You’ve probably heard that the universe is constantly expanding. There’s a bit of an update on that: it’s still expanding, and it’s happening far faster than scientists previously thought. They have no idea why and just seem a little concerned about it.
All the cosmic math should add up, but it doesn’t. That’s the conclusion of the H0 Distance Network (H0DN) Collaboration, a collection of 37 researchers from around the world representing a number of research institutions, who published their findings in the journal Astronomy and astrophysics.
The expansive team combined almost all methods of measuring cosmic distances into a single measurement. 73.5 kilometers per second per 3.26 million light years. This is the rate at which the universe is currently expanding. That doesn’t mean a thing to most people, but to the research team it means a lot because the rate at which we used to think the universe was expanding according to the Standard Model of cosmology was closer to 67. That doesn’t sound like a significant difference, but in physics it’s so large that it’s actually somewhat alarming.
Universe expansion is measured by the cosmic distance ladder
This means that the discrepancy is far beyond what can reasonably be chalked up to coincidence or minor technical errors. Either the universe is expanding significantly faster than we thought, or there is a major structural problem in how we have calculated its expansion.
To reach this conclusion, the researchers relied on something called the cosmic distance ladder, which is a chain of overlapping computational techniques that starts with geometric measurements of nearby objects and then extends outward using a variety of celestial bodies such as Cepheid stars, red giants, and Type Ia supernovae. The team turned the ladder into a web and cross-checked methods against each other to account for any biases.
All of this is to say that this new method stands up to scrutiny a little more than the previous methods. And if it turns out to be correct, it means that there are big, fundamental gaps in our understanding of all sorts of space phenomena, from dark energy to gravity. Either way, the bottom line here is that the universe doesn’t play nice with our calculations of its expansion, and no matter what scientists do, no matter what new innovative methods they use to calculate it, they just keep reaching the same conclusion over and over again: something strange is happening and they don’t know why.
