8th Class English Notes (Unit 7.1) Life on Mars?
This is Text-1 of chapter #7 “Robotics” in the 8th class English book. It provides students with 8th Class English Notes of Unit 7.1 titled “Life on Mars?”.
In this complete guide and key book, you get solved exercises of the 8th class English textbook (new edition) of Federal Board (FBISE) and all Khyber Pakhtunkhwa (KP) boards of Elementary and Secondary Education.
8th Class English Notes (Unit 7.1) Life on Mars?
Urdu Translation of the Lesson “Life on Mars?”
مریخ پر زندگی؟
1996 میں ایک مریخی شہاب ثاقب (meteorite) نے اس وقت قیاس آرائیوں اور مباحثوں کو جنم دیا جب سائنسدانوں نے بتایا کہ اس میں ماضی کی زندگی کے آثار موجود ہیں۔ اب یہ تلاش مریخ کی طرف منتقل ہو گئی ہے۔
جولائی 1996 میں اعلان کیا گیا کہ ڈاکٹر ڈیوڈ میکے اور ناسا کے جانسن اسپیس سینٹر کے سائنسدانوں کی ایک ٹیم نے ایک شہاب ثاقب ALH84001 میں ممکنہ بیکٹیریا (bacteria) کے فوسلز دریافت کیے ہیں جو مریخ سے آیا تھا۔ یہ شہاب ثاقب 1984 میں اینٹارکٹیکا (Antarctica) کے علاقے ایلن ہلز (Allan Hills) میں ملا تھا اور زمین پر 12,000 سال پہلے گرا تھا۔
سائنسدانوں نے پایا کہ اس پتھر، جسے ALH84001 کہا جاتا ہے، کا کیمیائی ترکیب منفرد ہے۔ اس میں معدنیات اور کاربن (carbon) کے مرکبات موجود تھے جو زمین پر مائکروبز (microbes) کے ذریعے بنائے جاتے ہیں۔ اس میں مقناطیسی آئرن آکسائیڈ (magnetic iron oxide) کے کرسٹل بھی تھے، جنہیں مگنیٹائٹ (magnetite) کہا جاتا ہے، جو بعض بیکٹیریا پیدا کرتے ہیں۔ مزید برآں، میکے نے ایک الیکٹران مائکروسکوپ (electron microscope) کے ذریعے پتھر کا جائزہ دکھایا جس میں گلوبیولز (globules) کی زنجیریں تھیں جو زمین پر بعض بیکٹیریا کی زنجیروں سے مشابہت رکھتی تھیں۔ “ہمیں یقین ہے کہ یہ واقعی مریخ کے مائیکروفوسلز (microfossils) ہیں،” میکے نے کہا، یہ بھی اضافہ کیا کہ یہ ثبوت “مریخی زندگی کا حتمی ثبوت” نہیں بلکہ “اس طرف اشارے” ہیں۔
کئی مختلف کیمیکلز اور مالیکیولر (molecular) ساختیں دلچسپ تھیں کیونکہ یہ زمین پر زندگی کے بائی پروڈکٹس (byproducts) کی طرح دکھتی تھیں۔ تاہم، یہ کیمیکلز اور ساختیں بغیر زندگی کے بھی بن سکتی ہیں۔ کچھ تو خلاء (space) میں دم دار ستاروں (comets) پر بھی پائی جاتی ہیں، اور سائنسدان نہیں سمجھتے کہ یہ مریخی زندگی سے آئی ہیں۔
ناسا کے محققین زمین پر زندگی کے بارے میں بحث سے مریخ کے لیے سبق لے رہے ہیں۔ اگر سب کچھ منصوبے کے مطابق ہوا، تو اگلے عشرے میں روورز (rovers) کی ایک نئی نسل مریخ پر پہنچ جائے گی۔ ان مشنز (missions) میں جدید بائیوٹیکنالوجی (biotechnology) شامل ہوگی جو مریخی جانداروں کے بنائے ہوئے انفرادی مالیکیولز (molecules) کو تلاش کرنے کے لیے تیار کی گئی ہے، چاہے وہ جاندار ابھی زندہ ہوں یا بہت پہلے مر چکے ہوں۔
مریخ پر زندگی کے وجود کے لیے، وہاں مائع پانی (liquid water) ہونا ضروری ہے۔ مریخ پر کافی پانی ہے، لیکن زیادہ تر برف کی صورت میں قطبی آئس کیپس (polar ice caps) اور زیر زمین دفن ہے۔ سرد درجہ حرارت کے باوجود، کچھ جگہوں پر سطحی برف کے نیچے مائع پانی ہو سکتا ہے کیونکہ نمک (salt) پانی کے نقطہ انجماد کو کم کرتا ہے۔ سیٹلائٹ ڈیٹا سے پتہ چلتا ہے کہ جنوب قطب کے نیچے ایک مستقل جھیل ہے، جو 20 کلومیٹر چوڑی ہے۔
مریخ پر زندگی کی تلاش زیادہ اہم ہو گئی ہے، جزوی طور پر مریخ کی سطح پر موجود دو روورز اور ایک مدار میں گردش کرنے والے خلائی جہاز کی تحقیقات کی وجہ سے۔ حالیہ مہینوں میں، انہوں نے ایک سلسلہ وار حیران کن دریافتیں کی ہیں جو ایک بار پھر سائنسدانوں کو یقین کرنے پر مجبور کرتی ہیں کہ مریخ پر زندگی موجود ہے یا ماضی میں موجود تھی۔ فروری میں نیدرلینڈز (Netherlands) میں ایک کانفرنس میں مریخ کے ماہرین کے ایک سامعین سے مریخی زندگی کے بارے میں سروے کیا گیا۔ تقریباً 75 فیصد سائنسدانوں نے کہا کہ ان کا خیال ہے کہ وہاں کبھی زندگی موجود تھی، اور ان میں سے 25 فیصد کا ماننا ہے کہ مریخ پر آج بھی زندگی موجود ہے۔
Exercise
Define the underlined words.
1. These missions will incorporate cutting-edge biotechnology designed to detect individual molecules.
- a. fossils
- b. new era
- c. latest or most advanced stage
- d. old technology
2. A Martian meteorite fueled speculation and debate in 1996.
- a. forming of a theory
- b. investment in stock
- c. problematic
- d. sure thing
3. Scientists found that the rock, called ALH84001, had a peculiar chemical makeup.
- a. common
- b. funny
- c. unique
- d. distinctive
4. In recent months, they’ve made a series of astonishing discoveries.
- a. extremely surprising or impressive
- b. big event
- c. insignificant
- d. boring
5. The evidence wasn’t absolute proof of past Martian life but rather pointers in that direction.
- a. flexible
- b. partial
- c. established
- d. indefinite
Exercise
1. Answer the questions.
1. What did Dr. David McKay discover that came from Mars?
Answer: Dr. David McKay found possible signs of bacteria fossils in a rock from Mars. It is called ALH84001.
2. Describe the distinctive features of the rock, ALH84001.
Answer: The rock ALH84001 had a unique mix of minerals and carbon compounds that, on Earth, are usually made by living things. It also had tiny crystals of magnetic iron that some bacteria make. It also showed small chains that look like those made by bacteria on Earth.
3. When and where did NASA find the rock from Mars?
Answer: NASA found the rock ALH84001 in Antarctica’s Allen Hills in 1984. It had landed there about 12,000 years ago.
4. What would NASA do next, if everything goes as planned?
Answer: If everything goes well, NASA plans to send new rovers to Mars. These rovers will have advanced tools to find molecules that could be made by living things on Mars, either now or in the past.
5. During the survey in February conference, what was the speculation of the Mars experts regarding life on Mars?
Answer: At a conference in February, most Mars experts (75%) thought that life once existed on Mars. Of those, 25% believe that Mars might still have life today.
Exercise
| Statements from the article | Give the meaning of the statements (Deductive skills) |
|---|---|
| a. Some 75 percent of the scientists said “they thought life once existed there,” and of them, 25 percent think that ‘Mars harbors life today’. | This means that many scientists believe that Mars used to have life. A smaller group among them also believes that life might still exist on Mars today. |
| b. “We believe that these are indeed microfossils from Mars,” McKay said, adding that the evidence wasn’t “absolute proof” of past Martian life but rather “pointers in that direction.” | Dr. McKay and his team found tiny structures that look like fossils of bacteria from Mars. However, they caution that this is not complete proof of life but only a strong hint. |
| c. For life to exist on Mars, there must be liquid water. There is plenty of water on Mars, but most of it is frozen in the polar ice caps and buried. | Life on Mars would need liquid water to survive. Although Mars has a lot of water, most of it is in the form of ice at the poles or buried underground. |
| d. Several different chemicals and molecular structures were exciting because they looked similar to byproducts of life on Earth. However, these chemicals and structures can also be created without life. | Scientists found chemicals and structures in the Martian rock that resemble those made by living things on Earth. But these can also be formed through non-living processes. |
Exercise
1. Complete the following sentences using an appropriate conjunction.
Answers
| Conjunctions | Appropriate Usage in Sentences |
|---|---|
| and, but, or | a. The evidence wasn’t absolute proof of past Martian life but rather “pointers in that direction.” |
| and, but, or | b. A Martian meteorite fueled speculation and debate in 1996. |
| and, but, or | c. There is plenty of water on Mars, but most of it is frozen in the polar ice caps and buried underground. |
| and, but, or | d. Some 75 percent of the scientists said they thought life once existed there, and of them, 25 percent think that Mars harbors life today. |
| but, until, because | e. Several different chemicals and molecular structures were exciting because they looked similar to byproducts of life on Earth. |
| and, but, or | f. Some are even present in deep space on comets, but scientists do not think that they came from Martian life anymore. |
| but, until, because | g. Although no signs of life on Mars have been found, scientists will continue to search because they are aware of the potential for life in extreme environments. |
2. Combine the pairs of sentences using the conjunction given in the brackets and rewrite them.
a. He went to work. He was unwell. (even though)
He went to work even though he was unwell.
b. They weren’t invited. They joined the party. (although)
They weren’t invited, although they joined the party.
c. Omer studied very hard. He won’t fail the exam. (so that)
Omer studied very hard so that he won’t fail the exam.
d. We tried calling you. You never received the call. (but)
We tried calling you, but you never received the call.
e. You can go. You finish the work. (when)
You can go when you finish the work.
f. I’ll stay at home. It is raining. (since)
I’ll stay at home since it is raining.
Exercise
Task: Prepare a research report on interesting facts and figures about Mars. Use pictorials and other graphics to make the report presentable and credible.
Research Report on Mars
Title: Exploring the Red Planet: Mars
Introduction: Mars, often called the Red Planet, has fascinated humans for centuries. Recent explorations have uncovered a wealth of information about this neighboring world, revealing both similarities and stark differences when compared to Earth.
Physical Characteristics:
- Diameter: Mars has a diameter of 6,779 km, making it significantly smaller than Earth, which has a diameter of 12,742 km.
- Moons: Mars has two small moons, Phobos and Deimos, whereas Earth has one large moon.
- Rotation Period: Mars has a rotation period of 24 hours and 37 minutes, which is remarkably similar to Earth’s 24-hour day.
- Orbit Period: A year on Mars lasts 687 Earth days, almost twice as long as a year on Earth.
Surface Conditions:
- Temperature: The surface temperature on Mars ranges from -153°C to 20°C, indicating a much colder environment compared to Earth’s -88°C to 58°C.
- Atmosphere: Mars’ atmosphere is thin and composed mostly of carbon dioxide (95.9%), with minor amounts of nitrogen (1.9%), argon (2%), oxygen (0.14%), and carbon monoxide (0.06%). In contrast, Earth’s atmosphere is rich in nitrogen (78.08%) and oxygen (20.95%).
Potential for Life: Despite the harsh conditions, the potential for past life on Mars intrigues scientists. If microbial life existed billions of years ago, it could provide significant insights into the origins of life.
Conclusion: Our understanding of Mars has grown tremendously through four decades of exploration. However, many questions remain unanswered, spurring continuous research and exploration. As we prepare for future missions, Mars stands as a testament to humanity’s quest for knowledge and our desire to understand our place in the universe.
Conclusion
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