100 Light Years
This essay analysis the probabiltity of radio contact with another civilization in the Universe.
Current Status
In 2009 the Kepler mission was launched with the aim of identifying extrasolar planets within a portion of the Milky Way Galaxy containing approximately 150,000 stars.
In May 10, 2016 the number of extra solar planets the Kepler mission had detected was nearly 5,525 extrasolar planets around stars.
Source: "NASA's Kepler Mission Announces Largest Collection of Planets Ever Discovered". NASA. May 10, 2016. Retrieved May 10, 2016.
Source: https://en.wikipedia.org/wiki/Kepler_(spacecraft)#2016
The mission is considered a success and is ongoing.
The mission has also caused the possibility of radio contact with another civilization to be reviewed.
The potential of this contact occurring can be examined in the following manner.
Speed and Distance Factors
The speed of electromagnetic radiation; radio signals in this case; in a vacuum is
= 299,792,458 m/sec
= 9460528400000 km/yr
= 1 light year / yr
For a radio signal to travel to a nearby Earth like planet; say Tau Ceti e
= 11.9 light years away
= 11.9 years to get there
= 11.9 years to get back to Earth.
Transmission and Reception Factors
If humans look out from the earth in any direction into the observable universe they look back into the past relative to their location.
Therefore if humans have only developed commercial radio communications since the 1920s relative to their total evolution then everywhere humans look into the universe will appear in a state of past technological evolution to humans.
If any civilization existed had developed commercial radio communications prior to humans then that civilization would have broadcast their signals into the universe.
If such signals had been broadcast then humans would have; since the 1920’s; been able to detect those signals.
Even if the civilization that created the signals had died out then its signals would still propagate through space and be able to be detected.
If humans have been broadcasting into space since the 1920’s up to the current year of 2017 then they have broadcast approximately 70 to 97 light years in radius around the Earth.
Currently no signal has been received in reply in this radius.
If the first modern SETI experiment in listening to a star is considered as occurring in 1960.
Source: https://en.wikipedia.org/wiki/Project_Ozma
Then the amount of time humans have been listening can be approximated as a distance of approximately 57 light years in radius around the Earth. Currently no signal has been received in this radius.
Responses
As of 2017 no response signals have been received up to a signal radius of approx. 57 to 100 light years.
Conclusions from Lack of Responses
Since no signals have been detected then it must be concluded that no such civilization has managed to reach a commercial radio communications level.
Therefore it can be extrapolated that due to the humans ability to only sense in the past, the lack of earlier proven developments of broadcast signals from outside the Earth, the lack of replies to human broadcasts, the lack of signals detected from other radio broadcasts and the amount of time humans have been scanning the universe for signals the universe has never had a civilization in it; until humans in the 1920s; that developed commercial radio communications.
Therefore within approx.100 light years no civilization exists at a technology level at or above our own civilization.
Time Dilation Broadcasts
If a civilization had reached a commercial radio communications level and broadcast signals but its location was within a dense part of the universe then there could exist a time dilation effect on the signal that prevent it from being heard.
Allowing for the current 100 light year radius of scanning to contain such a civilization then if a return signal was sent immediately back by an alien civilization we could expect a signal to reach Earth by
= 2017 + 100, 2117.
Earth has however only been listening for return signals with radio astronomy since 1960.
Therefore if a return signal was sent immediately back by an alien civilization we could expect a signal to be sent from Earth reach the other civilization and be sent back to Earth by
= 1960 + 100, 2060.
Time Dilation Responses
If a return signal was sent from Earth to the civilization then the timescale for a return signal would be
1960 + 100 + 100, 2160
Up to
2017 + 100 + 100, 2217.
Potential Contact Time Dates
Therefore potential contact with another civilization could possibly occur between 2160 and 2217 if any other civilizations existed within 100 light years of Earth, had not been detected due to time dilation.
Kepler Data and Drake Equation
Adding in the Kepler data into the Drake Equation gives us the possibility of other active, communicative extra-terrestrial civilizations existing in the area of the Milky Way Galaxy examined by Kepler.
R* = rate of star formation = 7
fp = stars formed with planets = 5,525 exoplanets detected by Kepler around a star (est 2015) / 150,0000 stars = 0.04
ne = stars with planets capable of developing life, potential earth type planets detected by Kepler around a star (est 2015) = 1. (Out of 5,525 discovered 15 are capable of supporting life so round up to Earth, Sol, Solar System of 1 planet per solar system.)
Source: https://www.nasa.gov/jpl/finding-another-earth
fl = planets on which life will develop (per star solar system Earth = 1 in 9) = 1 / 9 = 0.11
fi = planets on which intelligent life will develop (per star solar system Earth = 1 in 9) = 0.11 / 9 = 0.01
fc = planets able to communicate (per star solar system Earth = 1 in 9) = 0.01 / 9 = 0.001
L = lifetime of a communicating civilization = 1,000 years
N = Number of active, communicative extra-terrestrial civilizations in the Milky Way = 0.00031
Therefore adding in the Kepler data and relating it to the Drake Equation gives us the possibility of other active, communicative extra-terrestrial civilizations existing in the area of the Milky Way Galaxy examined by Kepler.
= 0.00031. Or 1. The Earth.
Source: http://www.as.utexas.edu/cgi-bin/drake.pl
Extent of Exploration and Implications
The Milky Way Galaxy is 31 to 37 kilo-parsecs, 100 to 120 kilo light years in diameter.
It has a thickness of 0.6 kilo-parsecs, 2 kilo light years.
This gives a volume of 120,000 x 120,000 x 2,000 light years. 28,800,000,000,000 cubic light years
The Milky Way galaxy has 200,000,000 to 400,000,000 stars in it.
The Kepler Mission has examined 150,000 stars.
This is only an examination of 0.04% of the whole Milky Way Galaxy.
From the Kepler Data and the Drake Equation the number of extra-terrestrial civilizations in the area of the Milky Way examined.
= 0.00031. Or 1. The Earth.
Extrapolating this ratio of 1 in 150,0000 will be an Earth like planet out to the whole number of stars in the Milky Way Galaxy provides a total number of Earth like planets of 400,000,000 / 150,000 = 2667.
Approx. 3,000 Earth like planets in the whole Milky Way Galaxy.
Extrapolating the volume of space containing this 1 in150,000 Earth like planet in a ratio to the whole Milky Way Galaxy to achieve a volume of space between the Earth like planets
= 4/3 Pi X R 3
= 4/3 X 3.142 X (100 x 100 x 100)
= 4/3 x 3.142 x 1,000,000.
= 1 Earth type planet in 4,188,790 cubic light years. The Earth.
= Total Earth like planet space volumes in the Milky Way Galaxy
= 28,800,000,000,000 cubic light years / 4,188,790 cubic light years.
= approx. 7,000,000 such volumes of space containing an Earth like planet.
Therefore combining the stars and volume results there could be between 3,000 Earth like planets in 7,000,000 potential areas in the whole Milky Way Galaxy that have an Earth / sol type of environment.
Milky Way Galaxy Data, Kepler Data, Drake Equation
Adding the stars and volume data in the Drake Equation again for the whole Milky Way Galaxy
R* = rate of star formation = 7
fp = stars formed with planets = 3,000 potential exoplanets around a star / 7,000,000 potential areas
= 0.0004
ne = stars with planets capable of developing life = 1 potential Earth type planets detected by Kepler around a star (est 2015) so for the whole Milky Way Galaxy at 1 in 150,0000 = 2,667 approx, 3,000
fl = planets on which life will develop (per star solar system Earth = 1 in 9) = 1 / 9 = 0.11
fi = planets on which intelligent life will develop (per star solar system Earth = 1 in 9) = 0.11 / 9 = 0.01
fc = planets able to communicate (per star solar system Earth = 1 in 9) = 0.01 / 9 = 0.001
L = lifetime of a communicating civilization = 1,000 years
N = Number of active, Earth like communicative extra-terrestrial civilizations in the Milky Way Galaxy =0.0000031. Or 1. The Earth.
Source: http://www.as.utexas.edu/cgi-bin/drake.pl
Space Travel Ability
If you consider the potential of travelling to the other planets and mining them at our current technological level humans can only travel at a maximum speed in space of 13.3 AU/yr.
1 AU = 0.000015 light years
13.3 AU = 0.0001995 light years travel distance in a year.
Therefore to travel 100 light years would take 501,253 Earth years.
To travel to the nearest detected Earth like planet ; say Tau Ceti e 11.9 light years away; would take 59,649 years at our current technological potential.
Therefore contact is a very limited possibility.
Space Resources
The resources of space are very limited.
Source: https://sites.google.com/site/architecturearticles/home/article-034-If there are less resources on Earth then where are they ?
Source: https://sites.google.com/site/architecturearticles/home/article-046 --Earth Resources and the Drake Equation.
Source: https://sites.google.com/site/architecturearticles/home/article-092---the-issues-of-helium-3-as-a-fusion-energy-source
Source: https://sites.google.com/site/architecturearticles/home/article-144---asteroid-mining-for-resources-and-energy
Conclusions
Potential contact with another civilization will possibly occur between 2160 and 2217 if any other civilizations exist within 100 light years of Earth.
The potential number of Earth like communicative extra-terrestrial civilizations in the whole Milky Way Galaxy should be 1.
As of 2017 no response signals to our own radio broadcasts have been received up to a signal radius of approx. 57 to 100 light years.
Therefore within approx.100 light years no Earth like communicative extra-terrestrial civilizations exists at a technology level at or above our own civilization.
As of 2015 no signals have been detected up to a signal radius of the origin of the Universe.
Therefore within current signal detection ability no Earth like communicative extra-terrestrial civilizations have existed or exists at a technology level above our own civilization in the Universe.
Humans in terms of transmission, detection and technological status are therefore quite alone in the Milky Way Galaxy and possibly the Universe as a technological, space faring, species.
Humans are also currently unable to currently colonize any nearby Earth like planets in our own solar system and are restricted to one habitation location.
Even if we did attempt exploration out to the edge of our current radio signal detection the lack of Earth like planets so far detected and the lack of signals from other civilizations indicate that it is a desperate, if heroic, proposal.
This leaves the humans on Earth, in Earth orbit, exploring and mining the solar system for the future decades.
Add into this our current context of energy, resource and environment depletion and the humans are forced to admit to themselves that they have this one survival location to tend for until they can make a technological jump in space exploration and detection and find a second habitation location off Earth.
Ian K Whittaker
Websites:
https://sites.google.com/site/architecturearticles
Email: iankwhittaker@gmail.com
25/03/2015
13/05/2017
14/10/2020
1967 words over 4 pages