# Solar System vs Stars Units Sizes Objects

The clearest difference is review sentiment: Stars Units Sizes Objects at 80% against Solar System's 38%. Stars Units Sizes Objects also leads on in-app purchases (none vs 1) and update cadence (every 4 months vs every 14 months). Solar System's advantage is ads (none vs shown) and ratings volume (25 vs 5). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Solar System 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 4.0. That said, the two scores are not equally well evidenced: Solar System has 25 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 38% of Solar System's written reviews are positive against 80% of Stars Units Sizes Objects's.

Solar System ships an update every 14 months, Stars Units Sizes Objects every 4 months. The most recent releases landed on June 8, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Solar System | Stars Units Sizes Objects |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.0 (25 ratings)](https://appshunter.io/ios/app/solar-system-hd/id848032263/reviews) | **[4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews)** |
| Number of ratings | **25** | 5 |
| Positive reviews | 37.5% of reviews | **80.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 14 months | **Every 4 months** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 52 MB | 124 MB |
| Requires iOS | 11.0 | 11.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Magicbox Animation Private limited](https://appshunter.io/developer/726115662) | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) |

## What reviewers say

### Solar System

[App page](https://appshunter.io/ios/app/solar-system-hd/id848032263)

Explore our solar system with detailed descriptions of the Sun, planets, and moon. Enjoy quality audio and comprehensive information to quickly grasp essential astronomical facts.

**Highlights:** Full solar system model, Detailed object descriptions, High-quality audio, Comprehensive astronomical information

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Solar System | $0.99 | 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 Solar System free?

Solar System 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, Solar System or Stars Units Sizes Objects?

Stars Units Sizes Objects is rated higher. Solar System averages 4.0 out of 5 from 25 ratings, while Stars Units Sizes Objects averages 4.2 from 5 ratings.

### Do Solar System or Stars Units Sizes Objects have ads?

Stars Units Sizes Objects shows ads; Solar System does not.

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

Solar System ships an update every 14 months, and Stars Units Sizes Objects every 4 months. Most recently, Solar System was updated on June 8, 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.*