<|im_start|>user
How many black holes are known to exists at the time<|im_end|>
<|im_start|>assistant
Based on scientific estimates, there could be millions or even billions of black holes in our galaxy alone, and there could be trillions or more across the entire observable universe. The number of black holes in the universe is constantly changing as they are created from the collapse of massive stars or through the merging of existing black holes.<|im_end|>
