英文解释：

1. The whole of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.

（整个空间和时间及其内容，包括行星、恒星、星系以及其他所有形式的物质和能量。）

2. The totality of all existence, including everything that exists, everything that has ever existed, and everything that will exist.

（所有存在的总和，包括现在存在的一切、曾经存在的一切以及将来存在的一切。）

日常用法举例：

1. Astronomers are studying the expansion of the universe to understand how it began and how it might end.

（天文学家正在研究宇宙的膨胀，以了解宇宙是如何开始的以及它可能会如何结束。）

2. The concept of a multiverse suggests that our universe is just one of many possible universes.

（多重宇宙的概念表明，我们的宇宙只是许多可能宇宙中的一个。）

3. The universe is vast and full of mysteries that scientists are still trying to unravel.

（宇宙浩瀚无边，充满了科学家们仍在努力解开的谜团。）

4. The universe is expanding, and this expansion is causing galaxies to move away from each other.

（宇宙正在膨胀，这种膨胀导致星系相互远离。）

5. The universe is not infinite; it has a finite size and age.

（宇宙不是无限的；它有有限的大小和年龄。）

6. The Big Bang theory explains how the universe began from a singularity and has been expanding ever since.

（大理论解释了宇宙是如何从一个奇点开始，并且从那时起一直在膨胀。）

7. The search for extraterrestrial life is a quest to find signs of life beyond our own universe.

（寻找外星生命的搜索是在我们自己的宇宙之外寻找生命迹象的探索。）

8. The universe is a fascinating subject that has inspired countless books, movies, and scientific theories.

（宇宙是一个迷人的主题，它激发了无数书籍、电影和科学理论的灵感。）