Non-Carbon-Based, and Extra-Planetary, Life Forms a Possibility

"The Black Cloud" - Could Non-Carbon Life Exist in Cold Clouds of Interstellar Dust?

[P]hysicists have discovered over the last few years intriguing evidence of life-like double-helix structures formed from inorganic substances in space which raises the question of whether extraterrestrial life could be composed of corkscrew-shaped formations of interstellar dust. The findings hint at the possibility that life beyond Earth may not necessarily use carbon-based molecules as its building blocks and they may also point to a possible new explanation for the origin of life on Earth.

The international team has discovered that under the right conditions, particles of inorganic dust can become organized into helical structures. These structures can then interact with each other in ways that are more usually associated with organic compounds and life itself.

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Hungry Heart: Role of the Universe's Earliest Black Holes

First black holes born starving

The first black holes in the universe had dramatic effects on their surroundings despite the fact that they were small and grew very slowly, according to recent supercomputer simulations carried out by astrophysicists Marcelo Alvarez and Tom Abel of the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University, and John Wise, formerly of KIPAC and now of NASA Goddard Space Flight Center. Several popular theories posit that the first black holes gorged themselves on gas clouds and dust in the early universe, growing into the supersized black holes that lurk in the centers of galaxies today. However, the new results, published in The Astrophysical Journal Letters, point to a much more complex role for the first black holes.

"I'm thrilled that we now can do calculations that start to capture the most relevant physics, and we can show which ideas work and which don't," said Abel. "In the next decade, using calculations like this one, we will settle some of the most important issues related to the role of black holes in the universe."

To make their discovery, the researchers created the most detailed simulations to date of the first black holes in the universe that formed from the collapse of stars. The simulations started with data taken from observations of the cosmic background radiation—the earliest view of the structure of the universe. The researchers then applied the basic laws that govern the interaction of matter, allowing the early universe in their simulation to evolve as it did in reality.

In the simulation, clouds of gas left over from the Big Bang slowly coalesced under the force of gravity, and eventually formed the first stars. These massive, hot stars burned bright for a short time, emitting so much energy in the form of starlight that they pushed nearby gas clouds far away. Yet these stars could not sustain such a fiery existence for long, and they soon exhausted their internal fuel. This caused one of the stars in the simulation to collapse under its own weight, forming a black hole located in a pocket of emptiness. With very little matter in the near vicinity, this black hole was essentially "starved" of food on which to grow.

"Quasars [extremely strong sources of radiation] powered by black holes a billion times more massive than our sun have been observed in the early universe, and we have to explain how these behemoths could have grown so big so fast," said Alvarez. "Their origin remains among the most fundamental unanswered questions in astrophysics."

One explanation for the existence of supermassive black holes in the early universe postulates that the first black holes were 'seeds' that grew into much larger black holes by gravitationally attracting and then swallowing matter. But in their simulation, Alvarez, Abel and Wise found that such growth was negligible, with the black hole in the simulation growing by less than one percent of its original mass over the course of a hundred million years.

Although the simulations do not yet completely rule out the theory, this makes it less likely that these first black holes could have grown directly into the supermassive black holes observed to have existed less than a billion years later, Alvarez said.

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"Naked Singularities" Could Negate All Laws of Physics

Fast-spinning black holes might reveal all - physics-math - 08 August 2009 - New Scientist

IT IS the ultimate cosmic villain: space and time come to an abrupt end in its presence and the laws of physics break down. Now it seems a "naked" black hole may yet emerge in our universe, after spinning away its event horizon.

In 1969, physicist Roger Penrose postulated that every singularity, or black hole, must be shrouded by an event horizon from which nothing, including light, can escape. His Cosmic Censorship Conjecture has it that singularities are always hidden.

If the conjecture doesn't hold, it would be bad news for cosmologists. If even one location in the universe cannot be described by the laws of physics, the future of the universe - as predicted by those laws - is cast into doubt. Our description of photons, for instance, may be undermined because those photons may have interacted with a naked singularity while zipping across the universe.

In theory, adding matter to a black hole could make it spin fast enough to shed its event horizon, but previously, physicists have calculated that the spin of black holes has an inherent speed limit that prevents such shedding. This limit is partly determined by the swirling tornado of space-time that surrounds a spinning black hole. Past simulations showed that if material was added that made space-time swirl faster, adding yet more material would be increasingly difficult because the increased centrifugal force might fling it outwards before it could reach the black hole's event horizon, spin it up and disrupt it.
Infalling matter can disrupt a black hole's event horizon, exposing a 'naked' singularity

However, these simulations began by adding matter to a black hole spinning at its maximum possible rate, say Ted Jacobson and Thomas Sotiriou at the University of Maryland at College Park. They simulated adding matter orbiting in the same direction to a black hole spinning just below its maximum rate. Their work suggests that the event horizon could then be disrupted and shed (www.arxiv.org/abs/0907.4146).

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Spitzer Space Telescope Discovers Galaxy, "Wild Creature of the Dark"

NASA - Coiled Creature of the Night

NASA's Spitzer Space Telescope has imaged a wild creature of the dark -- a coiled galaxy with an eye-like object at its center.

The galaxy, called NGC 1097, is located 50 million light-years away. It is spiral-shaped like our Milky Way, with long, spindly arms of stars. The "eye" at the center of the galaxy is actually a monstrous black hole surrounded by a ring of stars. In this color-coded infrared view from Spitzer, the area around the invisible black hole is blue and the ring of stars, white.

The black hole is huge, about 100 million times the mass of our sun, and is feeding off gas and dust along with the occasional unlucky star. Our Milky Way's central black hole is tame in comparison, with a mass of a few million suns.

The ring around the black hole is bursting with new star formation. An inflow of material toward the central bar of the galaxy is causing the ring to light up with new stars.

The galaxy's red spiral arms and the swirling spokes seen between the arms show dust heated by newborn stars. Older populations of stars scattered through the galaxy are blue. The fuzzy blue dot to the left, which appears to fit snuggly between the arms, is a companion galaxy. Astronomers say it is unclear whether this companion poked a hole in the larger galaxy, or just happens to be aligned in a gap in the arms.

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