ARTIFICIAL INTELLIGENCE- DOES IT REALLY HELP HUMANS OR DOES IT HARM THEM?

 

Many of the industry leaders behind the rapid AI advancements are concerned that AI poses an existential threat to humanity. AI tech has grown at such a rate that there has been no time for the law to catch up; there is no oversight over AI development, meaning it’s difficult to ensure it is being used ethically. Experts have expressed their perception of AI as a future extinction risk for the human race, and the jury is out on exactly why. Reasons cited by AI developers include making human careers and even the human mind obsolete, and the destabilization of society due to the rapid, malicious spread of misinformation. This aspect can now been seen on the social media where all types of nonsense is spread as gospel truth. Ultimately Social media had brought things to a stage where the dissemination between reality and fiction becomes blurred.

A significant number of companies and stakeholders, especially those in the Information and Technology sectors, have been eager to adopt AI into their companies with a hope to reduce overheads and get more work done faster and therefore make more profits. Though the majority of businesses don’t use AI at the current moment, the AI trend seems to have begun.

A 2023 study by McKinsey estimated that half of today’s work activities could become automated by 2060, signalling the potential for drastic changes to the workforce in the coming decades. The adoption of AI has already been associated with job cuts. AI advancements have left professionals across a wide range of industries concerned about the future of their roles, but some sectors are more vulnerable than others. 

In March 2023, Elon Musk, along with Apple co-founder Steve Wozniak, signed an open letter by the non-profit organization the Future of Life Institute urging AI developers to stop training AI models more powerful than GPT-4 for at least 6 months, citing “profound risks to society and humanity”. Such risks included flooding our information channels “with propaganda and untruth”, and the automation of fulfilling jobs that give humans purpose. Their argument is that the uncontrolled race to develop increasingly powerful AI systems is dangerous due to the lack of safety protocols and AI governance systems. With no collective oversight, the power to decide the future of AI is in the hands of independent companies.

A survey of 2700 AI researchers predicted a 50% chance of AI surpassing humans at every task by 2047. And more immediate worries cited by the majority of surveyed researchers include using AI to manipulate public opinion and control populations through large-scale disinformation perpetuated by advanced deep fake technology.

In May 2023, more than 350 executives, researchers, and engineers working in AI - including the CEOs of Google DeepMind, OpenAI, and Anthropic - signed another open letter stating that AI poses an extinction risk for humans, and mitigating the risks posed by AI should be a “global priority alongside other societal-scale risks, such as pandemics and nuclear war”. 

As per a 2023 report by the Pew research centre analysis, many of the jobs with the highest exposure to AI tend to involve getting and analysing data or information. The industry with the most jobs exposed to AI is professional, scientific, and technical services, with 52% of workers facing high exposure. So the STEM group(Science, Technology, Engineering and Mathematics)  would be hit the most by AI. Customer-facing roles that involve repetitive tasks like cashiers, service agents, and salespeople are exposed as well.

According to Business Insider, ChatGPT specifically is likely to lead to significant disruptions in the job market due to its ability to generate and analyse content at a rapid pace. Jobs that require content creation, coding, or data analysis are vulnerable to AI.

Based on the above insights, roles that are most exposed to AI include:

• Tech jobs, including data analysts and software engineers
• Sales and customer service representatives
• Media jobs like advertising, content creation, and journalism
• Finance jobs like advisors and analysts
• Lawyers
• Office support staff such as receptionists and office clerks
• Accountants
• Budget analysts
• Technical writers
• Web developers

A November 2023 survey by the U.S. Census Bureau found that only 3.8% of businesses surveyed reported using AI in the production of goods and services, but some industries were outliers. 13.8% of businesses in the IT sector reported that they were currently using AI, and businesses in the Professional, Scientific, and Technical Services sector weren’t far behind, with 9.1% of businesses in that category reporting AI usage.

IBM CEO Arvind Krishna told Bloomberg in an interview about his Company in 2023: "I could easily see 30% of jobs getting replaced by AI and automation over a five year period". It may pickup new recruits, say only about 10% for AI, which means 20% of the jobs would go poof. 

There are some people who say that AI would not replace people in jobs but that is mere hogwash. Most of the people who are researching AI themselves say it would. Of course, there was the Industrial revolution in Europe when workers from Agriculture migrated to the factories and cities where jobs were created. Yes, AI too would create jobs alright, but only in a much smaller number than it eats up. Those jobs would be for developing AI, and its security while it knocks off a large number of jobs in various sectors. And there is a huge difference between the Industrial revolution and the AI revolution. The Industrial revolution did not eliminate people from jobs, but actually created more jobs. But this AI revolution would not do so and can prove catastrophic to many.

METERORITE EVENTS IN RECORDED HISTORY.

 The TUNGUSKA explosion occurred near the Tunguska River in Russia northwest of Lake Baikal on June 30 1908. Luckily, it was a sparsely populated area with only 3 reported deaths. However, it flattened 80 million trees over an area of 2150 Sq Mtrs.

This blast is attributed to a meteor air burst in the atmosphere of a stony meteoroid about 50-60 meters across. It approached Earth at a speed of 27 Km/Sec. No crater was found as the object was supposed to have deteriorated at an altitude of 5 to 10 Km instead of directly hitting the earth. This is the largest impact event in the Earth’s recorded history.

An explosion of this size could have destroyed a large metropolitan area.

In the more recent times on 15^th February 2013, a 20-meter asteroid entered the earth at a velocity of 19 Km/Sec near CHELYABINSK in Russia. It weighed 12000-13000 tons. The meteor exploded in the air at a height of 30 Km. The atmosphere absorbed the bulk of the explosion's shock, creating a large shockwave equal to a 400-500 kiloton TNT blast, some 30 times the power of 30 Hiroshima bombs.               

This object approached the earth undetected before its atmospheric entry because its source direction was close to the sun. About 1500 people were injured as the shockwave hit 6 cities and damaged 7200 buildings.

Among these, the Chelyabinsk explosion was the most recent and mankind is very lucky that both in this case as well as the Tunguska event the meteors exploded in the atmosphere. Otherwise, a 12000 ton body hitting any area with a velocity of 19 Km/ Sec can cause a devastating impact.

These 2 events in recorded history clearly prove that such events are likely to happen again. We have to be particularly worried about Chelyabinsk-like events because the Chelyabinsk meteor approached the earth undetected as it came from the direction of the Sun. This is despite the NASA’s observations on NEO.  

A NEO (Near Earth Objects) Observations program had been launched by NASA and the EU in 1998 and is tracking the NEO’s. A NEO is by definition all those natural bodies that approach up to a distance of 1.3 AU (Astronomical Unit the distance from Sun to Earth 151 million KM).

If a NEO crosses the earth’s orbit and if it is larger than 140 meters, then it is considered a PHO (Potentially Hazardous Object). Most of the PHOs known are asteroids but a few are Comets.  

There are over 30500 known NEO Asteroids, and over 100 NEO Comets. NASA is continuously tracking these bodies.

ASTROBIOLOGY PART VII-EXO PLANETS

 The lifespan of a star decreases rapidly the heavier it is than Sun as per the following formula.

Lifespan of the star=lifespan of the Sun* (star mass/solar mass) raised to the power of -2.5

L_St=L_S*(M_st/M_s)^-2.5

The lifespan of the sun is estimated to be 10 billion years. By this equation a star with double the suns mass would only live for 1.80 billion years. If it is 3 times then it would only live 641 million years. In the latter 2 cases, there is not enough time for intelligent life to develop.

Therefore we have to concentrate only on F, G, K & M spectral class type of stars whose masses are closer to the Sun. Our Sun is a G type star.  The G type stars have solar masses from 0.8 times  to 1.1 times. These stars live for 17 billion years at the lower end to 8 billion years at the upper end. F types are between 1.2 to 1.6 solar masses. K type stars range from 0.5 to 0.8 solar masses. M type stars have masses less than half of the Sun. The smaller they are than the Sun, the long lived they would be.

76% of the stars in the Universe are M types which have half the mass of the Sun. Consequently, they live for 56 billion years. K types account for 12%, G& F classes along with other brighter stars make another 12 %.

The M type stars have very low temperatures (which is why they live long), so low that most of their energy is radiated in the infrared than the visible spectrum. They are known as Red Dwarfs. Proxima Centauri the nearest star to us is a Red Dwarf.

Since the life of M type stars is very long they have every chance of sustaining intelligent life provided other conditions are fulfilled. Since 76% of all the stars are of this type there are high chances of finding intelligent life on them.

Even if we see Proxima Centauri through the most powerful telescope we have, still we would see only a point of light. The 2 essential points required for life as it is known to us; a source of energy and a stockpile of essential elements are present in many planets. However, the 3^rd, liquid water is more difficult to find because it is available only in a narrow range of temperature.

The earth is 150 million Km from the Sun and lies in the habitable zone of our solar system. The situation would be similar in other G type stars (like our Sun). Such a habitable planets distance from their sun shrinks in cooler K & M types of stars but increases in hotter F type stars.

However, in the cooler M & F type of stars there is another factor that has to be taken into consideration that affects life. These stars are red dwarfs which radiate a lot of their energy below the visible part of the spectrum, in the infrared. On the other hand in F type stars a lot of their energy is radiated in the visible spectrum and the ultraviolet. As ultraviolet rays are harmful to life F type stars are less likely to have life on their surrounding planets than cooler stars.

Our sun too produces ultraviolet rays which are harmful for life, but luckily we are insulated from them by our Earth’s atmosphere. The Earth’s magnetosphere also protects us from the effects of space weather. This is a fast moving wind of charged particles emitted by the Sun. Our magnetosphere deflects most of these charged particles. Space winds like these would be very bad for life on planets that do not have a magnetic field.

So, there are many ifs and buts’ for life to evolve on a planet. Now that brings us back to the concept mentioned earlier; bio signatures. The most promising approach is through the Exoplanets atmosphere in which chemicals that advertise life are known as biomarkers.

Now, Oxygen is a waste product of living things, such as bacteria and plants. Another waste product that is produced by bacteria is methane. Methane consists of only 1% of the atmosphere, but even that would not be there if it is not constantly replenished by biological processes. If not for life producing them continuously as waste products both Oxygen and Methane would combine with other elements and disappear. There are some other non biological processes that can produce Oxygen and Methane, but they are not very likely. Therefore the presence of these 2 gases on any planet is the best biomarker that we know of.

Now as we mentioned earlier, both M and F type stars are red dwarfs and consist of 88% of all the stars. They emit radiation in the form of infrared rays which the Hubble Space Telescope was unable to detect. There is a very recent development in this area where the James Webb Space Telescope was put into space on Christmas day 25^th December 2021.

With greatly improved infrared resolution and sensitivity it can view objects some 100 times as far as the Hubble Space Telescope. So we might expect some newer discoveries by this space telescope. This would be used by Sara Seager, a professor of Astronomy at the Masachusetts Institute of Technology and her associates along with data from TESS (Transiting Exoplanet Survey Satellite) launched in April 2018.

Very difficult to say whether the team would be successful because life as known to us consists of only an infinitesimal percentage of the mass of the Universe and hence is very difficult to trace with our current level of science.   

So far more than 4000 Exoplanets have been found, about two thirds of them being discovered by the Kepler Space telescope launched by NASA in 2009 to find earth like planets orbiting other stars and it is now retired.

Now 4000 is a lot to check for life and we have to narrow it down. The University of Puerto Rico has prepared an online “Habitable Planets Catalogue” which narrows it down to 50. One of the 50 belongs to a nearby star Tau Ceti (12 light years away). This is a “G” type star like the sun and one of its planets Tau Ceti “e” is in the inhabitable zone for life. This may well be the closest star with life.

Even though, the star is close, with our current day science known to us it is impossible to travel that distance and get some information from it. That is possible only if we travel at more than the speed of light. As of now there is no means of doing so, and going through a wormhole is a fabulous fiction because the conditions in the wormholes are stupendously destructive and nothing can survive passing through them leave alone living beings.

Some fundamental particles are supposed to travel over the speed of light, but that is neither here nor there and does not establish in any way that anything else can travel over the speed of light.

There are some close contenders to Tau Ceti for having habitable life and they are the much nearer Proxima Centauri(4 light years) and the Barnard’s star (6 light years). However, these 2 stars do not belong to the spectral class of the Sun which is G and are the much dimmer M type (Red Dwarf star). As these stars are cooler, the habitable planets have to be closer to their Sun.

The prospects that M type stars to have life means that a higher probability of finding intelligent life. These stars are more numerous and form about 75% of the stars of the Universe. Moreover they have very long lifespans providing more chances for intelligent life to develop.

Since M type stars are cooler, they emit more of their light in the infrared which makes it more difficult for photosynthesis to occur and therefore for sustenance of plant life.

 

ASTROBIOLOGY PART VI-PLANETARY NEIGHBOURS

 Looking at all the habitats of life on the earth, 3 factors emerge as the essential prerequisites for life as we know it.

1.       Supply of energy with which organisms can exist. In the Earths case this is the Sun. In a few cases for some organisms, it can also be the Geothermal energy originating from within the Earth itself.

2.       Stock of basic elements needed to build Amino acids and Nucleotides—Carbon, Hydrogen, Oxygen & Nitrogen. All these elements are common throughout the Solar system in the form of Carbon dioxide, Methane & Ammonia.

3.       It is the 3^rd one that sets apart Earth from the other planets and moons. It is the presence of liquid water. It provides a solvent for biochemical reactions to take place. It is possible that other liquids may also play this role but as of now we do not know.        

It is very difficult to find liquid water on the other planets of the Solar system. If we look at our neighbors Venus and Mars, they are rocky planets of a similar composition to earth with Venus 5% smaller than Earth and Mars about half its size.

Mars gets lesser solar heating than the earth being 50% far away to the Sun than the earth, while Venus gets more solar heating being 25% near to the Sun than the Earth.

The problem on Venus is it has an atmosphere of Carbon dioxide which produces the Greenhouse effect by trapping the Suns radiation without letting it dissipate into space. This heats up Venus to a temperature of 460 degrees Celsius which of course is too hot for water. In the past before the Greenhouse effect took hold Venus would have had rudimentary form of single celled life and it is probable that such life may even now survive in the upper atmosphere of Venus about 50 Km from its surface where the temperature & pressure are similar to the earth. The dense clouds there contain all the ingredients for life including tiny droplets of liquid water. So life on Venus is still a possibility, however in a most rudimentary form.

On Mars the scientists do expect to find life, if not today, perhaps later. Climatic conditions of Mars were more Earthlike when life appeared on our Earth, but since then have gone in the opposite direction. Mars now has a very thin atmosphere having lost most of it on account of its smaller size and weaker gravity. The thin atmosphere coupled with the higher distance from the Sun makes the Temperatures on Mars rarely exceed 0 Degrees Celsius. Low temperature and low atmospheric pressure means no chance of liquid water on its surface.

The Martian surface shows many signs of being shaped by water having valleys carved out by ancient rivers and dried up lake beds. But according to current estimates they were formed 3 billion years ago when water was abundant on Mars. If we remember that at that time Earth already had life for 1 billion years in the form of primitive Prokaryotes, so the situation would have then been similar on Mars.

A dramatic incident occurred in August 1996 that seemed to support this possibility. The then US President Bill Clinton has announced about microscopic bacteria found in a meteorite. It was the first rock to be studied in 1984 by the government funded scientists of the US and the rock is named ALH84001. This rock weighed slightly less than 2 Kgs. We know that it came from mars because of its distinctive composition. Radiometric dating revealed that the rock was sitting on Mars, it was fractured and permeated by flowing water somewhere between 4 and 3.6 billion years ago.

It was then claimed by the scientists who unravelled that the fractures were colonized by Martian bacteria. Photographs taken with an Electron microscope revealed structures that looked like fossils of tiny bacteria. The magnetite obtained from the rock also looked like bacterial magnetite that occurs on the Earth. The meteorite also contained amino acids. I am posting a pic of the electron microscope at the end of this article. However, based on this it is very difficult to conclude if they are fossilized remains of Martian bacteria.

So far there have been many missions to mars, however, there is no conclusive proof that life exists there.

Now, it is defined that water is a must for life to originate. The inner planets Mercury, Venus & Mars have very less of it. But then, so also on Earth, mass wise. Water comprises of only one fiftieth of 1% or just 0.02% of our planets mass.

As one goes past the orbit of Mars, the picture changes drastically. The outer solar system consists of enormous amounts of water, but in frozen condition because the temperatures there are well below freezing point of water.  

Jupiter’s largest moon Ganymede and Saturn’s largest moon Titan are almost 50% water, but all frozen. However, in both these moons and the other moons in the outer solar system there is huge gravitational attraction acting as all the outer planets are huge. On the side of the moon facing the planets the attraction is particularly high and this causes volcanic activity in them which forms a good source of heat.   

The first moon of Jupiter “Io” is the most volcanically active in the entire solar system on account of the huge gravitational force of Jupiter acting on it. The next moon of Jupiter Europa has frozen seas of water. However, it is postulated that liquid water would be present in its depths where life can exist.

NASA is launching a spacecraft “Clipper” to explore Europa in about 2024, to be followed by “JUICE” from European Space Agency to explore the next moon ‘Ganymede” which also has ice oceans.

NASA has tentative plans for Europa lander which would touch down on its surface and conduct experiments. However, there are reservations for this program. However much we may sanitize a craft, millions of microbes still cling to it. If we transport these Earth microbes to Europa one does not know what the repercussions would be. If it has a thriving ecosystem, then it may get destroyed by the invasions of earthly microbes.

Jupiters moon “Enceladus” is another candidate for having icy oceans on its surface. It is just 500 Km in diameter. Scientists found that it shoots out water in the form of Geysers, sometimes as far as 900 Km into space. That would enable a spacecraft to analyze its composition without actually landing on it.

The final promising candidate in the solar system is “Titan” the largest moon of Saturn which is the only moon in the Solar system which has a significant atmosphere. In fact its atmospheric pressure is 50% more than that of earth. The commonest element in it is Nitrogen with the rest consisting of Methane and other Hydrocarbons. These hydrocarbons form smoggy clouds and hide its surface forever to view.

The Cassini space mission of NASA revealed that Titan consists of mountains of frozen ice and the lakes and rivers are formed by methane.  It has methane rain falling from methane clouds. It is possible that a different sort of life has evolved in Titan using Methane as a solvent than water.               

In 2009, Sarah Horst of the University of Arizona ran the Miller experiment tailored to conditions on Titan. This she had done without any liquid water. Yet the experiment yielded not just amino acids but also the nucleotides. In all likelihood the life either on Titan, Europa, Ganymede or Enceladus would only be microscsopic.

ASTROBIOLOGY PART V-LIFE STARTED SMALL

 We are well aware that life on our planet originated with single celled organisms and later became more and more complex with mutations. It may sound unbelievable but everything started with that first single celled organism. All the species including us have evolved from it with a series of mutations over billions of years. People say we have evolved from monkeys, but they came up much later and have originated from that single celled organism 400 crore years ago after so much of evolution. 

Now if we look around we find hundreds of life forms all around us. But those we see are multicellular organisms and but a fraction of the living species. They represent the domain of “Eukaryotes” which mostly contain microscopic organisms which can be a single cell like the Amoeba. There are 2 other domains of life Bacteria and Archaea together referred to as the “Prokaryotes”

There is one thing that is common in all forms of life and that is DNA. It is an enormously complex carbon based molecule made up of billions of atoms. It is present in every cell and is capable of making copies of itself. Mostly the duplicates are perfect but sometimes mutations occur. These mutations lead to evolution of a completely new species.

By tracing the similarities and differences between the species, it is clear that they evolved from a single ancestor. I give below the family tree of the life on earth.

Life Eukaryotes on earth started about 2 billion years ago and the first 2 billion years belonged to the Prokaryotes and there were no Eukaryotes at all. It was another billion years before the Prokaryotes evolved into non microscopic forms. Even today the Prokaryotes outnumber Eukaryotes in all the environments.

The Prokaryotes interest us in astrobiology because some Prokaryotes are able to survive in environments which the Prokaryotes find very inhospitable. There is a word called “Extremophile” coined in the 1970’s for organisms that love extreme environments. So even if the environment in some planets looks extremely inhospitable for us, it does not look so for the Extremophiles. They live in extremes of acidity or Alkalinity, high or low temperatures, in the complete absence of light or in the presence of radiation.

The Extremophile “Deinococcus Radiodurans” can live happily inside a nuclear reactor. Other species are found in salt lakes, in rocks deep within the earth’s crust or around Hydrothermal vents on the ocean floor where the pressure of water is crushingly high and the water is superheated to hundreds of degrees of Celsius.

What is Biochemistry and when does biology meet chemistry and combine into the double science? For Chemistry the DNA is another cell but it is self-replicating and therefore satisfies the definition of life given by NASA (“A self-sustaining chemical system capable of Darwinian Evolution”). Essentially there is no non bridgeable difference between inorganic matter and living systems and that under suitable physical conditions the emergence of life is highly probable.

An Oxygen free early earth looks a better place for life to evolve in the initial stages because it requires Ultraviolet rays that would be blocked by Ozone if Oxygen had been present. In 1952 a Phd student Stanley Miller set up an experiment to duplicate the evolution of complex organic molecules on earth. His apparatus consisted of a flask of water connected to a flask of gases-methane, ammonia & hydrogen which were present in the primordial earth. The lightning flash for ionization was provided initially by an electrical flash but the reruns were done by Ultraviolet rays. That experiment gave him 20 Amino acids the chemical building blocks of life. The experiment however, did not yield the 4 nucleotides that make the building blocks for DNA.       

In 2017, the Miller Experiment was replicated but with powerful laser discharges to simulate the plasmas entering from asteroid impact shock waves on earth and the 4 nucleotides got synthesized. Unlike today 4 billion years ago, the solar system was still young and contained lots of debris that made asteroid hits very common on earth. These impacts played a role in getting the chemical reactions for life going.

A NASA funded team has created the “Hachimoji” DNA in the laboratory very recently  in 2019.  Hachi means eight and moji means letter. Our 4 DNA bases have the standard codes A,G,C & T (Adenine, Guanine, Cytosine and Thymine). The Hachimoji DNA in addition has another 4; B,P,S & Z. It is capable of storing and transmitting information like the ordinary DNA, but it does that in a different way.

On the earth the bacteria produced Oxygen that led to the formation of the atmosphere and a natural screen from ultraviolet rays. That made earth hospitable for advanced forms of life. However, this took billions of ears.

ASTROBIOLOGY PART IV-INTERSTELLAR ENGINEERING

 Now supposing there are other civilizations in the Galaxy, can we detect them by their Technosignatures? If they are of our technological level, we can start by imagining what unusual feature about our own planet might reveal our presence to a distant observer. One is the night glow seen from space. The side of the earth facing away from the Sun is illuminated by millions of lights. But this is very faint and our instruments would not be able to detect it from a distance in light years. So this is not something that is very tell tale with our current set of instruments.

Industrial pollution in the atmosphere is a giveaway and is a techno signature. In this CFC’s or Chlorofluorocarbons are not produced by any natural process and hence can be detected if they are present. Our own James Webb space Telescope put into orbit last year has the capacity to do that if they are present in any other planets.

Now, there may be civilizations that may be millions of years ahead of us and therefore have far more advanced instruments than us and they may allow them to get over this problem of finding as to which planet is housing intelligent life. But, then again, if the speed of light is insurmountable and is a barrier that cannot be breached, then however advanced the civilization maybe, they cannot pierce through the barrier and therefore space travel seeking intelligent beings may technically prove to be impossible. Our movies fancifully show aircraft cruising over the speed of light.

                               INTERSTELLAR SPACESHIP 

 If anything can travel at the speed of light or over it, then Einstein’s mathematical deductions which hitherto stand unquestioned would fall apart. As per Einstein’s deductions, the mass of an object travelling at the speed of its light becomes infinite. Similarly it would shrink infinitely in the direction of its travel. With these two parameters in mind it is an impossibility to travel at the speed of light.

Accelerating the spacecraft to the speed of light is one thing, but then you have to deal with infinite mass and infinite shrinkage which is much more difficult than achieving the speed. Apart from that, at the speed of light time too stands still without any movement. Unless Einstein’s mathematical deductions are proved wrong, there is no way any civilization; however advanced it may be would be able to travel at the speed of light. If that is the case then none of the civilizations of one star can visit another star despite being highly advanced.        

Despite that, they can certainly communicate with each other through radio waves. But then, space is too vast. For that both the civilizations: the transmitter and the receiver have to be at least as advanced as us. Now communicating through radio waves is possible only for the nearer planets say 15 light years from each other. Otherwise the communication takes too long to get received.

There are 2000 stars within a distance of up to 50 light years. We have so far discovered 34 exoplanets (planets outside our solar system) of which 11 are considered to be in the inhabitable zone. Again, of these only 3 planets seem good for life.

They are

1) Gilsec 832c orbiting the star Gilsec 832 with a mass of over 5 times that of earth and an average surface temperature of -22 degrees C, lying 16 light years away from us.

2) Gilsec 667Cc orbiting the star Gilsec 667 with about 4 times the earth’s mass with a temperature of 29 degrees C at a distance of 22 light years.  

3) GJ180b orbiting the star GJ180 with about 2 times the earths mass  with a temperature of 39 degrees C, and is 38 light years away from us.

If any civilization manages to accelerate their spacecraft up to the speed of light, they require an enormous amount of thrust to do so. However efficient their fuel systems are, still there would be some loss of energy and this is the thing that is detectable. The spacecraft would generate radiation ranging from radio waves all the way up to gamma rays which can be detected at long distances. The problem is, such radiation is also emitted from natural sources. So to decipher it as intelligence made we have to look for orderly bursts unlike natural radiation.

The writer Erich Van Daniken in his book “The Chariots of the Gods” postulates that aliens had been visiting us throughout earth’s history and are also helping us to shape the history. However, he quotes several examples to buttress his theory which do not seem plausible and do not offer any such proof as he claims. I remember reading his books in fascination when I was at college, but even then it did not strike me as plausible.

Well the idea that aliens may have visited us during the millions of years of the evolution of life may well be likely, but what visited us would have been robot probes rather than aliens themselves. Today we explore the solar system the same way. The advantage of robot probes is that they can travel endlessly for thousands of years while the living beings cannot do that. The probes may travel at less than the speed of light and yet can explore many star systems given the time. Of course their communication back to their home planets would take an immense amount of time so the viability of such probes is limited by the distance. We possibly cannot send a probe to the stars and wait for 100 years for them to communicate back.

A physicist Von Neumann suggested the idea of probes when they reach a certain planet can replicate themselves using the material available there. That would multiply their number continuously enabling them to explore more area of space. Such probes are known as Von Neumann probes. Of course that is only theory so far.

Based on this theory Robert Freitas and Engineer published a paper study of such a probes viability in 1980. The result is very complex and it required many sub systems. Considering all that Freitas estimated that the weight of such probe to be 10 million tons at the minimum and it would take 1000 years to fabricate it. Anyways what would be the thrust needed to put that into space? So it is just a purely imaginary concept for us. However, the same cannot be said for a civilization which is far ahead of us in technology. They may be able to fabricate such probes far faster and would be capable of giving it a thrust to fly to the stars.

That being the case, it is probable that such a probe has visited earth at some point of time and not necessarily during the 300,000 years our species came into being. Even if one such probe landed on the earth in the millions of years when life evolved and became inert here after replicating other probes it would be impossible for us to even know the existence of that mother probe because it would be inert now.

Even if there is a small alien robotic probe in our solar system today, it would be impossible for us to detect unless it sends us radio signals. Otherwise considering its minuscule size its discovery can only made by chance rather than methodical research.

ASTROBIOLOGY PART III- EXTRA TERRSETRIAL COMMUNICATION

The first person who thought of communicating with aliens was Friedrich Gauss. In 1822 he suggested setting up of an array of 100 huge mirrors to reflect sunlight towards the moon. It was then believed that life existed on the moon and he felt it would be great to communicate with it.

Later when better observations made the moon lifeless, the attention then shifted to Mars. In 1892 the French astronomer Camille Flammarion proposed that huge geometric shapes be prepared on the Earth to be visible to the Martians. Then Marconi came in created the method of transmission of Radio waves.

In about 1900 Tesla heard something that looked like structured signals to him. However, he did not document it and merely mentioned about it. In all probability, it is more of his imagination than reality. Whether Tesla heard anything or not that gave rise to a new idea, that alien radio messages might be detectable to us and it had been given a name; SETI or Search for Extra Terrestrial Intelligence.

Seen in the visible light galaxies are made up of billions of stars. But there is another component that is more traceable to unravel their structure and that is the all-pervasive Hydrogen gas. It is far too cold to produce light at visible wavelengths, but it generates a prominent spectral line with a wavelength of 21 cm.

Spectral lines are characteristic signatures produced by different types of atoms. This particular one, the 21 Cm neutral Hydrogen line occurs much further down on the Electromagnetic spectrum than the visible light at a radio frequency of 1420 MHz. This magic frequency allows Radio astronomers to scan the galaxies much farther than what can be done with visible light.

Currently, most of our Astronomy is dependent on the analysis of Spectral lines. Because of them, Astronomers can detect the star's chemical composition as well as so much more data including the star's weight, density, distance, luminosity, and so on.

What is this Spectrometry on which a lot of theory of Astronomy is based on?

In an atom, an electron sometimes jumps from a high energy orbit to a lower energy orbit and emits the surplus energy as radiation. Similarly, sometimes an electron jumps from a lower energy orbit to a higher energy orbit which involves absorption of energy. In these cases, there is either release or absorption of energy which emits a specific wavelength of radiation.

If we look at the star through a Telescope we see a combination of all the visible wavelengths it emits. It is possible to split the wavelength in the Spectrometer to reveal the quantum jumps that are going on in the atoms.

Downward jumps produce emission lines that are brighter than the background spectrum and upward jumps produce darker absorption lines. By measuring the wavelength of the line, scientists can measure which element has produced it. Very low energy jumps would produce longer wavelengths associated with the radio waves. That is where the 21 cm Hydrogen line comes in.

The 21 Cm Hydrogen line was originally recognized as a window into galactic structure by Danish astronomer Jan Oort. He is better known for the Oort cloud (a cloud of planetesimals surrounding the Sun at distances from 2000 AU to 200,000 AU). AU is the Astronomical Unit which is nothing but the distance of the Earth from the Sun which is about 151 million Km.

Oort used the 21 Cm line to show that our galaxy as well as many other galaxies is spiral in shape. This can never be seen with visible wavelengths.

In 1959 “Nature” published an article saying that if the aliens were to set up a signal to let beings on other planets know that the aliens exist, nothing is better than to use the frequency of 1420 Mhz corresponding to the 21 Cm Hydrogen line.

The first person to put SETI into practice was Frank Drake (the fame of the Drake Equation for postulating the number of possible civilizations in the Universe) . He did it at the Green Bank Radio Observatory in West Virginia. He pointed the giant dish at 2 stars, Tau Ceti & Epslion Eridani, and listened on the critical frequency of 1420 Mhz but he could get nothing out of it.

I had already posted in another article about the Drake equation for postulating the number of civilizations in the Universe. The problem is too many variables in the equation are inexact and therefore the result would not be in confirmation with reality. Nevertheless, it takes into account all the variables and tries to arrive at some figure rather than leaving it to our wild guesswork and also to show that SETI is not really a waste of time.

In the 6 decades after Frank Drake pointed the Greenbank telescope at the 2 stars the SETI experiment yielded nothing except for a couple of explainable anomalies. The problem with SETI is it expects the aliens to transmit at the 1420 Mhz frequency. Perhaps that is naïve because we are projecting the human ways of thinking onto other civilizations. They may not use radio waves as we do but use some other medium to communicate, we never know.

The biggest problem for SETI is that it is not funded by any country but it is a private project. The funding comes from various private individuals. The Russian billionaire Yuri Milner is funding a 100 million USD program of SETI.

Now, even if we get a message from the aliens, how do we decipher it? The most famous of the messages sent by mankind at the initiative of SETI through the Arecibo dish. This is a 300 meter dish antenna at Arecibo in Puerto Rico. The problem with this dish is that it is built into a natural depression in the landscape and hence cannot choose other directions. Through this dish in 1974 a message was transmitted to the Globular cluster in Hercules 24000 light years away. So, it would take 24000 years to get there. The message contained brief description of the DNA, pictures of human beings, the solar system and the Arecibo telescope itself.

NASA’s Pioneer 10 & 11 carried gold-plated messages which are now heading out of the solar system. However, it would take a fantastic 4 million years before they get anywhere near another solar system.

Both Carl Sagan and later Stephen Hawking said that sending such messages to another aggressive civilization can be dangerous as those would make them spot us and destroy us. But to me, their reasoning looks flawed. Their coming here would mean they have to master the speed of light. If they can do that, then the technology of their instruments would be such that they can easily discover other life forms on other planets, if they do exist. So our helping hand to them would be utterly unnecessary.