What would happen if the sun took out our electrical power grid for an entire year? It may sound like the plot of a sci-fi movie, but this doomsday scenario could actually happen. Despite its calm appearance, the sun is a violent place, constantly releasing huge masses of energy known as coronal mass ejections. These storms have hit the earth before. The last big one struck more than 150 years ago in the Victorian era taking out worldwide telegraph service. The impact of a similar storm would be far more destructive in our modern age of hyper-connected telecommunication and total reliance on electricity and electronics. Fortunately scientists and engineers are building the world's largest solar telescope and launching the first ever spacecraft to fly to the sun to help us predict these potentially devastating events - and prepare for them.
Artificial selection is one example, eyes another, of the well-documented and inescapable process of evolution--change in a population of species over time--by natural selection. These are some of the things that molecules do.
Ideas about time and space are explored in the changes that constellations undergo over time, the redshift and blue shift measured in interstellar objects, time dilation in Albert Einstein's theory of relativity, the designs of both Leonardo da Vinci and spacecraft that could travel near light speed, time travel and its hypothetical effects on human history, the origins of the Solar System, the history of life, and the immensity of space. In Cosmos Update, the idea of faster-than-light travel by wormholes (researched by Kip Thorne and shown in Sagan’s novel Contact) is discussed.
Beneath the hood of your car lies the history of the Universe. The iron in your chassis, the gold in your stereo and the copper in your electronics all owe their existence to violent cosmic events that took place billions of years ago.
In just half a century, the human population has doubled to 7.4 billion, and during that time, astronaut and satellite photos have been capturing the startling changes on our planet. See how humans have made their mark reshaping the planet in our quest for new sources of food, power, and shelter. From glimmering new megacities like Shenzhen, China to areas affected by climate change like Mt. Kilimanjaro and Florida, witness Earth's changing look--the spectacular and the shocking--from 250 miles up.
2017 • Astronomy
Before moving on from Jupiter to Saturn, we’re going to linger for a moment on Jupiter’s moons. There are 67 known moons, and 4 huge ones that we want to explore in greater detail. Ganymede is the largest - larger, in fact, than any other moon in the solar system and the planet Mercury! Callisto, orbiting the farthest out, is smaller but quite similar to Ganymede in many ways. Io, meanwhile, is most noteworthy for its tremendous volcanic activity. There’s also water on Ganymede and Europa!