Of Solar Sails, Bets and Optimism

by | Aug 5, 2008 | , | 22 Comments

I've been surprised by the sizable reaction to my bet with Tibor Pacher, not just in terms of comments here but in related e-mails. For those of you who missed the original post, I found Tibor's prediction that the first interstellar mission would be launched by 2025 to be an irresistible target. Tibor posted the prediction on the Long Bets site, and the way this works is that someone willing to make a bet on the prediction puts down the money upfront and challenges the predictor to match it. Negotiations follow, the outcome being that if the terms are worked out and the bet is accepted, it is finalized. Both parties send in their money, and the money grows over the years in a long-term investment portfolio called the Farsight Fund. Ultimately, either the Tau Zero Foundation or (Tibor's choice) the SOS-Kinderdorf International, will enjoy the result. Now that Tibor and I have finalized the terms, the details will go up on Long Bets as soon as our funds arrive (which should be in a...

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Two Telescopic Anniversaries

by | Aug 4, 2008 | | 24 Comments

by Larry Klaes It's been a tough weekend, not only with the loss of the SpaceX Falcon booster but also the NanoSail-D sail experiment that flew aboard it. I'll have more on the loss of the sail tomorrow, but this may be a good day to look back and reflect on some of the titans of astronomical history, including the Hale instrument whose views of the heavens gave so many of us early inspiration. Tau Zero journalist Larry Klaes has been pondering these matters, and offers us a look at some of the people and instruments that proved essential in changing our view of the universe. Sixty years ago, on June 3, 1948, the most massive astronomical tool of the era was dedicated on Palomar Mountain near Pasadena, California. Known as the Hale Telescope, this instrument was much bigger than any telescope that had ever come before it. In its nearly three decades as the reigning largest telescope on Earth, the "Giant Eye" of the Palomar Observatory revealed new vistas of the heavens ranging from...

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Exotic Particles from Galactic Center?

by | Aug 2, 2008 | | 15 Comments

What could be causing gamma-ray photons to be streaming from the galactic core with a precise energy of 511 keV (8 X 10-14 joules)? It's an interesting question, one tackled by Ian O'Neill on his astroENGINE site, as posted by 21st Century Waves in this week's Carnival of Space. O'Neill notes the defining nature of this energy level, which turns out to be the exact rest mass energy of a positron, the antimatter equivalent of an electron. That fact suggests the annihilation of positrons in the galactic center, but what's causing it? The usual suspects just don't fit, as O'Neill is quick to note: The first thing that comes to mind is a gamma-ray burst, produced when a massive star dies and collapses as a supernova. But this is short-lived and not sustained. How about the supermassive black hole sitting in the middle of the Milky Way's galactic nucleus? This theory was recently discussed on Astroengine, but the production of antimatter (i.e. positrons) is more of a slow leak than...

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Simulating the First Stars

by | Aug 1, 2008 | | 3 Comments

Without the explosions of supernovae, the heavy elements so essential to life itself would be unavailable, and stars would lack the raw materials to form planets. Thus Carl Sagan's famous "We are star-stuff" quotation, an idea validated by our extrasolar studies, which allow us to correlate the presence of planets with the existence of heavy elements in their stars. Much remains to be done here, but stars with higher metallicity and more heavy elements do appear more likely to have planets. Volker Bromm (now at the University of Texas) puts it this way: "We're now just beginning to investigate the metallicity threshold for planet formation, so it's hard to say when exactly the window for life opened. But clearly, we're fortunate that the metallicity of the matter that birthed our solar system was high enough for the Earth to form. We owe our existence in a very direct way to all the stars whose life and death preceded the formation of our Sun. And this process began right after the...

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Charter

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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If you'd like to submit a comment for possible publication on Centauri Dreams, I will be glad to consider it. The primary criterion is that comments contribute meaningfully to the debate. Among other criteria for selection: Comments must be on topic, directly related to the post in question, must use appropriate language, and must not be abusive to others. Civility counts. In addition, a valid email address is required for a comment to be considered. Centauri Dreams is emphatically not a soapbox for political or religious views submitted by individuals or organizations. A long form of the policy can be viewed on the Administrative page. The short form is this: If your comment is not on topic and respectful to others, I'm probably not going to run it.

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