Add subfields and a Wikipedia link to text

cgobat · cgobat · commit 329982f582ab · 2023-01-27T14:43:34.000-07:00
diff --git a/topics/astronomy/index.md b/topics/astronomy/index.md
@@ -6,4 +6,4 @@ topic: astronomy
 wikipedia_url: https://en.wikipedia.org/wiki/Astronomy
 ---
 
-Astronomy is an academic discipline and major branch of science that deals with the study of matter, objects, and phenomena in outer space and the Universe.
+Astronomy is an academic discipline and major branch of science that deals with the study of matter, objects, and phenomena in [outer space](https://en.wikipedia.org/wiki/Outer_space) and the Universe. Subfields include astrophysics, planetary science, astrobiology, and astrochemistry.
