r/astrophysics↗
Astrophysics: the science of space
The branch of astronomy concerned with the physical nature of stars and other celestial bodies, and the application of the laws and theories of physics to the interpretation of astronomical observations.
173k subscribers147 posts / mo in Sep 2026131 authors / mosince 2010
r/astrophysics has 173k members (+33% over the last 12 months). It gets about 147 posts a month from 131 people. Top topics: Space & Physics Engineering, Big Bang Theory and Dark Matter Mysteries.
When to post on r/astrophysics
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How r/astrophysics has grown
Subscriber growth
Subscribers over time
Monthly activity
Posts, comments and authors per month
Topics and brands on r/astrophysics
Top topics
Share of the subreddit's posts
- Space & Physics Engineering2.7%
- Big Bang Theory1.5%
- Dark Matter Mysteries0.7%
- Black Holes0.7%
- Galaxy Exploration0.6%
Brands people mention
Most-mentioned brands and sites, last 12 months
- arXiv.org e-Print archive
- NASA
- Doi
- Institute of Physics
- Nature
Everything else about r/astrophysics
Posting rules and account requirements, how often posts get removed, who writes here (age, gender, countries), what people ask for, how they talk, and related subreddits — all in the full report.
Posts and activity for Sep 2026. Members from Reddit's subscriber counts. Read from the same data the app runs on. Our research