Editing 1606: Five-Day Forecast

 

{{w|Weather forecasting}} is an extremely difficult task, even if it is only for five days. In numerical models, extremely small errors in initial values double roughly every five days for variables such as temperature and wind velocity. So most {{w| Meteorology#Meteorologists |meteorologists}} only provides us with a five-day forecast.

In this comic [[Randall]] takes this to the extreme by first showing a [[Five-Day Forecast]] and then progressing to five-month, year, million, billion and finally trillion-year forecast.

When moving past the five days, the weather is just a qualified guess based on the time of year. In a month it is Christmas as shown in the second panel of the second row. And then it is winter with January and February so snow is likely, but certainly not something that happens on all days of a winter month.

Then we go into the far future, jumping a million year from panel to panel. But still the weather symbols stay the same. However, in 3 million years time aliens (or advanced humans) attack with energy beams from something looking like {{w| flying saucers}}. They are gone a million years later. The temperature range is still the same (except that it rises to 52 °F or 11.1 °C, a possible reference to global warming) in one panel. But then while the attack is going on the temperature rises to 275 °F (135 °C).

Once we get to the billion-year mark it actually becomes more meaningful to try to predict the "weather". Because now we reach the times when the {{w|Sun}} begins to change. Although the Sun will continue to burn hydrogen for about 5 billion years yet (while in its {{w|Sun#Main_sequence|main sequence|}}), it will still grow in diameter as it begins to exhaust its supply of fuel. The core will contract to increase the temperature, and the outer layer will then compensate by expanding slightly. This is what is indicated in panel two and three where the color of the Sun changes towards red as the surface becomes less hot as it expands away from the center of the Sun. The temperature will rise on Earth as indicated in the panels (105 °F = 40.5 °C and 371 °F = 188 °C). So in two billion years the temperature is hot enough that all the earth's oceans will have boiled away… Actually this will happen already in about [http://phys.org/news/2015-02-sun-wont-die-billion-years.html a billion years].

Then once there is {{w|Sun#After_core_hydrogen_exhaustion|no longer enough hydrogen}} the Sun will truly expand into a {{w|red giant}}. This should not happen until five billions years from now {{Citation needed}}, but in the forecast it is indicated to happen already in three. Maybe this is Randall taking liberties to show what happens during this phase, which would not fit into a five-billion-years forecast. Alternatively it is just indicating how uncertain these kind of forecasts are, or a statement that we may not know for certain that it will take five not three billion years.

Disregarding this, the fourth panel shows the temperature at Earth's position inside the red giant Sun. The color of the panel indicates that we are inside the Sun. The temperature is 71,488,106 degrees Fahrenheit (39,715,597 degrees Celsius). The current temperature of the center of the Sun is "only" 27 million degrees Fahrenheit (15 million degrees Celsius). And although that may rise by a factor of ten during {{w| Stellar nucleosynthesis |helium fusion}} then that will only be at the very core and not out in the solar atmosphere reaching out to Earth Here the temperature would only be of the order of thousands of Fahrenheit, since the Sun's outer temperature decreases as it increases its diameter. So this panels temperature also makes little sense. It may involve some ambiguities regarding what the forecast means; the edge of the red giant Sun is predicted to be somewhere near the current orbit of Earth, but the position of the Earth could change. The most likely prediction at the moment is for Earth to move outward, but if the planet is engulfed by the Sun, it would spiral inward, and at some point fall apart. So in some sense "here" for the forecast could become a position deep inside the Sun, where core temperatures could reach 100 million Kelvin.

The red giant phase only last half a million years, so a billion years after the Sun has been a red giant its outer atmosphere will for sure have disappeared leaving only a {{w|white dwarf}} to cool down. Given Randall's version of this time schedule, then it will have had about a billion years to cool down, but would still likely be the brightest object in the sky as seen from where the Earth once was. It is not indicated in the last panel, where we just see other stars of the Galaxy. The temperature is down to that of the {{w|Cosmic microwave background |background radiation}}. Today this radiation has a temperature of 2.72548 kelvin = -270.4245 °C = -454.7641 °F. So this is a few degree F colder than what is shown in the comic which states the temperature is -452 °F = 4.26 kelvin. This higher temperature may have been chosen to reflect that even the star light from other stars would increase the actual temperature.

In the last panel with trillion years, we jump right past the Sun's Red Giant phase, to a panel looking much like the one after five billions years with only other stars. Over the next three trillion years the stars become fewer and fewer and dimmer and dimmer as they run out of fuel and fewer new stars form. After four trillion years the background temperature even decreases one degree to -453 °F as the universe keeps expanding and the wavelength of the radiation does the same, thus decreasing its temperature.