Some cosmic rays detected on Earth are produced in violent events such as supernovae, but we still don’t know the origins of the highest-energy particles, which are the most energetic particles ever seen in nature. Cosmic rays are particles – mostly protons but sometimes heavy atomic nuclei – that travel through the universe at close to the speed of light. “A variation in the speed of light could solve the problem, but this too is impotent in the face of the question ‘why?’” 3 Ultra-energetic cosmic raysįOR more than a decade, physicists in Japan have been seeing cosmic rays that should not exist. A variation in the speed of light could also solve the horizon problem – but this too is impotent in the face of the question “why?” In scientific terms, the uniform temperature of the background radiation remains an anomaly. So, in effect, inflation solves one mystery only to invoke another. The trouble is that no one knows what could have made that happen – but see Inside inflation: after the big bang. But is that just wishful thinking? “Inflation would be an explanation if it occurred,” says University of Cambridge astronomer Martin Rees. You can solve the horizon problem by having the universe expand ultra-fast for a time, just after the big bang, blowing up by a factor of 10 50 in 10 -33 seconds. This “horizon problem” is a big headache for cosmologists, so big that they have come up with some pretty wild solutions. Nothing can travel faster than the speed of light, so there is no way heat radiation could have travelled between the two horizons to even out the hot and cold spots created in the big bang and leave the thermal equilibrium we see now. That may not seem surprising until you consider that the two edges are nearly 28 billion light years apart and our universe is only 14 billion years old. Look across space from one edge of the visible universe to the other, and you’ll see that the microwave background radiation filling the cosmos is at the same temperature everywhere. OUR universe appears to be unfathomably uniform. There may be a common mechanism in different illnesses. There may be diseases in which it has no effect. Researchers now need to identify when and where placebo works. “The relationship between expectation and therapeutic outcome is a wonderful model to understand mind-body interaction,” he says. We have a lot to learn about what is happening here, Benedetti says, but one thing is clear: the mind can affect the body’s biochemistry. The neuron activity decreased at the same time as the symptoms improved: the saline was definitely doing something. They found that individual neurons in the subthalamic nucleus (a common target for surgical attempts to relieve Parkinson’s symptoms) began to fire less often when the saline was given, and with fewer “bursts” of firing – another feature associated with Parkinson’s. He and his team measured the activity of neurons in the patients’ brains as they administered the saline. But apart from that, we simply don’t know.īenedetti has since shown that a saline placebo can also reduce tremors and muscle stiffness in people with Parkinson’s disease. So what is going on? Doctors have known about the placebo effect for decades, and the naloxone result seems to show that the placebo effect is somehow biochemical.
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