Space can be such a drag
It’s not easy being a galaxy in a cluster, hauled into the centre to die by the gravitational tug from larger objects
HUBBLE SPACE TELESCOPE, SUBARU TELESCOPE, 28 JANUARY 2019
The inky blackness between galaxies and stars in astrophotos might seem like empty space, but this is not always the case. The huge red beam stretching across this image of the Coma Cluster is generated by a process known as ‘ram-pressure stripping’. As galaxies move within a cluster, they are actually pushing through hot gas and dense plasma, which drags on the galaxies like the drag on a boat pushing through water. Galaxy D100, on the far right of the image, is being pulled towards the centre of the cluster by the gravitational tug of other galaxies there. As this happens, the drag causes enormous amounts of gas to be stripped from D100, creating a huge tail in its wake. Once the galaxy loses all of its gas, unable to create new stars, it will fade and die.