We still don’t know how fast the Universe is expanding

“As it stands today, we know the Hubble expansion rate better than we ever have, and yet our two different method of arriving at it seem to give irreconcilable values. There are a myriad of different measurements going on right now attempting to find out which camp is right, which camp is wrong, and exactly where the errors lie. If history has taught us anything, we can say for certain that two things will come of this: we’re going to learn something additional and wonderful about the nature of our Universe when this gets resolved, and that this current controversy won’t be the last one concerning how the Universe expands.”

It seems like the simplest, most fundamental quantitative question about the expanding Universe of all: how fast is it expanding? Even though it’s been more than 80 years since Hubble’s most career-defining discovery, we still don’t know the answer. In fact, the two main methods we have of measuring it give incompatible results. The largest-scale observations, like the cosmic microwave background and baryon acoustic oscillations, give a result that’s on the low side: 67 km/s/Mpc. On the other hand, distance ladder measurements, relying on individual stars, galaxies and supernovae, give a higher result: 74 km/s/Mpc. But these are known well enough that they’re inconsistent with one another.

This is a story that’s been ongoing since we first learned the Universe was expanding, but the next five years should be critical in resolving this tension. Find out why!


My characters karaoke “Helpless” from Hamilton! Chaos and blushing ensues…

Something I did for fun to relax from my thesis for a day. Gave myself no more than a day’s worth of time to finish it… ended up with somethin silly

FYI this is not my thesis, just a bonus epi!! Thanks for staying tuned ^^