Strange Mini Solar System Found

starexplorer writes "In 1990, Penn State's Alex Wolszczan found the first exoplanets. But he never got much credit from mainstream researchers, because his planets (3 of them, roughly Earth-sized) orbit pulsars and hold no chance for harboring life. Now he's found a 4th object on the outskirts of the system, SPACE.com is reporting. Call it a planet, call it an asteroid, Wolszczan says, but call the setup a dark, eerie twin of the inner half of our solar system. Also in the same story, news of a brown dwarf just 15 times the mass of Jupiter that has a planet-making disk of stuff around it. Together, more problems for astronomers, who still don't have a basic definition for the word planet or a firm idea of what separates planets from stars."

Comments

Re:Superman

[Rei]

I would love to see some of these extrasolar systems; the more we see, the more variety it looks like there is in the universe. "Hot jupiters" which orbit right close to their stars and even possibly exchange matter; the heat swells them up to many times their normal size. Brown dwarfs which give their closest moons enough light to possibly harbor life, while burning their deuterium slowly. Supercomets - planet-sized cometary bodies with huge comas. Planets without stars. "Water worlds" - bodies like Uranus or Neptune in a hotter orbit. And all sorts of other things.

I hope some day humans can see them in person. :)

Star vs Planet

[imemyself]

Would a star not be any object that makes light on its own(ie, not reflects it)? IANAA(Astronomer)

No chance of life?

[suso]

because his planets (3 of them, roughly Earth-sized) orbit pulsars and hold no chance for harboring life.

I wish people wouldn't say things like this. Humans barely have a grasp on what life really is and what conditions it can exist under, especially off our own planet. So how could we make a judgement that life couldn't exist around a pulsar, despite its homo-sapien threatening conditions.

Why on Earth does the name matter?

[TechyImmigrant]

We started out with a limited number of names for things. Planets, stars, the sun. They we found some more things like comets and asteroids.

Now we've found lots of things that come in between, requiring a different form of classification. The only problem is that people are trying to squeeze the definition of things we know about into a limited naming set.

To name something doesn't mean we understand it and being unable to name something doesn't mean we don't understand it.

People should stop worrying and be happy that we can describe these objects to a higher level of detail than can be described using the existing names we had for things floating in space.

It shouldn't be that hard.

[Corbin Dallas]

problems for astronomers, who still don't have a basic definition for the word planet or a firm idea of what separates planets from stars.

It's not as sexy as having a word like "planet", but all this confusion could be eliminated with a basic classification system that took into account distinguishing characteristics besides just it's mass.

As an example, one could define these objects through two primary attributes: The body's mass and the mass of that which it orbits. As I don't have exact mass data at hand, this example will use the following over-simplifications:

S = Solar Mass
G = Gas Giant Mass
R = Rock Planet Mass
M = Minor Mass ( appx Phobos to Pluto )
A = Asteroid Mass
D = Debrit ( 1m or smaller )

Of course, the real system would use exact scientific measurments rather than these crude examples.

Earth = SR ( Rock Planet Mass orbiting a Solar Mass )
Jupiter = SG ( Gas Giant Mass orbiting a Solar Mass )
Pluto = SM ( Minor Mass orbiting a Solar Mass )
Titan = GR ( Rock Planet Mass orbiting a Gas Giant Mass )
etc
etc

You could even create a symbol to represent the galactic center, which could be used in relation to stars and other free roaming bodies. Binary stars can be represented using SS, since they're orbiting each other.

Anyway, the point is that you can not come up with solid definitions of these bodies on mass alone. Take into account other major factors as this example does.

Re:Solar? It's not Solar at all, morons

[RubberDogBone]

It's that reporter for Space.com, Robert Roy Britt.

He has a habit of using the word "solar" for non-solar topics, and of course the Space.com stories end up on the wire services and are repeated by hundreds of TV talking heads. All that does is make the problem worse. It's bad enough that most people don't even know the name of their star. We don't need them attaching that name to totally unrelated objects.

Here's an unedited quote from him regarding a complaint on the same subject from one of his previous stories:

Thanks for your note. You are correct in the strict sense, but astronomy and language are evolving. We now know of many other systems that look familiar. And many astronomers have come use the term "solar system" to describe other planetary systems. It's becoming a bit like Kleenex in its generic usage.

I'm all for accuracy, but I think also that language is fluid, and if astronomers use the term interchangeably, then I think it's best I do so,
too. I also find it the most convenient term to convey a system of planets with a central star -- and there are hints of lone, wandering planets not
hosted by a star, so a distinction is helpful (at least until the latter situation is sorted out). I appreciate hearing from you because notes like
yours help me frame my approach to writing.

Leave differentiation to the experts?

[Meetch]

Looking here, I see lots of what I would normally consider insightful input into what could be eventual definitions of stars, supergiants, planets, asteroids and pebbles. However, as was mentioned the definitions are simply going to have to evolve with our understanding.

Would The Earth cease to be a planet just because something threw it forever out of our solar system? (Well actually, for now almost certainly yes, 'cos then there'd be no humans to define "planet" ;). At what point does an asteroid have to collect enough dust and become spherical enough to become a planet? Not all planets are spherical - Mercury is more elliptical from memory, thanks to effects of being in close proximity to a star... errr, the Sun. They wouldn't even have to necessarily spin - though that would help with roundness.

Also from recollection of earlier dictionaries, our moon would become a planet (or planetoid?) if some catastrophe yanked it away from the earth, to forever go around the sun - because it wouldn't then be a body orbiting a planet - a simple, but rock solid definition IMHO. Oh but hang on, what about all those little rocks orbiting Earth???

In that respect remember that some definitions are probably inherently transitional, depending on what they are doing. If it's a rock orbiting a sun, it's an asteroid, around a planet then it's a moon, if it's become round (has enough gravitational pull to hold itself together?) then it's a planet if it's going around a Sun - or is it, because what if the planet escapes?

I believe the dictionary definition of "moon" is pretty good already, but as for the rest... I hope you can see what I mean because it gives me a headache! If we set a strict definition of a type of celestial body, and then suddenly we discover that there are so many more bodies that just don't quite fit the category, then what? I don't fancy taking liquid paper to my dictionary. So I will leave splitting those hairs to the experts.