How to Calculate Weight on Another Planet

Calculate Weight on Another Planet | Gravity & Mass Explained :root { –primary-color: #004a99; –success-color: #28a745; –background-color: #f8f9fa; –text-color: #333; –border-color: #ccc; –light-gray: #e9ecef; –white: #fff; } body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: var(–background-color); color: var(–text-color); line-height: 1.6; margin: 0; padding: 0; display: flex; flex-direction: column; align-items: center; padding-top: 20px; padding-bottom: 40px; } .container { width: 100%; max-width: 960px; background-color: var(–white); padding: 30px; border-radius: 8px; box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1); display: flex; flex-direction: column; align-items: center; } h1, h2, h3 { color: var(–primary-color); text-align: center; margin-bottom: 20px; } h1 { font-size: 2.5em; } h2 { font-size: 2em; border-bottom: 2px solid var(–primary-color); padding-bottom: 10px; } h3 { font-size: 1.5em; margin-top: 25px; } .intro-summary { font-size: 1.1em; color: #555; text-align: center; margin-bottom: 30px; } .calculator-wrapper { width: 100%; background-color: var(–white); border-radius: 8px; padding: 30px; box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.05); margin-bottom: 40px; } .calculator-wrapper h2 { margin-top: 0; } .input-group { margin-bottom: 20px; width: 100%; } .input-group label { display: block; margin-bottom: 8px; font-weight: bold; color: var(–primary-color); } .input-group input[type="number"], .input-group select { width: calc(100% – 20px); padding: 12px 10px; border: 1px solid var(–border-color); border-radius: 5px; font-size: 1em; box-sizing: border-box; transition: border-color 0.3s ease; } .input-group input[type="number"]:focus, .input-group select:focus { border-color: var(–primary-color); outline: none; } .input-group .helper-text { font-size: 0.85em; color: #6c757d; margin-top: 5px; display: block; } .input-group .error-message { color: red; font-size: 0.8em; margin-top: 5px; display: block; height: 1.2em; /* Reserve space for error message */ } .button-group { display: flex; justify-content: space-between; margin-top: 25px; flex-wrap: wrap; gap: 10px; } .btn { padding: 12px 25px; border: none; border-radius: 5px; font-size: 1em; font-weight: bold; cursor: pointer; transition: background-color 0.3s ease, transform 0.2s ease; flex: 1; min-width: 150px; } .btn-primary { background-color: var(–primary-color); color: var(–white); } .btn-primary:hover { background-color: #003366; transform: translateY(-2px); } .btn-secondary { background-color: var(–light-gray); color: var(–text-color); border: 1px solid var(–border-color); } .btn-secondary:hover { background-color: #d3d9df; transform: translateY(-2px); } .btn-success { background-color: var(–success-color); color: var(–white); } .btn-success:hover { background-color: #218838; transform: translateY(-2px); } #results-container { margin-top: 30px; padding: 25px; border: 1px solid var(–border-color); border-radius: 8px; background-color: var(–light-gray); width: 100%; box-sizing: border-box; } #results-container h3 { margin-top: 0; color: var(–primary-color); text-align: left; } .result-item { margin-bottom: 15px; display: flex; justify-content: space-between; align-items: center; padding-bottom: 10px; border-bottom: 1px dashed var(–border-color); } .result-item:last-child { border-bottom: none; padding-bottom: 0; } .result-item span:first-child { font-weight: bold; color: var(–text-color); } .result-item span:last-child { font-weight: bold; font-size: 1.2em; color: var(–primary-color); } .primary-result { font-size: 1.8em; font-weight: bold; color: var(–white); background-color: var(–success-color); padding: 15px 20px; border-radius: 5px; text-align: center; margin-bottom: 20px; box-shadow: 0 2px 10px rgba(40, 167, 69, 0.4); } .formula-explanation { margin-top: 20px; font-style: italic; color: #555; text-align: center; font-size: 0.95em; } .chart-container { width: 100%; margin-top: 30px; padding: 20px; border: 1px solid var(–border-color); border-radius: 8px; background-color: var(–white); text-align: center; } .chart-container canvas { max-width: 100%; height: auto; display: inline-block; } .chart-caption { font-size: 0.9em; color: #6c757d; margin-top: 10px; display: block; } table { width: 100%; border-collapse: collapse; margin-top: 20px; box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05); } th, td { padding: 12px 15px; text-align: left; border: 1px solid var(–border-color); } thead th { background-color: var(–primary-color); color: var(–white); font-weight: bold; } tbody tr:nth-child(even) { background-color: var(–light-gray); } tbody td { font-size: 0.95em; } .table-caption { font-size: 0.9em; color: #6c757d; margin-bottom: 10px; display: block; text-align: center; } .article-section { width: 100%; margin-top: 40px; background-color: var(–white); padding: 30px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05); } .article-section h2 { text-align: left; border-bottom-color: var(–border-color); margin-bottom: 25px; } .article-section h3 { text-align: left; margin-top: 30px; color: #0056b3; } .article-section p { margin-bottom: 15px; } .article-section ul, .article-section ol { margin-left: 20px; margin-bottom: 15px; } .article-section li { margin-bottom: 8px; } .faq-item { margin-bottom: 15px; border-bottom: 1px dashed var(–border-color); padding-bottom: 10px; } .faq-item:last-child { border-bottom: none; } .faq-item strong { color: var(–primary-color); cursor: pointer; display: block; margin-bottom: 5px; } .faq-item p { margin-bottom: 0; font-size: 0.95em; display: none; /* Hidden by default */ } .faq-item.open p { display: block; } #related-tools { margin-top: 40px; width: 100%; background-color: var(–white); padding: 30px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05); } #related-tools h2 { text-align: left; margin-bottom: 25px; } #related-tools ul { list-style: none; padding: 0; margin: 0; } #related-tools li { margin-bottom: 15px; padding-bottom: 10px; border-bottom: 1px dashed var(–border-color); } #related-tools li:last-child { border-bottom: none; padding-bottom: 0; } #related-tools a { color: var(–primary-color); text-decoration: none; font-weight: bold; display: block; } #related-tools a:hover { text-decoration: underline; } #related-tools span { font-size: 0.9em; color: #555; display: block; margin-top: 5px; } footer { width: 100%; text-align: center; margin-top: 40px; font-size: 0.85em; color: #6c757d; } /* Responsive adjustments */ @media (max-width: 768px) { h1 { font-size: 2em; } h2 { font-size: 1.75em; } .container { padding: 20px; } .btn { flex: 1 1 100%; min-width: unset; } .button-group { flex-direction: column; gap: 15px; } .result-item { flex-direction: column; align-items: flex-start; } .result-item span:last-child { margin-top: 5px; } }

Calculate Weight on Another Planet

Curious about how much you'd weigh on Mars, Jupiter, or even the Moon? This calculator uses your Earth weight and the gravitational acceleration of celestial bodies to show you your weight on other planets.

Planet Weight Calculator

Enter your weight as measured on Earth.
Mercury Venus Earth Moon Mars Jupiter Saturn Uranus Neptune Pluto Choose a celestial body to calculate your weight.

Results

Your weight on selected planet: — kg
Your Mass (kg):
Gravitational Acceleration (m/s²):
Weight on Selected Planet (N):
Weight (N) = Mass (kg) × Gravitational Acceleration (m/s²)
Comparison of Gravitational Acceleration (m/s²) on Various Planets
Gravitational Acceleration of Solar System Planets
Planet Gravitational Acceleration (m/s²) Surface Gravity (g)
Mercury3.700.38
Venus8.870.90
Earth9.811.00
Moon1.620.16
Mars3.710.38
Jupiter24.792.53
Saturn10.441.06
Uranus8.690.89
Neptune11.151.14
Pluto0.620.06

What is Calculating Weight on Another Planet?

Calculating weight on another planet is a fascinating application of fundamental physics that helps us understand the differences in how gravity affects objects across the cosmos. It's not about changing your *mass*, which is the amount of matter in an object and remains constant, but about determining your *weight*, which is the force exerted on that mass by gravity. Since each celestial body possesses a unique gravitational pull, your experience of "heaviness" will vary significantly.

This concept is crucial for space exploration, enabling engineers and astronauts to anticipate the forces they will encounter. For the curious mind, it's a fun way to grasp the immense scale and diversity of gravitational forces in our universe. Understanding how weight changes is essential for anyone interested in astronomy, physics, or even science fiction.

Who should use it?

  • Students learning about physics and astronomy.
  • Space enthusiasts and amateur astronomers.
  • Anyone curious about the science behind gravity.
  • Educators developing science lessons.

Common misconceptions include:

  • Confusing mass with weight: Your mass (e.g., 70 kg) never changes, but your weight (the force you exert) does.
  • Assuming gravity is uniform everywhere: Each planet and moon has its own unique gravitational strength based on its mass and radius.
  • Believing weight is just a number: Weight is a force, measured in Newtons (N), although we often colloquially use kg to represent weight on Earth.

Weight on Another Planet Formula and Mathematical Explanation

The core principle behind calculating weight on another planet is Newton's second law of motion, specifically applied to the force of gravity. The formula is straightforward:

Weight = Mass × Gravitational Acceleration

Let's break down the variables and the process:

Understanding the Variables

To calculate your weight on another planet, we need two key pieces of information:

  • Your Mass (m): This is the intrinsic amount of "stuff" in your body. Mass is measured in kilograms (kg) and remains constant regardless of location. If you weigh 70 kg on Earth, your mass is 70 kg, whether you're on Earth, the Moon, or Jupiter.
  • Gravitational Acceleration (g): This is the acceleration experienced by an object due to gravity on the surface of a specific celestial body. It's measured in meters per second squared (m/s²). This value is different for every planet, moon, or star because it depends on the body's mass and radius.

The resulting weight is a force, measured in Newtons (N), according to the International System of Units (SI).

The Calculation Steps

  1. Determine Your Mass: This is usually the same as your weight measured in kilograms on Earth. For example, if you weigh 70 kg on Earth, your mass (m) is 70 kg.
  2. Find the Gravitational Acceleration of the Target Planet: Each planet has a known gravitational acceleration value. For instance, Earth's surface gravity is approximately 9.81 m/s². Mars's is about 3.71 m/s².
  3. Apply the Formula: Multiply your mass by the planet's gravitational acceleration.

Formula: W = m × g

Where:

  • W = Weight (in Newtons, N)
  • m = Mass (in kilograms, kg)
  • g = Gravitational Acceleration (in meters per second squared, m/s²)

While colloquially we use "weight" in kg, technically on Earth, your weight force is your mass times Earth's gravity (e.g., 70 kg * 9.81 m/s² = 686.7 N). When comparing weights across planets, we often just multiply your Earth-mass-equivalent-weight (e.g., 70 kg) by the ratio of the planet's gravity to Earth's gravity, which gives a result in kg-force or an equivalent perceived "weight" in kg on that planet. Our calculator provides both the force in Newtons and a perceived weight in kg for easier understanding.

Variables Table

Key Variables for Weight Calculation
Variable Meaning Unit Typical Range
Mass (m) Amount of matter in an object kilograms (kg) Varies per individual (e.g., 40-200 kg for adults)
Gravitational Acceleration (g) Force of gravity at the surface of a celestial body meters per second squared (m/s²) 0.16 (Moon) to 24.79 (Jupiter) for Solar System
Weight (W) Force exerted by gravity on a mass Newtons (N) Product of m × g

Practical Examples (Real-World Use Cases)

Let's see how this works with some practical examples:

Example 1: An Astronaut on the Moon

Imagine an astronaut whose mass is 80 kg. They are preparing for a mission to the Moon.

  • Input: Earth Weight (Mass) = 80 kg
  • Target Planet: Moon
  • Moon's Gravitational Acceleration (g): Approximately 1.62 m/s²

Calculation:

  • Weight on Moon (N) = 80 kg × 1.62 m/s² = 129.6 N
  • Perceived Weight on Moon (kg) = 80 kg × (1.62 m/s² / 9.81 m/s²) ≈ 13.15 kg

Interpretation: The astronaut, with a mass of 80 kg, would experience a weight of only about 13.15 kg on the Moon. This reduced weight is why astronauts can perform giant leaps and carry heavy equipment with relative ease on the lunar surface. The force they exert downwards is significantly less.

Example 2: A Probe on Jupiter

Consider a space probe designed to study Jupiter. The probe has a mass of 500 kg.

  • Input: Probe Mass = 500 kg
  • Target Planet: Jupiter
  • Jupiter's Gravitational Acceleration (g): Approximately 24.79 m/s²

Calculation:

  • Weight on Jupiter (N) = 500 kg × 24.79 m/s² = 12,395 N
  • Perceived Weight on Jupiter (kg) = 500 kg × (24.79 m/s² / 9.81 m/s²) ≈ 1263.5 kg

Interpretation: The 500 kg probe would feel incredibly heavy on Jupiter, experiencing a force equivalent to a mass of over 1200 kg! This immense gravitational pull has significant implications for spacecraft design, requiring robust structures capable of withstanding such forces.

How to Use This Planet Weight Calculator

Our calculator makes it simple to determine your weight on any planet in our solar system (and even Pluto!). Follow these easy steps:

  1. Enter Your Earth Weight: In the "Your Weight on Earth (kg)" field, input your current weight in kilograms. Remember, this value represents your mass.
  2. Select a Planet: Use the dropdown menu labeled "Select Planet" to choose the celestial body you're interested in (e.g., Mars, Jupiter, Moon).
  3. Calculate: Click the "Calculate Weight" button.

Reading Your Results:

  • Primary Result (Highlighted): This shows your perceived weight on the selected planet in kilograms. It's the most intuitive way to understand how "heavy" you'd feel.
  • Your Mass (kg): This value will remain the same as your initial Earth weight input, reinforcing that mass is constant.
  • Gravitational Acceleration (m/s²): This displays the specific gravity of the planet you selected.
  • Weight on Selected Planet (N): This shows the actual force of your weight on that planet, measured in Newtons.

Decision-Making Guidance:

While this calculator is for educational and curiosity purposes, understanding gravitational differences is vital for mission planning. For space agencies, knowing these values helps in designing suits, vehicles, and predicting astronaut capabilities. For enthusiasts, it's a great way to visualize the vast differences in cosmic forces.

Use the "Copy Results" button to easily share your findings or save them for later reference.

Key Factors That Affect Weight on Other Planets

While the core calculation is simple (Mass x Gravity), several underlying factors contribute to the gravitational acceleration of a planet, and thus your perceived weight. Understanding these helps appreciate the diversity of planetary characteristics:

  1. Planet's Mass: This is the most significant factor. More massive planets exert a stronger gravitational pull. Jupiter, being the most massive planet in our solar system, has the highest surface gravity.
  2. Planet's Radius: Gravity's strength also depends on how close you are to the center of the mass. A larger radius means you are farther from the center, which weakens the gravitational pull at the surface. This is why Saturn, despite being massive, has a lower surface gravity than Earth – it's much less dense and larger in radius.
  3. Planet's Density: Density (mass per unit volume) combines the effects of mass and radius. A highly dense planet will have stronger surface gravity than a less dense planet of the same mass.
  4. Atmospheric Pressure: While not directly affecting the gravitational force itself, a dense atmosphere can create atmospheric drag and affect measurements or perceptions of weight, especially for lighter objects or during descent. However, for calculating *your* weight (a fundamental force), we focus on the direct gravitational pull.
  5. Distance from the Sun (Indirect): A planet's distance from the Sun influences its formation and composition, which in turn dictates its mass and radius, thereby affecting its gravity. However, the direct relationship is between mass/radius and gravity, not distance itself.
  6. Geological Activity/Surface Features: While minuscule on a planetary scale, variations in terrain or gravitational anomalies (like mountains or trenches) can cause slight local variations in gravitational acceleration. For general calculations, we use the average surface gravity.
  7. Rotational Speed (Minor Effect): A planet's rotation causes a slight centrifugal force that counteracts gravity, making objects effectively weigh slightly less at the equator than at the poles. This effect is generally small compared to the mass/radius influence.

Frequently Asked Questions (FAQ)

Q: Does my mass actually change on other planets?

A: No, your mass (the amount of matter in your body) is constant. Only your weight, which is the force of gravity acting upon your mass, changes.

Q: Why do we use kg for weight on Earth but Newtons for force?

A: On Earth, we colloquially use kilograms (kg) to represent weight because Earth's gravity is relatively constant. However, scientifically, weight is a force (measured in Newtons, N). 1 Newton is roughly the force needed to accelerate 1 kg by 1 m/s². So, 70 kg on Earth is about 70 * 9.81 = 686.7 N.

Q: Is the gravitational pull the same everywhere on a planet?

A: Nearly, but not exactly. Gravity can vary slightly due to factors like altitude, terrain, and uneven mass distribution within the planet. However, for general calculations like this, we use the average surface gravitational acceleration.

Q: Can I calculate my weight on stars?

A: While stars have immense gravity, they don't have a solid "surface" to stand on. Calculating weight on a star is not practically feasible in the same way as on planets or moons due to their gaseous nature and extreme conditions.

Q: What is "surface gravity" often listed as a percentage of Earth's?

A: This is a way to compare gravity relative to Earth. For example, Mars has a surface gravity of about 38% of Earth's. This means an object on Mars will weigh about 38% of what it weighs on Earth. Our calculator uses the m/s² value, but this percentage is a common way to express it.

Q: Will I feel lighter or heavier on Jupiter compared to Earth?

A: You will feel significantly heavier on Jupiter. Jupiter's gravitational acceleration is about 2.5 times that of Earth, so you would weigh roughly 2.5 times more.

Q: How does this calculator handle dwarf planets like Pluto?

A: Our calculator includes data for Pluto, which is classified as a dwarf planet. It has significantly lower gravity than Earth, meaning you would feel much lighter there.

Q: What if I enter a very high weight? Will the calculator still work?

A: Yes, the calculator uses standard physics formulas. As long as you input valid numerical values for weight and select a planet, it will compute the resulting weight based on the provided gravitational acceleration data. It's designed for a wide range of inputs.

© 2023 Your Website Name. All rights reserved.

var planetData = { mercury: { gravity: 3.7, name: "Mercury" }, venus: { gravity: 8.87, name: "Venus" }, earth: { gravity: 9.81, name: "Earth" }, moon: { gravity: 1.62, name: "Moon" }, mars: { gravity: 3.71, name: "Mars" }, jupiter: { gravity: 24.79, name: "Jupiter" }, saturn: { gravity: 10.44, name: "Saturn" }, uranus: { gravity: 8.69, name: "Uranus" }, neptune: { gravity: 11.15, name: "Neptune" }, pluto: { gravity: 0.62, name: "Pluto" } }; var earthGravity = 9.81; // Standard gravity for Earth in m/s^2 function validateInput(id, errorId, min, max) { var input = document.getElementById(id); var errorSpan = document.getElementById(errorId); var value = parseFloat(input.value); errorSpan.textContent = "; // Clear previous error if (isNaN(value)) { errorSpan.textContent = 'Please enter a valid number.'; return false; } if (value <= 0) { errorSpan.textContent = 'Value must be positive.'; return false; } if (min !== undefined && value max) { errorSpan.textContent = 'Value is too high.'; return false; } return true; } function calculateWeight() { var earthWeightInput = document.getElementById("earthWeight"); var planetSelect = document.getElementById("planetSelect"); var earthWeightError = document.getElementById("earthWeightError"); var planetSelectError = document.getElementById("planetSelectError"); var validEarthWeight = validateInput("earthWeight", "earthWeightError", 1, 1000); // Assuming a reasonable max weight if (!validEarthWeight) { return; } var earthWeight = parseFloat(earthWeightInput.value); var selectedPlanetKey = planetSelect.value; var selectedPlanet = planetData[selectedPlanetKey]; if (!selectedPlanet) { planetSelectError.textContent = "Please select a planet."; return; } var mass = earthWeight; // Mass is equal to Earth weight in kg var gravity = selectedPlanet.gravity; var planetName = selectedPlanet.name; // Calculate weight in Newtons var weightInNewtons = mass * gravity; // Calculate perceived weight on the planet in kg (for easier comparison) var perceivedWeightKg = mass * (gravity / earthGravity); document.getElementById("displayMass").textContent = mass.toFixed(2) + " kg"; document.getElementById("displayGravity").textContent = gravity.toFixed(2) + " m/s²"; document.getElementById("displayWeightNewtons").textContent = weightInNewtons.toFixed(2) + " N"; var primaryResultDisplay = document.getElementById("primaryResult"); primaryResultDisplay.textContent = "Your weight on " + planetName + ": " + perceivedWeightKg.toFixed(2) + " kg"; updateChart(gravity, planetName); } function resetCalculator() { document.getElementById("earthWeight").value = "70"; // Sensible default document.getElementById("planetSelect").value = "earth"; // Default to Earth // Clear errors document.getElementById("earthWeightError").textContent = "; document.getElementById("planetSelectError").textContent = "; // Reset results display document.getElementById("displayMass").textContent = "–"; document.getElementById("displayGravity").textContent = "–"; document.getElementById("displayWeightNewtons").textContent = "–"; document.getElementById("primaryResult").textContent = "Your weight on selected planet: — kg"; // Reset chart (optional, or could recalculate with defaults) var ctx = document.getElementById("gravityChart").getContext("2d"); ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height); drawDefaultChart(); } function copyResults() { var mass = document.getElementById("displayMass").textContent; var gravity = document.getElementById("displayGravity").textContent; var weightNewtons = document.getElementById("displayWeightNewtons").textContent; var primaryResult = document.getElementById("primaryResult").textContent; var selectedPlanet = document.getElementById("planetSelect").options[document.getElementById("planetSelect").selectedIndex].text; var assumptions = "Key Assumptions:\n" + "- Your Mass (constant): " + mass + "\n" + "- Selected Planet Gravity: " + gravity + "\n" + "- Earth's Gravity Reference: " + earthGravity.toFixed(2) + " m/s²"; var textToCopy = primaryResult + "\n\n" + "Detailed Results:\n" + "- Your Mass: " + mass + "\n" + "- Gravitational Acceleration: " + gravity + "\n" + "- Weight on " + selectedPlanet + ": " + weightNewtons + "\n\n" + assumptions; // Use navigator.clipboard for modern browsers if (navigator.clipboard && navigator.clipboard.writeText) { navigator.clipboard.writeText(textToCopy).then(function() { // Success feedback (optional) var originalText = document.querySelector('.btn-success').textContent; document.querySelector('.btn-success').textContent = 'Copied!'; setTimeout(function() { document.querySelector('.btn-success').textContent = originalText; }, 2000); }).catch(function(err) { console.error('Failed to copy text: ', err); // Fallback for older browsers or if permission is denied copyToClipboardFallback(textToCopy); }); } else { // Fallback for older browsers copyToClipboardFallback(textToCopy); } } function copyToClipboardFallback(text) { var textArea = document.createElement("textarea"); textArea.value = text; textArea.style.position = "fixed"; // Avoid scrolling to bottom textArea.style.left = "-9999px"; textArea.style.top = "-9999px"; document.body.appendChild(textArea); textArea.focus(); textArea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Copied!' : 'Copy failed'; var originalText = document.querySelector('.btn-success').textContent; document.querySelector('.btn-success').textContent = msg; setTimeout(function() { document.querySelector('.btn-success').textContent = originalText; }, 2000); } catch (err) { console.error('Fallback copy failed: ', err); var originalText = document.querySelector('.btn-success').textContent; document.querySelector('.btn-success').textContent = 'Copy Failed'; setTimeout(function() { document.querySelector('.btn-success').textContent = originalText; }, 2000); } document.body.removeChild(textArea); } function toggleFaq(element) { var parent = element.parentElement; parent.classList.toggle('open'); } // Charting Logic var chartData = { labels: [], gravityValues: [], earthEquivalentValues: [] }; function initializeChart() { var planets = document.getElementById("planetSelect").options; var earthGravityVal = planetData.earth.gravity; for (var i = 0; i < planets.length; i++) { var planetKey = planets[i].value; var planetName = planets[i].text; var gravity = planetData[planetKey].gravity; var earthEquivalent = gravity / earthGravityVal; chartData.labels.push(planetName); chartData.gravityValues.push(gravity); chartData.earthEquivalentValues.push(earthEquivalent); } // Sort data for better visualization (optional, but nice) var combined = []; for (var i = 0; i < chartData.labels.length; i++) { combined.push({ label: chartData.labels[i], gravity: chartData.gravityValues[i], earthEquivalent: chartData.earthEquivalentValues[i] }); } // Sort by gravity descending combined.sort(function(a, b) { return b.gravity – a.gravity; }); chartData.labels = combined.map(function(item) { return item.label; }); chartData.gravityValues = combined.map(function(item) { return item.gravity; }); chartData.earthEquivalentValues = combined.map(function(item) { return item.earthEquivalent; }); drawChart(); } function drawChart() { var ctx = document.getElementById("gravityChart").getContext("2d"); // Clear previous chart if it exists ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height); var myChart = new Chart(ctx, { type: 'bar', // Changed to bar chart for better comparison data: { labels: chartData.labels, datasets: [{ label: 'Gravitational Acceleration (m/s²)', data: chartData.gravityValues, backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 1 }, { label: 'Earth Equivalent Gravity (x Earth)', data: chartData.earthEquivalentValues, backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color borderColor: 'rgba(40, 167, 69, 1)', borderWidth: 1 }] }, options: { responsive: true, maintainAspectRatio: true, scales: { y: { beginAtZero: true, title: { display: true, text: 'Value' } }, x: { title: { display: true, text: 'Planet' } } }, plugins: { legend: { position: 'top', }, title: { display: true, text: 'Gravity Comparison Across Celestial Bodies' } } } }); } function drawDefaultChart() { var ctx = document.getElementById("gravityChart").getContext("2d"); ctx.font = "16px Segoe UI"; ctx.fillStyle = "#555"; ctx.textAlign = "center"; ctx.fillText("Chart will appear after calculation.", ctx.canvas.width/2, ctx.canvas.height/2); } function updateChart(selectedGravity, selectedPlanetName) { // This function can be used to highlight the selected planet on the chart, // or redraw the chart if data changes dynamically beyond initial load. // For this setup, initializeChart() loads all data, and we just ensure it's drawn. if (typeof Chart !== 'undefined') { // Ensure Chart.js is loaded (though we're using native canvas) // Re-call drawChart if we had dynamic data sources for it. // Since chartData is static after init, it remains the same unless we re-fetch. } } // Initial setup when the page loads document.addEventListener("DOMContentLoaded", function() { initializeChart(); drawDefaultChart(); // Draw initial placeholder // Automatically calculate with default values on load calculateWeight(); }); // If Chart.js is NOT available, you'd need to implement canvas drawing manually // For this task, we'll assume a hypothetical `Chart` object is available or implement basic canvas drawing. // Since the prompt forbids external libraries and requires native canvas/SVG, we MUST implement drawing logic. // The current `drawChart` uses a hypothetical `Chart` object. Let's replace that with pure canvas. // **REPLACING CHART.JS WITH NATIVE CANVAS DRAWING** function drawChart() { var canvas = document.getElementById("gravityChart"); var ctx = canvas.getContext("2d"); var width = canvas.width; var height = canvas.height; // Clear canvas ctx.clearRect(0, 0, width, height); if (chartData.labels.length === 0) { ctx.font = "16px Segoe UI"; ctx.fillStyle = "#555"; ctx.textAlign = "center"; ctx.fillText("No data available for chart.", width / 2, height / 2); return; } var maxGravity = Math.max(…chartData.gravityValues); var maxEarthEquivalent = Math.max(…chartData.earthEquivalentValues); var maxValue = Math.max(maxGravity, maxEarthEquivalent); var barWidth = (width * 0.8) / chartData.labels.length; // 80% of width for bars var barSpacing = barWidth * 0.2; // 20% spacing var chartAreaWidth = width * 0.8; var chartAreaHeight = height * 0.7; // 70% for chart bars var paddingX = width * 0.1; var paddingY = height * 0.15; // Draw Y-axis and labels ctx.strokeStyle = '#ccc'; ctx.lineWidth = 1; ctx.beginPath(); ctx.moveTo(paddingX, height – paddingY); // Y-axis origin ctx.lineTo(paddingX, paddingY); // Y-axis top ctx.stroke(); // Draw X-axis and labels ctx.beginPath(); ctx.moveTo(paddingX, height – paddingY); // X-axis origin ctx.lineTo(width – paddingX, height – paddingY); // X-axis right ctx.stroke(); // Y-axis scale ticks and labels var numTicks = 5; for (var i = 0; i <= numTicks; i++) { var yPos = height – paddingY – (i / numTicks) * chartAreaHeight; var labelValue = (i / numTicks) * maxValue; ctx.textAlign = "right"; ctx.fillStyle = "#555"; ctx.fillText(labelValue.toFixed(1), paddingX – 10, yPos + 5); ctx.beginPath(); ctx.moveTo(paddingX – 5, yPos); ctx.lineTo(paddingX, yPos); ctx.stroke(); } // Draw Bars ctx.textAlign = "center"; for (var i = 0; i < chartData.labels.length; i++) { var barHeightGravity = (chartData.gravityValues[i] / maxValue) * chartAreaHeight; var barHeightEarthEq = (chartData.earthEquivalentValues[i] / maxValue) * chartAreaHeight; var xPos = paddingX + i * barWidth + barSpacing; // Bar for Gravity (m/s²) ctx.fillStyle = 'rgba(0, 74, 153, 0.6)'; ctx.fillRect(xPos, height – paddingY – barHeightGravity, barWidth / 2, barHeightGravity); ctx.fillStyle = '#004a99'; // Darker border color ctx.strokeRect(xPos, height – paddingY – barHeightGravity, barWidth / 2, barHeightGravity); // Bar for Earth Equivalent ctx.fillStyle = 'rgba(40, 167, 69, 0.6)'; ctx.fillRect(xPos + barWidth / 2, height – paddingY – barHeightEarthEq, barWidth / 2, barHeightEarthEq); ctx.fillStyle = '#28a745'; // Darker border color ctx.strokeRect(xPos + barWidth / 2, height – paddingY – barHeightEarthEq, barWidth / 2, barHeightEarthEq); // X-axis labels (Planet Names) ctx.fillStyle = "#333"; ctx.fillText(chartData.labels[i], xPos + barWidth / 2, height – paddingY + 20); } // Draw Legend var legendY = paddingY / 2; var legendXStart = paddingX + chartAreaWidth + 20; // Position legend to the right of the chart area // Gravity Legend Item ctx.fillStyle = 'rgba(0, 74, 153, 0.6)'; ctx.fillRect(legendXStart, legendY, 15, 10); ctx.fillStyle = '#004a99'; ctx.strokeRect(legendXStart, legendY, 15, 10); ctx.textAlign = "left"; ctx.fillStyle = "#333"; ctx.fillText('Gravity (m/s²)', legendXStart + 20, legendY + 10); // Earth Equivalent Legend Item var legendY2 = legendY + 20; ctx.fillStyle = 'rgba(40, 167, 69, 0.6)'; ctx.fillRect(legendXStart, legendY2, 15, 10); ctx.fillStyle = '#28a745'; ctx.strokeRect(legendXStart, legendY2, 15, 10); ctx.fillStyle = "#333"; ctx.fillText('Earth Equivalent (x Earth)', legendXStart + 20, legendY2 + 10); // Chart Title ctx.font = "bold 18px Segoe UI"; ctx.fillStyle = "#004a99"; ctx.fillText("Gravity Comparison Across Celestial Bodies", width / 2, paddingY / 2); } function drawDefaultChart() { var canvas = document.getElementById("gravityChart"); var ctx = canvas.getContext("2d"); ctx.font = "16px Segoe UI"; ctx.fillStyle = "#555"; ctx.textAlign = "center"; ctx.fillText("Chart data will load after initial calculation.", canvas.width / 2, canvas.height / 2); } // Override the DOMContentLoaded listener to ensure chart logic runs correctly document.addEventListener("DOMContentLoaded", function() { // Initialize chart data structure var planets = document.getElementById("planetSelect").options; var earthGravityVal = planetData.earth.gravity; chartData.labels = []; chartData.gravityValues = []; chartData.earthEquivalentValues = []; for (var i = 0; i < planets.length; i++) { var planetKey = planets[i].value; var planetName = planets[i].text; var gravity = planetData[planetKey].gravity; var earthEquivalent = gravity / earthGravityVal; chartData.labels.push(planetName); chartData.gravityValues.push(gravity); chartData.earthEquivalentValues.push(earthEquivalent); } // Sort data for better visualization var combined = []; for (var i = 0; i < chartData.labels.length; i++) { combined.push({ label: chartData.labels[i], gravity: chartData.gravityValues[i], earthEquivalent: chartData.earthEquivalentValues[i] }); } combined.sort(function(a, b) { return b.gravity – a.gravity; }); // Sort by gravity descending chartData.labels = combined.map(function(item) { return item.label; }); chartData.gravityValues = combined.map(function(item) { return item.gravity; }); chartData.earthEquivalentValues = combined.map(function(item) { return item.earthEquivalent; }); // Initial draw drawChart(); calculateWeight(); // Perform initial calculation with default values });

Leave a Comment