Comparison

Stars Units Sizes Objects vs Orbit

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

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
Read full description

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.

About

Orbit

Features
Read full description

The app is an accurate interactive simulation of the solar system that allows you to explore the movement of the planets and the Moon around the Sun in a simplified, dynamic model based on real astronomical calculations. The app uses Kepler’s equations of orbital motion to display the positions of the planets realistically, with the ability to track their changes over time live and in real time. Features * Realistic simulation of the motion of all planets in the solar system * Ability to switch between a heliocentric or geocentric model * Control the date and view planetary positions on any day * Smooth automatic time progression * Relative simulation of the Moon’s orbit around Earth * Dynamic space background that reflects the depth of the universe * Smooth performance with real-time animation updates * Simple visual design that supports educational understanding of the solar system *Add alerts for future astronomical phenomena. Scientific Concept The app is based on: * Kepler’s laws of planetary motion * Solving Kepler’s equation to determine the true position of planets * Calculating relative orbital distances for each planet * Simulating motion based on the number of days since the year 2000 (Epoch J2000) Objective This app is designed as an educational and interactive tool to help users understand how planets and the Moon move in a simple and engaging visual way, while maintaining scientific accuracy as much as possible.

Screenshots

Stars Units Sizes Objects4 screens
Orbit4 screens

Verdict

The call

The clearest difference is price: Stars Units Sizes Objects at Free against Orbit's $0.99. Stars Units Sizes Objects also leads on iOS requirement (11.0 vs 15.6). Orbit's advantage is ads (none vs shown) and update cadence (monthly vs every 4 months). On 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

CostPrice · In-app purchases · Ads · Monetization

Stars Units Sizes Objects is free to download; Orbit costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Stars Units Sizes Objects ships an update every 4 months, Orbit monthly. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.

Scorecard4 real differences · 6 level
Stars Units Sizes Objects versus Orbit: the parameters behind the verdict, then further details
ParameterStars Units Sizes ObjectsOrbit
PriceFree — better$0.99
Rating4.3 (6 ratings) — better—
Positive reviews80.0% of reviews—
Number of ratings6 — better—
Update frequencyEvery 4 monthsMonthly — better
AdsYesNo — better
In-app purchasesNoNo
MonetizationAd-supported—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS11.0 — better15.6
Further details — not scored
Size124 MB14 MB
Age rating4+4+
DeveloperMudarmeen MunlinOmran Adam

In-app purchases

None

Stars Units Sizes Objects

No in-app purchases

None

Orbit

No in-app purchases

Questions

Is Stars Units Sizes Objects free?
Stars Units Sizes Objects is free to download, with no in-app purchases.
Is Orbit free?
Orbit costs $0.99, with no in-app purchases.
Do Stars Units Sizes Objects or Orbit have ads?
Stars Units Sizes Objects shows ads; Orbit does not.
Which is updated more often, Stars Units Sizes Objects or Orbit?
Stars Units Sizes Objects ships an update every 4 months, and Orbit monthly. Most recently, Stars Units Sizes Objects was updated on October 24, 2026 and Orbit on October 27, 2026.

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