Is Dark Flow Real?

In 2008, a group of scientists led by NASA astrophysicist Alexander Kashlinksy detected a surprisingly rapid one-way flow of all the matter in the visible universe, a phenomenon which came to be known as “dark flow”. Kashlinsky’s team measured the flow of galaxy clusters through the universe’s background radiation, using temperature differences to infer the speed and directions of the movement of distant conglomerations of galaxies, and discovered that everything they measured was moving in a uniform direction at high velocity. A later study in 2010 confirmed the 2008 measurements. The movement caught the attention of cosmologists because it wasn’t readily explainable in terms of known astronomy — hence the term “dark” — and because it was possible evidence of effects from beyond the known universe, lending credence to certain multiverse theories. Perhaps, the speculation went, attraction from collections of matter outside the visible universe were the cause of the flow.

A new study of supernovas in distant galaxies, however, has detected a much slower flow than that found in the previous studies. The new study does also show a one-way flow, but it is in a slightly different direction and is much slower than the earlier measurements of flow. The new flow is more easily explained by in-universe causes, such as large galaxy clusters, and so does not necessarily suport the extra-universal explanations of the earlier dark flow measurements.

The result, as so often happens in science, is that it’s become clear that more data is needed. The earlier measurements call for an explanation, and seemingly point outside the known universe. The new results are interesting, but more mundane. It remains to be seen how the two can be reconciled. In the meantime, multiverse theories still await empirical evidence…

Read more about this story from National Geographic.

Comments are closed.