Dark energy accounts for 70% of everything in the universe, and yet we know almost nothing about it. Now a new model meant to explain some impossibly massive galaxy clusters is here, to make dark energy even more fiendishly complex.
We're not here to dispute the existence of dark energy — for that discussion, check out Dr. Dave Goldberg's explanation of why dark energy really is essential. But still, dark energy remains a great unknown, something that while we understand what it does — cause the expansion of the universe to accelerate — we don't really have any idea how it does this, or even what it actually is. These are, admittedly, rather large questions to be answered.
The best model we have right now for dark energy is the cosmological constant, which simply states that all of space has a certain amount of repulsive energy, and that amount is directly proportional to the size of the universe. So then, as the universe expands, the amount or repulsive energy naturally increases, which forces the universe to move apart — to expand, in other words — even faster. It's still vague on the details, admittedly, but it at least is a straightforward enough model that fits the data we currently have.
But Edoardo Carlesi and his team at the Autonomous University in Madrid, Spain have decided to play around with this basic idea. They have simulated a universe where the amount of repulsive energy found in each unit of volume can change over time. This new model is useful, they say, because it can explain how some galaxy clusters reached a mass of over a quadrillion suns when the universe was still only six billion years old, which should be impossibly early according to most models of the universe - there simply wasn't enough time for gravity to pull that much mass together. more at link
We're not here to dispute the existence of dark energy — for that discussion, check out Dr. Dave Goldberg's explanation of why dark energy really is essential. But still, dark energy remains a great unknown, something that while we understand what it does — cause the expansion of the universe to accelerate — we don't really have any idea how it does this, or even what it actually is. These are, admittedly, rather large questions to be answered.
The best model we have right now for dark energy is the cosmological constant, which simply states that all of space has a certain amount of repulsive energy, and that amount is directly proportional to the size of the universe. So then, as the universe expands, the amount or repulsive energy naturally increases, which forces the universe to move apart — to expand, in other words — even faster. It's still vague on the details, admittedly, but it at least is a straightforward enough model that fits the data we currently have.
But Edoardo Carlesi and his team at the Autonomous University in Madrid, Spain have decided to play around with this basic idea. They have simulated a universe where the amount of repulsive energy found in each unit of volume can change over time. This new model is useful, they say, because it can explain how some galaxy clusters reached a mass of over a quadrillion suns when the universe was still only six billion years old, which should be impossibly early according to most models of the universe - there simply wasn't enough time for gravity to pull that much mass together. more at link
