At the centre of spiral galaxies... (IMAGE) Scuola Internazionale Superiore di Studi Avanzati Caption A new SISSA study suggests that at the center of spiral galaxies there is a vast spherical region made up of dark matter particles where a direct interaction between the elementary particles that make up the dark matter halo and those that make up ordinary matter occurs. Credit Buddy_Nath on Pixabay Usage Restrictions The image is from Pixabay, please look at the PIxabay's restricion rules License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.