How 2 Cosmic Coincidences Paved the Way for Life in Our Solar System
Note: I have written this article in a new format. I have been thinking about this for a while. Let me know what you think about it.
Hope you like it!
The professor walked into the lecture hall carrying his laptop under his left arm. A bespectacled young man, half the professor’s age, followed him into the hall carrying a stack of notebooks.
“Good evening!” exclaimed the professor, as he kept the laptop on the center table and walked around it to approach the first bench where I was sitting.
The young man, the professor’s PhD scholar, dropped the notebooks on the table and sat down beside me.
“Today we have something very interesting to discuss,” said the professor. His deep brown eyes shone in excitement as he looked at me. “Tell me, why do you think life began on Earth only?”
“Because Earth is at the right distance from the Sun, and has enough gravity to hold an atmosphere,” I replied.
“Correct! Now,” he said as he clapped his hands, “let’s go back a step and discuss the conditions that favored the genesis of life during the formation of the Solar System.”
“Huh, that sounds interesting,” I remarked.
“It is! Here’s the issue, though — the topic of the formation of our Solar system is extremely intensive.
So for today’s discussion, I would like to share 2 amazing coincidences in the solar system’s history that led to life on Earth.”
Coincidence #1 — The supernova was triggered at the right place.
“Tell me what you know about the formation of the Solar System,” the professor asked me, as he sat on the table.
“Well, not much”, I confessed. “All I know is that a fragment of giant molecular cloud collapsed under its own weight. That eventually formed the Sun and the planets.”
“That’s not bad,” said the scholar. “Something needs to trigger that collapse. Do you know what a supernova is?”
“Yes. It’s an extremely energetic explosion that occurs when a heavy star is near the end of its life time.
Hold on. So are you saying a supernova triggered the collapse of the cloud fragment?”
“Exactly. The cloud was 65 light years across, while the fragments were around 3.5 light years across. The small fragment that became the solar system, however, was just 20,000 AU in size.”
“A few scientists have actually named the star that went supernova. Coatlicue,” quipped the professor. “The star would have been, at least, 30 times the mass of the Sun.”
“Whoa,” I blurted out.
“Hold that reaction,” said the professor as he gleamed in excitement. “Here’s the incredible coincidence. The supernova could have occurred anywhere in the galaxy. But it happened in this neighborhood, filled with the right compounds.”
“Compounds such as Hydrogen and Helium made up 98% of the fragment’s mass,” continued the scholar. “There were some trace amounts of Lithium too. They were crucial for triggering nuclear fusion and creating the Sun.”
“Interesting. What about the remaining 2%?” I asked.
“That consisted of heavier elements,” the scholar poised himself as he delivered his next important point. “These elements would later form the protoplanetary disk.”
“And those elements would be the founding blocks for the planet.”
“Exactly. You catch on quick!” exclaimed the professor.
I leaned forward on the desk as I tried to wrestle with the new knowledge. “So Coatlicue’s supernova happened at the right place, since it contained the right amount of the right materials. And I’m sure the size of the gas cloud would be an important factor too.”
“You got that right,” replied the scholar as he smiled at me.
Coincidence #2 — Jupiter was not heavy enough to trigger nuclear fusion.
“That’s a hell of a coincidence. What’s the second one?” I asked, as I looked at the professor with curiosity.
“Jupiter,” he answered as he got down from the table and started pacing left and right in front of me. “This gas giant has played pivotal roles in multiple points of our history.
You see, Jupiter is often called a failed star. That’s because it does’t have enough mass to fuse hydrogen in its core,” he looked at the scholar and signaled him to continue.
“But it is very much like the Sun. It’s mostly made of Hydrogen and Helium, and lacks a solid core. Because of that, its poles rotate slower than its equator. Just like the Sun!” exclaimed the scholar in excitement.
The professor stopped pacing and looked at me to continue. “If Jupiter had enough mass to trigger nuclear fusion, this system would have 2 stars instead of 1. Such systems are, actually, a very common occurrence.”
“I see,” I remarked, as I started thinking deeply. “If this was a 2-star system, then its evolution would have been completely different from what it is today. There would be no way a planet like Earth would form and contain life.”
“Well, I won’t say ‘no way’. There could be a way for a planet around a circumbinary star system to contain life. The probability is small, but not zero.”
“Got it. And instead of becoming a star, Jupiter became this system’s big brother and started shaping its evolution.”
“Exactly,” said the scholar. “This would be instrumental in the genesis of life on Earth.”
“Now that was a fascinating discussion,” said the professor as he rubbed his hands. He looked at the scholar and continued, “Please take my laptop and the notebooks to my office. I have some urgent work at the library.”
“Sure,” replied the scholar.
“Hold on,” I said when a realization dawned upon me. “How do we know that a supernova triggered the fragment’s collapse?” I asked as I got up from my bench.
“Ah that’s the right question. Why don’t we discuss that in our next meeting?” asked the professor, with a warm smile on his face.
“Alright!”
Hardik Medhi
Stay Curious
