Physics & Fun Calculators

Overview

Physics-based tools that recast familiar questions using real planetary data — how old you would be on Mars, what you would weigh on Europa. Each rests on published orbital periods and surface gravities, and each is arithmetic you can check yourself.

• Age on another planet is your age in Earth years divided by that planet's orbital period in Earth years.
• Weight scales directly with surface gravity; mass does not change at all.
• Every input value on this platform is a catalogued measurement with a recorded source.
• These are science, not astrology, and they sit in a different part of the platform for that reason.

Age on other worlds

A year is one orbit. Mars takes about 1.88 Earth years to orbit the Sun, so an age in Martian years is an Earth age divided by 1.88 — someone aged 30 on Earth is about 16 in Martian years. Mercury, at about 0.24 Earth years per orbit, gives the opposite result: that same person would be roughly 125.

The arithmetic is trivial; the value is in what it makes concrete. Neptune's orbital period is about 165 Earth years, which means no human has ever lived a Neptunian year and Neptune has completed barely one orbit since its discovery in 1846.

Weight versus mass

Mass is the amount of matter in an object and does not change with location. Weight is the force gravity exerts on that mass, so it scales directly with local surface gravity. On the Moon, where surface gravity is about 16.5 percent of Earth's, a person weighs about a sixth as much while their mass is unchanged.

Surface gravity depends on both mass and radius: it is proportional to mass divided by radius squared. This is why Mars, with about a tenth of Earth's mass, has roughly 38 percent of its surface gravity rather than a tenth — its smaller radius partly compensates.

A few results worth knowing

• Mars surface gravity is about 38 percent of Earth's; the Moon's is about 16.5 percent.
• Jupiter has no solid surface, so quoted 'surface gravity' refers to a defined pressure level in its atmosphere — about 2.5 times Earth's.
• Venus, despite being close to Earth in mass and radius, has surface gravity around 90 percent of Earth's.
• Pluto's surface gravity is around 6 percent of Earth's — a 70-kilogram person would weigh about the same as 4 kilograms does on Earth.
• A day is a separate matter from a year: Venus rotates so slowly that its rotation period exceeds its orbital period.

The platform's executable calculators

Beyond these illustrative cases, Asteria Star catalogues thirty working scientific calculators covering orbital, stellar, observational, exoplanet, cosmological and instrumental quantities — escape velocity, orbital period, distance modulus, angular resolution, equilibrium temperature and others.

Each records its formula, its inputs, and the provenance of the constants it uses, and each is evaluated rather than described. Where a published value on an entity page is derived rather than measured, the derivation is registered with its formula and assumptions so the distinction is never lost.

In-depth, individual pages in this category.

• Age on Mars

  →

  Your age in Mars years — the concept and the science.

• Age on Venus

  →

  Your age in Venus years — the concept and the science.

• Age on Mercury

  →

  Your age in Mercury years — the concept and the science.

• Age on Jupiter

  →

  Your age in Jupiter years — the concept and the science.

• Weight on the Moon

  →

  Your weight on the Moon — the concept and the science.

• Weight on Mars

  →

  Your weight on Mars — the concept and the science.

Continue in the data

Catalogues, hubs, and reference pages that hold the underlying records for this topic.

• Scientific calculatorsThe thirty executable calculators, with formulae.
• Solar SystemThe measured masses, radii, and periods used here.
• Physics basicsGravity, orbits, and the underlying principles.

Frequently asked

How do I calculate my age on another planet?

Divide your age in Earth years by that planet's orbital period expressed in Earth years. Mars takes about 1.88 Earth years per orbit, so a 30-year-old is about 16 in Martian years. Mercury takes about 0.24, so the same person would be roughly 125.

Why would I weigh less on Mars but have the same mass?

Because mass and weight are different quantities. Mass is how much matter you contain and does not change with location. Weight is the gravitational force on that mass, so it scales with local surface gravity — about 38 percent of Earth's on Mars. Your mass is identical in both places.

Why doesn't Mars have a tenth of Earth's gravity if it has a tenth of the mass?

Because surface gravity depends on radius as well as mass — it is proportional to mass divided by radius squared. Mars is substantially smaller than Earth, so its surface sits closer to its centre of mass, which partly compensates for the lower mass and leaves surface gravity at around 38 percent rather than 10 percent.

Does Asteria Star have working calculators?

Yes — thirty of them, covering orbital, stellar, observational, exoplanet, cosmological and instrumental quantities. Each is executable, records its formula and inputs, and carries provenance for the constants it uses. They are catalogued under the calculators hub.