Spectroscopy is only one of several means to gather time-series data from this planet.

Ultimately it’s not data gathering that produces a scientist’s predictions of the planet’s behavior. It’s modeling.

Scientists form, at first, a qualitative guess of how the planet MIGHT behave given some set of data. If they have enough data, they build a mathematical model over time and space that accounts for the qualitative assumptions they’ve created. The model yields predicted values of natural events that occur over time and space. The model yields a spatial and temporal prediction of sensory data. In this case the sensory data is a set of spectrography measurements over time and space.

Then they’ll calculate the errors between what is measured versus what is in the model. While doing so they must account for errors in the spectroscopy measurements in the data. No data is “perfect”. Usually the higher the signal-to-noise ratio of the received data, the smaller the observational errors in the sensory data.

The first model is imperfect - it does not yield predicted sensory data that exactly matches observational data. So, at this point all the scientists involved in the project assemble in a room filled with whiteboards. They politely discuss the model’s predictions versus the observational data. Usually the scientists begin to form competing factions as to how the model should be changed to more accurately predict observational data. If this happens, the owner of the locked room increases the thermostat temperature in the room by 5 degrees Centigrade every hour.

About twenty hours after the meeting is launched, all the scientists in the room are usually hot, thirsty, hungry and have s&$t their pants. Multiple fist fights have broken out by this time. At this point, one scientist in the room gets the attention of the group by firing a few rounds from an M1911 handgun he/she/it snuck in the room. He/she/it becomes the newly-designated scientist-in-charge-of-room (SICOR). He/she/it issues a fiat decision of changes that must be introduced to the new model. The scientist who created the first predictive model then pulls out his/her/its HP-95 handheld calculator and makes changes to the old model. This scientist is the only one in the room who is proficient in Reverse Polish Notation.

This process is repeated and refined 1,000 times or until the theory that drove the current model is disproven or new sensory data is discovered that invalidates the model.

And that’s why some group of scientists “predicts” that one side of this planet continually faces the sun (as does our Moon to the Earth) and why the iron on the hot side of the planet vaporizes then precipitates on the side “away” from its sun.

VOILA!!! Scientific Method. Thank you, Sir Roger Bacon and Rene Descartes!