As we get older, life changes. The same goes for our planet. In “The Story of Earth,” Robert M. Hazen, a professor of Earth science at George Mason University, lays out the history of our world from its infancy as a cloud of cosmic dust to the green and verdant sphere we currently enjoy.
Given the age of the Earth — about 4.567 billion years — there’s a lot to cover in about 300 pages: the creation of the moon, the birth of the oceans and the formation of microbes. The dinosaur age, about 230 million years ago, isn’t even discussed until the final 50 pages of the book.
According to Hazen, Earth will continue to evolve in ways that might make you a little melancholy. For instance, the moon is drifting away from us, at a rate of about an inch and a half per year. In a couple of hundred million years, the difference will be pretty noticeable. Also, in about 5 billion years, Hazen says, the sun will probably engulf our planet. But long before that, our oceans will evaporate, rendering our world a desert waste — a gloomy prognosis, indeed.
Everything starts out fine. And then, without warning, the dreck hits the fan and you’re smoking cigarettes while eating a whole tub of ice cream, even though you know better. In “This Is Your Brain in Meltdown,”three researchers explain the biological reactions that cause people to crack under pressure.
Until recently, scientists thought that when the going got tough, the hypothalamus — an evolutionarily ancient structure at the base of the brain — released a wave of hormones that sped up your heart rate, increased blood pressure and scrambled your thoughts. New research suggests this isn’t the whole story. Stress actually has a lot to do with the prefrontal cortex, a more recently evolved area of the brain that controls our higher cognitive abilities.
During the onset of stressful events (important exams, approaching tigers, etc.) the prefrontal cortex shuts down, allowing the older components of our minds — such as the amygdala, which helps regulate emotional activity — to take the helm. In other words, our lizard brain gets to be in charge. Thus, our ability to perform complex actions is hindered, and it becomes tougher to control such impulses as the urge to down that whole tub of mint-cookie Ben & Jerry’s.