The three kids, Beanie, Riya and Rishi, had gone to Tadoba forest, a tiger reserve, during the summer vacation with their parents. They were nature lovers and loved going to the forest. It was an exciting trip, as they saw six tigers during the safari trips. They were absolutely thrilled seeing the majestic animals at very close range. On the last day, after finishing dinner, they were lucky to see the rare sight of a shower of meteorites blazing a trail and vanishing in the night sky. But they were so exhausted by the heat and humidity during the safari that they went early to bed. Tomorrow they would be going back home. The three children were staying in one room and soon fell asleep.

Quite late into the night they were awakened by a loud clattering noise at the door, as if someone had thrown a stone. Rishi wanted to open the door and have a look, but Riya warned him not to go out, lest some wild animal roaming outside the cottage attack him. They might have made the noise.

Next morning Rishi woke up very early and opened the door. There was no one outside, but his foot touched a stone lying on the floor of the front verandah of the cottage. He picked up the stone, which was a dull, darkish colour. It had a bumpy, uneven surface with fine cracks, was light and small, its size fitting into the palm of his hand. He had a mind to throw it on the lawn outside, but kept it in a dark corner at the edge of the verandah so that others would not trample on it after crossing the door. When the other two children woke up, he showed them the stone. No one seemed to be interested.

After some time they went to have breakfast. On returning, they found the stone just in front of the door, on the spot where there was a big patch of sunlight. Rishi was surprised. He said, "Riya, how did it come here? I had placed it on the edge of the verandah." Beanie said, "Yes, Rishi dada, it was in the corner. I noticed it when I went out for breakfast." Riya said, "Someone in our absence must have shifted it." Beanie picked up the stone and placed it near her right ear. On shaking it, there was a very, very faint sloshing sound, as if there was some water inside it. She exclaimed, "It seems there is water inside the stone!" The others in turn pressed their ears close to the stone and heard the sound. They also saw that the stone glowed, quite different from its earlier dull colour. It seemed that the Sun's energy had somewhat brightened the stone. Just at that time Doel Mashi, aunt of Beanie and mother of Riya and Rishi, appeared. "Riya, Rishi, what are you doing wasting your time with a useless stone? Go, get ready. We have to leave in an hour."

The three of them decided to keep the stone in the shade of a tree on the front lawn. Then they went into the room to get ready, lest they get scolded again. After about half an hour, when they came outside, they were shocked to see the stone in the middle of the lawn, where the Sun shone brightly. The stone had moved again! This was something very mysterious. Rishi said, "It is clear that the stone can move on its own, and it needs the energy of the Sun." Curious as ever, Beanie placed the stone close to her ear again and was shocked to hear a very faint sound. It was a teeny-weeny voice saying, "Hi, folks. Why are you fiddling with me?" Beanie was scared, and in a hushed voice said, "Riya didi, someone inside the stone is talking to me. Can you hear its voice?" But Riya and Rishi heard nothing. Rishi teased, "Beanie, you must be imagining things." "But I distinctly heard something, Rishi dada." Beanie felt very embarrassed.

Riya kept the stone in her pocket and walked towards the swimming pool. After some time Riya came rushing back. "Beanie, Rishi, the stone is moving in my pocket. Beanie is right. When I brought it near my right ear, it angrily said, 'Why are you disturbing me? I was enjoying the Sun on the lawn and now you have put me in a dark place. I am in a bad mood.'" Whatever it might be, the thing was really funny and had a mind of its own.

But the matter was really serious, however absurd it might seem that a stone was talking! Riya told Beanie, "It seems friendly. Why don't you talk to it again?" Beanie hesitated, and then asked, "Who are you?" After a long silence, the stone said, "I am Luca." "And may I know who you are?" "I am Beanie, and here are my two cousins, Riya and Rishi." They asked, "Where have you come from?" "I have come from the asteroid Bennu." The kids were startled to hear the reply. Luca continued, "Bennu is near a bluish round planet which we see every day. But wait, where am I now? I must be in Bennu." "No, Luca, you are not! You are on that blue planet, which we call Earth, our home." "Oh my God! How will I go back home? It is so, so far away. I have left my parents and all my friends and relatives in Bennu." They could hear Luca crying. They all felt sorry and tried to console her. "Don't worry, Luca. We will do everything to get you back home."

There was silence for a long time. Then Luca said, "That's so kind of you. It makes me feel so good." "But tell us, Luca, how did you come all the way from Bennu?" "Actually, I had gone out of my home when suddenly there was a strong gust of wind and dust started swirling around. There was a lot of rubble nearby, and I took shelter in a cave where the ground was soggy. The cave collapsed and I was trapped inside the rock. I felt that we were tossed around and blown away by the wind into the air. I cannot remember what happened next, except that all of a sudden I felt quite hot and heard a loud noise of something breaking up." Beanie interrupted. "I can tell you what happened, Luca. The rock carrying you, on entering Earth's atmosphere, had caught fire and broken into fragments of small stones, and one small one with you inside had crashed into the Earth. And that is how you landed on our doorstep."

Rishi was inquisitive about how Luca looked. "Luca, we can't see you, nor can you see us. How do you live inside the small stone?" Luca replied, "I am like a jelly-like, bluish blob. In our home there is water underneath the surface and the ground is mostly soggy. This water and air are trapped inside the stone, and I can breathe. There are very fine cracks in the surface of the stone which let in sunlight only. They don't allow the water and the air to seep outside. We live by turning sunlight, water and carbon (pulled from the trapped air) into food, from which we get energy."

Riya said, "Now I understand why you were moving to get as much sunlight as possible. Your dull colour also changes in the sunlight. All of you in Bennu are stellivores, that is, Sun-eaters, just like our plants, which produce their own food in the same manner. We call it photosynthesis." Beanie agreed. "In our small lily pond in Shantiniketan, I have seen the lilies at dawn open up and turn their petals towards the Sun and follow the path of the Sun during the daytime. At night, the leaves droop and close tightly together." Luca asked, "Are you also stellivores?" Rishi said, "No, we are not Sun-eaters. We get food from outside by eating plants and other things." But Luca moaned, "You all have to do something quickly to return me to my home, or else I will die."

Suddenly they heard a shout from Doel Mashi. "What are you all doing again with that stone? Throw it away and come immediately. The car has come and we have to go back home. It's a long journey. There is no time to waste." Riya immediately put Luca into her bag. "Luca, we are now putting you in a dark place, for your own good. Just be still and absolutely quiet for some time, please."

The car started. Poor Luca was continuously fidgeting in the bag, but she was quiet. They reached home in the evening. Rishi rushed to his room and placed Luca under a table lamp. The light was strong. Slowly the dull colour of the stone turned bright. Rishi shouted, "It is getting back energy, even without the Sun!" Riya hissed, "Rishi, don't shout. Ma will hear. Speak softly." The kids were overjoyed and took turns in lovingly touching the stone.

Beanie was concerned. "Riya didi, what will happen now? We have promised that we will send Luca back to Bennu. How can we do it? And how long can Luca live?" The three cousins sat down thinking hard. It was late evening. Returning Luca to Bennu seemed hopeless. Feeling sad, Beanie sat down before the TV to watch her favourite programme, featuring Stitch. On browsing the channels, suddenly a news channel caught her attention. Someone was talking about sending a spacecraft to Bennu. She called Riya and Rishi. Both looked at the person and were excited. "It is Prof. Santanu Sen, Mama's friend, giving an interview. He is a very famous space scientist. Let's hear what he is saying."

Prof. Sen was talking. "We feel proud that NASA is collaborating with ISRO to send a robotic spacecraft, Osiris 2, to explore Bennu. Imagine you are a detective, and someone hands you a tiny, dusty piece of a space rock that is older than Earth itself! That is exactly what scientists did with a space rock named Ryugu. A robotic spaceship travelled far into space, scooped up dirt from this asteroid, and brought it back to Earth. Here is why this space dust is so important."

"It is a time capsule. Ryugu is like a leftover Lego brick from when our solar system was built. By studying it, we can learn exactly what the universe was made of billions of years ago."

"It holds the secrets to water. Scientists found that Ryugu has water trapped inside its rocks. This helps us understand how Earth got its deep, blue oceans."

"It has the building blocks of life. The space dust contains special ingredients called amino acids, which are used to build living things. This means the ingredients for life might have come from space!"

Beanie was about to shout, "We have the living thing!" But Rishi cupped his hand over her mouth. "Shhh, Beanie! Ma will hear. Thank God she is in the kitchen frying something, which is making a lot of noise."

Prof. Sen continued. "When the Earth was a brand-new baby planet, about 4.5 billion years ago, it was a very wild and hot place. It didn't have oceans, trees, or any life at all. It was a hell on Earth, with a large number of volcanoes, and it was recovering after the giant collision with another planet, Theos, which created the Moon. During that time, millions of asteroids and comets crashed into Earth in a giant space crash-party called the Late Heavy Bombardment. Here is how the Ryugu asteroid helps us understand that crazy time."

"The Delivery Trucks. Scientists think that early Earth was too hot to hold onto water or the ingredients for life on its own. The asteroids, acting like cosmic delivery trucks, smashed into Earth and dropped off these ingredients!"

"The Perfect Match. When scientists looked inside the Ryugu sample, they found the exact same kind of water and life-building blocks that we have on Earth today."

"The Proof. This proves that when those space rocks bombarded early Earth, they weren't just making giant craters. They were actually delivering the water and ingredients needed to jumpstart life! So, without that ancient asteroid bombardment, Earth might just be a dry, empty rock today!"

When the lady anchor asked Prof. Sen why the sample is so vital, Prof. Sen replied, "The Ryugu sample is incredibly important for the theory of Panspermia! Panspermia is the fascinating idea that life on Earth didn't actually start here. Instead, the basic ingredients for life (or even tiny space microbes) were made far away in deep space and were 'seeded' onto Earth by crashing asteroids or comets. The dirt from Ryugu gives this theory a huge boost. Here is why."

"The Genetic Lego Bricks. Scientists analysed the Ryugu samples and discovered that they contain all five key nucleobases (the chemical letters used to build DNA and RNA), along with over twenty types of amino acids. Since these are the exact blueprints used to create every living thing on Earth, it shows that these ingredients exist naturally in deep space!"

"No Earthly Cheating. In the past, when scientists found these life ingredients inside space rocks that fell to Earth, sceptics would say, 'The rock just got dirty from Earth's soil after it landed.' Because the Hayabusa2 spaceship caught the Ryugu sample directly in space and sealed it in a super-clean container, we know with certainty that these life-building blocks are originally from outer space."

"Imagine you are a detective again, and you have just solved the mystery of the Ryugu space rock. Suddenly, another robotic spaceship zooms back to Earth and drops off a brand-new, even bigger package of space dust! This package came from an asteroid named Bennu. A NASA spaceship named OSIRIS-REx travelled for years, did a quick 'high-five' with the asteroid to scoop up its dirt, and brought it back to Earth. Here is why this new Bennu space dust is so exciting for scientists."

"The Biggest Treasure Ever. The spaceship didn't just bring back a tiny pinch of dust. It brought back a whole cupful! It is the biggest jackpot of asteroid dust humans have ever collected. This means scientists all over the world can study it for years."

"Super Rich in Water and Carbon. When scientists opened the box, they found that Bennu is packed with carbon (which is the main ingredient used to build everything from trees to you and me!) and water. It's like finding a recipe book for how to make a living planet."

"A Space Guard Duty. Bennu is an asteroid that passes quite close to Earth. By studying its rocks, scientists can figure out exactly what it is made of. This helps us plan how to protect Earth if a big asteroid ever gets too close in the future! Just like Ryugu, Bennu's dust is a perfect time capsule from the birth of our solar system, but with even more clues to help us understand where we came from."

"Bennu is smaller, wetter, and packed with more carbon, while Ryugu is bigger and got extra-toasty hot a long time ago. Even though scientists think these two space rocks are like space 'siblings' that broke off from the very same giant parent rock long ago, they grew up a bit differently."

"Size. Ryugu is twice as wide as Bennu! Ryugu is about as big as a massive mountain in space, while Bennu is smaller, about the size of a very tall skyscraper like the Empire State Building."

"Water and Heat. Ryugu got baked by more heat in the past, so it has less water trapped inside its rocks. Bennu stayed a bit cooler and is super juicy, with more water-soaked clay and carbon."

"Colour and Sparkle. If you look at them through a super-powered telescope, Ryugu looks a little reddish, while Bennu looks a bit bluer and has cool patches of light and dark spots. When scientists study both boxes of dust side by side, it is like having two different puzzle pieces from the same ancient cosmic family!"

The three cousins felt dizzy. Was it possible that Luca's ancestors had landed on Earth billions of years ago, riding the asteroids, which had given rise to so many species or forms of life on our planet, and ultimately to animals and humans like us? And here, in front of the three of them, they were witnessing a repeat of that same event, but this time a stone with a living Luca inside, an event that had probably never happened in human history. It was unbelievable. The cousins were stunned by the enormity of their discovery. They realised how lucky they were, and how Chance plays an important role in our lives. It was again by Chance that a big asteroid suddenly crashed into the Earth and wiped out the dinosaurs. If the dinosaurs were alive, we would not be here. Suddenly Beanie said, "What does Luca mean?" They searched Google, and Rishi uttered a cry. "It reads, 'Last Universal Common Ancestor.'"

Luca's existence is a direct natural result of a theory discovered by the famous scientist Charles Darwin, whereby all living organisms, from microbes to whales, descended from earlier ones in one vast tree of life. We humans share a common ancestor with chimpanzees and bonobos that lived about 6 to 8 million years ago. All monkeys and apes are thought to have branched from a common ancestor about 25 million years ago. Keep going back down the tree far enough and you will find a common ancestor of all mammals, then all vertebrate organisms, and so on. Luca represents the point where the three domains of all life, eukarya (including animals, plants and fungi), bacteria, and archaea (another kind of microbe), converge to a single stem.

And then the breaking news came from Prof. Sen. "It is the cleanest, oldest space puzzle we have ever tried to solve, the Riddle of Life. We expect to find traces of life in Bennu. The third spacecraft, Osiris 2, will be launched from a place near Mumbai after two days." Rishi jumped from the sofa in excitement.

The three of them rushed into their room, closed the door and huddled together. Riya, in a fit of excitement, said, "I have an idea. Let me talk to Mama and tell him that we would like to see the robotic spacecraft tomorrow. We will take the stone and somehow slip it inside Osiris 2. This is the only way we can save Luca." "But Riya, why can't we tell Mama about Luca and give Luca to the scientists for research?" said Rishi. Beanie said, "We will break our promise to Luca. Also, Luca will not be of help to the scientists, as she is contaminated by Earth's atmosphere and soil. They will do experiments on the poor thing and kill her. If the scientists want a pure specimen, let them find one when Osiris 2 lands."

After a lot of discussion, all three agreed to send Luca back. Riya rang up Prof. Sen. "Santanu Mama, I am Riya, this side." "How are you, sweet angel?" "We are fine. Mama, I will request you for something which you cannot refuse." "What is it?" "We want to see a robotic spacecraft, meaning Osiris 2, tomorrow!" "But that's impossible." "Please, Mama. This is a once-in-a-lifetime opportunity." "Okay, let me try. Are both of you coming?" "We are three. Our cousin Beanie will also come with us."

There was no phone call the next day. In the meantime, Luca was getting weak. Under the bright lamp at night, she was not glowing brightly. She was losing strength. Her voice sounded weak. "When will I go home?" she cried. The cousins felt so helpless. Doel Mashi, seeing them sad, said, "The holidays will end three days from now and it is back to studies. That explains your long faces." At night, Beanie dreamt of holding Luca in her hands and playing with her. She was cute and smiling, bluish-white in colour, dancing with her tiny wavy arms and legs.

They had almost given up hope when Santanu Mama rang up Riya late at night. "Uff! You children have bothered me so much. Tomorrow at 3 pm sharp, come to my field office at the launch site. We have a window of only five minutes to see the spacecraft, after which everything will be sealed for the launch preparation. Don't be late!" The kids rolled on the floor in joy and hugged each other. Luckily, Doel Mashi was not at home. She would have been curious and asked a lot of uncomfortable questions.

The next day Riya called up the driver and, using Google Maps, reached the site at 2.30 pm. They were taken to Santanu Mama's chamber. There was a lot of activity, with people in blue and white suits running around. A car took them to the launch site, and there in front of them stood Osiris 2. They climbed up the ladder and a hatch was opened so that they could see the computers and instruments on board. A stern security guard stopped them at the hatch, but seeing Santanu Mama, he smiled and waved them on. Once inside, Rishi slipped the stone, kept in his pocket, into a tiny hole on a berth high above. "Bye, bye, Luca, we will miss you." A voice announced, "Time is up." They climbed down the ladder, boarded the pick-up car and went straight to Mama's office. All three of them were perspiring. Mama was very busy, and in no time they left, after thanking him profusely. Once inside the car, all three of them screamed and yelled and fell back on their seats, exhausted by the strain and tension.

The next day Osiris 2's launch was shown worldwide on TV. Rishi, watching intently, shouted, "There is Luca!" Riya said, "Rishi, don't talk nonsense!" Rishi insisted. "I saw a bluish colour on the window. The stone must have fallen down by the violent push felt during the launch and cracked." But they were very concerned. "How will Luca survive?" Beanie assured them that now that she was free to move, Luca would be smart enough to explore and find a nook with the right combination of gases and water in the airtight capsule to breathe. There were also bright lights inside the spacecraft to make up for the Sun's energy. "We must not forget that Luca is very tough, living on a barren, rocky rubble like Bennu."

After a long journey, Osiris 2 approached Bennu. Beanie had come down from Gurgaon and joined her two cousins. They watched live on TV the robot landing and, in a few seconds, scooping dirt from Bennu and flying away. The moment the lander touched the ground, they saw a tiny, tiny blue spot jump out in a flash and move away very fast from the lander. It was Luca! She was running on the ground, free at last to join her family. The cousins clapped their hands and danced around, shouting, "Luca! Hurrah, Luca!" Doel Mashi was perplexed. "Why this excitement? Tell me, what mischief were you up to?" Riya said, "Ma, it is the biggest mischief we have done and will ever do." They smiled at each other, as they knew they would share for all time the secret of the Origin of Life on Earth.

THE END