Scientists Puzzled: Why does the Universe Accelerate in its Expansion?
The latest issue of Science magazine pointed out in its News Focus section that cosmologists are puzzled over how to explore the mysterious dark energy, which causes the acceleration of the expansion of the universe.
Ever since 1929, cosmologists have discovered that the universe has been expanding, which has led to the Big Bang theory - the origin of everything in the universe. Although experts have not been able, nor have they been anxious to explain the cause of the Big Bang, they have assumed that because of the pull of gravity, the expansion of the universe should have slowed down after it has cooled off. However in 1998, researchers inadvertently discovered while trying to measure the distance of from a supernova to the earth, that the distance was further than they had expected. This discovery, which sent shock waves across the astronomy community, prompted scientists to propose the theory that the expansion of the universe is accelerating. This theory was later validated in the research of background radiation of cosmos microwaves. Scientists remain puzzled about what factors have caused the universe to expand. They could only call this force "dark energy."
It has been reported that scientists are stuck in the measurement of dark energy. They believe that observation of more remote stars with more powerful telescopes might be of help. NASA and the U.S. Department of Energy (DOE) are expected to launch a $600 million space telescope designed to measure dark energy under a program named Joint Dark Energy Mission (JDEM). Still, one of the leaders of the JDEM program, Charles Bennett, an Astrophysicist from Johns Hopkins University, was full of doubt himself. "We don't know what dark energy is, and there are different ways to measure it and different aspects to measure. There are unknowns in all directions." Some cosmologists have questioned this program itself. They thought that land-based telescopes could provide more useful data. They have submitted several feasibility reports to NASA and the DOE.
Scientists, currently, only expect to use these telescopes to measure "the relationship of the distance of light has traveled and redshift" to determine if the density of dark energy remains constant. The term "redshift" comes from the understanding that as space expands, light traveling through it stretches to longer and redder wavelengths. Light's wavelength increases more quickly if space is stretching faster. "Redshift" is the accumulation of these stretches. However, scientists have not reached consensus over objects to measure, such as supernovae or entire galaxies, which in turn, has affected the decision on using space telescopes or land-based telescopes.
Facing these questions, Charles Bennett, based on the spirit of exploration, said, "You shouldn't look at a space mission as an improvement over what you know today. You should look at it as an improvement over what you'll know tomorrow."
Above are the thoughts of some scientists. In the cultivation community, a different approach to the explanation of the universe is taken. There, it is held that to truly understand the mysteries of the universe and time-space, one has to genuinely practice true cultivation.
Source: The Quest For Dark Energy: High Road Or Low? Adrien Cho (2005) Adrian Cho, Science: 1482-1483