On Universe, Claire L. Evans looks back on the starry-eyed futurism of the 1970’s, when Gerard O’Neill envisioned “massive colonies of human habitation in space—self-sustaining environments capable of hosting hundreds of thousands of people.” These colonies, housed in spinning cylinders, “would float in space at Lagrangian points, points of stable gravitational equilibrium located along the path of the moon’s orbit.” Today our ambitions are a bit less grand—and perhaps we should focus on taking care of the perennial spaceship Earth. But with unlimited room to grow and plenty of solar energy, the possiblities for cosmic urbanization are interesting (to say the least). Meanwhile, Greg Laden reports that the Herchel Space Observatory has confirmed the presence of molecular oxygen in space—not enough to breathe outright, but perhaps enough to collect for the space settlements of the future. The O2 was discovered in the Orion star-forming complex, 1300 light-years away.
The Universe is a little less than 14 billion years old. Humanity, maybe 200,000. We have reached for knowledge at every step, and recorded what we could. The pace of our knowledge seems to accelerate; the 20th century tranformed our understanding of reality, as had the previous millenium. In 2011, we gather more information than ever before, and our knowledge seems almost complete. But it’s funny how things change. On Built on Facts, Matt Springer says James Clerk Maxwell’s electromagnetic equations are as good today as they were in the 1860’s, despite a little thing called relativity. Matt writes, “Lorentz covariance is built right in, though it’s a bit hidden. But Maxwell and Faraday and Ampere and the rest didn’t know that.” On Starts With a Bang, Ethan Siegel shows how improving telescopes turned an 18th century “smudge” into a 19th century “nebula.” It took until 1929 for a man named Hubble to discover that M31 is a separate galaxy: Andromeda, our nearest neighbor. Twenty years ago, NASA launched a telescope into orbit and named it after Hubble. They pointed it at the darkest part of the sky for days, and discovered little galaxies everywhere. But Hubble’s heyday is over, and its successor is on the chopping block.