# Back in Time vs Stars Units Sizes Objects

The clearest difference is price: Stars Units Sizes Objects at Free against Back in Time's $7.99. Stars Units Sizes Objects also leads on device support (3 vs 1) and iOS requirement (11.0 vs 16.0). Back in Time's advantage is ads (none vs shown) and rating (4.6 vs 4.2). On review sentiment, update cadence and in-app purchases there is nothing between them.

Stars Units Sizes Objects is free to download; Back in Time costs $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Back in Time holds the better App Store score, 4.6 against 4.2. That said, the two scores are not equally well evidenced: Back in Time has 25 ratings behind it against 5, so its average is the more settled of the two. Written reviews point the same way: 84% of Back in Time's written reviews are positive against 80% of Stars Units Sizes Objects's.

Back in Time ships an update every 7 months, Stars Units Sizes Objects every 4 months. The most recent releases landed on October 7, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Back in Time | Stars Units Sizes Objects |
| --- | --- | --- |
| Price | $7.99 | **Free** |
| Rating | **[4.6 (25 ratings)](https://appshunter.io/ios/app/back-in-time/id450345693/reviews)** | [4.2 (5 ratings)](https://appshunter.io/ios/app/stars-units-sizes-objects/id1576148571/reviews) |
| Number of ratings | **25** | 5 |
| Positive reviews | **83.7% of reviews** | 80.0% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 7 months | **Every 4 months** |
| Monetization | Paid | **Ad-supported** |
| Size | 836 MB | 124 MB |
| Requires iOS | 16.0 | **11.0** |
| Devices | iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Landka](https://appshunter.io/developer/450345696) | [Mudarmeen Munlin](https://appshunter.io/developer/1348165664) |

## What reviewers say

### Back in Time

[App page](https://appshunter.io/ios/app/back-in-time/id450345693)

Explore the history of the Universe, Earth, Life, and Civilization through an immersive, interactive journey. This app uses custom animations, timelines, and interesting facts to bring historical events to life. It's designed to help users understand the connections between events and see the bigger picture.

**Highlights:** Interactive timeline of events, Custom animations and videos, Over 350 remarkable images, Little-known interesting facts, Offline access, Multilingual support

**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 Back in Time free?

Back in Time costs $7.99, with no in-app purchases.

### Is Stars Units Sizes Objects free?

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

### Which has better reviews, Back in Time or Stars Units Sizes Objects?

Back in Time is rated higher. Back in Time averages 4.6 out of 5 from 25 ratings, while Stars Units Sizes Objects averages 4.2 from 5 ratings.

### Do Back in Time or Stars Units Sizes Objects have ads?

Stars Units Sizes Objects shows ads; Back in Time does not.

### Which is updated more often, Back in Time or Stars Units Sizes Objects?

Back in Time ships an update every 7 months, and Stars Units Sizes Objects every 4 months. Most recently, Back in Time was updated on October 7, 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.*