Theory:

The lesson "An Alien Hand" is written by Jayant Narlikar. He is an Indian astrophysicist and honorary professor at the Inter-University Centre for Astronomy and Astrophysics. The lesson is about a boy named Tilloo, and he is the protagonist of the lesson.
 
The lesson opens with a conversation going on between Tilloo and his mother. Tilloo's mother scolded him by stating how often he had been told not to travel through the underground passage. But Tilloo, on the other hand, was a naughty boy who desired to take the restricted route. While his mother was scolding Tilloo, he had a question in his mind. As a result, he approached his mother with a question, wondering why his father used to go there every day. The reason behind the statement was the boy wished to know why he was not permitted to use that way when his father could.
 
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Mother scolding Tilloo

When Tilloo inquired about his father's frequent visits to the forbidden way, his mother explained that it was his father's profession, and he had to go that route to get to work. Here "that way" refers to the "underground passage" where Tilloo's father used to go to work. Also, he would return from his work in the same direction.
 
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The underground passage where Tilloo's father used to go to work

On the other hand, there remained a common question about what was hidden under the forbidden route or the mystery behind the restricted path. Later, the narrator stated that not just Tilloo but the majority of the people were interested in knowing what was laid under the banned route. In addition, he said that it was not easy for everyone to use the underground passage. The reason behind his statement was that Tilloo's father was using it because he was one of the members of the special team who was permitted or received special authorization to use it as a part of his job.
 
Furthermore, the narrator stated that Tilloo's father was one of the members who had been chosen to use that underground passage. The statement implies that it was not safe for everyone to use the restricted way, and only a few selected members could use that passage.
 
Later the narrator said that the above conversation was constantly going on between Tilloo and his mother whenever Tilloo insisted on following his father. From the above statements, one can easily understand it was not safe to use the underground passage
 
Later the narrator stated that after getting scolding's from his mother, Tilloo couldn’t stop him from finding out what was in the prohibited passage. On a fine day, while Tilloo’s father was having a short nap after eating his lunch at home, Tilloo decided to learn what was hidden in the underground passage. So he tried to get hold of his father’s security card without his knowledge. The security card was used to unlock the closed door.
 
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Tilloo’s father was enjoying a siesta at home
 
Tilloo, after getting hold of the security card from his father, later considered escaping from his mother’s watchful eyes. Tilloo managed to get away from his mother because she would not allow him to use that way and she would scold him for not obeying her words. Even though disobeying the mother was the wrong thing, his curiousness made him do so. Therefore he planned well and made his way to the prohibited route without drawing his mother’s attention.
 
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Security card

When he got close to the forbidden path, he saw a metallic door that stopped him from moving further. Tilloo, on the other hand, had seen his father accessing the security card to open the metallic door numerous times. Later Tilloo had inserted the card into the slot with that thought in mind. When the card was inserted inside the metallic door, it opened quickly and noiselessly.
 
Later, when the door got opened, he stepped into a well-lit tunnel. Then Tilloo noticed the magic card he slipped to one slot came through another slot in the wall. Later he took the card and moved gently towards an upward slope. The upward slope was the way leads him to reach the surface of the planet from the underground passage. While he was moving towards the upward slope, Tilloo desired to see the sun and stars closer. He was interested in seeing the stars and sun because he had read about them in his book and had never seen them before. Also, he knew that if it were daytime, he would probably see the sun and if it were night time he could see the stars. Unfortunately, in the end, what he expected did not happen. The reason behind the statement was Tilloo thought that it would be easier to look at the sun and stars, and sadly, his wish didn't come true. It meant that he did not see either sun or stars.
 
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Tilloo thought of seeing sun and stars
  
When Tilloo had taken his father’s security card without his knowledge, he didn’t think getting to the underground passage would be difficult. Tilloo, on the other hand, had misjudged the security mechanism. He was unaware of the fact that the hidden cameras were noticing him. As he was a young boy, he had no idea how the technology worked, and he believed that seeing the sun and stars would be more accessible.
 
However, the undetectable mechanical devices had recognised Tilloo’s entry in the underground passage and had submitted his photos to the Central Bureau. It meant that when he used his security card to unlock the metallic door, some hidden cameras had noticed that an intruder had entered the premises. The invisible mechanical devices had identified his presence and sent his photos to the Central Bureau. Meanwhile, before Tilloo walked ten steps forward, he felt a strong hand on his shoulder. It was none other than security staff. The security staff arrived at the underground passage after getting the information from the Central Bureau. Later he stopped Tilloo before he could move on.
 
Then the security staff took him gently to Tilloo's house. It meant he didn't scold the boy for approaching the forbidden route. On the other hand, he kept a firm grip on him, refusing to let him run away or escape. Later, the security staff left Tilloo at his house. Tilloo’s mother, on the other hand, looked quite worried and angry. His mother felt anxious because he had gone there unaware of the risks he would encounter on the planet's surface.
 
On the other hand, Tilloo's mother was angry because she had cautioned him many times not to go that way. Because it was a spot where a few selected people were allowed, and his father was one among them. Later, the enraged mother began scolding the poor boy. While Tilloo was being scolded, someone unexpectedly came for his assistance. It was none other than his father, and he had got up from his sleep.
 
Later Tilloo’s father told his wife that he would explain to Tilloo about the restricted path. The reason behind his statement was that his wife had warned him several times, but he never paid attention, so his father thought of explaining to him what would happen if he reached the underground passage. His father believed that if he thoroughly explained the dangers in the path, he would not make the same mistake again.
 
Then Tilloo’s father began to explain to him the nature of his job and its dangers. Later his father stated that he was working on a planet's surface where ordinary people cannot survive. For instance, people need oxygen to breathe, but it wasn't easy to survive on the planet’s surface because the air was very thin to breathe. Also, the temperature in that place seemed to be very low. It could freeze a person to death. Moreover, the person would die if they lived on the surface of the planet without any proper precautionary measures.
 
While hearing the dangerous statement from his father, Tilloo questioned how his father managed to survive on the surface of the planet. Later his father stated that he would go to the planet's surface using well-equipped suits with a reservoir of oxygen. Also, the suit would keep him warm, and he used specially designed boots that would help him to walk easily on the surface of the planet. In addition, he stated that he had been trained well to survive and work on the planet's surface. He mentioned the above things to his son to understand how difficult it was to stay on the planet’s surface.
 
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A man wearing special suit with a reservoir of oxygen

Furthermore, Tilloo’s father stated that his forefathers had formerly lived organically on the planet’s surface without getting any harm. It meant that his forefathers lived on the surface of planet quite naturally. They lived for millions of years. The times, however, had changed. The sun, which had previously provided them with food, had turned against them. It indicated that his forefathers had lived contentedly on the surface, unharmed, but that the sun had become harsher over time, and whatever nourishment it had offered them had become wild. As a result, living on the surface was dangerous. In addition, Tilloo’s father stated that there was only a small change in the sun, yet it was enough to upset the planet’s natural balance. And so, Tilloo and his family were living beneath the surface of the planet.
 
In addition to the sun's harshness, Tilloo's father explained the extinction of living creatures from the planet's surface. At first, the birds became extinct, followed by them, animals became extinct. Later the fish could not survive there because of the heat. These living creatures got extinct because of the heat produced by the sunrays. However, human beings managed to survive only because of superior technology. Due to the advanced technology, they were able to survive underground under artificial conditions. The reason they can survive under artificial conditions was because of solar energy.
 
While Tilloo's family and other members lived beneath the planet's surface, solar energy played an essential role in their lives. Also, his father stated that solar energy generated sufficient power to make their lives comfortable. In addition, he said that the machines that were providing solar energy should always be in good working condition. They were leading their life successfully with the help of the artificial supply of energy. Moreover, he added that some of the life-saving devices were on the surface of the planet, and his job was to look after the conditions of the machine and service them. Here the term "service" means that looking after the running state of the device.
 
After hearing about the dangerous and challenging aspect of working on the planet's surface, Tilloo asked his father if he could join the team once he grew up. It showed his curiosity and interest in that field. Later, his father agreed that he could join that team once he grew up. While the father and the son were speaking about it, Tilloo's mother interrupted in between and stated that if he wanted to become like his dad, he would have to be a good boy and follow his parent's words. This was the usual advice given to Tilloo by Tilloo's mother.
 
The next day, Tilloo's father went to work. When he arrived at his workplace, he noticed that the Control Room was full of excitement. The excitement might be because they had seen something unusual. In addition, a large crowd of people who had gathered in front of the large television screen were curious to know what was that. They observed something in the form of a dot that appeared in the plain background, telecasted on the television screen.
 
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Control Room

Furthermore, a Supervisor working on the last shift remarked that it could not be a star because it kept on changing its position. In addition, he claimed that their computer was tracking the object's path and when he saw that, he realised that it was approaching them.
 
After seeing the object's movement, Tilloo's father asked whether it was a spacecraft. Other team members joined with him in the new shift while he was conversing with the Supervisor. Later the Supervisor stated they also think it would be a spacecraft. They also had to keep an eye on its movements to figure out what it was.
 
Tilloo's father later inquired as to how and from where the spacecraft had been sent. He thought it was because no other life had been discovered in the solar system except on their planet. It means that there was no life on the other neighbouring planet. Later, Tilloo's father recalled how his forefathers had a well-developed space programme and explored the solar system and discovered that they were "alone" in the universe. It means that no other life forms were there on the planet at that time.
 
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Solar system

Also, Tilloo's father stated that during his ancestors period, the manned and unmanned spacecraft were sent to identify whether any presence of lives was there. The manned spacecraft have been operated with the help of a crew member, and the unmanned spacecraft could be used without any crew member. Later, the spacecraft discovered that there were no signs of lives except them in the galaxy. Moreover, these pieces of information had been already recorded in the Central Bureau's records.
 
Tilloo's father later remarked that nowadays, there were shortages of energy and underground existence. They were allowed to survive under artificial conditions due to the upset in the natural equilibrium, which resulted in energy shortages. They had lots of vitality naturally during his forefathers' time. He also remarked that they no longer had a space programme and that all they could do was watch helplessly from the Control Room. Finally, the question of who these strangers remained. The reason behind the comment was if they had enough energy and spacecraft, they would have been able to identify the strangers and from where they had been sent to their planet.
 
On the other hand, the meeting room at the Central Bureau grew so quiet that an outsider would think it was deserted. It means that the meeting room was silent, and a person from outside would probably believe that no one was there in the conference room. On the other hand, the conference room was not vacant; it was full of Committee members. The Central Committee members then seemed to be unusually quiet. The reason behind their silence was that the committee was expecting the President to make an important announcement. They were waiting for the announcement from the President and could start their work only after the instructions from their President.
 
Then the President informed his colleagues that he would give the report when he receives it. Moreover, he stated that the situation might alter when he speaks, pausing to collect his documents before continuing. It means he was gathering information and expecting the situation to change at any time, so he was waiting for a proper response about the spaceship.
 
While having a conversation with the colleagues, the President mentioned that the two spacecraft were approaching them. One of the two was orbiting their planet, while the other was still far away from the planet. In addition, he indicated that it was most likely from their neighbouring planet. On the other hand, the President had doubts about how to handle and react to the spaceship. The reason behind the President's statement was that he wanted to hear the perspectives of his colleagues. As a result, he sought number one's advice and opinions.
 
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Spacecraft
 
The defence team was led by Number One. He was renowned for his boldness and wisdom. Number One stated that if they wished to destroy the spacecraft, they could do it with the help of their weapons. Moreover, he suggested that it was not a good idea. Also, he stated that they couldn't disable the spacecraft while they were in space. It meant that destroying the spaceship in space was not a good deal. It would be easier to disable them effectively at any time once they landed on the surface. He further stated that the reports said that there were no living beings in the spacecraft, which contained only instruments. As a result, he said that it was preferable to disable them anytime once they had landed.
 
The President asked the opinion of Number Two after hearing Number One's response. The committee's second member was a scientist. Later, the second scientist indicated that his suggestions were "not to interfere" and "observe things". It means that they did not know the power of the senders, and with the help of silent observation, they would analyse what it would be. Also, they were still in darkness about the intentions of the spacecraft. It means that they were not sure what their intention was, and the question remained unanswered. As a result, it was preferable not to divulge their presence on the planet.
 
Moreover, the second scientist added that they should keep their existence a secret because they have no idea about their objectives. If they destroy or make these spaceships ineffective, the spaceships may reveal their presence. It means that it was safe not to disclose their identity on the surface of the planet.
 
Later the President looked at the Number Three, and he was a social scientist. A social scientist is an expert in or student of human society and social relationships, or any subject within this field, such as economics or politics. Typically, the social scientist did not agree with the second scientist's points or suggestions. However, this was one of the rare situations when he agreed with the second. He also proposed that they should keep their surface operations to a bare minimum to the impression that the planet is lifeless. Also, if no one disabled or destroyed the spacecraft, it would, luckily, inform the senders that no one lived on this planet.
 
Later the President thought of speaking to his colleagues. Meanwhile, his phone rang, and he was unable to speak to his team. Then, he took up the receiver and listened for a minute silently. It means he was paying attention to the person on the other end of the line. After listening to the phone call, the President announced to his colleagues that the first spacecraft had landed.
 
According to Tilloo, that day was a red-letter day. The term "red-letter day" refers to a day that was particularly notable or unforgettable. It was a momentous day for him because he had finally got what he wanted. He desired to go to his father's workplace. At last, his father had taken him to the Control Room with him that day. While he entered the Control Room, he saw the alien spacecraft on the big TV screen.
 
After looking at the alien spacecraft, Tilloo had several doubts in his mind. So he enquired his father about what the spacecraft contained, and also he stated that it looked funny. Later, Tilloo's father nodded his head and said that they were also unsure what was inside the alien spacecraft and that they had received orders from higher officials to observe it from a far distance. Tilloo's father also claimed that they could control all of the components of the alien spacecraft and use their power if they were causing problems. Finally, Tilloo's father pointed to a large panel with a variety of coloured buttons. The control panels were kept for accessing the spacecraft's movements. Otherwise, the spaceship would be controlled using the control panels if it was causing any mischief. Later, Tilloo glanced longingly at them. It meant that he longed to touch the control buttons.
 
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Coloured buttons
 
After noticing the coloured panel, Tilloo saw something suddenly moving in the spacecraft, and so he asked his father to look at that. On the other hand, the other persons in the Control Room also noticed the movement in the spacecraft. Everyone in the Control Room looked at the screen.
 
While they looked at the screen, a mechanical hand arose from the spacecraft, and it started to approach the planet's surface. Moreover, it bent and touched the soil. People were astonished to see the things displayed on the screen. They were unaware of what was happening around the surface of the planet. In addition, the telescopic lens of the TV camera zoomed into the tip of the mechanical hand. It was done because to know what the alien robotic hand was doing.
 
While everyone was looking at the screen, Tilloo looked at the control panel and its attractive buttons. The attractive switches and panels captured his interest. In addition to looking at the attractive panels, he was interested in touching the red coloured button. Among all the controls, he had an irresistible desire to press the red one. Tilloo probably pressed the red button due to the attractiveness of the colour, or else, among all the colours, the red seemed to be dominating one. Later Tilloo moved closer to it.
 
Later, Tilloo's interest in pressing the most visible red button resulted in an uncomfortable high-pitched sound. Tilloo had found himself in the centre of attention. On the other hand, his father grabbed him roughly and tried to restore the machine to its normal position. Tilloo's father had done it because to avoid problems. Also, they should not reveal their existence because they did not know the motives and intentions of the spacecraft. As a result of his mischief, the mechanical hand stopped functioning.
 
On the other hand, a news conference was held by NASA on Earth, and a scientist started to explain why the mechanical hand had ceased moving. It meant that the spacecraft was sent from the Earth, and unfortunately, it stopped functioning. In most cases, while dealing with spacecraft, the scientist must answer his higher authorities and the press if any trouble occurs. So, when the mechanical hand was no longer moving, NASA held a news conference in which a scientist gave a brief explanation of why it had stopped moving.
 
It was evident from the press conference that Tilloo and the rest of the characters lived under the Martian surface. Aliens refer to people from another world. According to the Martians, people from the Earth seemed to be Alien.
 
While everything had been going smoothly with the Viking Mission, there remained a problem, though. The problem was occurred due to Tilloo. As a result, the robotic hand stopped functioning. The main motive of the mechanical hand was to dig up Martian soil for analysis. Unfortunately, it had failed, and they were not sure what's caused the issue. Later, the scientist reported to the press that they were unsure what the cause was, but he addressed that their experts were confident that they'd rectify the problem soon.
 
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Viking Mission I on Mars*
  
Following the first press conference, after sometimes NASA released another announcement. At the second press release, the scientist stated that the mechanical hand had been reactivated, and he congratulated the technicians for their hard work. It meant that when it stopped working, the scientist had stated that they would deal with the problem and fix it as quickly as possible. Similarly, the technical team had laboured tirelessly to activate the mechanical hand. The team, on the other hand, was unable to identify why the mechanical hand stopped working. They were unaware of the fact that the hand of Tilloo was the cause for the problem.
 
In addition, the scientist stated that the soil samples had been taken and sent for evaluation, and the answer to whether there is life on Mars will be announced shortly in a news conference. There are eight planets in the solar system, and Mars is the closest to Earth in terms of location and physical properties. As a result, the Viking Mission scientists were enthusiastic about the chance of finding life on Mars. They were, however, in for a letdown. It meant that what they expected didn't happen. At last, the Viking Mission found that on Mars, there were no indications of life.
Reference:
Viking Mission I on Mars*: Public Domain, Wikimedia Commons.