Don’t capitalize universe.
Otherwise, keep on writing science-y stuff in a science-y way, with scientific notation for huge numbers and all that.
If you, like, totally hate anything in passive voice because your high school English teacher — or one of your undergrad professors in anthropology, maybe — told you that every to be verb is BAD, even for science papers where passive voice is often the standard, you can change the example to Astronomers estimate that there are between 10^22 and 10^24 stars in the universe. I happen to like the active-voice version better, but I wanted to show you that you don’t have to use active voice all the time.
(There will be no “Writing Glitch” post tomorrow, because I will be busy with real-life stuff: helping cook a large bird, for one thing, and then eating the large bird.)