Dark Matter In Our Own Backyard Revealed By Nature’s Perfect Clocks
“This is the first time this powerful technique, of using both the orbital periods and the change in orbital periods of binary pulsars, has been leveraged to measure the galactic acceleration of objects in our own neighborhoods. It also marks the first time that, successfully, we’ve measured what the gravitational potential of our own galaxy is without needing to resort to assumptions that may not necessarily be well-founded.
Moreover, and perhaps most excitingly, three big advances should be coming in the near future: longer baselines of time over which these pulsars can be observed, additional binary pulsars that will help reduce the statistical errors in the study, and, with improved instrumentation and techniques, binary pulsars at greater distances. This last one is the most interesting to many, as they’ll either directly reveal our galaxy’s dark matter, or cast significant doubt on our assumptions that a large halo of dark matter actually surrounds our own galaxy. With more and better data on the way, these binary pulsar systems are finally shedding light on the dark matter that’s eluded us for so long.”
Stars go around the galaxy, right? But do they make clean, elliptical paths like the planets in our Solar System? They only will if our galaxy is in equilibrium, and not being disturbed by our interactions with our galactic neighbors. But our galactic neighbors are interacting with us, and we haven’t quantified by how much. Does that means our estimates for how our galaxy’s gravitational acceleration works are flawed?
We don’t need to assume or argue; thanks to binary pulsars, we can measure it! Here’s what we learn from our very first time successfully leveraging this technique.