A not all the quotes are anonymous.B You preclude the fact that some of the comments may also be by experts.C Because of course Twitter is such an effective forum to debate scientific papers in the first place.
Quote from: Star One on 12/11/2015 06:40 amA not all the quotes are anonymous.B You preclude the fact that some of the comments may also be by experts.C Because of course Twitter is such an effective forum to debate scientific papers in the first place.You can quibble with how Brown worded it, but his basic point is obviously correct: These things being real requires that the ALMA observations got stupendously lucky, or an implausible population, or both. The fact that the ALMA people claim to have seen two of these things (with at least one author common between the two papers) should really ring alarm bells. If you read the papers, you also find that additional unlikely coincidences are required to explain the apparent motion of these things and why these things weren't seen before.Brown is far from the only outer solar system expert calling this out as implausible, pretty much everyone in the field I've seen comment has been similarly skeptical.
I remember when Sedna was discovered, and 10 years later we've found this new object that orbits even further out. If this leads to a "super-Earth" it could be our first glimpse of this kind of planet, there have been so many found orbiting other stars but not ours.
Quote from: Bubbinski on 03/26/2014 07:04 pmI remember when Sedna was discovered, and 10 years later we've found this new object that orbits even further out. If this leads to a "super-Earth" it could be our first glimpse of this kind of planet, there have been so many found orbiting other stars but not ours.A super-Earth way out there would likely have a dense atmosphere because of its strong gravity and brutal cold temperatures (example: Titan). A 22'd Century parachute probe anyone?
Also, it is really important to examine the effects of a close flyby of a brown dwarf or similar small object. What happens to distant orbits if a 100-Jupiter mass object passed 1 lightyear from the Sun a billion years ago?
Is there any plans for another instrument similar to ALMA, then at least you might be able to get some independent secondary validation?
Quote from: Star One on 12/12/2015 12:15 pmIs there any plans for another instrument similar to ALMA, then at least you might be able to get some independent secondary validation?ALMA is by far the most expensive astronomical instrument on Earth (I think it has cost about $1.2B), so you won't be seeing a copy soon. The problem with these observations is that there's currently really nothing except ALMA that has the sensitivity and resolution to confirm (or disprove) this. Not sure if even JWST would help, if the objects are very cold. All astrophysical explanations (extreme TNOs, rapidly varying background sources etc.) seem unlikely, so of course the possibility of some sort of artefact with ALMA or processing of observations must be considered (and that is also mentioned in the papers). On the other hand, the detections are fairly strong, so it'd be strange and disconcerting if ALMA produces such spurious sources.
Also blogs. Comments on blogs are usually reliable and accurate and unbiased.
ALMA is by far the most expensive astronomical instrument on Earth (I think it has cost about $1.2B), so you won't be seeing a copy soon. The problem with these observations is that there's currently really nothing except ALMA that has the sensitivity and resolution to confirm (or disprove) this. Not sure if even JWST would help, if the objects are very cold.
The problem with these observations is that there's currently really nothing except ALMA that has the sensitivity and resolution to confirm (or disprove) this. Not sure if even JWST would help, if the objects are very cold.
Quote from: as58 on 12/12/2015 12:49 pmThe problem with these observations is that there's currently really nothing except ALMA that has the sensitivity and resolution to confirm (or disprove) this. Not sure if even JWST would help, if the objects are very cold. Should be noted this depends which on which of the scenarios you are looking at. Nothing can replicate the ALMA observations, but if "Gna" really is a ~200-800km centaur, it should be easily observable with existing ground based telescopes. In fact it would be bright enough to argue against this model, but it's possible something big slipped through the cracks.The other problem for follow up is that the possible orbits are very poorly constrained. Even if JWST could detect say, a super earth in the inner Oort cloud, it would be very tough to argue for the time to do a large scale survey with it.
I was wondering if the Event Horizon Telescope would help. I know it is still in the making, getting all the telescopes all over the globe to actually work at the same time but perhaps it could help. The other telescope I am thinking would be the Allen Telescope Array after phase 4. I know that they have been having trouble fundraising to keep it running on phase one, let alone expand but perhaps it could rival ALMA when completed
How could ALMA do a good follow up on this, if there's no other telescope like it that can be used? If a different team of scientists runs an observing program on ALMA and finds this same object a few months from now, in a slightly different location near where it was last observed, would that increase the confidence level?
Some of the scenarios envisaged for the possible new Solar System object, whose discovery with the ALMA facility has been recently claimed in the literature, are preliminarily put to the test by means of the orbital motions of some planets of the Solar System. It turns out that the current ranges of admissible values for any anomalous secular precession of the perihelion of Saturn, determined in the recent past with either the EPM2011 and the INPOP10a planetary ephemerides without modeling the action of such a potential new member of the Solar System, do not rule out the existence of a putative Neptune-like pointlike perturber at about 2500 au. Instead, both a super-Earth at some hundreds of au and a Jovian-type planet up to 4000 au are strongly disfavored. An Earth-sized body at 100 au would have a density as little as ∼0.1−0.01 g cm−3, while an unusually large Centaur or (Extreme) Trans Neptunian Object with linear size of 220−880 km at 12−25 au would have density much larger than ∼1 g cm−3.
Tentative planetary orbital constraints of some scenarios for the possible new Solar System object recently discovered with ALMAQuoteSome of the scenarios envisaged for the possible new Solar System object, whose discovery with the ALMA facility has been recently claimed in the literature, are preliminarily put to the test by means of the orbital motions of some planets of the Solar System. It turns out that the current ranges of admissible values for any anomalous secular precession of the perihelion of Saturn, determined in the recent past with either the EPM2011 and the INPOP10a planetary ephemerides without modeling the action of such a potential new member of the Solar System, do not rule out the existence of a putative Neptune-like pointlike perturber at about 2500 au. Instead, both a super-Earth at some hundreds of au and a Jovian-type planet up to 4000 au are strongly disfavored. An Earth-sized body at 100 au would have a density as little as ∼0.1−0.01 g cm−3, while an unusually large Centaur or (Extreme) Trans Neptunian Object with linear size of 220−880 km at 12−25 au would have density much larger than ∼1 g cm−3.So a Neptune-size body at around 2500 AU is not ruled out -- at least not by Saturn's orbital motions.
Quote from: Mongo62 on 12/17/2015 12:48 amSo a Neptune-size body at around 2500 AU is not ruled out -- at least not by Saturn's orbital motions.Perhaps that's the missing gas giant that some believe was expelled from the Solar System.http://blogs.discovermagazine.com/badastronomy/2011/11/16/did-jupiter-toss-a-giant-planet-out-of-the-solar-system/
So a Neptune-size body at around 2500 AU is not ruled out -- at least not by Saturn's orbital motions.
Quote from: Star One on 12/17/2015 06:44 amQuote from: Mongo62 on 12/17/2015 12:48 amSo a Neptune-size body at around 2500 AU is not ruled out -- at least not by Saturn's orbital motions.Perhaps that's the missing gas giant that some believe was expelled from the Solar System.http://blogs.discovermagazine.com/badastronomy/2011/11/16/did-jupiter-toss-a-giant-planet-out-of-the-solar-system/I'd call it a fair possibility. Whatever the object is, they might be able to compute its orbital history in the same way we learned that the gas giants migrated...with this would-be-planet being one of the casualties. If it's the size of Earth or greater odds are it more likely originated within the Solar System instead of the Oort cloud where it would have gained mass more swiftly.Too early to say yet. It could still be a bright Kuiper-like body or even Alpha Centauri's planet.Hopefully Hubble can swing into action to help as it did for New Horizons.