The Current Understanding of Universe Expansion
The expansion of the universe has perplexed scientists for decades. While Edwin Hubble discovered nearly a century ago that galaxies are moving away from us, faster the further away they are, calculating how fast has proved difficult. Initial estimates of the Hubble constant, the rate of expansion, were around 50 km/s per 3.3 million lightyears. This value has since been revised to 67 km/s based on background radiation from the early universe.
New Research Finds Faster Nearby Expansion
Two new studies have recalculated the Hubble constant using a “cosmic distance ladder” of accurate measuring techniques. This included observing Cepheid variables, Type 1A supernovae in other galaxies, and eclipsing binary star systems. Their analysis finds the expansion rate is approximately 73 km/s, around 9% higher than the previous value. A separate team confirmed a similar result.
Implications and Explanations
This creates a dilemma, as we now have two accurate but different values for the expansion rate. Possible explanations include that the universe accelerated over time, formulas used for early universe calculations are incorrect, or dark energy levels changed. However, none provide a clear answer yet. The universe may also have an irregular density or shape not accounted for.
What We Need to Know More
Future studies aim to recalculate the Hubble constant with less error margin. The LIGO gravitational wave detector may also allow more precise expansion measurements by detecting neutron star collisions across the universe. As we gather more data from various locations, hopefully within the next year we can gain a better understanding of the expansion rate in different parts of the universe. For now, this new research shows we still have much to learn about the mysteries of the expanding cosmos.
In conclusion, while our knowledge of the expanding universe has advanced greatly, this recent discovery highlights how little we still understand about its fundamental nature. Further research is needed to resolve the conflict between expansion rate values and provide insight into what may have changed over cosmic time. With upcoming studies and detectors, answers could emerge within the next year to shed light on this cosmological conundrum and our place in the grand scheme of the universe.