# Exoplanet Explorer vs Stars Units Sizes Objects

The clearest difference is in-app purchases: Stars Units Sizes Objects at none against Exoplanet Explorer's 4. Stars Units Sizes Objects also leads on iOS requirement (11.0 vs 17.6). Exoplanet Explorer's advantage is ads (none vs shown) and update cadence (every 2 weeks vs every 4 months). On price there is nothing between them.

Both are free to download. Exoplanet Explorer sells 4 in-app purchases, starting at $2.99 per 3 months. Stars Units Sizes Objects asks for nothing beyond the download.

Exoplanet Explorer holds the better App Store score, 4.6 against 4.2. That said, the two scores are not equally well evidenced: Exoplanet Explorer has 70 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 100% of Exoplanet Explorer's written reviews are positive against 80% of Stars Units Sizes Objects's.

Exoplanet Explorer ships an update every 2 weeks, Stars Units Sizes Objects every 4 months. The most recent releases landed on October 11, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Exoplanet Explorer | Stars Units Sizes Objects |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (70 ratings)](https://appshunter.io/ios/app/exoplanet-explorer/id1457614833/reviews)** | [4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews) |
| Number of ratings | **70** | 5 |
| Positive reviews | **100.0% of reviews** | 80.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 2 weeks** | Every 4 months |
| Monetization | Freemium | **Ad-supported** |
| Size | 169 MB | 124 MB |
| Requires iOS | 17.6 | **11.0** |
| Devices | **iPhone, iPad, Mac, Apple Watch, Vision Pro** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Carsten Knoblich](https://appshunter.io/developer/541438854) | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) |

## What reviewers say

### Exoplanet Explorer

[App page](https://appshunter.io/ios/app/exoplanet-explorer/id1457614833)

Explore a vast catalog of over 6,000 confirmed exoplanets with detailed scientific data. Compare worlds, visualize habitable zones, and track new discoveries. Ideal for stargazers, students, educators, and researchers.

**Highlights:** 6,000+ confirmed exoplanets, Detailed scientific data, Advanced filtering and sorting, Planet comparison tool, Habitable zone analysis, Home screen widgets, Apple Watch companion app

**Features:** Family Sharing, Apple Watch app

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 3 months subscription | $2.99 | per 3 months |
| 12 months subscription | $6.99 | per year |
| Big supporting tip | $2.99 | one-time |
| Really big supporting tip | $4.99 | 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 Exoplanet Explorer free?

Exoplanet Explorer 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, Exoplanet Explorer or Stars Units Sizes Objects?

Exoplanet Explorer is rated higher. Exoplanet Explorer averages 4.6 out of 5 from 70 ratings, while Stars Units Sizes Objects averages 4.2 from 5 ratings.

### Do Exoplanet Explorer or Stars Units Sizes Objects have ads?

Stars Units Sizes Objects shows ads; Exoplanet Explorer does not.

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

Exoplanet Explorer ships an update every 2 weeks, and Stars Units Sizes Objects every 4 months. Most recently, Exoplanet Explorer was updated on October 11, 2026 and Stars Units Sizes Objects on September 22, 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.*