“It’s kind of like your coffee cup cooling down … when your coffee cup reaches the temperature of the room it is in, that’s equilibrium…. The stars, which are burning hydrogen, are like the coffee cup - they’re hot and slowly cooling down….. The question is, when will it end? … And all you can say is we are closer to the heat death than we anticipated.”
Charles "Charley" H. Lineweaver, professor at the Research School of Astronomy and Astrophysics at Australian National University
Australian researchers led by Charley Lineweaver have measured the amount of entropy that exists now in the Universe. They found that the Universe has much less energy available than had been previously measured, which has a potentially long-term scary implication: the Universe aging faster.
Their analysis of the entropy within the universe found that it is about 30 times higher than other projections had previously measured. In other words, according to these researchers, the universe has a thirty times higher entropy number than what was earlier calculated. Entropy is a measure of energy expenditure of any system, such as the Universe.
The universe began with a low entropy number (low disorder). As the universe ages its entropy number gets higher (higher disorder) as it expends more energy. Thus, the higher entropy number (the more entropy), the more energy has been expended. Entropy is calculated to find out how efficient a system is, such as an engine or a universe, and how quickly the system will run down.
The team is trying to find out how much energy will be available to life forms anywhere in the universe, and where this energy is. The first step in this procedure is to determine the entropy of the universe.
The measurements by Lineweaver and Egan are based largely on the number of the black holes in the universe, along with their masses, a key to figuring out entropy in the universe, but they considered all contributions to the entropy of the observable universe: stars, star light, the cosmic microwave background. They also made an estimate of the entropy of dark matter.
Lineweaver and team concluded that it's the entropy of super-massive black holes that dominates the entropy of the universe. When they used the new data on the number and size of super-massive black holes, they found that the entropy of the observable universe is about 30 times larger than previous calculations.
Dr. Lineweaver compared their results and its message for life in the universe to a car's gas tank. He states, “It’s a bit like looking at your gas gauge and saying `I thought I had half a gas tank, but I only have a quarter of a tank.”
“But I can’t tell you how many kilometres you can go on that quarter of a tank yet,” Lineweaver added.
Currently, Lineweaver is looking into a measurement on how much longer the universe will be able to support life. However, this figure will be difficult to come up with because astronomers are unsure about how much energy was available at the beginning of the Big Bang.
Casey Kazan via material provided by Australian National University
The abstract to their paper ("A Larger Estimate of the Entropy of the Universe") is found on the ArXiv.org website
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