According to the general theory of relativity, the closer the speed of a moving object is to the speed of light, the slower time passes, and this effect has been experimentally proven. Also, our universe is expanding, and the rate of expansion increases the further away we are from the Earth.
[▲ Figure 1: General relativity predicts that the faster an object moves, the slower time passes, and modern cosmology predicts that the farther the universe, the faster it expands. Taken together, the two theories suggest that objects in the farthest universe should appear in slow motion (Credit: The University of Sydney)]
Combining these two elements, from the earthwhen you see the distant universethe celestial bodies there areAppears in slow motion compared to when looking at nearby space objectsmust. In order to prove this prediction, it is necessary to capture not only the momentary state of the distant universe, but also the changing state in “real time”.
Through the analysis of Type Ia supernovae, whose brightness is said to be constant, previous studies have shown that up to about half of the 13.8 billion year history of the universe is consistent with the predictions of general relativity. A delay was observed. However, it has been difficult to observe a type Ia supernova that has occurred in the universe farther than that, and it has been difficult to observe the time dilation in the universe farther away. Other astronomical phenomena that can be observed even if they occur in the distance cannot prove the time delay because the change in brightness is not constant and it is technically difficult to observe the distant universe. I wasn’t able to do it.
[▲ Figure 2: Imaginary drawing of a quasar. There is a supermassive black hole at the center, which releases energy in the process of sucking in a large amount of matter (Credit: NASA, ESA & J. Olmsted (STScI))]
A research team led by Geraint F. Lewis of the University of Sydney and Brendon J. Brewer of the University of Auckland has found that “quasarBy analyzing the observation data of “, we analyzed how the flow of time is observed. A quasar that shines very brightly in visible light has a huge black hole at its center, and it is thought that a huge amount of energy is released when the black hole sucks in a large amount of matter.
The amount of energy emitted from quasars is not constant, but increases and decreases over time, causing quasars to brighten and darken. Theoretically, it is possible to detect the delay in time if we liken this change to the “hands of a clock” that ticks the time. However, it is difficult to reliably capture changes in a quasar’s brightness over several days.
Lewis and Brewer analyzed data from 190 quasars observed at various wavelengths over the past 20 years to investigate how quasars “tick”. It is unclear whether the changes in quasar brightness can be used as clocks, and past research has failed to detect them.
However, in this study, we were able to prove that quasars have such properties. As a result of the analysis,Over 12 billion years ago(Approximately 1 billion years after the birth of the universe)In our universe, time moves about five times slower than it does in our present universe.was able to detect
Of course, the fact that the early universe appears to be in slow motion, which is five times slower, is a phenomenon that occurs only when we are observing from a great distance. Even if we were to use a time machine to return to the universe at that time, time would seem to flow at the same speed as it does in the present universe before we left.
However, the observationally demonstrated slowing down of time proves something else. It is almost universally accepted in modern cosmology that the universe is expanding and that the distant (i.e. early) universe contains quasars, the earliest forms of galaxies. Is it true?” is not an easy question to answer. The analysis, which shows that quasar brightness does indeed appear to change slowly, suggests that quasars were indeed objects in the early universe and that the universe was expanding at a significant rate. It’s an interesting study in that it proves it in a different way.
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Text: Riri Ayae
