About

The What-If Observatory works out hypotheticals in public arithmetic. Each step of a chain carries a rating, so you leave with a number you can recompute and you can see where the sums stop and the guessing starts. The motto is Serious arithmetic for unserious questions.

The name needs a warning. This is not an astronomy or stargazing site, and no sky is being watched. “Observatory” is a figure of speech: point a question somewhere, calibrate the premises, take the reading, and say when the cloud comes in.

What is here

Five sections, each with its own kind of sum:

• What If takes one hypothetical with a named, checkable premise and follows it to the step where the arithmetic gives out. Yellowstone, the Carrington event and a Moon at half its distance are in this section.
• Two-Road Estimates answers how many, how much and how long along two roads with separately sourced inputs, then prints the gap between them. The Fermi paradox leads this section.
• Old Forecasts, Graded grades named forecasts item by item as hit, costume error, miss or untestable. Each one has a quantity to recompute: run the figures Jules Verne gave for his 900-foot cannon and the passengers feel an average of about 22,000 g.
• Utopias, Audited asks who paid, who did the work and what it would have cost. Plato's ditch around Atlantis gets treated as an earthworks job, with Plato's story labeled as a story.
• Paradoxes, Unpacked covers named paradoxes with something to calculate, among them Schrödinger's cat and the twin paradox. The assumptions inside the question and the competing answers sit side by side.

Who it is for

The site is written for people who like asking what if: curious general readers, from high school level up, who would rather see the working than take a figure on trust. Teachers will find estimates and paradox diagrams to use in class. Science fiction readers will find real communities and the source texts behind imagined ones.

We do the sums. You do the doubting. Pages give you what you need for that: the inputs, their sources and the formula. Several add a small table that changes one parameter so you can rerun it.

It will not tell you what the future holds. There are no forecasts of markets, elections, technology trends or doomsday dates here, only hypotheticals and forecasts that have already come due. Nothing here is medical, financial or legal guidance. All of it happens on paper, so nothing is meant to be tried at home, and no page offers exam answers ready to copy.

Where the site stands

Imagination costs nothing. What counts is knowing the step where you started imagining, so every hypothetical here publishes its dotted line. That is this site's stance on how to write a hypothetical, not a general claim about scientific method.

Five positions follow from it, and you are free to disagree with any of them:

• A what-if with no number in it is fan fiction. Every chain contains at least one figure you can recompute.
• A mocked forecast may have guessed the need right and the form wrong. Grading asks about the function first and the form second. This is an angle to test, not a claim about how often it happens, and complete hits and complete misses are graded as what they are.
• Two roads and the gap between them beat one precise number with no history. That is a preference in how results are shown. It does not make two roads more reliable than one, since shared bias can survive agreement. A good first-hand measurement is quoted at its stated precision and can be rated clear on its own.
• The accounts and the housework of a utopia often get buried under its charter. Who washed up, who kept the books and who inherited are set beside leadership, ideas and outside conditions. Where the records point to several causes, or to a community that simply changed and carried on, the page says that.
• Check the question before announcing an answer. Taking a paradox's question apart is often more honest than declaring it solved, but the main schools are still listed and no argument is called closed. If the question holds up, the page says so.

The site stays out of doctrinal disputes in living religions, living politicians and current parties, and real population policy. Where the history of a utopia touches eugenics, the page records and criticizes it and does not build hypotheticals on it.

How pages are checked

Every formula is re-run in code, and the formulas and inputs are published as CSV. Each input has a named source. The Check my math table at the end of a page marks each step's source grade, whether it was recomputed, and its Seeing rating, which runs from clear through hazy to overcast.

Quotations go back to the original page or a public-domain scan where that can be read. Where it cannot, the page names who the quotation came through. A re-run tests the arithmetic and nothing more: the source chain answers for the inputs, and the Seeing rating answers for the assumptions. The full rules are in How We Rate a Reading.

Three working terms

• The dotted line is the step in a chain where sources and models stop constraining the result.
• Two-road agreement is the state of two estimates, with different main input sources, landing within 3 times of each other.
• The costume error is a forecast that got the need right and dressed it in a technology that never arrived.

These are tools for reading single cases. None of them is a historical law.

The look of the site

The colors come from the cheap four-color printing of old pulp magazines: a heavy magenta, a cyan and a yellow on aged newsprint. In dark mode the paper falls away and the inks brighten.

Illustrations in that halftone style are marked as illustrations. They are not old magazine art, photographs or historical records, and they carry no scale. Anything whose proportions matter is a figure drawn from the same CSV as the numbers. What you may reuse, and how, is on Reuse and Licenses.

If something is wrong

Write to contact@whatifobservatory.com. There is no form, and no reply time is promised. A confirmed error gets corrected, and the change is recorded at the foot of the page and on the Corrections page.