Pick a system
Click center · Double-click auto zoom · Wheel zoom at cursor · Drag pan · hover for photos and details. On touch: tap info · double-tap zoom · two fingers pinch.
The Size Ladder
A logarithmic ladder that stands several hundred objects in order of size, from a proton at about 10⁻¹⁵ m all the way up to the observable universe at about 10²⁷ m.
Everything in one column
From a proton to the observable universe spans more than forty orders of magnitude. This view puts all of it on a single logarithmic axis, so atoms, cells, mountains, planets and galaxies share one column. Every object is fixed at the position its real size dictates, which means any two of them can be compared by simply reading the gap between their slots. Two axes are available, size and mass, so the same catalog can be re-sorted by how heavy things are instead of how big.
The ladder is fixed; the camera moves
Zooming and panning never rearrange the ladder. Only the camera moves; the objects keep the slots they started in. That is what makes it possible to dive deep into one region, come back out, and still know where what you just looked at sits in the whole range. Use the wheel or a pinch to change magnification and drag to travel up and down, then park on whatever band interests you and compare the neighbors around it.
The rule behind the spacing
The reason for a log axis is blunt: drawn linearly, a proton has zero width and a galaxy eats the entire screen. Compressing logarithmically fits forty-odd orders of magnitude into one view and turns distance along the axis into a ratio between sizes. Neighboring entries are separated by forty percent of the larger one's size, just enough that they never touch, which keeps crowded bands legible where many objects land close together. The listed figures are representative values, so consult primary sources when you need exact dimensions.
When to reach for it
Pick something you have a feel for, then scan up and down from it; the objects you had no intuition about acquire one, measured in orders of magnitude from your anchor. It is especially useful for ranges people usually blur together, like the gap between a cell and an atom, or between Earth and the Sun. Switching to the mass axis turns up cases where the size ordering and the weight ordering disagree, which is worth a second look. Astronomical objects you meet along the way can be read about further in the site's encyclopedia.
Look it up here
- What is the diameter of the Earth? Earth measures 12,742 km across, and the size ladder shows how many rungs separate it from everything else. Show it here →
- How much bigger is the Sun than the Earth? The Sun is about 109 times the diameter of Earth, and the ladder shows just how far apart the two sit. Show it here →
- How small is an atom? A hydrogen atom is about one angstrom across, and its nucleus is roughly 100,000 times smaller again. Show it here →
- Where does the Sun land if you compare by mass? Switching the ladder to mass puts the Sun, Earth and a single atom on one axis, orders of magnitude apart. Show it here →
FAQ
Why a logarithmic scale?
Put a proton at about 10⁻¹⁵ m and the observable universe at about 10²⁷ m on the same linear ruler and everything small collapses into a single point. Logarithmic compression is what fits a range of more than forty orders of magnitude into one screen, and it makes distance along the axis mean a ratio.
Do the objects move around when I zoom?
No. Each object stays in the slot its real size assigns it, and zooming or panning only moves the camera. That is why you can dive into one part of the range and come back without losing track of where it sat in the whole.
Can I sort by mass instead of size?
Both axes are available: size comparison and mass comparison. Switching axes re-stands the same objects in order of weight, which makes it easy to hunt for entries whose mass ranking disagrees with their size ranking.