Most of the universe is made up of a kind of matter. It's called "dark matter". None of us have ever seen it, and It's also very difficult to study.
Past research suggested there is more dark matter around younger galaxies (星系) than the ancient ones from the early days of the universe, but where did the dark mater come from? After studying some 1,500 galaxies, researchers led by Alfred Riley found the amount of dark matter around these huge stars and planets is about the same as it ever was.
We can't see dark matter in space because it doesn't reflect (反射) light, but we can study it by studying the influence the matter has on all around it. It gives a pull, just like "normal" matter.
By explaining the size of a galaxy and the speed at which stars on its edges (边缘) are moving, scientists can learn how much dark matter is around it.
Recently, scientists use the same way to study many hundred galaxies, both young and old.
They believe there's not much of a difference in the amount of dark mater between ancient galaxies and much younger ones.
However, not all of them fully agree with this new finding. The model researchers used has been called into question, especially as it relates to measurements (测量) of faraway high-mass (高质量的) galaxies which have been studied by others searching for dark matter.
Well have to wait and see how this all goes, but the results are certainly interesting and will no doubt further the conversation about where the universe's dark mater lies.
