# Encyclopedia vs Stars Units Sizes Objects

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.

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.

## The numbers

| Metric | Encyclopedia | Stars Units Sizes Objects |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.8 (14 ratings)](https://appshunter.io/ios/app/encyclopedia-solar-system/id1124568774/reviews) | **[4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews)** |
| Number of ratings | **14** | 5 |
| Positive reviews | **83.3% of reviews** | 80.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 62 months | **Every 4 months** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 322 MB | 124 MB |
| Requires iOS | 15.0 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Good Spider, LLC](https://appshunter.io/developer/1487595667) | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) |

## What reviewers say

### Encyclopedia

[App page](https://appshunter.io/ios/app/encyclopedia-solar-system/id1124568774)

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.

**Highlights:** 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

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version | $2.99 | one-time |


### Stars Units Sizes Objects

[App page](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571)

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.

**Highlights:** 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

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Encyclopedia free?

Encyclopedia is free to download, with in-app purchases available.

### Is Stars Units Sizes Objects free?

Stars Units Sizes Objects is free to download, with no in-app purchases.

### Which has better reviews, Encyclopedia or Stars Units Sizes Objects?

Stars Units Sizes Objects is rated higher. Encyclopedia averages 3.8 out of 5 from 14 ratings, while Stars Units Sizes Objects averages 4.2 from 5 ratings.

### Do Encyclopedia or Stars Units Sizes Objects have ads?

Stars Units Sizes Objects shows ads; Encyclopedia does not.

### Which is updated more often, Encyclopedia or Stars Units Sizes Objects?

Encyclopedia ships an update every 62 months, and Stars Units Sizes Objects every 4 months. Most recently, Encyclopedia was updated on September 3, 2026 and Stars Units Sizes Objects on September 7, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*