At 97 kilometers, I looked down and could see the hole our spacecraft had made in the thin, light blue oxygen layer around Earth. It looked as if there was a trail behind us, which disappeared as soon as I looked at it. I continued my self-guided tour and turned to gaze into space. I love the mysteries of the universe and all the questions that have crossed our minds over thousands of years, from exploration and hypotheses. Starlight reaches us years after stars explode, black holes absorb energy, and satellites show us entire galaxies in areas once thought to be completely devoid of matter... all of this has excited me for years. Where does matter in the universe come from? Where does it go? And why is it expanding? I know so little.