If there was more than one planet on each orbit, eventually they would collide with each other.
Answer:
Air molecules scatter blue light more efficiently than other colors.
Explanation:
The sunlight has many colors and each of them has a different wavelenght. The color blue has shorter wavelengths and higher frequencies than the other colors. So, as sunlight goes through the air, the blue part causes charged particles to oscillate faster than the red part does and it is scattered more efficiently than the other colors and that's the reason for the sky to be blue.
Answer:
I don't think it was because your room wasn't clean. The main cause of bed bugs is travel, which means most likely you got one on you when you went outside or something, and you accidentally got it into your room. Bed bugs hitchhike on luggage, clothing, people, etc.
If there are blood stains or dark/rusty spots on your bed/pillow, there are definitely bed bugs. The bloodstains/spots come from you crushing the bed bugs accidentally. The place where bed bugs are (in this case, your room), may also begin to smell bad. You might also see eggs laid by the bed bugs.
Let me know if you have any other questions. Good luck!
The another name for the equatorial coordinate system is B. Celestial.
Happy Studying! ^=^