UNKNOWN SPACE FILES / ONE CONNECTED UNIVERSE
Space Lab.
Change the numbers.
Rewrite the universe.
How big could our Sun become?
Expand its radius and compare it with the inner planets’ present-day orbits.
Orbit distances and solar radius share one scale. Planet dots are enlarged.
Animation shows changing size, not the passage of actual years.
The science & the simplifications
The Sun is expected to leave its current stable phase in roughly 5 billion years and become a red giant. This is a size explorer, not a stellar-evolution forecast: the 100–250× settings are illustrative giant sizes, not dated milestones or an exact maximum. Today’s radius is taken as 695,700 km; 1 AU is 149,597,871 km.
Orbits are held at their present average distances. Real orbits change as the Sun loses mass, and tides also matter. A surface crossing an orbit in this diagram does not predict the exact fate of that planet. Earth becomes uninhabitable long before the Sun reaches its orbit. Colours are illustrative.
Read more: ESA — The Sun · NASA — Aging into gianthood.
One hour for you. How long far away?
Move a hovering clock closer to a black hole and compare it with a clock far from its gravity.
Clock hands compare rates. Position diagram is schematic, not to scale.
One animation cycle represents one minute on the far-away clock, played at 10× speed.
The science & the simplifications
For a stationary clock outside a non-rotating, uncharged black hole, the rate relative to a clock infinitely far away is √(1 − rₛ/r). Here rₛ = 2GM/c² is the event-horizon radius. Far-away time = your elapsed time ÷ this rate.
This models hovering at one chosen radius, not falling inward or orbiting. Hovering needs thrust that becomes unbounded at the horizon; the tool never reaches or crosses it. It omits motion, rotation, tidal forces and light-travel delays. Your own clock always feels normal to you. At a fixed r/rₛ, the ratio is independent of black-hole mass.
Read more: Einstein Online — Time dilation.
Same jump. A different world.
Compare how high and how long you would jump on Earth, the Moon and Mars.
All three markers launch together at the same speed. Height is to scale.
Less gravity means more height and more time in the air — with the same take-off speed.
The science & the simplifications
Take-off speed v = √(2gEarth × Earth jump height). Maximum height = v²/(2g); flight time = 2v/g. The animation uses h(t) = vt − ½gt² and stops each marker on landing. Approximate surface gravity: Earth 9.81, Moon 1.62 and Mars 3.71 m/s².
This is a vertical motion model with constant gravity and no air resistance. It assumes identical take-off speed; it does not simulate muscles, suits or terrain. Marker sizes are not physical sizes.
Data reference: NASA — Planetary fact sheets.
Build your own world.
Change its mass, size and temperature. Watch its gravity, density and escape speed transform.
Planet size is compared with Earth. Colour and atmosphere are illustrative.
The science & the simplifications
Surface gravity relative to Earth is mass ÷ radius². Escape speed scales with √(mass ÷ radius), and average density with mass ÷ radius³. Mass and radius use Earth as 1.
The world type and appearance are educational estimates. A real planet’s composition, atmosphere, pressure, magnetic field and history cannot be determined from three sliders.
Design a planetary orbit.
Choose a star, move the planet and stretch its path. Kepler decides how long a year lasts.
The ellipse shape and star position are schematic. Values use a two-body Kepler model.
The science & the simplifications
For masses measured in Suns, distance in AU and period in Earth years, Kepler’s third law becomes P = √(a³/M). The displayed speed is the circular-orbit speed at the average distance; speed varies around an eccentric orbit.
The star and planet sizes are enlarged. This ignores other planets, relativity, tidal effects and stellar evolution.
Could your alien world hold liquid water?
Pick a star, set the orbit and build an atmosphere. The result is a clue—not a verdict on life.
The coloured band is an approximate liquid-water zone. Real habitability is far more complex.
The science & the simplifications
The equilibrium estimate uses stellar luminosity, distance and reflected light, then adds a chosen greenhouse warming. The approximate zone uses stellar flux limits of 1.1 and 0.35 times Earth’s sunlight.
Liquid water also needs suitable pressure and chemistry. Clouds, atmospheric circulation, flares, tidal locking, oceans and geology can change the answer dramatically. “Potentially temperate” does not mean inhabited.
Launch an asteroid at Earth.
Change its size, speed, material and angle. Then watch the energy hit the ground.
The crater and effects are rough educational estimates, not a hazard forecast.
The science & the simplifications
Mass assumes a spherical asteroid. Kinetic energy is ½mv². The crater estimate is a deliberately rough scaling based on projectile size, speed, density and impact angle.
Real outcomes depend on entry breakup, target rock, ocean depth, terrain and complex shock physics. Do not use this simplified tool for real-world hazard planning.
Travel from a human to the observable universe.
Move through powers of ten and feel how quickly ordinary scale disappears.
Each stop uses a representative diameter or span. The visual zoom is logarithmic.
The science & the simplifications
This is a logarithmic size explorer. It compares a 1.8 m human, Earth, the Sun, Earth’s orbit, Neptune’s orbit, the Oort Cloud, the Milky Way, the Local Group and the observable universe.
Some boundaries—especially the Oort Cloud and Local Group—are approximate. The observable universe is about 93 billion light-years across; the entire universe may be much larger.