Except that doesn’t apply to all members of the family, particularly Ceres, which is considered an interloper in the Gefion family.
Not relevant. To use an earlier analogy, a poodle still was a poodle even of you put it through a wood chipper. And that isn’t changed if a Saint Benard comes in and sits in the bits.
Or
What happens to a body millions of years after the proto-panetary disc disperses/is used up ain’t got nothing to do with how objects formed in that disc.
It isn’t that a tenth object gets found. In both instances - asteroids and KBOs - it’s been that there’s been no good place to stop after that. If Pluto or Ceres is a planet, then wherever you draw the line between planet and non-planet in order to not have dozens of planets is arbitrary. If that wasn’t the case, they’d still be planets.
I’m afraid I’m not following you. The definition of planet has nothing to do with how an object was formed.
What you aren’t following is the science. The fact that millions of years after the end of planetary formation a rock in space is smashed to debris also has nothing to do with how an object was formed–and noting to do with “clearing its orbit” which is about formation, not future distruction.
And clearing its orbit is absolutely about how it was formed.
New study challenges Planet 9 hypothesis. Argues that it’s a sampling error in the Trans-Neptunian orbits.
New Scientific American article which notes:
Nobody has found Planet Nine yet. If it’s really out there, it’s too far and too faint for almost any existing telescope to spot it. But that’s about to change. A new telescope, the Vera C. Rubin Observatory in Chile, is about to open its mechanical eyes. When it does, it should catch millions of previously undetected celestial phenomena, from distant supernovae to near-Earth asteroids—and, crucially, tens of thousands of new objects around and beyond Pluto.
If Brown’s hidden world is real, Rubin will almost certainly find it or strong indirect evidence that it exists. “In the first year or two, we’re going to answer that question,” says Megan Schwamb, a planetary astronomer at Queen’s University Belfast in Northern Ireland—and, just maybe, the solar system will once again have a ninth planet.
There was a discovery in April of significance:
Well there are a good number of dwarf planets out there, but finding one as big as say- Mars? Or a giant, that is gonna be tough.
And sure, we could call Pluto a planet, but if so, there are at least 10 (Eris), maybe 12 “planets”. Pluto is way smaller ( it is .002 of what was originally estimated- not counting Lowells idea that is was 7x the mass of the Earth) ) than we originally thought, Charon was making it look larger. It is smaller than at least 7 moons. It is a fifth the size of the Moon.
Yes, if Lowell was right and Pluto was 7x the mass of the earth, it would still be classed as a planet. Or even the later calculated estimate of 1 Earth mass.
But this does sound interesting. let us see if it pans out to another actual planet or just more dwarf planets.
I’ve seen more than one astronomer pretty confidently say that if there’s a ninth planet, Rubin will see it, such is its field of view and sensitivity. It’s pretty rare to hear this level of confidence so it’s pretty exciting.
Of course, I also like the idea of the 9th planet actually being a tiny black hole, but in that case I don’t think Rubin is equipped to detect it. ETA: nope, I’m wrong, VRO will in fact be able to detect flares from a primordial black hole (cite)!
I hope it occurs. I expect he will detect something, anyway.
Sure Rubin will see it, but who’s going to pick it out of all the noise and clutter etc. that that telescope will produce? Some of the telescopes we have today could see it and probably have. But no one’s identified it yet.
But I think they mean see it and recognize it for what it is.
It will repeatedly make surveys of the whole sky and be able to spot virtually anything moving. Pretty much the same thing we’ve been doing on patches of the sky, and making important discoveries as we go, but now, basically, no stone left unturned.
Pretty much any decent telescope would be able to see it, once you know exactly where to look, and spend enough time exposing. When they say they’ll be able to find it, they mean picking it out of the noise.
How much of the sky (i.e. our solar system) has been surveyed from earth? 10%, 50%, 75%, 100%? (really asking)
Depends on what standards you set for the survey. A human near the Equator can scan the entire sky over the course of a year, but only at the naked-eye level. The Sloan Digital Sky Survey has done the entire sky several times over, at a much better than naked-eye level, but there’s still a lot it can miss.
At the other end of the scale, only a few square degrees have gotten the Ultra-Deep-Field treatment.
I have photos of the mirror for this telescope being made.
Proudly made at the U of A in Tucson, AZ
I haven’t read Brown’s and Batygin’s paper, but I note they dismiss the possibility that various passing stars could be the culprits in sending TNOs into Neptune-crossing orbits:
The problem with this is that passing stars are not something from the “distant past”. Rather they happen fairly frequently, in astronomical terms. On average, a star will pass through the Oort Cloud (roughly 1 light year away) about once every 100,000 years. The most recent was Scholz’s Star, that passed by only 80,000 years ago.
As far as the Rubin Telescope, it’s going to image the same field of stars several times, either on the same night or on successive nights and then those images will be automatically compared and differences found will be reported. So people don’t have to blink-compare images like what was done to discover Pluto. However, they expect something like 10 million differences to be reported every night!
Yeah, the vast majority of those differences will just be noise, but then people† have to sort through them to find the relative few that are meaningful. So yes, they might find Planet 9 in the first year. Or it may take much longer.
†The general public will be able to help with this. You can sign up with Zooniverse if you want to join in.
By a telescope form a few decades ago? 100%. They commonly took pictures of the entire night sky, and examined them for fuzzy or moving objects.
Mind you they had no way back then of seeing stuff like Eris. Or this hypothetical 9th planet.
Eris, at apparent magnitude 18.7, is quite bright for a Kuiper Belt Object. That would have been very easily found by telescopes going back more than a century.
The first KBO (after Pluto) discovered was 1992 QB1 (now known as 15760 Albion) has an apparent magnitude of 23.3, which could also have been found by telescopes for a long time. It was discovered in 1992, after all, and could have been discovered much earlier. However, they had to make an extremely long exposure to find it, which is something most astronomers rarely did.
But note that they discovered it with a 2.2 meter telescope. By today’s standard, that’s a fairly small professional telescope. With larger telescopes, they don’t need quite as long exposures.
Yeah, there’s alway a tradeoff. To do full-sky surveys, and especially to do them repeatedly (so you can see that objects are moving), you need some combination of large field of view and short exposures. To detect faint objects, you need some combination of small fields of view and long exposures. In both cases, more aperture always helps, but more aperture is generally very expensive, and at the high end introduces its own problems. And unfortunately, you need both wide, repeated surveys and detection of faint objects to discover things like new Kuiper belt objects.
Once you’ve discovered them, it gets a lot easier, because now you don’t have to look at the full sky, just where the object is, and so you can switch to just doing small-field long-exposure work, without the tradeoff. But first you have to know where to look.