Does a halo of mysterious dark matter swirl around every galaxy?

Many galaxies seem to have bubbles of dark matter enveloping them, but finding out if every galaxy is like this is an ongoing area of research, writes Chanda Prescod-Weinstein

By Chanda Prescod-Weinstein

IF YOU ever visit a nature reserve that has worked with the International Dark-Sky Association to preserve its view of the stars, then on a clear night you can see the Milky Way. Although we are certain our home galaxy is a spiral, to the naked, uninformed eye, it looks like a curved strip made up of many little dots of light. There are so many stars that they can seem uncountable.

Although those little lights seem mystical, they can also feel familiar, like a distant street lamp. We now know that they are far away suns, …