|SCIENCE & TECHNOLOGY|
Mining the moon
Mining the moon
ON January 25 this year, ITAR-TASS news agency quoted Nikolai Sevastyanov, head of the Energia space corporation, as saying that Russia is planning to mine helium-3, present in trace amounts in lunar soil.
They intend to set up a permanent base there by 2015; by 2020, they hope to deliver the gas at industrial-scale, thereby beating the US by three years.
Around January 3, this year, Harrison H. Schmitt, the only trained geologist to fly on lunar landing missions has published a book titled “Return to the moon”. It is virtually a blueprint to harvest and use helium-3 from the Moon.
Schmitt, currently a professor at the University of Wisconsin-Madison Fusion Technology Institute knows the value of helium-3, as a source of energy. Schmitt’s book and Russian’s helium-3 mining programme highlighted the efforts to gather the moolah from the moon. A ton of helium-3 costs about $ 3 billion!
Where does the helium-3 in the moon come from? Hydrogen nuclei fuse together in the sun to form helium nuclei. Normal helium nuclei have two neutrons and two protons. But about one in every ten thousand helium atoms comes out with one neutron less, forming helium-3.
The helium-3 atoms become a part of the solar wind, the outward flow of fast-moving charged particles from the sun. It has been hitting the surface of the moon for over the past 4.5 billion years. The helium-3 atoms get embedded in lunar rock and soils. Since meteorites tilled the surface, these atoms get distributed in the first few metres of lunar soil. Every sample collected during the Apollo missions contained helium-3.
Fusion of Helium-3 with deuterium, an isotope of hydrogen, produces a proton and an alpha particle and releases vast amounts of energy. One kg of helium-3 fused with 0.67 kg of deuterium, generates about 19 mega-watt years of energy.
According to Prof Gerald Kulcinski, University of Wisconsin, a specialist in fusion reactors, helium-3 fusion with deuterium produces little residual radioactivity, whereas deuterium-tritium fusion releases 80 per cent of their energy in the form of neutrons. Helium-3 is thus a perfect, nonpolluting fuel. According to one estimate, 40 metric tons of helium-3 has the energy equivalence of all the power pumped in- to the US grid in 2005.
In 1988, Kulcinski estimated that solar wind deposited 1.1 million tons of helium-3 on the moon. The amount of helium-3 available on earth is about 300 kg arising as a byproduct of the maintenance of nuclear weapons. It could continue to produce about 15 kg annually. The road to the moon is not very crowded. Currently, USA, Russia, China, Europe, Japan and India intend to explore the lunar landscape.
India has scheduled for launching its first mission to the moon (Chandrayaan-1) by 2007-2008. Its objectives include mapping topographic features in 3D with high resolution and obtaining the distribution of various minerals and chemical species covering the lunar surface using remote sensing payloads. India’s mission will be a lunar polar orbiter at an altitude of about 100 km, with an operational life of about two years.
Scientists must resolve many difficult technical issues to derive benefit from helium-3 technology. They have to heat a million tons of lunar soil to 800 degree Celsius to extract a mixture of many gases, including helium-3. After sorting out, this mixture offers about 70 tons of helium-3. The gas is expensive to transport.
The reactors to convert helium-3 to energy could take years to develop. Deuterium and helium-3 fuse only at higher temperature. But specialists do not think that these difficulties are insurmountable.
Astronomers using the Hubble Space Telescope have revealed something just as constant as the North Star: a hidden companion. Polaris, as the bright star and navigational aid is formally called, now has two known stellar companions.
The first, Polaris B, has been known since 1780 and can easily be seen with even a smaller telescope; the second, Polaris Ab, had long eluded direct detection given its proximity to Polaris and its relative faintness.
The North Star is a super-giant more than two thousand times brighter than our sun, while its newly photographed second companion is a dwarf star just 2 billion miles (3.22 bn km) from it, astronomers said. They presented the results at the 207th meeting of the American Astronomical Society.
Ceramics for bones
Beneath the shimmer of an oyster’s mother-of-pearl, an intricate microstructure bestows both strength and toughness on the natural ceramic. Now, scientists have come up with a way to replicate that structure in humanmade substances.
The process exploits one of the most common transformations in nature-the freezing of water-so it’s remarkably simple and potentially inexpensive and environmentally friendly, its developers say.
These researchers, at the Lawrence Berkeley (Calif.) National Laboratory, have used their new approach to create an exceptionally rugged substance that may serve as a scaffold for new bone growth. The method also works well with nonbiological materials, report Sylvain Deville and his colleagues in the Jan. 27 Science. Using it, the team has fabricated novel metal-ceramic composites that benefit from a seashell-like internal architecture. Mollusks such as abalone and oysters create their iridescent armor, known as nacre, from brittle calcium carbonate microcrystals and pliant proteins arranged like bricks and mortar, respectively.
Why do all planets rotate around an axis? What is the force that makes them rotate at a constant speed?
When such a question comes to our mind there seems to be a feeling that a sweet well-behaved planet is sitting there unmoving and quiet when something happens that makes it rotate and then continues to push it around at a constant speed. Such a feeling is misplaced. Rotation and revolution are movements that are integral to the manner in which the planet is created.
The creation process is dynamic. For example it may happen that when a cloud of material is going around a central star the particles, large and small, in that cloud star accreting due to mutual force of gravity to ultimately make a conglomerate that begins to look like a planet. This conglomerate would then have the motions that are resultants of the momentum and angular momentum of the initial particles and stones.
The probability that the angular momentum will be exactly zero is also zero. Therefore the planet will emerge with some positive angular momentum. In other words it is most likely that it will be rotating.
There is a bias introduced by the initial processes and early history of formation of the solar system. It is believed that primarily the whole of the solar system was a single complex happening. A slowly rotating large cloud of gas and dust started to collapse. In order to conserve the angular momentum the speed of rotation increased. The equatorial part of the cloud resisted the inward fall of the material while towards the poles there was no effect of the centrifugal force.
The shape of the cloud tended to look like a disc with a bulge at the centre. The central part became our sun when the heat generated through inward falling of matter created temperatures where thermonuclear reactions could start. The material at the fringes of the cloud basically inherited the rotation direction of the initial cloud, though it was spread into disc.
The coagulations of the material into clusters lead to the birth of planets. So rotation and revolution was their inheritance.
There is no force within them that caused or causes their motion. The motions of the planets can be changed if they happen to collide with other large masses, as might have happened more frequently in the early history of the solar system.
The important thing to remember is that a moving mass would continue to move in its path unless there was an external force on it. Luckily that happens fairly infrequently if we measure time in human life spans.