Encyclopedia vs Stars Units Sizes Objects
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Encyclopedia
Explore the solar system with extensive articles and high-definition images. This app offers comprehensive information, engaging content, and a user-friendly interface, making it suitable for both children and adults interested in space.
- Thousands of articles and HD photos
- Comprehensive solar system information
- Engaging and easy-to-understand content
- Offline availability
- Badge collection for reading
- Intuitive user interface
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Explore 386 illustrated articles about planets, moons, dwarf planets, asteroids, comets, astronomy, missions, discoveries, and the science of our solar system. Search article titles and full text, open clear article pages, and follow linked topics without losing your place. Reading progress and themed badges help you build a path through the collection. Explore the solar system from several angles: - Timeline view follows discoveries, missions, scientists, and changing ideas. - Graph view reveals relationships between worlds, spacecraft, people, and concepts. - Map view adds geographic context for observatories, discoveries, and missions where source material provides it. - References and image credits keep source attribution visible. Thirty articles are free to read. A one-time purchase unlocks the complete encyclopedia for offline reading, including maps, timelines, and graphs. Monthly or annual Premium includes the complete encyclopedia plus AI chat, with a seven-day free trial for eligible new subscribers. People who bought the original Full Version can restore permanent offline encyclopedia access; AI chat remains a separate Premium feature. AI chat answers grounded questions about the solar system and links back to relevant articles so you can continue reading and check the context. Article text is adapted from Wikipedia contributors under Creative Commons Attribution-ShareAlike 4.0. Every article includes source, revision-history, and image-credit links. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Stars Units Sizes Objects
Explore the vastness of the universe, from the smallest particles to the largest cosmic structures. Compare object sizes, view detailed images, and perform unit conversions across a wide range of astronomical scales. Learn about stars, galaxies, and the incredible distances between them.
- Compare object sizes
- View object images
- Pinch/Zoom and Pan images
- Unit conversion for distances
- Explore scales from Planck length to observable universe
- Learn about stars and galaxies
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Size of the smallest to largest objects and stars. Compare the size of objects in the universe. Object images. Pinch/Zoom image. Pan/Move image. Rotate image. Double tap to reset an image. From the smallest to the largest one. From planck length to observable universe. From Yoctometre, Zeptometre, Attometre, Femtometre, Picometre, Nanometre, Micro, Millimetre, Centimetre, Metre, KiloMetre, Lightyear, Parsecs, Billion Lightyears to 93 Billion Lightyears. Size of objects, particles, atoms, cells, stars and galaxies. Get to know the stars. Get to know the spaces. get to know the universe. How small is this world. How big is the universe. And How great is the creator. How far is the star distance from earth. Two way 18 distance unit conversion. planck length, yoctometer, zeptometer, attometer, femtometer, picometre, nanometre, micrometre, Millimeter, Centimeter, Meter, Kilometer, Inch, Foot, Mile, Astronomical, Lightyear, Parsecs. Perform auto conversion when picker is changed. Share conversion result. Reset unit convertor.
Screenshots
Verdict
The clearest difference is in-app purchases: Stars Units Sizes Objects at none against Encyclopedia's 1. Stars Units Sizes Objects also leads on update cadence (every 4 months vs every 62 months) and rating (4.2 vs 3.8). Encyclopedia's advantage is ads (none vs shown). On price, review sentiment, ratings volume and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Encyclopedia sells 1 one-off in-app purchase. Stars Units Sizes Objects asks for nothing beyond the download.
Stars Units Sizes Objects holds the better App Store score, 4.2 against 3.8. Both are backed by a comparable volume of ratings — 14 and 5 respectively. Written reviews complicate that: 83% of Encyclopedia's written reviews are positive against 80% of Stars Units Sizes Objects's, so the app with the better star average is not the one people write more warmly about.
Encyclopedia ships an update every 62 months, Stars Units Sizes Objects every 4 months. The most recent releases landed on September 3, 2026 and September 7, 2026 respectively.
| Parameter | Encyclopedia | Stars Units Sizes Objects |
|---|---|---|
| Price | Free | Free |
| Rating | 3.8 (14 ratings) | 4.2 (5 ratings) — better |
| Positive reviews | 83.3% of reviews — better | 80.0% of reviews |
| Number of ratings | 14 — better | 5 |
| Update frequency | Every 62 months | Every 4 months — better |
| Ads | No — better | Yes |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Ad-supported — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 322 MB | 124 MB |
| Age rating | 4+ | 4+ |
| Developer | Good Spider, LLC | Mudarmeen Munlin |
Customer experience
Encyclopedia
Stars Units Sizes Objects
In-app purchases
Encyclopedia
- Full Version$2.99
Stars Units Sizes Objects
No in-app purchases
Questions
Is Encyclopedia free?
Is Stars Units Sizes Objects free?
Which has better reviews, Encyclopedia or Stars Units Sizes Objects?
Do Encyclopedia or Stars Units Sizes Objects have ads?
Which is updated more often, Encyclopedia or Stars Units Sizes Objects?
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