August 2005

An Early Solar Sail Paper Re-emerges

August 22, 2005

The theories behind solar sailing go back a long way — some would trace them to the days of Kepler. But papers on actual mission design began to emerge only in the 1950s, when ‘Russell Saunders’ (the pseudonym of aeronautical engineer Carl Wiley) wrote a sail description for a 1951 issue of John Campbell’s Astounding [...]

Read the full article →

A Challenge to Planetary Migration Theories

August 20, 2005

Just how young is the average meteorite? One way to study the question is through the chondrules that make up stony meteorites. Chondrules are mineral deposits formed by rapid cooling; they give the appearance of tiny, spherical bits of glassy rock. Stony meteorites are generally called chondrites because they contain such chondrules. And it’s generally [...]

Read the full article →

On the Publication Schedule

August 19, 2005

Unless I am traveling, Centauri Dreams publishes Monday through Saturday. Entries are usually available by early afternoon EST, with the exception of the Friday and Saturday postings, which may appear later in the day. This schedule will occasionally be modified as events warrant. A lack of posts for several days running simply means I am [...]

Read the full article →

On the Interstellar Bibliography

August 19, 2005

Of the many contributions of Robert L. Forward to interstellar studies, the bibliography he produced with Eugene Mallove was one of the most useful to theorists in the field. The last appearance of the Forward/Mallove collaboration was in the Journal of the British Interplanetary Society in 1980, including 2700 items in seventy subject categories; since [...]

Read the full article →

On the Age of Habitable Planets

August 19, 2005

Response to the August 12 post about Fermi’s Paradox was heavy, an indication that the physicist’s famous question — Where are they? — will not go away. A number of readers asked for background on my statement (drawn from Milan Ćirković’s paper) that the average age of Earth-like planets in the Milky Way is now [...]

Read the full article →

A Boost for Solar Sails

August 18, 2005

James Benford’s JPL experiments pushing an ultralight carbon sail with a microwave beam were the first solid demonstration that the beamed sail concept would work. Both James and brother Gregory were deeply involved in the design of the Cosmos 1 solar sail mission, and understandably disappointed that its microwave experiment — aimed at demonstrating a [...]

Read the full article →

Changing the Shape of the Milky Way

August 17, 2005

Getting an overview of our own galaxy is tricky work. After all, we live in one of its spiral arms, so we see through a swarm of surrounding stars that mask the true galactic shape. Astronomer Ed Churchwell at the University of Wisconsin describes the effort as an attempt to define the boundaries of a [...]

Read the full article →

A Catalog of Extrasolar Planets

August 16, 2005

We now have 156 confirmed extrasolar planets orbiting 133 stars, making for 17 multiple planet systems. Keeping up with these fast-breaking discoveries is a challenge, but Julia Espresate at the Instituto de Astronomía (Ciudad Universitaria, Mexico) has produced two useful catalogs now available on the arXiv site. The first lists stellar data including spectral type, [...]

Read the full article →

‘Extremophiles’ Offer Clues to Life on Other Worlds

August 15, 2005

How did the mechanism for protein synthesis — the ribosome — come into being? Answering that question would be useful not just in the study of life on Earth, but also in learning where else in the universe we might expect to find life. Intense work on the subject is ongoing at the University of [...]

Read the full article →

A Novel Solution to Fermi’s Paradox

August 12, 2005

Enrico Fermi’s famous question “Where are they?” continues to resonate among scientists and laymen alike. After all, shouldn’t the universe be teeming with life, and hasn’t intelligent life had enough time to spread through our own galaxy? Some estimates put the average age of Earth-like planets in the Milky Way at 6.4 billion years, whereas [...]

Read the full article →

← Previous Entries

Next Entries →