Read on Twitter
Finding the center of the solar system is a journey involving superdense stars that spin faster than a kitchen blender blade, colossal black holes eating other, and literal ripples warping the fabric of spacetime. https://www.syfy.com/syfywire/pulsars-black-holes-spacetime-center-of-the-solar-system
2/ Writing the article was fun. The science of finding the center of mass of the solar system is important, but from a science communication standpoint it’s actually not the central part of the story. It’s *why* we need to find it.
3/ It’s OK to say the Earth orbits the Sun, but in a very real sense everything (including the Sun!) in the solar system orbits the barycenter, the center of mass. For many things the difference isn’t enough to worry about, but for some it’s absolutely critical.
4/ We pick up regular signals from lots of objects in space. Pulsars send out nearly perfectly timed blips of energy, making them cosmic clocks of unequaled precision. But we have to exactly time when those pulses get to Earth, which is constantly moving… around the barycenter.
5/ If you use the Sun as the center of the solar system you get different timings on their arrival versus using the barycenter. So knowing where the barycenter is becomes critical. Once we have that, we can use the pulsar timings to measure some pretty amazing things…
6/ When black hoes collide, they send out gravitational waves which warp the fabric of space. When a wave like this moves through the Universe, it changes the distance between us and a pulsar (note: It’s WAY MORE complicated than this), changing the timing of the pulse arrivals.
7/ So by observing lots of pulsars in different places in our galaxy, astronomers can measure the gravity waves, helping them spot colliding and merging supermassive black holes across the Universe!
And this doesn’t work unless we know where the solar system barycenter is.
And this doesn’t work unless we know where the solar system barycenter is.
8/ More fun: Because the planets orbit the Sun, the barycenter location changes constantly, so you wind up with equations describing the motion. That’s what the news is about; they found a way to narrow down the uncertainties in the predicted barycenter location.
9/ The barycenter location can now be found to about 100 meters accuracy. ONE HUNDRED METERS. In a solar system *tens of billions* of kilometers across. Not bad.
(I am actually SERIOUSLY impressed by this)
(I am actually SERIOUSLY impressed by this)
10/ Like I said, the science of finding it is cool, but WHY we need to know where it is… that’s the incredible part.
11/11 I’ve been wanting to write about the pulsar timing array for a while now. This was a great excuse. So please go on that journey, and see why centering yourself allows you to explore some of the most bizarre and amazing things in the entire cosmos. https://www.syfy.com/syfywire/pulsars-black-holes-spacetime-center-of-the-solar-system
