# Interactive Solar System vs Stars Units Sizes Objects

The clearest difference is price: Stars Units Sizes Objects at Free against Interactive Solar System's $1.99. Interactive Solar System's advantage is ads (none vs shown) and update cadence (fortnightly vs every 4 months). On in-app purchases, device support and iOS requirement there is nothing between them.

Stars Units Sizes Objects is free to download; Interactive Solar System costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Interactive Solar System ships an update fortnightly, Stars Units Sizes Objects every 4 months. The most recent releases landed on September 18, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Interactive Solar System | Stars Units Sizes Objects |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Rating | — | **[4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews)** |
| Number of ratings | — | **5** |
| Positive reviews | — | 80.0% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | **Fortnightly** | Every 4 months |
| Monetization | — | Ad-supported |
| Size | 52 MB | 124 MB |
| Requires iOS | 12.0 | **11.0** |
| Devices | iPad, Apple TV | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Ventura Educational Systems](https://appshunter.io/developer/371324172) | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) |

## What reviewers say

### Interactive Solar System

[App page](https://appshunter.io/ios/app/interactive-solar-system/id1240878228)

**Features:** macOS Compatibility

**In-app purchases:** none


### 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 Interactive Solar System free?

Interactive Solar System costs $1.99, with no in-app purchases.

### Is Stars Units Sizes Objects free?

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

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

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

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

Interactive Solar System ships an update fortnightly, and Stars Units Sizes Objects every 4 months. Most recently, Interactive Solar System was updated on September 18, 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.*