Cars - although they've been with for just about a century, they have radically transformed the lifestyle of pace of the whole planet. People can now travel greater distances and experience a higher level of indipendence. But what if suddenly, cars were to be no longer? This question has arised following first the continuous depletion of our fuel resources, and now, it is greatly emphasised by global warming and emission control. Over the past decade there have been substancial developments in alternative power technologies for mobile vehicles. In this article we will go through the different forms of technologies, their pros and cons, and how does the future look for all of them.

Hybrid Technology
Hybrid vehicles have been around for quite a few years. Most of them function by having a standard fuel engine (diesel or petrol), and then a battery pack paired with electric motors on each wheel. Energy is created by the main fuel engine, however part of it is harvested in the battery packs and energy from braking, going down hills is also stored there. These vehicles however, are just a transitory technology, in what main energy will in the future be derived probably from Hydrogen or Bio-Fuels. Hybrid vehicles are becoming more popular. The only drawback is the increase in premium that a buyer must pay for the vehicle, although price difference is decreasing as the technology evolves.

Fully Electric Cars
Fully electric cars have been around also for a few years, but have had a very poor penetration typically because of the excess weight taken by the batteries since they have to deliver all the power for the car, their low speed (not more than 80kmph in most cases) and poor milage (about 100-150km) covered per charge. Additionally, charging times vary from 8 to 12 hours, which can be an inconvenient. Finally, charging could only happen at home, and thus the car's niche market was limited to urban usage. However, things are changing fast. Lately, sports cars are being constructed as fully electric cars. With new battery technologies, which deliver lighter and more power batteries, new cars are being constructed which can acheive speeds in excess of 200kmph, have a distance autonomy of over 300km (and this will increase at a steady 35-50% rate each year), and best of all, can achieve a 95% charge from flat in 8 minutes! Charging points for the cars are being installed in several fuel stations and parking areas. This is definitely a technology that will be extremely popular in the following decade.

Solar Powered Cars
Solar Power - more specifically photovoltaic technology - has been around for the past 40 years or so. Concept cars powered by solar energy have been around for over a decade, however none has made it to the production line, mainly for one simple reason - solar energy harvesting technology is not powerful enough to drive a car. Even though prospectives for the technology are bright, and in a couple of decades can reach a level where solar energy on its own will be enough to power a vehicle decently, the future of this technology lies mainly in the integration of the photovoltaic cells with fully electric cars or hybrid cars, which will help in charging the battery when the car is in direct sunlight, and thus reduce on the base charging time/bill.

Hydrogen Powered Cars
Hydrogen is definitely the power of the future. Featuring zero carbon emissions (combustion produces just water vapour), and can be utilized via fuel-cell technology, which has no moving parts and is extremely more energy efficient than internal combusion engines. Hydrogen can be produced by electrolysis of water, and is therefore potentially widely and unlimitedly available. The only drawback of hydrogen is that is a very low density gas, and cannot be converted to a liquid at room temperature. However, new technologies for "packing" larger amounts of hydrogen in tighter space at reduced pressures are being developed, using complex carbon arrays, that have increased the density by a six-fold over previous technologies. Hydrogen will find its place on the market in hydrogen-electric hybrid cars. Some manufacturers are already planning to produce in series hyrdogen-electric hybrid vehicles.

Bio Fuels
Bio Fuels such as Bio-Ethanol and Bio-Diesel are chemical compounds similar to the crude-oil derived counterparts, but derived from crops and fruits grown commercially. These are being considered as the transition fuel on the way to Hydrogen, as they are easier to produce, and most car engines operate on them. The future of bio fuels lies mainly in aviation and marine industry, as, especially in the case of aviation, no alternative technology known till now can store enough energy in a low mass as to move air planes over large distances carrying heavy loads.

Methane
Methane is a gas derived from a variety of natural and industrial processes. It is cheap to manufacture and distribute. The only problem it has for integration into cars is that it requires very heavy containers so as to carry it around, not as much as hydrogen though. It can also power a fuel cell. Methane will probably assist in the transition of vehicles from liquid fuels to hydrogen. It is also the gas of choice that will power a number of mobile devices in the future.

As it is apparent, the auto industry is moving towards greener energies, and at the same time not compromising performance as we know it today. Obviously, cars will tend to get lighter, and SUV's have a very grim future ahead. Nonetheless, technology is progressing at an amazing pace, and it can safely be stated that the transition from liquid carbon based fuels, to clean, non-carbon based technologies in the automotive industry has started.

One of the most enduring questions is how life could have begun on Earth. Molecules that can make copies of themselves are thought to be crucial to understanding this process as they provide the basis for heritability, a critic More..al characteristic of living systems. Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.

The work was published on Thursday, January 8, 2009, in Science Express, the advanced, online edition of the journal Science.

In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.

For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself. Some tentative steps along this road had previously been taken by the Joyce lab and others, but no one could demonstrate that RNA replication could be self-propagating, that is, result in new copies of RNA that also could copy themselves.
In Vitro Evolution

A few years after Tracey Lincoln arrived at Scripps Research from Jamaica to pursue her Ph.D., she began exploring the RNA-only replication concept along with her advisor, Professor Gerald Joyce, who is also dean of the faculty at Scripps Research. Their work began with a method of forced adaptation known as in vitro evolution. The goal was to take one of the RNA enzymes already developed in the lab that could perform the basic chemistry of replication, and improve it to the point that it could drive efficient, perpetual self-replication.

Lincoln synthesized in the laboratory a large population of variants of the RNA enzyme that would be challenged to do the job, and carried out a test-tube evolution procedure to obtain those variants that were most adept at joining together pieces of RNA.

Ultimately, this process enabled the team to isolate an evolved version of the original enzyme that is a very efficient replicator, something that many research groups, including Joyce's, had struggled for years to obtain. The improved enzyme fulfilled the primary goal of being able to undergo perpetual replication. "It kind of blew me away," says Lincoln.
Immortalizing Molecular Information

The replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other - what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits.

"This is the only case outside biology where molecular information has been immortalized," says Joyce.

Not content to stop there, the researchers generated a variety of enzyme pairs with similar capabilities. They mixed 12 different cross-replicating pairs, together with all of their constituent subunits, and allowed them to compete in a molecular test of survival of the fittest. Most of the time the replicating enzymes would breed true, but on occasion an enzyme would make a mistake by binding one of the subunits from one of the other replicating enzymes. When such "mutations" occurred, the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture. "To me that's actually the biggest result," says Joyce.

The research shows that the system can sustain molecular information, a form of heritability, and give rise to variations of itself in a way akin to Darwinian evolution. So, says Lincoln, "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Knocking on the Door of Life

The group is pursuing potential applications of their discovery in the field of molecular diagnostics, but that work is tied to a research paper currently in review, so the researchers can't yet discuss it.

But the main value of the work, according to Joyce, is at the basic research level. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts." He is quick to point out that, while the self-replicating RNA enzyme systems share certain characteristics of life, they are not themselves a form of life.

The historical origin of life can never be recreated precisely, so without a reliable time machine, one must instead address the related question of whether life could ever be created in a laboratory. This could, of course, shed light on what the beginning of life might have looked like, at least in outline. "We're not trying to play back the tape," says Lincoln of their work, "but it might tell us how you go about starting the process of understanding the emergence of life in the lab."

Joyce says that only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life. "We're knocking on that door," he says, "But of course we haven't achieved that."

The subunits in the enzymes the team constructed each contain many nucleotides, so they are relatively complex and not something that would have been found floating in the primordial ooze. But, while the building blocks likely would have been simpler, the work does finally show that a simpler form of RNA-based life is at least possible, which should drive further research to explore the RNA World theory of life's origins.

The paper is titled "Self-sustained Replication of an RNA Enzyme," and the work was supported by NASA and the National Institutes of Health, and the Skaggs Institute for Chemical Biology.