I read that a Korean astronomer observed the breakdown of gravity in binary star systems at low acceleration. What does that mean?

Question

And what is the MOND theory, which this analysis seems to support?

In: 6

Answer 1

>And what is the MOND theory, which this analysis seems to support?

There are tons of observations and measurements we make of distant galaxies that don’t match what should be going on based on their light alone.

The simplest explanation is that there is more mass than just stars and gas, aka ‘dark’ matter. We can posit that this dark matter exists with a given density, and that *single* number accounts for *dozens* of observational discrepencies.

There are other explanations that don’t involve dark matter. Modified Newtonian dynamics (MOND) involve using Newton’s mechanics and altering them to develop a model that explains the observations. The problem with MOND explanations, is that typically involve many arbitrary quantities and numbers to fit the model to the data, which is poor science (and, arguably, not science at all).

The dark matter explanation can explain *dozens* of observations with just a single number (the density of dark matter), whereas MOND explanations involve lots of unknown quantities that can be freely selected to fit the model to the data.