With the American Astronomical Society getting ready to convene its 217th meeting in Seattle on the 9th, it seems fitting to talk about one of the most splendid 'nearby' stellar objects, the Andromeda Galaxy, otherwise known as M31. Edwin Hubble was the first astronomer to resolve individual stars in the galaxy, but working with Milton Humason, he did something even more significant, studying Cepheid variable stars inside it whose brightness varies in a regular pattern that indicates their absolute magnitude. These 'standard candles' made it possible to find M31's distance, which Hubble showed was much greater than that of any stars in the Milky Way. We were learning in Hubble's day that the 'spiral nebulae' once thought to be part of our own galaxy were distant 'island universes' in their own right, a vast expansion of the size of the cosmos as humans understood it. M31 is the closest spiral galaxy to ours at roughly 2.5 million light years, offering up a spectacular view of as many...
Sails and Infrastructure: Thinking Big
Suppose we have developed an Earth-Moon industrial system, one that lets us use an electric launch system on the Moon to upload mass for chemical processing and the extraction of raw materials. What's the next step toward extending it to the entire system? One idea, as Joseph Friedlander has been explaining on the NextBigFuture blog, is to do interesting things at the L4-L5 points, where stable gravitational pockets exist. Friedlander is thinking about building solar sails in space, and in this regard he echoes nanotechnology maven Eric Drexler, who wrote about sail technologies in The Engines of Creation (1986). Here's Drexler on the subject: To build lightsails with bulk technology, we must learn to make them in space; their vast reflectors will be too delicate to survive launch and unfolding. We will need to construct scaffolding structures, manufacture thin-film reflectors, and use remotely controlled robot arms in space. But space planners already aim to master construction,...
All Eyes on the Data
It’s an interactive morning here in the eastern US, one in which partial solar eclipses can be viewed from more or less anywhere on the planet, asteroids can be chased by school children using data from automatic telescopes in Hawaii, and exoplanet discoveries can be made by gas workers in South Yorkshire. Let’s start with the eclipse, as seen in the image at left that was fed into the Twitterstream by space journalist extraordinaire Daniel Fischer. The accompanying tweet tells us that Fischer was in Aachen with a German TV crew when the photo was made. Those with unlimited cash can chase eclipses physically, and there is a certain romance in the act, but the real world is made up mostly of those of us who can’t be in the right place at the right time, which is why webcasts from Barcelona to Lahore were worth watching as they covered the event, or tried to. This eclipse was visible to those in Europe, northern Africa and western Asia whose local skies cleared in time to make it...
Deep Space and Human Motivations
If you charted the appearance of certain stars in books through the last two centuries, which ones would get the most hits? It's an interesting question that Greg Laughlin (UC-Santa Cruz) ponders on his systemic site, using Google's Ngram viewer as his tool. Ngram lets you plug in the terms of your choice and chart their appearance, using the vast collection scanned into Google Books. When Laughlin plugged in Alpha Centauri, it seemed a safe term to use. The closest star(s) to our own are always going to get a fair amount of attention. He added Proxima Centauri, Beta Pictoris, 51 Pegasi and 61 Cygni. The chart (shown below) is a bit startling when you realize that the blue spike at its left represents not Alpha Centauri but 61 Cygni, but everything becomes clear when you add in the fact that 61 Cygni was the first star other than the Sun to have its distance measured, making it a major player in 19th Century astronomical references. Greg also reminds us of the Scottish polymath...