For the past three months, something has been very wrong along the Peruvian coast. Nearly 3,000 dolphins have washed ashore dead, making it one of the largest marine mammal die-offs ever recorded...and it likely isn't even close to over.
Sun-like stars become brighter over the course of their long lives, which means that the Sun once provided Earth with far less heat than it does now - so much less, in fact, that life should have been impossible.
The geological evidence suggests that there have been liquid oceans on Earth dating back at least 3.5 billion years, a fact that was crucial to the emergence of the very first lifeforms. The only problem is that that's utterly impossible.