A recent study, conducted in part by UCSB researchers, has confirmed with increased precision the size and age of the universe.
The new research verifies both the age of the universe as 13.75 billion years old — accurate within 170 million years — and the Hubble constant, which is used to denote the size of the expanding universe. The study also provides further insight into the strength of dark energy, which causes the universe’s expansion.
The study, which will be published in The Astrophysical Journal this month, was conducted using gravitational lensing that measures large distances in space by comparing time lapses between various sources of light that have been affected by the gravitational pull of several masses in the universe.
Postdoctoral physics scholar Matthew Auger, a researcher on the project at UCSB, said, according to Einstein’s theory of general relativity, light — like all other matter — feels the effects of gravity. Light is therefore pulled toward massive objects, such as galaxies, as it moves through the universe.
“In our recent work, we used an additional property of gravitational lensing — the fact that a ‘time delay’ is created between the different images formed by the gravitational lens — as a geometric probe of the structure of the universe,” Auger said. “If we can measure the time delays and how much mass is in the lens, we can then infer something about the size, age and composition of the universe, and this is exactly what we did.”
Moreover, associate physics professor and researcher Tommaso Treu said the study, in conjunction with past research, has shed more light on the perplexing nature of dark energy.
“[These findings] add another piece of the puzzle, confirming that most of the energy in the universe is in the form of something completely unknown, called dark energy,” Treu said. “It is a mysterious thing that causes the universe to accelerate instead of slowing down, as it’d be expected to do if it were filled with ordinary matter.”
By combining these findings with studies conducted with various other methods, Auger said scientists hope to better understand the concept of dark energy.
“Dark energy is one of the biggest mysteries in physics right now,” Auger said. “It’s going to be a very hard problem to solve, but our work has demonstrated that combining different experiments — experiments with strong gravitational lenses like ours, but also experiments with the cosmic microwave background, supernovae and other methods — significantly improves how well we can infer properties of this dark energy.”
Even with numerous contributions — the research was conducted by the Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, University of Bonn, UCSB, UC Davis and the Kapteyn Astronomical Institute in the Netherlands — Treu said it took almost a decade to complete the study.
Now that gravitational lensing has proven to be an effective and precise way of gathering information on dark matter, Auger said future research in this field will lead to a more complete understanding of the processes of the universe.
“I think one of the bigger impacts our work will have will be in helping our community of cosmologists recognizes that complementary experiments, particularly with strong lenses, provide the most promising methods for understanding dark energy,” Auger said. “We’ve demonstrated that one single object, the gravitational lens B1608, can significantly help to understand the universe. The next step is to expand this method to many more gravitational lens systems.”