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I've always thought that a good model or theory predicts observations (like a new particle, or an unseen planet) and is confirmed to be accurate by those observ
by sspiff 3y ago
I've always thought that a good model or theory predicts observations (like a new particle, or an unseen planet) and is confirmed to be accurate by those observations.
A new model that is designed to fit existing observations that don't match our expectations based on the old model, without it correctly predicting new unexpected observations, seems like a rather weak proposition to me.
- Wowfunhappy 3y agoThis new model was designed to fit existing observations without the presence of dark matter, and turns out to also predict the orbits of planets without planet nine.
- Arech 3y agoMOND was there years before Batygin (co-author of planet Nine hypothesis) was born.
- Izkata 3y ago> co-author of planet Nine hypothesis Are you referring to what he published in 2016? Because it's much older than that, we used to call it Planet X.
- lamontcg 3y ago"Planet Nine" is a term of art that refers specifically to the 2016 theory. "Planet X" refers specifically to a theory proposed by Percival Lowell in 1906 about the orbit of Uranus which was disproven in 1993 by Voyager 2 flyby data. They are both more specific theories than just "a trans-Neptunian planet we haven't discovered" which is overly broad.
- dragonwriter 3y agoSomewhat related are "Nemesis", the 1984 hypothesis of a distant companion red or brown dwarf to the Sun, and "Tyche", the 1999 hypothesis of a gas giant in the Oort Cloud. On "Planet X" specifically, the effect it was offered to explain was determined to have been measurement error after recalculation of Neptune's mass and consequently effect on Uranus's orbit in 1993 based on Voyager 2 data.
- Izkata 3y agoThe general theory was called planet X before pluto was demoted; X just means 10. https://science.nasa.gov/solar-system/planet-x/ https://science.nasa.gov/solar-system/planet-x/
- lamontcg 3y agoExcept you and that article are quite wrong and the naming of the "Planet X" theory happened in 1894 long before the discovery of Pluto in 1930, back when astronomers also thought there was only 8 planets: > In 1894, with the help of William Pickering, Percival Lowell (a wealthy Bostonian) founded the Lowell Observatory in Flagstaff, Arizona. In 1906, convinced he could resolve the conundrum of Uranus's orbit, he began an extensive project to search for a trans-Neptunian planet,[18] which he named Planet X, a name previously used by Gabriel Dallet.[11] The X in the name represents an unknown and is pronounced as the letter, as opposed to the Roman numeral for 10 (at the time, Planet X would have been the ninth planet). https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Planet_X https://en.wikipedia.org/wiki/Planets_beyond_Neptune#Planet_...
- gorkish 3y ago> A new model that is designed to fit existing observations that don't match our expectations based on the old model, without it correctly predicting new unexpected observations, seems like a rather weak proposition to me. This description roughly applies to General Relativity; there are clearly merits to both approaches.
- canjobear 3y agoThe first step is to propose a model that explains stuff. Then you test it on new predictions.
- catlifeonmars 3y agoGod did it. In all seriousness, I think the bar is higher than just “here is an explanation that makes sense”. The new model has to explain stuff better than existing established models.
- canjobear 3y agoSometimes it's nontrivial to show that a theory predicts something, even if the thing is already observed.
- throwawaymaths 3y agoMOND has successfully predicted: - "no dark matter" in dense ellipticals and lenticular - external field effect (including keplerian descent for the milky way) - early galaxies