# Stars Units Sizes Objects vs DIY Solar System

The clearest difference is ads: DIY Solar System at none against Stars Units Sizes Objects's shown. DIY Solar System also leads on rating (4.5 vs 4.2) and review sentiment (100% vs 80%). On price, update cadence, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

DIY Solar System holds the better App Store score, 4.5 against 4.2. Both are backed by a comparable volume of ratings — 5 and 16 respectively. Written reviews point the same way: 80% of Stars Units Sizes Objects's written reviews are positive against 100% of DIY Solar System's.

Stars Units Sizes Objects ships an update every 4 months, DIY Solar System every 2 months. The most recent releases landed on September 7, 2026 and June 3, 2026 respectively.

## The numbers

| Metric | Stars Units Sizes Objects | DIY Solar System |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews) | **[4.5 (16 ratings)](https://appshunter.io/ios/app/diy-solar-system/id1644242890/reviews)** |
| Number of ratings | 5 | **16** |
| Positive reviews | 80.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Ad-supported | **Free** |
| Size | 124 MB | 180 MB |
| Requires iOS | **11.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) | [The Lawrence Hall of Science](https://appshunter.io/developer/462994550) |

## What reviewers say

### 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


### DIY Solar System

[App page](https://appshunter.io/ios/app/diy-solar-system/id1644242890)

Explore the solar system with interactive activities and an augmented reality planet walk. Learn about space travel, design a moon base, and identify celestial objects. Developed by leading science institutions, this app makes learning about space engaging for families and educators.

**Highlights:** Interactive space activities, Augmented reality planet walk, Design a moon base, Grow a space garden, Control a Mars rover, In or Out space game, NASA imagery

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Stars Units Sizes Objects free?

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

### Is DIY Solar System free?

DIY Solar System is free to download, with no in-app purchases.

### Which has better reviews, Stars Units Sizes Objects or DIY Solar System?

DIY Solar System is rated higher. Stars Units Sizes Objects averages 4.2 out of 5 from 5 ratings, while DIY Solar System averages 4.5 from 16 ratings.

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

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

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

Stars Units Sizes Objects ships an update every 4 months, and DIY Solar System every 2 months. Most recently, Stars Units Sizes Objects was updated on September 7, 2026 and DIY Solar System on June 3, 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.*