forked from gemmadanks/technosignatures
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathcocconi_morrison.py
56 lines (42 loc) · 2.08 KB
/
cocconi_morrison.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
"""Formulae from Cocconi & Morisson 1959.
G. Cocconi and P. Morrison, “Searching for Interstellar Communications,” Nature, vol. 184, pp. 844–846, 1959.
"""
import math
from utils import light_years_to_metres
from constants import SUN_RADIUS, LIGHT_SPEED
def luminosity_sunlike(frequency):
"""Compute luminosity at given frequency from sun-like star (Cocconi & Morrison 1959).
Args:
frequency: frequency of radiation (Hz)
"""
return pow(10, -15) * pow(frequency, 2) * 4 * math.pi
def flux_sunlike(frequency, distance):
"""Compute flux at given frequency from sun-like star (Cocconi & Morrison 1959).
Args:
frequency: frequency of radiation (Hz)
distance: distance from star (metres)
"""
return luminosity_sunlike(frequency) / pow(distance, 2)
def flux_from_galaxy(frequency, diameter_mirror=100):
"""Compute background flux at given frequency from the galaxy (Cocconi & Morrison 1959).
Args:
frequency: frequency of radiation (Hz)
diameter_mirror: diameter of the detector (metres)
"""
return (pow(10, -12.5) / frequency) * pow((LIGHT_SPEED / (diameter_mirror * frequency)), 2)
def power_from_galaxy(frequency, diameter_detector):
"""Compute background power at given frequency from the galaxy (Cocconi & Morrison 1959).
Args:
frequency: frequency of radiation (Hz)
diameter_detector: diameter of the detector (m)
"""
return flux_from_galaxy(frequency, diameter_mirror=diameter_detector) * pow(diameter_detector, 2)
def frequency_minimum(light_years_to_star, diameter_detector, constant=1e4):
"""Compute the minimum frequency for a SETI signal to be distinguished above background radiation.
Accounts for radiation from star and radiation from the galaxy (Cocconi & Morrison 1959).
Args:
light_years_to_star: distance to star in light years
diameter_detector: diameter of the detector (m)
"""
distance_to_star = light_years_to_metres(light_years_to_star)
return constant * pow((distance_to_star / diameter_detector), 0.4)