English: Unit 5 “Are We Alone?” – Space Exploration, Modal Verbs and Speculation – First Year Secondary – Algerian Curriculum

الأولى ثانوي, تربية وتعليم, دروس الثانوي ضع تعليق

Introduction

Welcome to Unit 5 of the First Year Secondary English programme! This unit is titled “Are We Alone?” and explores one of humanity’s most fascinating questions: Is there life beyond Earth? In this unit, you will learn vocabulary related to space and astronomy, practise using modal verbs to express speculation and deduction, read about scientific discoveries in space exploration, and develop your ability to express opinions and make predictions in English. This topic is not only exciting but also highly relevant to the Algerian English curriculum for first-year secondary students across all streams.

Learning Objectives

Learn and use vocabulary related to space, astronomy, and space exploration
Use modal verbs (must, might, may, could, can’t) for speculation and deduction
Read and understand authentic texts about the universe and the search for extraterrestrial life
Write a short paragraph expressing opinions and speculating about space
Practise asking and answering questions about space discoveries

Part 1: Key Vocabulary — Space and the Universe

English Word	Part of Speech	Definition	Example Sentence
Universe	noun	All existing matter, space, and time	The universe contains billions of galaxies.
Galaxy	noun	A large system of stars held together by gravity	Our solar system is in the Milky Way galaxy.
Solar System	noun	The sun and the planets that orbit around it	There are eight planets in our solar system.
Extraterrestrial	adj/noun	Existing or occurring outside Earth	Scientists search for extraterrestrial life.
Spacecraft	noun	A vehicle designed for travel in space	NASA launched a new spacecraft to Mars.
Astronaut	noun	A person trained to travel in space	The astronaut conducted experiments on the ISS.
Telescope	noun	An instrument used to observe distant objects	The Hubble telescope has shown us amazing images.
Constellation	noun	A group of stars forming a pattern	Orion is one of the most famous constellations.
Orbit	noun/verb	The curved path of a celestial object around another	The Earth orbits the sun every 365 days.
Aliens	noun	Beings from another planet (informal)	Do you believe aliens might exist somewhere?
Exoplanet	noun	A planet outside our solar system	Thousands of exoplanets have been discovered.
Intelligent Life	noun phrase	Life forms capable of reasoning and communication	SETI searches for intelligent life in the universe.

Part 2: Grammar — Modal Verbs for Speculation and Deduction

In this unit, we focus on using modal verbs to express how certain or uncertain we are about something. These are called modals of deduction and speculation. They are very common in discussions about space and the unknown.

The Main Modal Verbs

Modal Verb	Level of Certainty	Meaning	Example
Must	Very certain (yes)	I am almost sure this is true	There must be life somewhere in the universe.
Could	Possible	It is possible	There could be water on that exoplanet.
May	Possible	It is possible (more formal)	The spacecraft may reach Mars next month.
Might	Less certain	It is possible but not very likely	Humans might live on Mars one day.
Can’t	Very certain (no)	I am almost sure this is impossible	We can’t be alone in this huge universe.

Structure

Affirmative: Subject + modal + base verb
Example: There might be life on other planets.

Negative: Subject + modal + not + base verb
Example: This discovery cannot (can’t) be a coincidence.

Continuous form (speculating about now): Subject + modal + be + verb-ing
Example: Scientists might be working on a new telescope right now.

Perfect form (speculating about the past): Subject + modal + have + past participle
Example: Ancient people must have seen comets and feared them.

Comparing Certainty Levels

Use this scale from highest to lowest certainty:

100% certain it is true: There is life in the universe. (no modal needed)
95% certain (logical deduction): There must be life in the universe.
50-70% certain (possibility): There may / could be life in the universe.
30-40% certain (weak possibility): There might be life in the universe.
95% certain it is false: That can’t be a real alien; it must be a trick.
100% certain it is false: That is not an alien spacecraft. (no modal needed)

Part 3: Reading Comprehension — The Search for Extraterrestrial Intelligence

Are We Alone? The Search Begins

For thousands of years, humans have looked up at the night sky and asked: are we alone in the universe? Today, scientists are closer than ever to finding an answer. With powerful telescopes like the James Webb Space Telescope, astronomers have discovered thousands of exoplanets — planets that orbit stars outside our solar system. Some of these exoplanets are in what scientists call the “habitable zone,” meaning they might have the right conditions for liquid water and, possibly, life.

The Search for Extraterrestrial Intelligence (SETI) is a scientific project that listens for signals from intelligent beings in space. Although SETI has not found any confirmed signals from aliens yet, researchers continue to scan the skies. They believe that if intelligent life exists elsewhere, it might send radio signals that we could detect with our technology.

In our own solar system, scientists are exploring Mars and the moons of Jupiter and Saturn. Evidence suggests that liquid water may exist beneath the icy surface of Europa (Jupiter’s moon) and Enceladus (Saturn’s moon). If this is true, then microbial life could exist there. The question of whether we are alone remains one of the greatest mysteries of science.

Reading Comprehension Questions

What is an exoplanet?
What does “habitable zone” mean?
What is SETI and what does it do?
Why are scientists interested in Europa and Enceladus?
Which modal verbs are used in the text? What do they express?

Model Answers

An exoplanet is a planet that orbits a star outside our solar system.
The “habitable zone” is the area around a star where conditions might be right for liquid water and life.
SETI is the Search for Extraterrestrial Intelligence — a scientific project that listens for signals from intelligent beings in space.
Scientists are interested in these moons because evidence suggests liquid water may exist beneath their icy surfaces, so microbial life could exist there.
The modal verbs used are “might”, “could”, and “may” — they express possibility and speculation.

Part 4: Writing — Expressing Opinions and Speculating

In this section, you will learn how to write a short paragraph expressing your opinion about space and the possibility of extraterrestrial life. Use the modal verbs you learned in Part 2.

Useful Expressions for Speculating

I think / believe that… — I think there might be life on other planets.
In my opinion… — In my opinion, we must continue exploring space.
It is possible / likely that… — It is possible that humans could live on Mars in the future.
There is no doubt that… — There is no doubt that space exploration is important.
I am convinced that… — I am convinced that we can’t be the only intelligent beings.

Model Paragraph

“In my opinion, the universe is too vast for us to be alone. There must be millions of planets with conditions suitable for life. Scientists have already discovered many exoplanets, and some of them could have liquid water. I believe there might be intelligent beings somewhere in the universe, but they may be too far away for us to communicate with. Space exploration is very important because it could help us answer the question: are we alone? I think governments must invest more money in space research.”

Your Turn: Writing Task

Write a paragraph (80-100 words) answering ONE of these questions:

Do you believe there is life on other planets? Why or why not?
Should governments spend money on space exploration or on solving problems on Earth?
What do you think the future of space travel will be like?

Remember to use at least three modal verbs (must, might, may, could, or can’t) in your paragraph.

Part 5: Practice Exercises

Exercise 1: Choose the correct modal verb

We don’t know for sure, but there ______ (must / might / can’t) be life on other planets.
The lights in the sky are moving strangely. It ______ (can’t / must / might) be a drone — it’s too fast!
Scientists have found water on Mars, so there ______ (must / can’t / might) have been life there in the past.
That bright object in the sky ______ (must / can’t / might) be Venus — it’s too bright to be a star.
We haven’t found aliens yet, but they ______ (must / could / can’t) exist somewhere in the universe.

Model Answers: 1. might, 2. must, 3. might, 4. must, 5. could

Exercise 2: Rewrite the sentences using modal verbs

Perhaps there is water on that exoplanet. → There ______ water on that exoplanet.
I am sure this fossil came from Mars. → This fossil ______ from Mars.
It is impossible that humans will live on Jupiter. → Humans ______ on Jupiter.
Perhaps ancient people saw a comet and thought it was a god. → Ancient people ______ a comet and thought it was a god.
I am almost certain that space tourism is the future. → Space tourism ______ the future.

Model Answers: 1. There might/may/could be water on that exoplanet. 2. This fossil must have come from Mars. 3. Humans can’t live on Jupiter. 4. Ancient people might have seen a comet… 5. Space tourism must be the future.

Exercise 3: Complete the sentences about space

“Are we alone?” is a question that ______________________.
If we find intelligent life, we ______________________.
Space exploration is important because ______________________.
In the future, humans might ______________________.
I think the government should ______________________.

Part 6: BAC Exam Tips — Modal Verbs for All Streams

Although this is a first-year unit, modal verbs for speculation and deduction appear in the BAC exam as well. Here are some tips:

Sciences and Technology streams: You may see modals of deduction in scientific texts. Pay attention to context clues that show certainty vs. possibility.
Letters and Philosophy stream: You will need to use modals in argumentative essays. Use “must” for strong arguments and “might/could” for weaker ones.
Economics stream: Modals appear in reading comprehension questions. Be ready to explain the difference between “may” (formal possibility) and “might” (less certain).

Key Exam Expressions

Speculation (present): modal + base verb — “The object may be a satellite.”
Speculation (past): modal + have + past participle — “The signal must have come from deep space.”
Deduction (logical conclusion): must / can’t — “It must be a planet; it can’t be a star.”

Summary

In this unit, you have learned:

Vocabulary: Key terms related to space, the universe, and exploration
Grammar: Modal verbs for speculation and deduction (must, might, may, could, can’t)
Reading: An authentic text about the search for extraterrestrial intelligence
Writing: How to express opinions and speculate in a paragraph
Skills: Using modal verbs to express different levels of certainty

Remember: the question “Are we alone?” is not just about science — it’s about using language to express what we think, what we believe, and what we wonder about the world around us. Keep practising your modal verbs and space vocabulary!