Exoplanet Explorer vs Stars Units Sizes Objects
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Exoplanet Explorer
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.
- 6,000+ confirmed exoplanets
- Detailed scientific data
- Advanced filtering and sorting
- Planet comparison tool
- Habitable zone analysis
- Home screen widgets
- Apple Watch companion app
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Explore the universe of exoplanets — over 6,000 confirmed worlds orbiting distant stars, updated from leading scientific archives. Track new discoveries as they happen and dive into the data behind every planet. EXPLORE THE COSMOS Search, filter, and sort the complete catalogue of confirmed exoplanets. Find planets by discovery method, star type, orbital characteristics, or habitability potential. Every entry includes detailed scientific data from peer-reviewed sources. ATMOSPHERIC SPECTRA Browse JWST and Hubble transmission spectra for planets where atmospheric data is available. Toggle molecular overlays for CO2, CH4, H2O, CO and more to see which absorption features have been detected. 3D SYSTEM VIEW Step into a planetary system in 3D — see each planet's orbit around its host star with realistic shading and a visualisation of the habitable zone. On iPhone and iPad you can also place a system into your environment in AR. COMPARE WORLDS Analyze exoplanets side-by-side — or compare them with Solar System planets like Earth, Jupiter, and Mars. Compare sizes, masses, orbital periods, star properties, and habitability scores to understand what makes each world unique. HABITABLE ZONE VISUALIZATION See exactly where planets orbit within their star's habitable zone — the region where liquid water could exist. Identify potentially Earth-like worlds and understand the conditions for life beyond our solar system. FEATURES • 6,000+ confirmed exoplanets with detailed scientific data • Atmospheric spectra with molecular overlays • 3D system view with AR mode • Advanced filtering and sorting • Planet comparison tool with Solar System reference • Habitable zone analysis • Spotlight search with deep linking • Home screen widgets • Apple Watch companion app • Bookmark favorites with iCloud sync • Available on iPhone, iPad, Mac, Apple Watch, and Apple Vision Pro GO PREMIUM Enjoying the app? Premium takes it further — unlimited bookmarks, the full planet comparison tool, and additional widgets. A small yearly upgrade that makes a big difference. Whether you're a curious stargazer, student, educator, or researcher, Exoplanet Explorer puts the cosmos in your pocket. Terms of Use (EULA): https://the-exoplanets.space/eula/ Privacy Policy: https://the-exoplanets.space/privacy/
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 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.
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. 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.
| Parameter | Exoplanet Explorer | Stars Units Sizes Objects |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (70 ratings) — better | 4.2 (5 ratings) |
| Positive reviews | 100.0% of reviews — better | 80.0% of reviews |
| Number of ratings | 70 — better | 5 |
| Update frequency | Every 2 weeks — better | Every 4 months |
| Ads | No — better | Yes |
| In-app purchases | Yes | No — better |
| Monetization | Freemium | Ad-supported — better |
| Devices | iPhone, iPad, Mac, Apple Watch, Vision Pro — better | iPhone, iPad, iPod |
| Requires iOS | 17.6 | 11.0 — better |
| Further details — not scored | ||
| Size | 169 MB | 124 MB |
| Age rating | 4+ | 4+ |
| Developer | Carsten Knoblich | Mudarmeen Munlin |
Customer experience
Exoplanet Explorer
Stars Units Sizes Objects
In-app purchases
Exoplanet Explorer
- 3 months subscription7 Days trial$2.993 Months
- 12 months subscription7 Days trial$6.991 Year
- Big supporting tip$2.99
- Really big supporting tip$4.99
Stars Units Sizes Objects
No in-app purchases
Questions
Is Exoplanet Explorer free?
Is Stars Units Sizes Objects free?
Which has better reviews, Exoplanet Explorer or Stars Units Sizes Objects?
Do Exoplanet Explorer or Stars Units Sizes Objects have ads?
Which is updated more often, Exoplanet Explorer or Stars Units Sizes Objects?
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