But how does the standard candle method work? Suppose you are standing at night in a long and dark street with several lampposts on the side of the road. Now suppose that all the lampposts have the same type of lamp with the same power. You can see that the farther away bulbs appear dimmer than the closer ones. Based on the inverse square law for light, we know that light weakens proportionally to the distance. Now, if you can calculate or know the brightness of each light, you can calculate the distance of each light.
Another American astronomer named Edwin Hubble in 1929 was able to find a number of Cepheus variable stars in other galaxies and calculate their distance. Based on these distances and other measurements, he concluded that the universe was expanding.
Different methods, different results
The standard candlestick method is a powerful way to measure the universe. Researchers are always looking for different candles at farther distances to measure the distance of stars.
In some new efforts to measure the world, including the SHOES project, led by Adam Rice, Nobel Prize winner, Cephasian variables are used as a standard candle alongside an exploding star called a type Ia supernova. There are also other methods, such as cosmic background radiation, to measure the Hubble constant. The background radiation is the light or beam that started its journey in the universe shortly after the Big Bang.
The problem here is that these two measurements, one of which uses the supernova and the other the Cephasian variable and the other method which uses the cosmic background radiation, differ by almost 10%. Astronomers call this difference the Hubble tension and are looking for new measurement methods to solve it.
New method: gravitational convergence
In a new way, researchers used Rafsdal’s supernova to measure the expansion rate of the universe. In 2014, they took several pictures of a They observed the supernova. A “converged” supernova was observed for the first time. In fact, instead of seeing one supernova, the Hubble telescope observed five supernovae.