Curious Kids is a series for children in which we ask experts to answer questions from kids. What is the smallest thing in the universe that actually exists? – Mimi, 12, Abeokuta, Nigeria To find an ...

Scientists discovered a distant jellyfish galaxy with star-forming "tails" stretching back 8.5 billion years.

The surface of Earth is finite. We can measure it. If it was expanding, then its size would grow with time. And once again, good ol' Earth helps us understand what the universe might be doing beyond ...

Add Yahoo as a preferred source to see more of our stories on Google. In space, there are four dimensions: length, width, height and time. scaliger/iStock/NASA via Getty Images Plus About a century ...