Brian Cox continues his exploration of the solar system with a visit to a planet that dwarfs all the others: Jupiter. Its size gives it a great power that it has used to manipulate the other planets.
Asteroids have a bad reputation as deadly rocks from space. They wiped out the dinosaurs and will be back for us. But that's only half the story. Ancient asteroids built the Earth. And they may have brought life to its barren surface. Asteroids will shape our future as much as our past. They are the perfect location for deep space colonies and could be the stepping stones that eventually send humans out into the cosmos. From icy worlds with more fresh water than Earth to flying mountains of pure metal, a hundred miles wide, scientists are striving to unlock their secrets. Could these enigmatic space rocks hold the key to how life in the Universe arises and is extinguished?
Last week we covered multiple star systems, but what if we added thousands or even millions of stars to the mix? A star cluster. There are different kinds of clusters, though. Open clusters contain hundreds or thousands of stars held together by gravity. They’re young, and evaporate over time, their stars let loose to roam space freely. Globular clusters, on the other hand, are larger, have hundreds of thousands of stars, and are more spherical. They’re very old, a significant fraction of the age of the Universe itself, and that means their stars have less heavy elements in them, are redder, and probably don’t have planets (though we’re not really sure).
Beginning with the separation of the fuzzy thinking and pious fraud of astrology from the careful observations of astronomy, Sagan follows the development of astronomical observation. Beginning with constellations and ceremonial calendars (such as those of the Anasazi), the story moves to the debate between Earth and Sun-centered models: Ptolemy and the geocentric worldview, Copernicus' theory, the data-gathering of Tycho Brahe, and the achievements of Johannes Kepler (Kepler's laws of planetary motion and the first science-fiction novel).
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