What Is Space? An Introduction to the Universe

What Is Space? An Introduction to the Universe

By Yuvraj Dhillon

Have you ever looked up at the sky and wondered about the unknown universe and celestial bodies beyond our world? Perhaps you spotted the moon glowing above your village, a bright planet streaking the horizon, or a sky full of stars on a cloudy night when a power outage left everyone in the village in darkness. That dark mass above us all is not empty. This is space, a boundless realm encompassing stars, planets, galaxies, nebulae, black holes, and far more uncharted territory that will leave your mind racing.

There’s nothing more thrilling to humans than space, connecting us all with science, history, imagination, and the future. I’m Yuvraj, a high school student in New Jersey, and this, my friends, is one of my first blog posts. I may not yet have a career in astronomy, but I have been devouring any source of information on the subject for the past few months, and I wanted to share the knowledge with you all, hoping that it inspires you.

📑 What You’ll Learn

Where Does Space Begin?

The Earth’s atmosphere surrounds the planet like a shroud, providing us with the air we breathe, protecting us from the sun’s radiation, and insulating the planet enough to allow life to thrive on its surface. However, the atmosphere does not have a clear end, as it gradually dissipates into space with altitude. Jets fly through the lower part of the atmosphere, and weather balloons can rise even higher. Rocket ships fly through the atmosphere and beyond.

Scientists define the beginning of space as the Kármán line, an imaginary line 100 km above the surface of the Earth. This might seem far, but if the Earth was the size of a globe in your classroom, the Kármán line would be a millimeter above the suface. We are technically always within touching distance of space in our everyday lives. NASA has more information on this here.

How Big Is the Universe?

Picture yourself on a road trip across the country. Now imagine that road is 93 billion light years long! The observable universe is huge in size, with a diameter of about 93 billion light years. Light-years are units of distance equivalent to the distance light can travel in a year. That’s 300,000 km every second. That’s hard to imagine, but the universe is even bigger! In fact, it would take light billions of years to cross the observable universe.

The universe contains about 2 trillion galaxies, and each galaxy has around a billion stars! If you tried to count the number of stars in the universe, it would be similar to counting every grain of sand in every beach in the world. Then, imagine if each grain of sand represented an entire galaxy containing a billion stars. That’s how big the universe is! To better put this into perspective, NASA published this article on sizes in the universe.

How Was It All Created?

The entire universe, including all of the matter within it, came into existence in a singularity 13.8 billion years ago. This phenomenon is referred to as the Big Bang.

However, the phrase is misleading because many people think of a huge explosion of matter in space when we use the word bang. Instead, the big bang was an expansion of space itself. This expansion caused matter to cool enough for atoms to form, which in turn created stars, planets, and eventually the oceans, forests, and life on our planet.

The atoms in our own bodies formed in the stars, which means we are literally made of stardust. The same stardust that makes up every human on this planet. This connection to the universe was what sparked my interest, and it’s what I think is the most fascinating thing about space.

What Is Space Made Of?

Although space can seem empty to us, it contains many wonders. Some of the objects we see are stars, planets, moons, asteroids, comets, and black holes. Let’s learn about what these objects are!

Stars are giant spheres of glowing gas that create their own light and energy. Our very own star, the sun, creates light and heat that make life on Earth possible. Planets are objects that orbit stars and have a rocky surface or are gas giants like Jupiter, the largest planet in our solar system. Moons are space rocks that orbit planets; Earth only has one, but planets like Jupiter and Saturn have dozens each.

Other objects in space include asteroids, which are space rocks that mainly orbit the sun, and comets, which have a glowing halo of gas and dust. Black holes are regions in space with gravity so strong that not even light can escape them. Contrary to popular belief, black holes do not suck in everything around them. Objects must get close enough to a black hole to get pulled in, but that doesn’t happen often. Black holes are one of the most fascinating objects in space. ESA has a great article for kids about these and other objects in space.

Our Solar System

Our solar system is comprised of eight planets that orbit our sun. From nearest to farthest, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. I remember this by using the mnemonic device: “My Very Educated Mother Just Served Us Noodles.”

Each planet has its own features; for example, Mercury, the closest planet to the sun, is the smallest and fastest planet. The temperature on Venus, the hottest planet in our solar system, can reach up to 465 degrees Celsius, hot enough to melt lead. Earth is the only planet known to support life, and it’s the only planet that contains liquid water. Mars contains the largest volcano in the solar system, Olympus Mons, which is three times as tall as Mount Everest!

Meanwhile, Jupiter is so large that 1,300 Earths would fit inside it, and Saturn’s rings are made of ice and debris. Neptune has the fastest winds in our solar system, while Uranus is the only planet that rotates on its side. I found all of this information in a fascinating NASA Space Place article.

How Humans Explore Space

There are so many objects to explore in space, but how exactly do humans study them? There are so many incredible technologies that humans use to explore space! Let’s learn about them.

Rockets are necessary to launch spacecrafts into orbit or beyond. They are the engines that power our travel beyond the Earth. Satellites are objects humans launch into space that orbit the Earth or another planet; they help provide GPS, weather forecasts, television signals, and phone coverage. Telescopes like the Hubble and James Webb Space Telescope are essential for making observations about other galaxies and the early universe. They let us peer into the depths of space and witness events happening millions of light years away!

Robots like NASA’s Perseverance study the surface of other planets. The Persecution team is currently studying Mars, searching for evidence of past life and collecting samples to bring back to Earth. Astronauts live aboard the International Space Station, conducting research that benefits humans back on Earth. Special spacecrafts like landers make it possible for us to descend onto the moon or other planets. NASA’s website has information on all of these space technologies.

NASA and ISRO: Two Agencies Leading the Way

Speaking of space technologies, there are two space agencies that have led the way in space exploration: NASA and ISRO.

NASA was founded in 1958 and has seen many successes, including the Apollo 11 mission in 1969 that first landed humans on the moon. More recently, NASA unveiled the James Webb Space Telescope, which is the newest and most powerful telescope in history, able to see galaxies from the dawn of time. The company has also had many spacecrafts, like Perseverance mentioned earlier, and they’re currently workign on the Artemis program that will send astronauts back to the moon and then to Mars. Learn more about NASA here.

ISRO, India’s space agency, was founded in 1969 and has had many groundbreaking missions as well. Last year, their Chandrayaan-3 mission made India the first nation to land near the moon’s south pole, which is believed to contain water ice. There are only four countries that have successfully landed on the moon, and now India joins their ranks. ISRO also made history in 2013 with the Mangalyaan Mars Orbiter Mission, which successfully reached Mars on its first try at a fraction of the cost of other nations’ missions. The agency is currently working on Gaganyaan, a project to send Indians into space for the first time. ISRO’s website has more information on these accomplishments.

What stands out to me about these space agencies is their dedication to collaboration and sharing knowledge, as they’re doing now with the Artemis Accords. By cooperating with each other, they accelerate discoveries and advance their knowledge of the universe.

While it’s fun to talk about space missions, it’s also important to learn about why space exploration matters to all of us here on our small planet.

Why Space Matters to All of Us

We don’t realize how much space exploration affects us in our daily lives. Every time we use a GPS, check the weather, or watch TV, we are using space technologies! In the event of natural disasters, satellites can help rescue workers locate people in need. Beyond that, space inspires us and leads us to ask deep questions about the origins of our universe, life, and beyond. I think those questions are the most important because they drive us all to be better and to learn more about the world. The same curiosity fuels our thirst for knowledge about space, and it’s what will lead us to the next big breakthrough in space exploration.

Facts That Still Surprise Me

Here are some of my favorite facts:

You are constantly moving, even when you aren’t. You are spinning along with the Earth, which is orbiting the sun, which is hurtling through the Milky Way.
The sun is a star! It only appears larger and brighter than the stars we see in the night sky because it is much closer to us.
Not all planets have the same length of day. Because different planets rotate at different speeds, a day on Jupiter is much shorter than a day on Earth.
When you look at stars at night, you are actually seeing the light they emitted long ago.

Keep Looking Up

Space puts things into perpective.

It makes us realize how small we are in this grand universe, but we are also incredibly lucky to be able to comprehend the universe at all! We are intelligent beings with fascinating minds that can formulate questions about the origins of space and then go out and answer them, one discovery at a time.

We have to wonder about the unknown, and that’s what makes us human. So whether you’re in New Jersey or Nairobi, in Los Angeles or Lagos, you can be a part of exploring this amazing universe! You don’t need a telescope to fall in love with space; you just need to look up and take an active interest in your solar system and beyond.

The next great explorer could be you, and maybe they’re reading this blog right now! I can’t wait to see what the future holds for space exploration, and I can’t wait to see what role you play in it. If you want to follow along with your own journey of discovery, head to www.StellarScholars.org.

About the Author

I’m Yuvraj Dhillon, an upcoming sophomore at West Windsor-Plainsboro High School in New Jersey. I found my passion for space science after learning about the historic ISRO Chandrayaan-3 mission and have been learning everything I can about astronomy and astrophysics since then. I started this blog, Stellar Scholars, to educate myself and those around me, and I hope to inspire my peers and others who may not have the resources to learn about space to further their curiosity beyond the classroom. In the future, I hope to pursue a degree in either aerospace engineering or astrophysics and contribute my share to expanding human knowledge of the universe.

StellarScholars.org

References

The following resources are my trusted primary sources for my post, and I encourage you to explore them for more incredible facts:

NASA:

NASA Space Place: All About the Planets — This page gives a fascinating overview of all of the planets in our solar system!
NASA Space Place: Weather on Other Planets — An article comparing the weather on other planets to Earth’s.
NASA Space Place: How Many Moons Does Each Planet Have? — Another interesting article about the planets in our solar system.
NASA – Make a Model Solar System — A cool hands-on activity to build a model solar system.
NASA – Perseverance Rover — Information about NASA’s rover and its discovery on Mars.
NASA – James Webb Space Telescope — Details about the newest and most advanced space telescope, the James Webb Space Telescope.
NASA – Artemis Program — Information about NASA’s Artemis program to return humans to the moon and onward to Mars.

ISRO:

ISRO – For Students — ISRO has a student section with interesting information for budding space scientists.
ISRO – Space Books for Children — ISRO also has free educational books available for anyone interested in learning about space science!
ISRO – Chandrayaan-3 — Information regarding ISRO’s recent historic mission to the moon.
Antriksh Jigyasa — ISRO’s free online courses for students.

ESA:

ESA Kids: The Solar System — A fascinating page for students interested in space science.
ESA Kids — Games, videos, and more!

I always encourage my readers to fact-check their information by referring to these incredible primary sources. After all, that’s what good scientists do!

Stellar Scholars – Let's learn and explore Space together