RBSE Solutions Class 10 Science Chapter 17 Search of Life Outside Earth

I. Multiple Choice Questions

Question 1. What is the meaning of the term 'alien'?
(a) Magic
(b) Extra terrestrial life
(c) Strange creature
(d) A cow-like animal
Answer: (b) Extra terrestrial life
In simple words: The word 'alien' means something that comes from outside Earth, specifically referring to life forms not from our planet.

🎯 Exam Tip: When defining terms, always use clear and concise language. For scientific terms, explain what they mean in a simple way.

Question 2. Where is the possibility of extra terrestrial life?
(a) On a star
(b) Anywhere
(c) On earth-like planet
(d) On any planet
Answer: (c) On earth-like planet
In simple words: Scientists believe that alien life, if it exists, is most likely to be found on planets that are similar to Earth, with conditions that could support life. These planets are often called exoplanets.

🎯 Exam Tip: Remember that "extra-terrestrial" refers to anything outside Earth. The key to life's possibility lies in conditions similar to Earth's, like water and suitable temperatures.

Question 3. Which was the first spaceship to go beyond the solar system?
(a) Chandrayan 2
(b) Mangalvan
(c) Pioneer 1
(d) Pioneer 10
Answer: (d) Pioneer 10
In simple words: Pioneer 10 was the first spacecraft launched by humans that traveled past all the planets in our solar system and went into interstellar space. It carried a special plaque with a message from Earth.

🎯 Exam Tip: Knowing the names and achievements of important space missions is vital for questions about space exploration.

Question 5. Where do you need to go to watch the sunrise 15 times in a day?
(a) Poles
(b) International Space Station
(c) Moon
(d) Mars
Answer: (b) International Space Station
In simple words: Astronauts on the International Space Station (ISS) orbit Earth very quickly, seeing many sunrises and sunsets each day because of their high speed and orbit path. This makes it possible to see the sun rise multiple times in a single 24-hour period.

🎯 Exam Tip: Understand how orbiting works. The faster an object orbits, the more times it crosses the sunrise/sunset line in a given period.

Search Of Life Outside Earth Very Short Answer Type Questions

Question 6. Where are some people living outside the earth?
Answer: Some people are currently living in the International Space Station, which orbits Earth. Astronauts from different countries stay there for long periods to conduct scientific experiments. Space stations are vital for long-term human presence beyond Earth.
In simple words: Astronauts live on the International Space Station (ISS), which is outside Earth.

🎯 Exam Tip: When answering questions about human presence in space, mention specific locations like the International Space Station (ISS).

Question 7. The problem of global warming has arisen because of which organism?
Answer: The problem of global warming has mainly arisen due to human activities. Humans contribute to global warming through various actions like burning fossil fuels, deforestation, and industrial processes. Reducing these activities is crucial for the planet's health.
In simple words: Global warming is mainly caused by humans.

🎯 Exam Tip: Clearly state the primary cause. For environmental issues, connecting them to human activities is often key.

Question 8. “The physical environment on earth and all organisms, together work as a living unit”. What is the name of this hypothesis?
Answer: This hypothesis is known as the Gaia Hypothesis. It suggests that all living things on Earth, together with their surroundings, form a complex interacting system that helps keep the Earth suitable for life. This idea views Earth as a single, self-regulating superorganism.
In simple words: This idea is called the Gaia Hypothesis. It says Earth's living things and environment work like one big living system.

🎯 Exam Tip: When asked for a specific theory or hypothesis name, provide it accurately and then briefly explain its core concept.

Search Of Life Outside Earth Short Answer Type Questions

Question 10. How many earth-like planets are possibly there in the Milky Way?
Answer: Our Milky Way galaxy has about 1 billion solar systems. Many of these solar systems likely contain planets similar to Earth. These planets might have the right conditions, such as liquid water and a suitable atmosphere, to support life. This makes the possibility of life existing on many other planets quite high.
In simple words: There are many billions of solar systems in the Milky Way, and many of them might have planets similar to Earth that could support life.

🎯 Exam Tip: Use numbers and estimates from scientific data when available to support your answer. Focus on conditions necessary for life.

Question 11. What is the meaning of the term 'alien'?
Answer: The term 'alien' refers to extra-terrestrial life, meaning life that originates from outside Earth. Scientists believe that the basic molecules needed to create life, like those found on Earth, are common throughout the universe. Because of this, the chances of alien life existing are thought to be quite high. This alien life could be more or less developed than the variety of life we see on Earth.
In simple words: 'Alien' means life not from Earth. Scientists think the building blocks for life are common, so there's a good chance alien life exists, possibly in many forms.

🎯 Exam Tip: Define the term clearly, then elaborate on the scientific reasoning behind the concept, such as the ubiquity of essential molecules.

Question 12. As per Darwin how was the first life form created on earth?
Answer: According to Darwin's Theory of Evolution, Earth initially formed as a hot, molten sphere that gradually cooled over time, creating a suitable environment. As the Earth cooled, elements in the atmosphere combined to form simple compounds, which then developed into more complex compounds. These complex compounds included basic molecules necessary for life, such as water, amino acids, and nucleic acids. When these fundamental molecules condensed, the very first life forms were created almost instantly. This process highlights how simple chemicals can evolve into complex living systems.
In simple words: Darwin's theory explains that Earth cooled down from a hot state. Simple elements combined to make complex molecules, like water and amino acids, which then quickly formed the first life on Earth.

🎯 Exam Tip: Briefly outline the key stages: cooling Earth, formation of simple compounds, then complex organic molecules, leading to the first life forms.

Question 13. Scientists were apprehensive about what at the time of launch of Pioneer 10?
Answer: When Pioneer 10 was launched, scientists were worried that advanced alien civilizations might mistake it for an attack from Earth. They feared that if an advanced alien civilization encountered Pioneer 10, they might see it as a threat and retaliate against human civilization. This concern shows the caution and uncertainty surrounding early space exploration and potential contact with alien life.
In simple words: Scientists worried that Pioneer 10 might be seen as an attack by advanced alien life, causing them to fight back against humans.

🎯 Exam Tip: Focus on the specific fear mentioned: misinterpretation of the mission as an act of aggression by aliens, leading to retaliation.

Search Of Life Outside Earth Long Answer Type Questions

Question 15. What was our concept about extra-terrestrial life at the time of launch of Pioneer 10? What step was taken to save us from imaginary apprehensions?
Answer: By 1972, when Pioneer 10 was launched, many scientists strongly believed that highly advanced life could exist on other planets. However, some also worried about possible attacks from these alien civilizations. Pioneer 10 was designed to travel beyond our solar system, past Jupiter, and scientists thought it might eventually meet an advanced alien civilization. To prevent any misunderstanding, a special gold-anodized aluminum plaque was attached to Pioneer 10. This plaque showed figures of a man and a woman in a friendly pose, along with messages in a universal language, to clearly show that the spacecraft's journey was peaceful and meant for exploration, not aggression. This thoughtful addition highlights humanity's hope for peaceful contact.
In simple words: When Pioneer 10 launched, scientists thought advanced alien life might exist and feared attacks. To show peaceful intentions, a plaque with images of humans and a friendly message was put on the spacecraft.

🎯 Exam Tip: Discuss both aspects: the scientific belief in extra-terrestrial life and the measures taken to address potential fears or misunderstandings during contact.

Question 16. Explain a day at the International Space Station by assuming yourself as an astronaut.
Answer: If I were an astronaut on the International Space Station (ISS), my day would begin at 5:00 AM Greenwich Mean Time (GMT). My first tasks would be morning chores, which involve strapping myself to the toilet seat in zero gravity. After that, I would suck toothpaste from a tube to brush my teeth. This would be followed by a 30-minute jog on the treadmill for exercise. Breakfast, served in color-coded plastic tubes, would be nutritious but often bland. After eating, I'd move to a high-tech laboratory chamber to work with fellow astronauts, perhaps conducting an experiment on how plants grow without gravity. During breaks, I would take photos of Earth, which passes by quickly, offering views like India shining like a jewel at night. After about eight hours of hard work, it would be time for rest. This routine helps maintain health and scientific progress in space.
In simple words: As an astronaut on the ISS, my day would start early with chores, brushing teeth, and exercising in zero gravity. I'd eat tube-food, do plant experiments, take Earth photos, and then rest after a long workday.

🎯 Exam Tip: Describe the daily routine chronologically, highlighting specific activities that are unique to living in space, like managing zero gravity and exercise.

Question 17. How do the scientists think about extra terrestrial life? What are your thoughts on this topic?
Answer: Scientists have varying views on extra-terrestrial life. One group believes that life could not have started on Earth but instead came from microorganisms continuously arriving from elsewhere in the universe. Another group thinks there might be life outside Earth, but it might not be as advanced as life here, suggesting that merely having a rocky planet with water isn't enough to sustain it. My personal thoughts are that alien life could exist in many stages of development. It's possible that on some planets, alien life is extremely advanced, while on others, it might only exist as simple microorganisms. The vastness of the universe makes the existence of diverse life forms highly probable.
In simple words: Scientists have different ideas about alien life; some think it came from space, others think it's less advanced than Earth life. I believe alien life could be anywhere from tiny germs to very smart beings on different planets.

🎯 Exam Tip: Present different scientific viewpoints clearly and then articulate your own opinion based on logical reasoning and scientific understanding, as requested.

Question 18. Explain the importance of artificial satellites.
Answer: Artificial satellites are very important for many reasons:

• Valuable information is gathered about Earth's atmosphere and the troposphere, which helps us understand our planet better.
• Signals for television and radio are sent across vast distances by these satellites, connecting people worldwide.
• They enable modern telecommunication systems, making global communication possible.
• The internet relies heavily on these satellites for its widespread development and use.
• Satellites help in creating much better weather forecasts, which is vital for many human activities like farming and travel.

Each of these functions contributes significantly to our daily lives and scientific advancement.
In simple words: Artificial satellites are important because they give us weather data, send TV and radio signals, power phone calls and the internet, and help us predict the weather.

🎯 Exam Tip: List the key applications of artificial satellites clearly, focusing on communication, data collection, and practical benefits.

Question 19. What is the significance of India in the field of space research?
Answer: India is a leading nation in space research globally. It has developed advanced rocket launchers and satellites, including the capability to build SLV, PSLV, and GSLV vehicles for launching satellites. India performs these launches at a much lower cost than many developed countries, making its satellite launch services highly attractive and cost-effective internationally. This affordability has drawn many nations to India, allowing ISRO (Indian Space Research Organisation) to earn significant foreign exchange. India has launched numerous satellites into space, which are used for collecting data for accurate weather forecasts, transmitting signals for radio, television, mobile phones, and the internet, and helping with business and commerce operations. This success showcases India's growing technological prowess in space.
In simple words: India is a top country in space research, building its own rockets like PSLV and GSLV at low cost. India launches many satellites for weather, communication, and internet, earning money and helping businesses.

🎯 Exam Tip: Highlight India's key achievements in space research, such as developing various launch vehicles, cost-effectiveness, and contributions to global satellite services.

Search Of Life Outside Earth Additional Questions Solved

I. Multiple Choice Questions

Question 2. Who was the first man to go into space?
(a) Yuri Gagarin
(b) Edwin Eldrin
(c) Neil Armstrong
(d) Rakesh Sharma
Answer: (a) Yuri Gagarin
In simple words: Yuri Gagarin from Russia was the very first person in history to travel into outer space. His flight marked a major step for human space exploration.

🎯 Exam Tip: Remember the names of famous astronauts and their specific achievements, such as "first man in space" or "first man on the moon."

Question 3. Who was the first man to step on moon?
(a) Yuri Gagarin
(b) Edwin Eldrin
(c) Neil Armstrong
(d) Sunita Williams
Answer: (c) Neil Armstrong
In simple words: Neil Armstrong was the first human to walk on the moon, a historic event in space exploration.

🎯 Exam Tip: Distinguish between the first person in space and the first person to walk on the moon, as these are common historical facts tested.

Question 4. Which was the first Indian satellite?
(a) Bhaskar
(b) Rohini
(c) Aryabhata
(d) Indira
Answer: (c) Aryabhata
In simple words: Aryabhata was India's very first satellite, launched into space. It marked the start of India's journey in space technology.

🎯 Exam Tip: Know important national achievements in space, such as the name of the first satellite launched by your country.

Search Of Life Outside Earth Very Short Answer Type Questions

Question 1. What is the full form of NASA?
Answer: The full form of NASA is National Aeronautics and Space Administration. It is the government agency responsible for the United States' civilian space program and aeronautics research. NASA plays a huge role in exploring space and understanding Earth.
In simple words: NASA stands for National Aeronautics and Space Administration.

🎯 Exam Tip: For acronyms, state the full form clearly. If possible, add a brief detail about what the organization does.

Question 2. What is the full form of ISRO?
Answer: The full form of ISRO is Indian Space Research Organisation. This is India's national space agency, which designs and launches satellites and rockets. ISRO has made India a leader in space exploration at low costs.
In simple words: ISRO stands for Indian Space Research Organisation.

🎯 Exam Tip: Make sure to spell out the full name of national space agencies accurately.

Question 3. What is the full form of SLV?
Answer: The full form of SLV is Satellite Launch Vehicle. This was one of India's early rockets designed to put satellites into space. SLV was important for developing India's independent space capabilities.
In simple words: SLV means Satellite Launch Vehicle.

🎯 Exam Tip: Understand that SLV refers to a category of rockets designed to carry satellites.

Question 4. What is the full form of PSLV?
Answer: The full form of PSLV is Polar Satellite Launch Vehicle. This is a very reliable Indian rocket used to launch satellites into polar orbits, which are important for Earth observation and remote sensing. PSLV is known for its high success rate and cost-effectiveness.
In simple words: PSLV means Polar Satellite Launch Vehicle.

🎯 Exam Tip: Differentiate between different types of launch vehicles by their full forms and primary uses.

Question 5. What is the full form of GSLV?
Answer: The full form of GSLV is Geosynchronous Satellite Launch Vehicle. This is a powerful Indian rocket used to launch heavier satellites into geosynchronous transfer orbits, which are useful for communication satellites. GSLV has helped India launch its own large communication satellites.
In simple words: GSLV means Geosynchronous Satellite Launch Vehicle.

🎯 Exam Tip: Note that GSLV is for heavier satellites and typically for geosynchronous orbits, distinct from PSLV's polar orbits.

Question 7. ISRO was earlier known by which name?
Answer: ISRO was earlier known as Indian National Committee for Space Research (INCOSPAR). This committee was formed in 1962 and later became ISRO in 1969. This change marked a formal establishment of India's dedicated space agency.
In simple words: Before it was ISRO, it was called the Indian National Committee for Space Research (INCOSPAR).

🎯 Exam Tip: Be aware of the historical names and evolution of important organizations, especially government agencies.

Search Of Life Outside Earth Short Answer Type Questions

Question 1. Write a short note on initial space missions of USSR.
Answer: The USSR took the lead in early space exploration by launching Sputnik-1, the first man-made satellite, in October 1957. Sputnik-1 orbited Earth at a distance of 939-215 km and sent back data about the upper atmosphere through radio beeps before burning up upon re-entry. The USSR continued to lead, sending the first animal (Laika, in Sputnik 2) and the first man, Yuri Gagarin, into space. They also achieved the first spacewalk, landed an unmanned spaceship on a celestial body, and established the first space station, Salute-1. These missions set many precedents in space travel.
In simple words: The USSR started space missions by launching Sputnik-1, the first satellite. They also sent the first animal and human (Yuri Gagarin) to space, performed the first spacewalk, landed a probe, and built the first space station.

🎯 Exam Tip: When describing initial space missions, list key "firsts" such as the first satellite, first animal, first human, and first space station, along with names and dates if possible.

Question 2. Comment on the beginning of space research in India.
Answer: Space research in India began in 1948 with the establishment of the Physics Research Institute in Ahmedabad. The effort gained significant momentum when the Indian government formed the Indian National Committee for Space Research (INCOSPAR) in 1962, under the leadership of Dr. Vikram Sarabhai. This committee set up the Thumba Rocket Launching Station, which started space research on higher parts of the atmosphere. In 1969, INCOSPAR was renamed the Indian Space Research Organisation (ISRO). Since its beginning, ISRO has been at the forefront of space technology development, consistently pushing India to greater heights in space exploration.
In simple words: India's space research began in 1948. It got a big push in 1962 with INCOSPAR, led by Dr. Vikram Sarabhai, which later became ISRO in 1969.

🎯 Exam Tip: Include key milestones, founding figures, and the evolution of the organization (e.g., INCOSPAR to ISRO) to show a complete understanding.

Question 3. Write a short note on private initiatives in the field of space research.
Answer: Many private companies have started showing interest in space, primarily aiming to explore space tourism and earn money. Google encouraged these efforts with the Lunar X Prize, a competition to land a robot on the moon. For example, Team Indus worked to achieve this. Companies like Moon Express have even received permission from NASA to transport people from Earth to the moon. It is possible that some
In simple words: Private companies are getting involved in space research, mostly for space tourism. Companies like Google, Team Indus, and Moon Express are working on projects like moon landings and space travel for profit.

🎯 Exam Tip: Mention the motivations (e.g., space tourism, profit) and specific examples of private companies or initiatives in space research.

Question 4. How do the astronauts get food and drink?
Answer: Astronauts receive their food in plastic bags, each labeled with the astronaut's name. There are special systems to warm or cool the food as needed. However, after some time, the food tends to become bland in taste, leading astronauts to eagerly await fresh supplies sent from Earth. Drinks are consumed by sucking them directly through a straw from specially designed pouches, preventing liquids from floating away in zero gravity. This carefully managed system ensures astronauts get nutrition in challenging space conditions.
In simple words: Astronauts get food in special plastic bags that can be warmed or cooled. They suck drinks through straws. The food can taste bland, so they wait for fresh supplies.

🎯 Exam Tip: Detail the practical aspects of food and drink consumption in space, emphasizing adaptations to zero gravity and the challenges like taste.

Question 5. What are the harms of living in space?
Answer: Living in weightlessness for extended periods has several negative effects on astronauts' health. To counter these harmful effects, astronauts perform regular exercises using special equipment like treadmills installed on the space station. Furthermore, prolonged stays in the confined environment of a small chamber with only a few colleagues can negatively impact an astronaut's mental well-being and psychology. These physical and mental challenges highlight the difficulties of long-duration space missions.
In simple words: Living in space without gravity harms astronauts' health, so they exercise a lot. Staying in a small space with few people for long periods can also affect their minds.

🎯 Exam Tip: Discuss both the physical and psychological challenges of space living, and mention how astronauts try to mitigate these harms.

Search Of Life Outside Earth Long Answer Type Questions

Question 1. Explain the successes which India has achieved in the field of space technology.
Answer: India has achieved remarkable success in space technology. It has significantly improved its rocket capabilities, developing its own Satellite Launch Vehicle-3 (SLV-3), which was able to carry Indian satellites into space. Although the first SLV-3 launch failed, scientists learned from it and successfully launched the Rohini satellite. Indian satellites play a crucial role in transmitting signals for radio, telephone, internet, television, telemedicine, and distance education. India also developed the highly reliable Polar Satellite Launch Vehicle (PSLV), which can place satellites in polar orbits. Its cost-effectiveness makes it a preferred choice for many countries to launch their spacecraft, earning ISRO substantial foreign exchange. Additionally, India developed the Geosynchronous Satellite Launch Vehicle (GSLV) for launching heavier geosynchronous satellites and successfully sent a mission to the moon, Chandrayaan. India gained global recognition when its scientists tasted
In simple words: India has done very well in space. We built rockets like SLV-3, PSLV, and GSLV to launch satellites for communication, TV, internet, and telemedicine. Our rockets are affordable, so other countries use them too. We also sent a mission to the moon called Chandrayaan.

🎯 Exam Tip: Focus on specific Indian achievements: indigenous launch vehicles (SLV, PSLV, GSLV), their uses (communication, Earth observation), cost-effectiveness, and missions like Chandrayaan.