The Universe expands. It’s in its nature to do so. Scientists are currently facing a major scientific crisis, one that can even change physics once more. The dark unknown matter around which scientists are orbiting is the rate at which the Universe expands. Different ways of measuring it result in different speeds and this puts physics under an existential crisis.
The expansion debate
One of the measurements, called the Planck experiment, rates the speed at 67.4 kilometres per second for each megaparsec. Its error seems to be 0.5 km/s/Mpc. Max Plank won the Nobel in 1918 for understanding that energy can’t be divided indefinitely.
The old method used supernovas’ brightness measurements. This one rates the expansion at 74.0 km/s/Mpc. It can give an error of 1.4 km/s/Mpc.
The difference between the two rates is too big to be accepted. Something, somewhere, is wrong with the science. But what makes the mathematics say that the Universe is expanding 10% faster than it did at the beginning, right after the Big Bang? It is the theories that are wrong or measurements?
Two coordinates are used to calculate the rate of expansion. The speed at which objects are receding from us, and the distance they’re at. It looks like the speed isn’t the issue. Distance is.
Distance is measured with the help of what the scientists call “standard candles.” Supernovas and Cephids stars are such standard candles, due to their reliable brightness. Consistent and quantifiable brightness makes distance measurement possible.
A possible reconciliation
Wanting to make another measurement, the cosmologist Wendy Freedman of the University of Chicago used another standard candle: the red giants. Her results were different once again, but they were between the other two. Her measurement says the Universe grows at 69.8 km/s/Mpc.
From her point of view, this puts the crisis to rest. “Theoretical components and constraints you can get from existing observations suggest that, at the moment, this is not a serious issue,” Freedman says.
The show goes on
A new study made by astrophysicists Licia VerdeVerde and Raul Jimenez, from the University of Barcelona, and Uffe Gråe Jørgensen, an astrophysicist at the University of Copenhagen, gives a possible answer.
It seems that the former belief, according to which red giants don’t aren’t influenced by the planets they swallow, was wrong. They change. Every time they do it, a dim occurs. This revelation can cast a shadow of doubt over all the measurements made so far.