four to five times that of Jupiter only 100 light years away.

They got several good looks at it using infrared telescopes in Hawaii and Chile and have been able to study its atmosphere, detecting high levels of methane for example. and estimating its temperature around 430 degrees Celsius.

Now objects kind of like this have been found before, though never this close to Earth, but a lot of those bodies were probably Brown Dwarfs: small, would-be stars that don't have enough mass to trigger the Hydrogen fusion reactions that make stars burn.

What make this one different is that astronomers found it floating along something called the AB Doradus Moving Group, which, yes, sounds like a Greek furniture delivery company, but it's actually a roving gang of about 30 fairly young stars hurtling through the galaxy, minding their own business together.

Since the newfound planted was found among these stars, astronomers figure it's about the same age as them, about 50 - 120 million years old.

This age, along with the data about its atmosphere and temperature, led the scientists to conclude that it's not nearly massive enough to be a Brown Dwarf, so the odds are pretty good that we're looking at a Rogue Planet here.

Now Brown Dwarfs are a very common astronomical body and they're very nearly planets themselves. The line between Brown Dwarfs and super large gas giants is a fuzzy one. The current cut-off is at about thirteen Jupiter masses.

The big difference between Brown Dwarfs and planets seem to be fusion. Brown Dwarfs aren't large enough to fuse Hydrogen, but they do fuse some less common nuclei like Helium-3 and Lithium.

Also, this discovery continues to stir a debate about what a planet actually is. We used to say that anything similar to the planets that we have around our sun was a planet. Then we found a bunch of super huge planets and had to change the definition to something more like anything orbiting a star that doesn't have fusion going on inside of it.

Now, apparently even orbiting a star isn't necessary and a planet is just a collection of stuff in space that's big enough to form a sphere but small enough that there's no fusion going on inside of it.

Now I'm a fan of calling this a Rogue Planet, but some people have suggested less-awesome names like Interstellar Planet or Nomad Planet or Orphan Planet, but that's just kind of sad.

On the other hand, the word Rogue is kind of problematic in that it gets people thinking that it's, like, headed right for us and it's totally going to ruin Kirsten Dunst's wedding.

Well I know all about your 2012 doomsday collision theories, and the apocalypse continues to be not nigh. The new planet and its moving group are located in the southern constellation Dorado and are wheeling around the center of the galaxy just like we are.

Honestly the biggest problem with this planet is its name. You know what they're calling it? That! I can't say that!

A lone planet, ejected from its solar system, making us reconsider the very definition of what a planet is. That needs a better name! So, discuss!

Thank you for watching this episode of SciShow News. If you want to keep up-to-date on all the latest breaking news in science, you can go to youtube.com/scishow and subscribe.

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