An Application of Spectroscopy To Science Fiction Astronomy

Version 1.1.7 of 23/4/2021-1:00 p.m.

Let's see if we can do some detective work to determine the characteristics of the Predator home-world.

predator vision without helmet
The vision of the Predator species (without vision enhanced technology) as shown in the movie "Predator" ([8]), with colors enhanced.

The Predator species without its vision-enhanced helmet sees the Earth plant-life as above[1][2]. Sampling the most luminous area of the above photograph with Photoshop, we find for example: RGB = 255,22,22. Running the Maple program in [1], we find that these values correspond roughly to λ=680nm.

Using the assumption that the Predator species has evolved to see through the dominant wavelength of their main star's spectrum, λ=680nm (similar to how human vision evolved to have maximum sensitivity around λ~555nm) and applying Wien's displacement law from [2], we find that the temperature of the main component in the star system of the Predator home-world, has a temperature T (in Kelvins) such that:

T*λ=2.898*106nm*K, hence for λ=680nm, T~4261°K

Using the Black Body spectral distribution again from [1], we can see the spectrum of the main stellar component:

predator planet spectrum
The spectrum of the main stellar component of the Predator home-world.

After consulting with [3], the above means that the main star in the Predator's home-world is very likely a class K star. In the second Predator sequel, we can actually see that the Predator planet is illuminated by two stars:

predator planet
The home-world of the Predator species as shown in "Aliens vs. Predator: Requiem" ([7]), with colors enhanced.

Indeed, the brightest star looks like a K-type star. Using [1], we can see the overall color for a star of T~4261°K. Since (5000-3500)/10=150 and (4261-3500)/150~5, the approximate class is K5.

maple star 1 color color                     sample star 1 color
Color of the main stellar component in the home-world of the Predator species.
Left: RGB=255,240,211, calculated using [1]; Right: 255, 247,211, sampled from the photo above, using Photoshop.

Using again [1] and sampling the second stellar component in the photo, we can see the color of the second star.

maple star 2 color color                     sample star 2 color
Color of the second stellar component in the home-world of the Predator species.
Left: RGB=255,180,94, calculated using [1]; Right: 254,195,91, sampled from the photo above, using Photoshop.

Maple gives a T~2100°K for the second component. Consulting with [3], this means the second component is a class M star. Since (3500-2000)/10=150 and (3500-2100)/150~9, the star's class is M9.

The stellar pair in the Predator's home-world is therefore approximately K5-M9. Consulting with [3] and [5], and discarding possible errors from the above calculations, the closest stars which fit the bill are Alpha Centauri B (K1) and Proxima Centauri (M5 red dwarf)(!).

Stars of class M show lines belonging to molecules and all neutral metals but hydrogen lines are usually absent. Titanium oxide can be strong in M stars, usually dominating by about M5. Vanadium oxide bands become present by late M ([3]).

Interestingly enough, such stars are immediate attractors for another dangerous entity, the Derelict ([6]), which spectroscopically scans entire star systems in search of sentient life around them. Scanning the K5-M9 combo from afar spectroscopically, would likely produce something of an average between K5 and M9, probably towards K7-K9, since the M type component looks like a red dwarf, with a limited luminosity (see picture above).

Indeed, the two species, the xenomorphs (which are creations of the Derelict) have met with the Predator species in the current science-fiction scenarios. So at least some of the astrophysical aspects of the Predator home-world are scientifically consistent with the dominant scenario.

Unfortunately there's a major discrepancy which ruins the nice analysis, above. In the last movie "Aliens vs. Predator: Requiem" ([7]), we see that one of the dying Predators aboard the space-ship which crashes on Earth after the emergence of the Predalien, initiates an S.O.S. signal when the movie shows the time to be 00:04:03 and the signal is intercepted by the Predator in the Predator home-planet when the movie shows the time to be 00:05:23. Assuming the movie keeps approximately the correct time, this means that the Predator home-world must be 1:20 light-minutes away from Earth.

1:20 light-minutes is ~ 300000(km/s)*80(s) = 24000000(km) = 24 million km's. The Earth orbits the sun at a distance of 150 million km's, so adding 150 + 24 million = 174 million km's. There's nothing at this distance from the sun. The next closest planet is Mars, at a distance of ~ 228 million km's.

When the Predator examines the S.O.S. message, the playback sequence shows what appears to be inter-stellar travel, and indeed, this species supposedly has such a capability. The problem is that regardless of the latter, any S.O.S. message is essentially electromagnetic radiation, so it travels at most with the speed of light, so this is a relativistic inconsistency[3], since a message to Alpha Centauri would need approximately 4.37 years to reach the Predator home-planet, if the Predator home-planet indeed resided there.


  1. To see a Numerical Analysis application on the same species with its vision enhanced technology, click here.
  2. To see a Color Matching application on the same species with its vision enhanced technology, click here.
  3. Unless of course the species has found a method to send and receive messages at super-luminal speeds or relativity is wrong.


  1. This author, "The Science of Color, the Emission Spectra of the Elements and Some Lamp Engineering Applications". (online)
  2. Wikipedia's "Black Body". (online)
  3. Wikipedia's "Stellar Classification". (online)
  4. Wikipedia's "List of Nearest Stars". (online)
  5. Wikipedia's "List of Nearest Bright Stars". (online)
  6. This author, "The Genius of The Derelict". (online)
  7. Wikipedia's "Aliens vs. Predator: Requiem". (online)
  8. Wikipedia's "Predator". (online)
  9. Related on Quora.