Ever wondered how our entire universe came to exist? Physical... Show more
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0
C
Christine Mendoza
12/12/2025
Earth Science
The Series of Big Bang
445
•
Dec 12, 2025
•
The Big Bang Series: Formation of Light Elements
C
Christine Mendoza
@christinemndz
1 / 5
What Is Physical Science?
Physical science is your gateway to understanding the non-living world around you. It's the systematic study of everything from tiny atoms to massive galaxies, covering how matter moves, what electricity and magnetism do, and how light works.
This field connects ancient wisdom with cutting-edge discoveries. You'll explore how our understanding of the universe has evolved from early civilizations to modern space technology and medical breakthroughs.
Physical science applications are everywhere in your daily life - from the weather you experience to the technology in your phone, and even the cosmetics you might use.
Fun Fact: Physical science helps explain phenomena ranging from atmospheric events to space exploration, making it one of the most practical subjects you'll study!
Cosmology: Studying Our Universe
Cosmology is the fascinating science that tackles the biggest questions: How did the universe begin? How will it end? It's basically the ultimate detective story about existence itself.
There are two main approaches to cosmology. Religious cosmology uses spiritual beliefs to explain creation, like the concept of creatio ex nihilo (creation from nothing) found in Genesis. Physical cosmology relies on scientific evidence and experiments to piece together the universe's story.
Key scientific breakthroughs shaped our understanding. Nicolaus Copernicus showed that the sun, not Earth, sits at the center of our solar system. Albert Einstein's theory of relativity revealed that the universe is actually expanding. This led to the Big Bang theory, which explains how everything started.
Think About It: The shift from thinking Earth was the center of everything to understanding we're part of an expanding universe completely changed how humans see their place in the cosmos.
The Big Bang Theory Explained
The Big Bang theory describes how our universe began expanding about 13.8 billion years ago from an incredibly tiny point called a singularity. This wasn't an explosion in space - it was space itself expanding!
Here's what happened step by step: First, the universe started as a singularity containing all space, time, matter, and energy. Then it expanded rapidly through a process called inflation. As it grew, it cooled down significantly.
During this cooling, nucleosynthesis occurred - nuclear fusion created the first atomic nuclei. Finally, electrons joined with these nuclei through recombination, forming the first actual atoms in the universe.
The evidence is rock-solid. Scientists like Vesto Slipher observed galaxies moving away from Earth using redshift measurements. Edwin Hubble calculated distances between galaxies, while Wilson and Penzias discovered cosmic microwave background radiation - basically the leftover energy from the Big Bang still humming through space today.
Amazing Fact: The universe is only 5% ordinary matter - the rest is mysterious dark matter and dark energy!
Big Bang Nucleosynthesis: Creating the First Elements
Big Bang Nucleosynthesis (BBN) was like the universe's first chemistry lab, producing light elements during the initial expansion. This process created hydrogen isotopes, helium, lithium, and beryllium - the building blocks for everything that came after.
The process started when protons and neutrons fused together, creating deuterium (heavy hydrogen) and releasing high-energy photons. However, there was a catch called the deuterium bottleneck - these newly formed atoms kept getting destroyed by intense heat and radiation.
Once the universe cooled enough, deuterium became stable and triggered a cascade of fusion reactions. This temperature drop was crucial because it allowed the BBN process to really get going and create more complex elements.
Modern astronomy confirms the universe is 13.8 billion years old, with ordinary matter making up just 5% of its total composition. The rest remains one of science's greatest mysteries.
Key Insight: The deuterium bottleneck shows how precise conditions had to be for element formation - too hot and atoms get destroyed, too cool and fusion stops!
Fusion Reactions: Building Heavier Elements
The BBN process involved several types of fusion reactions that built increasingly complex elements. Think of it like cosmic Lego blocks - simple pieces combining to make more elaborate structures.
Deuterium nuclei could fuse in two ways: either forming tritium (radioactive hydrogen) plus a proton, or creating helium-3 plus a neutron. These reactions provided the raw materials for even heavier elements.
Helium-4 formation was particularly important, happening through three different fusion pathways. It could form from proton-tritium fusion, deuterium-tritium fusion, or deuterium-helium-3 fusion. This versatility made helium-4 abundant in the early universe.
The process continued with helium-4 fusing with tritium to create lithium-7, though this lithium often broke apart again when hit by protons, producing two helium-4 nuclei. Helium-4 could also combine with helium-3 to form beryllium-7, though this isotope was unstable.
Cool Connection: These same fusion reactions power the sun today - the universe has been recycling these processes for billions of years!
We thought you’d never ask...
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Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The Big Bang Series: Formation of Light Elements
C
Christine Mendoza
@christinemndz
Ever wondered how our entire universe came to exist? Physical science gives us incredible insights into the cosmos, from the Big Bang that started it all 13.8 billion years ago to how the first atoms formed in space. Understanding these... Show more
What Is Physical Science?
Physical science is your gateway to understanding the non-living world around you. It's the systematic study of everything from tiny atoms to massive galaxies, covering how matter moves, what electricity and magnetism do, and how light works.
This field connects ancient wisdom with cutting-edge discoveries. You'll explore how our understanding of the universe has evolved from early civilizations to modern space technology and medical breakthroughs.
Physical science applications are everywhere in your daily life - from the weather you experience to the technology in your phone, and even the cosmetics you might use.
Fun Fact: Physical science helps explain phenomena ranging from atmospheric events to space exploration, making it one of the most practical subjects you'll study!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cosmology: Studying Our Universe
Cosmology is the fascinating science that tackles the biggest questions: How did the universe begin? How will it end? It's basically the ultimate detective story about existence itself.
There are two main approaches to cosmology. Religious cosmology uses spiritual beliefs to explain creation, like the concept of creatio ex nihilo (creation from nothing) found in Genesis. Physical cosmology relies on scientific evidence and experiments to piece together the universe's story.
Key scientific breakthroughs shaped our understanding. Nicolaus Copernicus showed that the sun, not Earth, sits at the center of our solar system. Albert Einstein's theory of relativity revealed that the universe is actually expanding. This led to the Big Bang theory, which explains how everything started.
Think About It: The shift from thinking Earth was the center of everything to understanding we're part of an expanding universe completely changed how humans see their place in the cosmos.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The Big Bang Theory Explained
The Big Bang theory describes how our universe began expanding about 13.8 billion years ago from an incredibly tiny point called a singularity. This wasn't an explosion in space - it was space itself expanding!
Here's what happened step by step: First, the universe started as a singularity containing all space, time, matter, and energy. Then it expanded rapidly through a process called inflation. As it grew, it cooled down significantly.
During this cooling, nucleosynthesis occurred - nuclear fusion created the first atomic nuclei. Finally, electrons joined with these nuclei through recombination, forming the first actual atoms in the universe.
The evidence is rock-solid. Scientists like Vesto Slipher observed galaxies moving away from Earth using redshift measurements. Edwin Hubble calculated distances between galaxies, while Wilson and Penzias discovered cosmic microwave background radiation - basically the leftover energy from the Big Bang still humming through space today.
Amazing Fact: The universe is only 5% ordinary matter - the rest is mysterious dark matter and dark energy!
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Big Bang Nucleosynthesis: Creating the First Elements
Big Bang Nucleosynthesis (BBN) was like the universe's first chemistry lab, producing light elements during the initial expansion. This process created hydrogen isotopes, helium, lithium, and beryllium - the building blocks for everything that came after.
The process started when protons and neutrons fused together, creating deuterium (heavy hydrogen) and releasing high-energy photons. However, there was a catch called the deuterium bottleneck - these newly formed atoms kept getting destroyed by intense heat and radiation.
Once the universe cooled enough, deuterium became stable and triggered a cascade of fusion reactions. This temperature drop was crucial because it allowed the BBN process to really get going and create more complex elements.
Modern astronomy confirms the universe is 13.8 billion years old, with ordinary matter making up just 5% of its total composition. The rest remains one of science's greatest mysteries.
Key Insight: The deuterium bottleneck shows how precise conditions had to be for element formation - too hot and atoms get destroyed, too cool and fusion stops!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Fusion Reactions: Building Heavier Elements
The BBN process involved several types of fusion reactions that built increasingly complex elements. Think of it like cosmic Lego blocks - simple pieces combining to make more elaborate structures.
Deuterium nuclei could fuse in two ways: either forming tritium (radioactive hydrogen) plus a proton, or creating helium-3 plus a neutron. These reactions provided the raw materials for even heavier elements.
Helium-4 formation was particularly important, happening through three different fusion pathways. It could form from proton-tritium fusion, deuterium-tritium fusion, or deuterium-helium-3 fusion. This versatility made helium-4 abundant in the early universe.
The process continued with helium-4 fusing with tritium to create lithium-7, though this lithium often broke apart again when hit by protons, producing two helium-4 nuclei. Helium-4 could also combine with helium-3 to form beryllium-7, though this isotope was unstable.
Cool Connection: These same fusion reactions power the sun today - the universe has been recycling these processes for billions of years!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user