Imagine that you’re an astronomer in the early years of the 17th century. The telescope hasn’t yet been invented, so you scan the night sky only with the unaided eye. Then one day you see a remarkable sight: A bright new star appears, and for the next few weeks it outshines even the planet Venus. It’s so bright it can even be seen in broad daylight. It lingers in the sky for many months, gradually dimming over time.That’s what the German astronomer Johannes Kepler ; skywatchers elsewhere in Europe, the Middle East and Asia saw it too. We now know it wasn’t really a new star but rather a...…Imagine that you’re an astronomer in the early years of the 17th century. The telescope hasn’t yet been invented, so you scan the night sky only with the unaided eye. Then one day you see a remarkable sight: A bright new star appears, and for the next few weeks it outshines even the planet Venus. It’s so bright it can even be seen in broad daylight. It lingers in the sky for many months, gradually dimming over time.That’s what the German astronomer Johannes Kepler ; skywatchers elsewhere in Europe, the Middle East and Asia saw it too. We now know it wasn’t really a new star but rather a...WW…

Charles Darwin’s On the Origin of Species rattled Victorian readers in 1859, even though it said almost nothing about how the idea of evolution applied to human beings. A dozen years later, in 1871, he tackled that subject head-on. In The Descent of Man, and Selection in Relation to Sex, published 150 years ago this month, Darwin argued forcefully that all creatures were subject to the same natural laws, and that humans had evolved over countless eons, just as other animals had. “Man,” he wrote, “still bears in his bodily frame the indelible stamp of his lowly...…Charles Darwin’s On the Origin of Species rattled Victorian readers in 1859, even though it said almost nothing about how the idea of evolution applied to human beings. A dozen years later, in 1871, he tackled that subject head-on. In The Descent of Man, and Selection in Relation to Sex, published 150 years ago this month, Darwin argued forcefully that all creatures were subject to the same natural laws, and that humans had evolved over countless eons, just as other animals had. “Man,” he wrote, “still bears in his bodily frame the indelible stamp of his lowly...WW…