SOS Explorer vs Stars Units Sizes Objects
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SOS Explorer
Explore interactive animated datasets of Earth and space phenomena, from planetary rings to climate change models. This app brings complex environmental processes to life in an intuitive and captivating way, making learning accessible anywhere.
- Streaming high-resolution datasets
- Educational videos
- User-guided tours
- Analysis tools
- 100+ datasets
- Global and flat map views
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SOS Explorer (SOSx) Mobile is a free, flat screen mobile app version of the popular NOAA Science On a Sphere (SOS). This revolutionary software takes SOS datasets, usually only seen on a 6-foot sphere in large museum spaces, and makes them accessible, portable, and interactive anywhere. SOSx Mobile can immerse the user in animated images such as Saturn’s rings, atmospheric storms, climate change, and ocean temperatures to help explain sometimes complex environmental processes in a way that is intuitive, captivating, interactive, and entertaining. A desktop version, called SOS Explorer, is also available. Thank you for using SOS Explorer (SOSx) Mobile. We are committed to continually improving our software and providing you with an engaging and educational experience. We hope you enjoy the new features and enhancements in version 1.2! Please continue to share your feedback with us as we work on improvements. We appreciate your patience and support. Features include: • Streaming, high-resolution datasets • Educational videos • User-guided tours • Analysis tools • 100+ datasets • Global and flat map views Sample datasets: • Recent Hurricane Seasons • Bird Migration • Earthquake Activity • Snow and Ice • Ocean Currents • Historical Tsunamis • Facebook Friendships • Air Traffic • Planets of the Solar System • Climate Change Models • 360 Underwater Imagery • Narrated Movies • ...and so much more!
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 rating: SOS Explorer at 4.7 against Stars Units Sizes Objects's 4.2. SOS Explorer also leads on ads (none vs shown) and monetization model (free vs ad-supported). Stars Units Sizes Objects's advantage is update cadence (every 4 months vs every 11 months). On price, review sentiment, in-app purchases and device support 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.
SOS Explorer holds the better App Store score, 4.7 against 4.2. Both are backed by a comparable volume of ratings — 20 and 5 respectively. Written reviews point the same way: 86% of SOS Explorer's written reviews are positive against 80% of Stars Units Sizes Objects's.
SOS Explorer ships an update every 11 months, Stars Units Sizes Objects every 4 months. The most recent releases landed on October 9, 2026 and September 22, 2026 respectively.
| Parameter | SOS Explorer | Stars Units Sizes Objects |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (20 ratings) — better | 4.2 (5 ratings) |
| Positive reviews | 85.7% of reviews — better | 80.0% of reviews |
| Number of ratings | 20 — better | 5 |
| Update frequency | Every 11 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 | 249 MB | 124 MB |
| Age rating | 4+ | 4+ |
| Developer | University of Colorado Boulder | Mudarmeen Munlin |
Customer experience
SOS Explorer
Stars Units Sizes Objects
In-app purchases
SOS Explorer
No in-app purchases
Stars Units Sizes Objects
No in-app purchases
Questions
Is SOS Explorer free?
Is Stars Units Sizes Objects free?
Which has better reviews, SOS Explorer or Stars Units Sizes Objects?
Do SOS Explorer or Stars Units Sizes Objects have ads?
Which is updated more often, SOS Explorer or Stars Units Sizes Objects?
Other comparisons
