Size: 1/14646 of the Earth; 870m in diameter
Weight: Lighter than Earth; 450,000,000,000kg
Temperature: Very much higher and colder than the Earth; -50 to 60 degrees Celcius
Density: Heavier than water, 1.27g/cm3
Composition: Rocks with carbon
Satellite: No satellite
Recent exploration missions: Hayabusa 2 by JAXA (2018-2019)
Something curious about the Ryugu
1. How is the brightness/darkness?
Ryugu is really dark and too black to reflect the sunlight. This is because Ryugu contains lots of carbon; it’s like pencil tips and black inks used for Japanese calligraphy. By the way, do you know that all living creatures on Earth contained carbon inside? Researchers think that carbons composing lives on Earth might have been brought by asteroids, like Ryugu, a long time ago.
2. What is its birthplace?
We don’t really know when or where Ryugu was made. But we know that Ryugu has very low density, which means that it has lots of voids. And the voids may have resulted from rocks’ repetitious impacts on each other. Ryugu is close to Earth now, but scientists believe it was located in the asteroid belt, far from Mars, 9 million years ago. More than 1 million asteroids like Ryugu exist in the asteroid belt between Mars and Jupiter.
3. Jumping up!
Ryugu’s gravity is approximately 1/80,000th, which means we would feel our weight much lighter if we were standing up on Ryugu. If we jumped up hard on Ryugu, we wouldn’t be able to come back to Ryugu again. Ryugu has so many rocks, and thus building a house on Ryugu would be complicated. Besides, since Ryugu is moving across the path of Earth, Ryugu will likely hit Earth someday in the future. Thus, overall, living on Ryugu would be very difficult!
Checklist
- Humans can live there (Yes or No): No…no atmosphere with too little gravity
- Humans can breathe there (Yes or No): No, no atmosphere at all
- Humans can walk on the surface there (Yes or No): Yes, but if you jump, you’ll not be there
- The temperature of its surface is (Hot or Cold): Hot and Cold!
- It is a (sinking or floating) object: Sinking, it’s made of rocks
- Water exists there (Yes or No): Yes and No; no liquid water but some rocks contain water