Crystals From Space

Happy New Year! In October, The Whole Pie, this blog recounted the Nobel Prize-winning discovery by Dr. Daniel Schechtman of quasicrystals. Unlike most crystalline structures, quasicrystals form mathematical patterns that do not repeat. Dr. Schechtman discovered quasicrystals in 1982, waiting 29 years for his prize.

At first noone believed him. Someone handed Schechtman a crystallography book and suggested he reread it. He was asked to leave his research group. It was 2 years before he could get a paper published. Nobel winner Linus Pauling condemned Schechtman's work. He had great difficulty getting other researchers to confirm his results.

The first evidence of extraterrestrial life came from a Martian meteorite. Naturally formed quasicrystals were discovered during 2009 in the Koryak mountains of Russia. No one could explain how they formed. The January 2 Proceedings of the National Academy of Sciences contains a paper claiming that these quasicrystals arrived on Earth via another meteorite. The paper proposes that naturally occurring quasicrystals formed in deep Space. Evidence for the extraterrestrial origin of a natural quasicrystal

“Our evidence indicates that quasicrystals can form naturally under astrophysical conditions and remain stable over cosmic timescales.”

According to the paper, these quasicrystals formed about 4.5 billion years ago. At one time scientist doubted that quasicrystals existed at all. Daniel Schechtman faced great opposition to his findings. Discovery in Russia of natural quasicrystals was baffling. They may have originated in Space near the dawn of our solar system.

Asteroid Life

Speaking of asteroids and life, this article just appeared in COSMOS magazine:

Meteorite Shows How Precursors of Life Evolved

"Organic matter found in a meteorite shows how the chemical precursors of life developed in deep space, with some asteroids acting like 'molecular factories' transforming life's ingredients before shipping them to Earth."

The article refers to the Tagish Lake meteorite, which was found in British Columbia in 2000. Examination of the meteorite has found organic molecules, the precursors of life. Many scientists have suggested that life may have began somewhere in Space, its precursors landing on Earth via meteorite or comet impacts. We may all be descended from extraterrestrial life.

More Life From Meteorites

Disclaimer: This scientist had the pleasure of working with researchers who found signs of fossilised life in an Antarctic Martian meteorite. Since 1996 many others have claimed alternate explanations for the fossils. The most recent research from the Mars meteorite team focused on magnetites. These were found in patterns that could not be produced except via biology. Though many have claimed in the press that the 1996 findings were disproven, the evidence for life in meteorites continues to grow.

Richard B. Hoover of NASA's Marshall Space Flight Center has spent the last 10 years travelling to remote spots like Antarctica in search of CI1 carbonaceous chondrite meteorites. These rare meteorites are thought to originate in asteroids and comets. In a paper published Friday in the Journal of Cosmology, he claims evidence that life is common in the solar system.

Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites

The Scanning electron Microscope image is from the Ivuna meteorite, found in Tanzania. This filament is encased in a carbonaceous sheath. It is very simlar to Earthly bacteria, both in shape and chemical makeup. It is hard to imagine how it could have formed, except through biology.

Using examples from multiple CI1 meteorites, Hoover advances the argument that life is common: in asteroids, moons and comets. Life's appearance on Earth could have been the result of meteorites/comets. We could all be descendants of Space travellers. Hoover's paper adds to evidence of life from multiple Martian meteorites. The evidence for extraterrestrial life continues to grow. As we dreamed via science fiction stories, life could be everywhere.

Arsenic and Old Life

From my presentation in Buenos Aires: Meteorite ALH84001, in which signs of fossil life were discovered in 1996.

Last Thursday astrobiology researchers working at Mono Lake in California announced discovery of microorganisms that can thrive on arsenic. This discovery could widen the definition of organic chemistry. Other scientists have already questioned these results. The science of astrobiology has long met with skepticism.

In 1996 NASA scientists found signs of fossil life on this meteorite, picked up from Antarctica in 1984. The rock forming ALH84001 is over 3.5 billion years old. Martian life could be very old, possibly predating life on Earth. Fossils from another world may be one of the great scientific finds of our time.

McKay et al proposed that a combination of features in ALH84001 could best be explained by a biogenic hypothesis:

1) Carbonates formed at relatively low temperatures involving water

2) Possible microfossils (biomorphs) simlar to Earthly bacterial forms

3) Polyaromatic hydrocarbons (PAH) associated with carbonates

4) Nanophase magnetite (Fe304) similar to that produced by bacteria

From time to time others try to attack these discoveries. Recently a paper claimed that the carbonates could have formed by other means, implying that all the findings are invalid. The most convincing evidence, and subject of the most recent work, is nanophase magnetite. As seen in a microscope, magnetites in ALH84001 form crystalline patterns that could not be formed by simple heating. Such patterns are formed by magnetitic bacteria on Earth.

Science thrives on skepticism, and great discoveries are almost always questioned. Several lines of data still point to life on a Martian meteorite. The question may not be completely settled until we have new samples from Mars. Humans may have discovered what they have long wondered about, life from another world.

Life From Mars

Humans have long asked about life on Mars. In 1976 the Viking Lander brought experiments designed to find chemical reactions indicative of life. To scientists' surprise, those reactions were found in abundance. Researchers explained the positive results as chemical reactions, even inventing reactions that had never been observed on Earth. After Viking, Mars was officially called lifeless.

25 years ago this month geologist Robbie Score spent her Christmas holiday Wintering in Antarctica. On December 27, 1984 she was hunting for rocks on the Far Western Icefield near the Allan Hills. She spotted an odd grapefruit-sized rock on the ice. Score immediately identified it as a meteorite, and its greenish colour made it distinct from other meteorites found nearby. Bobbie Score named the rock ALH84001, an Allan Hills meteorite found in 1984. For nine years the odd green rock sat on a shelf unnoticed, but Robbie Score may have stumbled upon one of history's great finds.

An early classification identified ALH84001 as coming from an asteroid. In 1993 geologist Duck Mittlefehldt, a friend of Robbie Score, reexamined the little meteorite and concluded that it had arrived from Mars. Later analysis showed that the rock had first crystallized 4.5 billion years ago, near the dawn of our solar system. 16 million years ago it was launched from Mars by a meteorite impact. After wandering the solar system for millions of years, the green rock landed in Antarctica 13,000 years ago.

The biggest surprise was yet to come. In 1996 colleagues David McKay, Everett Gibson and Kathie Thomas-Keprta discovered signs of bacterial life on ALH84001. They foundd several major bits of evidence, including magnetites and fossil-like forms. Magnetites are used by living organisms to sense direction. After an initial blast of publicity, other researchers found alternate explanations. The debate over life on Mars raged on.

The team's latest paper, Origins of magnetite nanocrystals in Martian meteorite ALH84001, does a good job of demolishing competing theories. Afer painstaking work, the team shows that alternate explanations of the magnetites are contradictory. This paper will convince many on the fence that life has been discovered from Mars. NASA press release.

The Martian bacteria were thriving at a time when astrophysics says that the Sun was only 75% as bright, and both Earth and Mars were frozen solid. Reality has not cooperated with theory, for evidence says that both planets had temperatures suitable for life. This is the "Faint Young Sun Paradox." Fortunately the Sun turns fuel to energy according to E=mc^2. If the speed of light were changing according to GM=tc^3, solar luminosity would be changed exactly enough to make temperatures comfortable for life.

When evidence is found that c is changing, others are quick to come up with alternate explanations. This is how "dark energy" got started. As with life on Mars, an abundance of evidence will show a changing speed of light.

Night at the Museum Pt. 2

Sometimes reality exceeds our dreams, and the Museum of Natural History is far larger than any movie set. In the opposite corner from Rose Center for Earth and Space is the Hall of Meteorites. This room has not been placed closer because it can't be moved. The Cape York meteorite fragment here weighs 34 tons! This rock from Space is so heavy that it is mounted on supports descending into bedrock.

Touching a big meteorite is a priceless experience. They are dense because they are made of nickel and iron forged by heat into metal. Sliced sections show the silver-grey texture of steel. Banging on a meteorite with the naked fist produces a ringing sound. Sometime in their past these rocks were exposed to intense heat, forged into a metal that survived the lesser heating of impact. For many centuries, meteorites were humanity's only supply of metals. The Cape York meteorite was mined by local Inuit for steel.

In this room are travellers from the asteroids, Mars and Beyond. the Zagami meteorite (lower photo, top) comes to us from Mars. The Camel Donga meteorite displayed below came from asteroid Vesta. How a tiny body like Vesta could have been so hot was a complete mystery. The lack of olivine in meteorites is another mystery.

The Brenham meteorite was found in a Kansas field. Farmers there in the 1880's often bumped into mysterious metallic rocks. A homesteader named Eliza Kimberly recalled a meteorite she had been shown as a schoolgirl. For five years she collected samples and wrote letters to scientists, despite teasing by her husband and neighbours. (Her work wasn't accepted by the arxiv, either.) Finally a scientist was convinced to examine her meteorites and the woman was proved right. The meteorites she found were billions of years old, dating from a time near Earth's formation.

Elsewhere in the hall is a model of Arizona's Barringer Crater. For many years this hole in the Earth was thought to be a product of volcanoes. A Princeton graduate and lawyer named Daniel Barringer became bored with the office and headed West to be a mining engineer. He tried to take geology at Harvard, but dropped the class when an instructor called his questions "childish." Gaining success in his chosen field, Barringer became obsessively interested in the crater. He spent years and most of his fortune making excavations and trying to convince the science community. Within Barringer's lifetime the world realised he was right too.

There are lessons in this room for all scientists. There have been many times (like today) when the textbooks' explanation for the Universe is lacking. Good ideas can come from outside the mainstream of science, even from a Kansas farm. These ideas may be ignored at first, even ridiculed. Determination and years of work can lead to the truth, even within a lifetime.

The books claim that Earth's nickel-iron core remains hot due to "radioactive decay." We can't get samples of the core, but meteorites like Eliza Kimberly's date from the time of Earth's formation. From their composition and what is known about Earth's density, scientists have concluded that Earth's core is also made of nickel-iron. These meteorites may be considered as samples similiar to the core.

The hypothesis of "radioactive decay" may also be tested here. Earth's core has temperatures exceeding thousands of degrees, hot enough to melt rock. The book claims that isotopes within Earth's core cause it to be hot. Since the Hall of Meteorites contains similiar samples, are any of them about to melt? If they contained even a tiny amount of radioactive isotopes, it would not be safe to go near this room. If they contained any isotopes, those would have decayed to nothing long ago. Today these rocks are cold as the New York Winter, yet Earth's core continues to produce heat.

If Earth's core formed around a singularity, that tiny object would generate heat indefinitely. Today it would have the mass of a small moon and the diameter of a grain of sand, far too tiny to suck us up. The tiny amount of Earth that it eats is far less than the mass that arrives each year via these meteorites. Presence of a singularity would also explain Earth's magnetic field and how Earth formed from dust grains in the first place. Like Eliza Kimberly and Daniel Barringer, a scientist should not be afraid of bold steps.

This week Robot Guy hosts the new Carnival of Space!