Earth's Core vs Stars Units Sizes Objects
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Earth's Core
Explore the internal structure of our planet with a detailed view of Earth's layers. Discover the composition, temperature, and depth of each section, from the crust to the core. This educational tool provides a fascinating look beneath your feet.
- Visualize Earth's internal structure
- Explore planet layers
- Discover layer temperatures
- Learn layer depths
- Detailed look inside the planet
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The Earth's Core App lets you see our planet’s internal structure. Just point your mobile to the center of the Earth and experience a deep look inside our planet. Right beneath your feet, thousands of kilometers deep, lies a giant ball of molten Iron as hot as the surface of the sun! Explore the Layers of the Earth and their names, discover the temperature and depth of each layer. Feedback and ideas: please send to support@cosmic-watch.com
Stars Units Sizes Objects
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.
- 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
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Size of the smallest to largest objects and stars. Compare the size of objects in the universe. Object images. Pinch/Zoom image. Pan/Move image. Rotate image. Double tap to reset an image. From the smallest to the largest one. From planck length to observable universe. From Yoctometre, Zeptometre, Attometre, Femtometre, Picometre, Nanometre, Micro, Millimetre, Centimetre, Metre, KiloMetre, Lightyear, Parsecs, Billion Lightyears to 93 Billion Lightyears. Size of objects, particles, atoms, cells, stars and galaxies. Get to know the stars. Get to know the spaces. get to know the universe. How small is this world. How big is the universe. And How great is the creator. How far is the star distance from earth. Two way 18 distance unit conversion. planck length, yoctometer, zeptometer, attometer, femtometer, picometre, nanometre, micrometre, Millimeter, Centimeter, Meter, Kilometer, Inch, Foot, Mile, Astronomical, Lightyear, Parsecs. Perform auto conversion when picker is changed. Share conversion result. Reset unit convertor.
Screenshots
Verdict
The clearest difference is ads: Earth's Core at none against Stars Units Sizes Objects's shown. Earth's Core also leads on review sentiment (100% vs 80%) and monetization model (free vs ad-supported). Stars Units Sizes Objects's advantage is update cadence (every 4 months vs every 70 months). On price, rating, ratings volume and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 4.3 for Earth's Core against 4.2 for Stars Units Sizes Objects. Both are backed by a comparable volume of ratings — 4 and 5 respectively. Written reviews are what separate them: 100% of Earth's Core's written reviews are positive against 80% of Stars Units Sizes Objects's.
Earth's Core ships an update every 70 months, Stars Units Sizes Objects every 4 months. The most recent releases landed on September 30, 2026 and September 22, 2026 respectively.
| Parameter | Earth's Core | Stars Units Sizes Objects |
|---|---|---|
| Price | Free | Free |
| Rating | 4.3 (4 ratings) — better | 4.2 (5 ratings) |
| Positive reviews | 100.0% of reviews — better | 80.0% of reviews |
| Number of ratings | 4 | 5 — better |
| Update frequency | Every 70 months | Every 4 months — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Free — better | Ad-supported |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 54 MB | 124 MB |
| Age rating | 4+ | 4+ |
| Developer | Celestial Dynamics AG | Mudarmeen Munlin |
Customer experience
Earth's Core
Stars Units Sizes Objects
In-app purchases
Earth's Core
No in-app purchases
Stars Units Sizes Objects
No in-app purchases
Questions
Is Earth's Core free?
Is Stars Units Sizes Objects free?
Which has better reviews, Earth's Core or Stars Units Sizes Objects?
Do Earth's Core or Stars Units Sizes Objects have ads?
Which is updated more often, Earth's Core or Stars Units Sizes Objects?
Other comparisons
