May 2006

A Triple Planetary System and More

May 18, 2006

Finding three planets around a single star is newsworthy in itself, but when the planets are Neptune-class things get more interesting. And when one of these worlds is found to be in the star’s habitable zone, Centauri Dreams definitely drops everything for a closer look. Not only that, but the system around HD 69830, a [...]

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A Clear View of Distant Worlds

May 17, 2006

Yesterday’s post on UMBRAS and occulter technology focuses attention on the characteristics of light, some of them counter-intuitive but well demonstrated. And since we’ve also been talking recently about the nearby star Epsilon Eridani, I’ve chosen an image of that star to illustrate some of the problems with planetary detections. What you see below is [...]

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Occulters and Their Uses: A Helpful Resource

May 16, 2006

‘Umbras’ is Latin for ‘shadows,’ and it becomes a fitting acronym for projects to block the light of stars so that astronomers can see the planets around them. The unwound acronym is Umbral Missions Blocking Radiating Astronomical Sources, which refers to both an imaging technique and a class of space missions. The basic idea is [...]

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Probing the Epsilon Eridani System

May 15, 2006

In Centauri Dreams‘ imagination, the name Epsilon Eridani is magic. Like many of us, my earliest speculations about life on other worlds always came back to the nearby, Sun-like stars like Tau Ceti, Epsilon Eridani and Centauri A and B. Frank Drake used the first two as his targets for Project Ozma in 1960, an [...]

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A Universe Before the Big Bang

May 13, 2006

We seem to be awash in exotic physics, an administrative category I created on this site only a couple of days ago to house the trillion-year crunch story and the ‘light in reverse’ work at the University of Rochester. It seems an appropriate time, then, to look at an investigation reported in the Physical Review [...]

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Faster than Light in Reverse?

May 12, 2006

If you thought the trillion-year crunch was mind-boggling, how about light that moves backwards, and does so at speeds faster than c? From the University of Rochester comes word that Robert Boyd, a professor of optics there, has slowed light to negative speeds. To do this, the experimenter sent a pulse of laser light through [...]

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Trillion Year Crunch

May 11, 2006

How to explain dark energy, which is pushing distant galaxies away at an accelerating rate? The cosmological constant that would account for the phenomenon — originally conceived but then rejected by Einstein — is far smaller than one would expect from conventional Big Bang scenarios. In fact, the observed vacuum energy (a possible explanation for [...]

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Organic Particles from the Early Solar System

May 10, 2006

Can we say anything definitive about organic materials in the early Solar System? Perhaps so, judging from recent news from the Carnegie Institution. Researchers there have found organic particles from the days of Solar System formation inside meteorites. The material is similar to what is found in interplanetary dust particles believed to have come from [...]

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Habitable Worlds and the Gas Giant Problem

May 9, 2006

I remember wondering, while still getting acclimated to the odd existence of ‘hot Jupiters’ in those amazing first years of exoplanet discovery, what the view from a terrestrial world in one of those systems might be like. After all, a Jupiter-sized mass in close solar orbit must make for some unusual visual effects. Do terrestrial [...]

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Of Lightsails and Solar Arrays

May 8, 2006

Rudolph Meyer’s work on solar arrays and ion propulsion elicited quite a few e-mails asking for further information. I don’t yet have the Acta Astronautica paper that spells out the details — nor do I know just how detailed Meyer gets — but I’ll try to provide some answers soon. In the interim, I was [...]

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