Filaments of Missing Matter?

by | May 8, 2008 | | 14 Comments

It's hard enough to figure out what dark energy and dark matter are, a task that will occupy physicists for a long time to come. But even if we confine ourselves to 'normal' or 'baryonic' matter (accounting only for some four or five percent of the universe), we're still left with a problem. Baryons are heavy subatomic particles like protons and neutrons that experience the strong nuclear force, and the problem is that even these relatively familiar particles are only partially accounted for. So where is the missing baryonic matter? The answer may lie in a thin haze of hot, low-density gas that connects galactic clusters. Call it WHIM, for warm-hot intergalactic medium. Dutch and German scientists now think they have uncovered a filament of such gas that connects the clusters Abell 222 and Abell 223. The properties of the gas, visible primarily in the far ultraviolet and X-ray bands, fit with simulations in terms of density and temperature. The scientists used the XMM-Newton X-ray...

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Arecibo Observatory May be Safe at Last

by | May 7, 2008 | | 12 Comments

By Larry Klaes Any good news from Arecibo is welcome, and Larry Klaes here delivers it. The observatory, threatened with closure despite its key role in the hunt for Earth-crossing asteroids, may have found at least temporary deliverance. Politics seems to have played a role, as Larry notes, but for once with results that benefit science rather than compromising it. Meanwhile, a new study of the Chixculub impact 65 million years ago tells us that a hail of carbon cenospheres -- tiny carbon beads -- may have fallen planet-wide following the strike. The more we learn about past impacts, the more we realize how important a role our planetary radars play in forestalling future catastrophe. What exists on the island of Puerto Rico that is over 1,000 feet across, could hold ten billion bowls of cereal, pick up a cell phone call from the planet Venus, once sent a message to any potential inhabitants of a distant globular star cluster, discovered the first planets around another star, has...

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A Space-Based Asteroid Telescope

by | May 6, 2008 | | 14 Comments

One of the world's largest impact craters (see below) lies under Mexico's Yucatan peninsula, evidently a major player in the demise of the dinosaurs. Chicxulub is 180 kilometers in diameter, the subject of continuing research by the man who identified it, Alan Hildebrand (University of Calgary). So you could say Hildebrand has an idea what massive impacts from asteroids can do to the Earth's surface, having studied the environmental effects caused by this one and mapping the crater's structure to identify mineral, oil and gas resources. That interest has led Hildebrand into an ongoing asteroid hunt, and explains his current plans to build and launch a space-based observatory designed to look for near-Earth objects. The scientist currently uses use a retrofitted satellite tracking telescope in NEO work here on Earth. The instrument, based at the University of Calgary's Rothney Astrophysical Observatory (some 75 kilometers southwest of the city) is an extensive re-build, a Cold War era...

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The Odds on Interstellar Panspermia

by | May 5, 2008 | | 15 Comments

Our recent look at panspermia concepts was largely devoted to the transmission of life via microbes or spores here in our own Solar System. The even richer question of how life might pass from star to star is far more problematic, but as a follow-up to that earlier story, I want to look at work that graduate student Jess Johnson did with Jonathan Langton and advisor Greg Laughlin at the University of California, Santa Cruz. Their work suggests that while life might readily survive an interstellar journey, it is unlikely to wander close enough to seed another system. Ponder the era here on Earth known as the Late Heavy Bombardment (LHB). After the period of planetary accretion ended some 4.4 billion years ago, life apparently began. But 3.8 to 4 billion years ago, the LHB saw the planet again pummeled, causing debris to be ejected into space. Looking specifically at the mass that is ejected at 16.7 kilometers per second in the direction of the Earth's motion (this is Solar System...

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Near-Term Concepts for a Fast Ticket Outward

by | May 3, 2008 | | 10 Comments

From the first anniversary edition of the Carnival of Space, I'll send you this week to Brian Wang's discussion of two propulsion concepts for the near future. VASIMR (variable specific impulse magnetoplasma rocket) is under active development at Franklin Chang Diaz' Ad Astra Rocket Company, a site to monitor for developments in a technology that offers potential specific impulses from 1,000 to 30,000 seconds. That's a major upgrade compared to conventional rocket designs, and one that could conceivably get us to Mars in as little as 39 days. The Finnish solar electric sail concept, which we've also looked at here, may be well enough along for a flight test in 2010, assuming the budgetary gods are smiling. Our next step outward depends upon bumping up trip times to relatively nearby destinations like Mars and the asteroids, and these are two of the more promising concepts for making that a reality.

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Black Holes in Intergalactic Space?

by | May 2, 2008 | | 7 Comments

Physicists have recently theorized that the merger of two black holes would create gravitational waves that could eject the resultant object from its galaxy. Now such a black hole event has been observed for the first time. Theory predicted that the gravitational waves would be emitted primarily in one direction, pushing the newly enlarged black hole in the opposite, and that is what we seem to be looking at, according to scientists at the Max Planck Institute for Extraterrestrial Physics (MPE). We can't see black holes themselves, nor have we yet directly detected gravitational waves. But we can observe the interactions around black holes, in this case the broad emission lines of gases carried with the recoiling black hole as it exits its galaxy, which contrast with the narrow emission lines of the gases the object left behind. These data allowed the object's speed -- a scorching 2650 kilometers per second -- to be measured. The recoil caused by the merger is pushing the black hole,...

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Scattering Life Through the Cosmos

by | May 1, 2008 | | 11 Comments

Olaf Stapledon's Last and First Men (1930), amongst other wonders, pictures our descendants millions of years hence moving from world to world as they attempt to save the species. The Moon approaches the Earth, an imminent peril the 'Fifth Men' escape by terraforming Venus, unfortunately destroying indigenous life forms there. Later, the Fifth Men move on to Neptune, and when their existence there is endangered, they make an attempt to save themselves as a species by seeding their cells among the stars. Interestingly enough, Francis Crick (famed as a co-discoverer of the structure of DNA) suggested in 1973 that life could have been intentionally sent from elsewhere in the universe with the express purpose of finding a new home, an idea that made the later work of Fred Hoyle and Chandra Wickramasinghe seem positively tame. We're talking panspermia, the idea that life can survive long journeys through space to seed other planets (a notion Hoyle addressed in 1982's Evolution from...

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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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