Galactic GPS for the Interstellar Highway
Pulsar Power, the Next Big Thing: The European Space Agency’s Ariadna initiative is studying a totally awesome navigation system that creams the one you'll find in your new Porche: they are examining the feasibility of navigation relying on millisecond pulsars, rotating neutron stars that spin faster than 40 revolutions per second. The pulses of these dead stars can be used as exquisitely accurate timing mechanisms.
Pulsars have huge advantages over a traditional deep space satellite network to fix a ship's position — it doesn’t scale and costs a fortune. Autonomous navigation is clearly preferable, tying the navigation system to natural objects like pulsars.
Pulsars rank at or near the top of freaky phenomena found in our Universe. In the early 1930s, California Institute of Technology astrophysicist, Fred Zwicky, an immigrant from Bulgaria, focused his attention on a question that had long troubled astronomers: the appearance of random, unexplained points of light, new stars.
It occurred to Zwicky that if a star collapsed to the sort of density found in the core of atoms, the result would be an unimaginably compacted core: atoms would be crushed together with their electrons squeezed into the nucleus, forming neutrons and a neutron star, with a core so dense that a single spoonful would weigh 200 billion pounds. But there's more, Zwicky concluded: with the collapse of the star there would be huge amounts of leftover energy that would result in a massive explosion, the biggest in the known universe that we called today supernovas. Most neutron stars house incredibly large magnetic fields. If they are spinning rapidly they make fabulous clocks, cosmic radio beacons we call pulsars. Pulsars can keep time to an accuracy better that one microsecond per year. Some pulsars generate more than 1000 pulses per second, which means, as Lawrence Krauss wrote in The Physics of Star Trek, that an object with the mass of the Sun packed into an object 10 to 20 kilometers across is rotating over 1000 times per second, or more that half the speed of light!
Will spacecraft traveling through interplanetary space be able to determine their positions by using signals from dead stars as astronomical clocks? Pulsar signals are quite weak and will put demands upon spacecraft constrained by mass and power consumption limitations.
What is the likelihood of artificial muscles made from electro-active polymers replacing mechanical parts in spacecraft? Will it ever be possible to conceive an interstellar highway in which spacecraft journey across the galaxy using the delicate gravitational balance between neighboring stars?
Ariadna will be devoted to short, inexpensive studies involving research into radical new space technologies, including:
* Advanced power systems: Research looking beyond photovoltaic systems (solar cells) into power systems for future space missions. This includes investigation of in-space power production systems for transmission to Earth, such as Solar Power Satellites.
* Biomimicry: Development of methodologies and solutions to space-related engineering problems through the imitation of plants and animals. This biologically inspired research includes behavioral models, structures and materials, mechanisms and processes, sensors and communications, survivability and adaptability.
Posted by Casey Kazan.
Image: a newly discovered nebula around the black hole or neutron star in the center is shown in blue,and is in the center of the expanding, fragmented shell of material thrown off in the supernova explosion, which is shown in red. CREDIT: Norbert Bartel and Michael F. Bietenholz,
York University; Artist: G. Arguner
Errata: Fred Zwicky an immigrant from Bulgaria
Fritz Zwicky was the first astronomer to conduct a systematic search for supernovae, finding more than any one individual in history without the aid of supercomputers. He coined the term itself translated from German, Haupt Nova, Supernova. Fritz Zwicky was born in Varna, Bulgaria, and remained a Swiss citizen his entire life. He spent his early childhood in Mollis, Switzerland, and later studied in Zurich, Switzerland, at the Federal Institute of Technology before emigrating to the United States.
Posted by: barbarina zwicky | June 02, 2009 at 09:04 PM
thank you
Posted by: sohbet sitesi | June 17, 2009 at 05:00 AM
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