New dwarf planet added to our solar system
- Thread starter phavoc
- Start date
Reynard
Emperor Mongoose
We used to call them asteroids and comets. Now they're dwarf planets. The impressive thing s they can find and analyzed them. Three to four times the distance of Pluto's orbit. Definitely calls for a micro-jump. Now only if it were a planetoid ship.
700km roughly spherical equals 6 Death Stars...
That's no dwarf planet, that's a space station!
700km roughly spherical equals 6 Death Stars...
That's no dwarf planet, that's a space station!
Reynard said:
Actually "dwarf planets" are not just "asteroids and comets", they're specifically the subset of asteroids and comets that are large and massive enough to be spherical. Though there'd be no reason to go to this one, beyond doing a survey.
It is impressive though that Pluto was discovered essentially by chance in 1930 and it was a big deal, and now discovering a "dwarf planet" has become fairly passé. It's just one of several such bodies out there, and thousands (millions?) more that are just smaller icy bodies.
If the putative Planet Nine turns out to be real though, that'd be a more interesting destination, at least scientifically.
mancerbear
Mongoose
I actually think that the Earth having a second moon is more exciting
http://blogs.discovermagazine.com/crux/2015/03/02/earth-second-moon/#.V4WRCP5f2JA
http://blogs.discovermagazine.com/crux/2015/03/02/earth-second-moon/#.V4WRCP5f2JA
mancerbear said:
They're not really "second moons" - they don't orbit Earth itself, they're just objects that orbit the sun have been captured into orbital resonances that bring them close to earth and away and back again on a regular basis (though the situation is usually temporary, lasting only a few hundred or thousand years). They're more properly "quasi-satellites" (see https://en.wikipedia.org/wiki/Claimed_moons_of_Earth#Quasi-satellites_and_trojans ), though click-baity articles prefer to call them "second moons" to get more attention (apparently we have a lot of second moons. Amusingly the article you linked to is from 2015 and is actually about the asteroid Cruithne, not the more recently discovered "second moon" that you're presumably actually excited about - http://www.jpl.nasa.gov/news/news.php?feature=6537 ).
Tenacious-Techhunter
Mongoose
Eventually, they’ll find a Kuiper Belt object larger than Mercury, and they’ll have to start calling Mercury a Dwarf Planet too, or, at the very least, rethink their stupid name scheme.
Tenacious-Techhunter said:
There's no point in starting the planet definition argument here again, because then everyone will be chipping in with their opinions on how planets should be defined etc, and it's really not relevant here. I agree it's a lousy definition, but there's no much anyone can do about it right now and certainly nobody here has any sway on what it should be.
Tenacious-Techhunter
Mongoose
I’m less complaining about said naming scheme and more pointing out that said naming scheme is doomed. You would think that scientists, of all people, would be in the best position to make themselves not look stupid...
“You jerks made us call Pluto a ‘Dwarf Planet’, and now that you have one bigger than Mercury, you want us to call that a Dwarf, but not Mercury?!?!?!”
“You jerks made us call Pluto a ‘Dwarf Planet’, and now that you have one bigger than Mercury, you want us to call that a Dwarf, but not Mercury?!?!?!”
Tenacious-Techhunter said:
A better one will come along at some point. It's a dumb scheme, and a lot of people (particularly planetary scientists, who actually didn't have much say in its definition) don't like it at all. Yes, it's doomed, and many better ones have been proposed in the meantime. One of those will probably be adopted eventually. Otherwise, if you want to complain about it, talk to the IAU.
In fact, a terrestrial "dwarf planet" bigger than Mercury in the outer system would probably be a catalyst for that - because the vague, undefined "clearing its orbit" criterion may or may not be be fulfilled (if it's the only planet within 10 AU then has it "cleared its orbit"?). That may be the kick up the arse required for the IAU to sort out the mess they made. Other schemes have calculations that can be done to determine this parameter, but the IAU definition is lacking such detail.
A superearth/mini-neptune sized Planet Nine would clear its orbit by most of the alternative schemes used to quantify that parameter though.
Tenacious-Techhunter
Mongoose
I hear that the Asteroid Belt counts against Jupiter having cleared its orbit... so what does that make Jupiter? No one is going to say Jupiter isn’t a planet. 
Tenacious-Techhunter
Mongoose
Yes, but some argue that it hasn’t finished all its pellets, and, therefore, isn’t a planet.
:roll:
OK, look. Jupiter has cleared its orbit - anyone who claims otherwise doesn't know what they're talking about. The fact that it shares is orbit with trojan asteroids is not relevant because the numerical methods around for calculating "clearing the orbit" look at the mass of the object compared to everything else in similar orbits, and Jupiter outmasses any asteroids in its neighbourhood by a factor of billions. Ditto for Earth, for that matter. Therefore they are "full" planets.
When you look at Pluto, it doesn't outmass everything around it by anywhere near as much, in fact it's very similar in mass to some. Therefore it's a dwarf planet. Ditto for Ceres in the asteroid belt.
When you look at Mercury, there isn't anything in its neighbourhood to outmass (and the few objects that do cross its orbit are tiny). It's a planet, not a dwarf planet - and it never can be a dwarf planet even if a Mercury-sized KBO were to be discovered because it's still cleared its orbit either way. The real issue is that we'd have to figure out whether a Mercury-sized KBO should be called a dwarf planet or a real planet (which depends on what's in nearby orbits, and whether orbits are near enough to even be considered part of its neighbourhood), not if Mercury is still a planet (because yes, it will still be a planet).
Can we move on now?
OK, look. Jupiter has cleared its orbit - anyone who claims otherwise doesn't know what they're talking about. The fact that it shares is orbit with trojan asteroids is not relevant because the numerical methods around for calculating "clearing the orbit" look at the mass of the object compared to everything else in similar orbits, and Jupiter outmasses any asteroids in its neighbourhood by a factor of billions. Ditto for Earth, for that matter. Therefore they are "full" planets.
When you look at Pluto, it doesn't outmass everything around it by anywhere near as much, in fact it's very similar in mass to some. Therefore it's a dwarf planet. Ditto for Ceres in the asteroid belt.
When you look at Mercury, there isn't anything in its neighbourhood to outmass (and the few objects that do cross its orbit are tiny). It's a planet, not a dwarf planet - and it never can be a dwarf planet even if a Mercury-sized KBO were to be discovered because it's still cleared its orbit either way. The real issue is that we'd have to figure out whether a Mercury-sized KBO should be called a dwarf planet or a real planet (which depends on what's in nearby orbits, and whether orbits are near enough to even be considered part of its neighbourhood), not if Mercury is still a planet (because yes, it will still be a planet).
Can we move on now?
Tenacious-Techhunter
Mongoose
The point is that calling the Kuiper Belt Object a Dwarf in comparison to Mercury is stupid. The naming convention is doomed.
I have heard scientists make the argument that the Asteroid Belt qualifies as within Jupiter’s neighborhood. Which, if true, makes the whole “Dwarf Planet” thing even more stupid.
I have heard scientists make the argument that the Asteroid Belt qualifies as within Jupiter’s neighborhood. Which, if true, makes the whole “Dwarf Planet” thing even more stupid.
Tenacious-Techhunter said:
Well... nobody's done that. And nobody will unless the situation actually arises. And my point is that a Mercury-sized KBO would still be a large member of a belt of objects, and Mercury wouldn't. I agree that the definition is very flawed though, and it probably will change at some point.
I can't find any evidence that anyone did say that. And even if they did I'd presume they're being facetious or going to absurd extremes to try to prove a point. (or it was said by Alan Stern, who is often "a tad overenthusiastic" - to the point of embarrassing himself - about criticising the IAU's planet definition).
Rikki Tikki Traveller
Cosmic Mongoose
Orbital "areas" are defined by an objects gravitational Sphere of Influence, which is a scientific term that depends on the mass of the object and of nearby objects and relative distance to the sun. It is a scientific term that has a specific meaning and isn't going to change.
If an object has cleared all other objects that orbit within it's sphere of influence as it orbits the sun, then it is a Planet. If it hasn't, then it isn't a planet.
I agree the term "DWARF" may have to be changed, we could call all these things "George" but they would still never be a planet under this definition.
Ceres is a large object, but it has not cleared out objects within its sphere of influence in it's orbit around the sun, so it isn't a planet.
The asteroid belt orbits outside the Sphere of Influence of Jupiter, so the argument that the asteroid belt prevents Jupiter being classified as a planet is scientifically incorrect.
If they ever find a 10th "planet" and it has not cleared its sphere of influence around the sun, even if it is more massive than Neptune, will not be classified as a planet. HOWEVER, based on the early orbital research, it appears that there IS an orbit that has been cleared about the sun way out there. This was how they theorized that there is a 10th planet (most recent evidence). By looking at the period and direction of the orbits of objects that cross that cleared area, they calculated the orbit of the hypothetical planet. Now they are looking for visual evidence of it. BUT, since they have an entire torus with a radius of a couple dozen AU's to search, and it is canted relative to the plane of the rest of the planets, it could take a while - or they could find it tomorrow.
If an object has cleared all other objects that orbit within it's sphere of influence as it orbits the sun, then it is a Planet. If it hasn't, then it isn't a planet.
I agree the term "DWARF" may have to be changed, we could call all these things "George" but they would still never be a planet under this definition.
Ceres is a large object, but it has not cleared out objects within its sphere of influence in it's orbit around the sun, so it isn't a planet.
The asteroid belt orbits outside the Sphere of Influence of Jupiter, so the argument that the asteroid belt prevents Jupiter being classified as a planet is scientifically incorrect.
If they ever find a 10th "planet" and it has not cleared its sphere of influence around the sun, even if it is more massive than Neptune, will not be classified as a planet. HOWEVER, based on the early orbital research, it appears that there IS an orbit that has been cleared about the sun way out there. This was how they theorized that there is a 10th planet (most recent evidence). By looking at the period and direction of the orbits of objects that cross that cleared area, they calculated the orbit of the hypothetical planet. Now they are looking for visual evidence of it. BUT, since they have an entire torus with a radius of a couple dozen AU's to search, and it is canted relative to the plane of the rest of the planets, it could take a while - or they could find it tomorrow.
