"Hello Galaxy": A New Galactic Telegram
This post celebrates Arecibo Message on the eve of its golden jubilee.
Initially this was written as a richer post, prefaced by A Short Essay on Our Existence.
In mid-1974, directly from the Arecibo Observatory in Puerto Rico, Frank Drake and Carl Sagan transmitted the first message to space from the then most powerful radio telescope, now demolished.
Rather than omnidirectional (in all directions), the signal was directed towards a dense group of stars, the M13 cluster. Remember: the more stars, the more chances of life.
It should still take 25,000 years to reach its destination. Should, but will not.
The target they aimed the telescope at, in the direction of M13, it went unnoticed that when the message arrives there, M13 will have changed position. Should any civilisation be present in the path of the target region by the time the signal hits, it may still be detected. To illustrate how powerful the signal is, the message was transmitted for 3 minutes consuming 3 TW, costing upwards of $10 million in energy bill.
So, what to include in this message so that an intelligent technological civilisation, with no knowledge of our culture, can interpret it?
Let's dissect the message.
The Arecibo Message
The transmitted radio waves were frequency modulated
and can be immediately converted to binary representation
00000010101010000000000001010000010100000001001000100010001001011001010101010101010100100100000000000000000000000000000000000001100000000000000000001101000000000000000000011010000000000000000001010100000000000000000011111000000000000000000000000000000001100001110001100001100010000000000000110010000110100011000110000110101111101111101111101111100000000000000000000000000100000000000000000100000000000000000000000000001000000000000000001111110000000000000111110000000000000000000000011000011000011100011000100000001000000000100001101000011000111001101011111011111011111011111000000000000000000000000001000000110000000001000000000001100000000000000010000011000000000011111100000110000001111100000000001100000000000001000000001000000001000001000000110000000100000001100001100000010000000000110001000011000000000000000110011000000000000011000100001100000000011000011000000100000001000000100000000100000100000001100000000100010000000011000000001000100000000010000000100000100000001000000010000000100000000000011000000000110000000011000000000100011101011000000000001000000010000000000000010000011111000000000000100001011101001011011000000100111001001111111011100001110000011011100000000010100000111011001000000101000001111110010000001010000011000000100000110110000000000000000000000000000000000011100000100000000000000111010100010101010101001110000000001010101000000000000000010100000000000000111110000000000000000111111111000000000000111000000011100000000011000000000001100000001101000000000101100000110011000000011001100001000101000001010001000010001001000100100010000000010001010001000000000000100001000010000000000001000000000100000000000000100101000000000001111001111101001111000
At glance these 1,679 digits don't seem to make sense, and it's up to the recipient to reflect on this number. Two clues emerge: oddity and semi-prime (product of primes 23 x 73). Therefore, we can reorganise digits in 2D using 23 rows and 73 columns —or vice versa.
The first configuration gives a jumbled matrix with nothing visually obvious in it.
0000001010101000000000000101000001010000000100100010001000100101100101010
1010101010100100100000000000000000000000000000000000001100000000000000000
0011010000000000000000000110100000000000000000010101000000000000000000111
1100000000000000000000000000000000110000111000110000110001000000000000011
0010000110100011000110000110101111101111101111101111100000000000000000000
0000001000000000000000001000000000000000000000000000010000000000000000011
1111000000000000011111000000000000000000000001100001100001110001100010000
0001000000000100001101000011000111001101011111011111011111011111000000000
0000000000000000010000001100000000010000000000011000000000000000100000110
0000000001111110000011000000111110000000000110000000000000100000000100000
0001000001000000110000000100000001100001100000010000000000110001000011000
0000000000001100110000000000000110001000011000000000110000110000001000000
0100000010000000010000010000000110000000010001000000001100000000100010000
0000010000000100000100000001000000010000000100000000000011000000000110000
0000110000000001000111010110000000000010000000100000000000000100000111110
0000000000010000101110100101101100000010011100100111111101110000111000001
1011100000000010100000111011001000000101000001111110010000001010000011000
0001000001101100000000000000000000000000000000000111000001000000000000001
1101010001010101010100111000000000101010100000000000000001010000000000000
0111110000000000000000111111111000000000000111000000011100000000011000000
0000011000000011010000000001011000001100110000000110011000010001010000010
1000100001000100100010010001000000001000101000100000000000010000100001000
0000000001000000000100000000000000100101000000000001111001111101001111000
Remove a digit for clarity, still doesn't ring a bell.
1 1 1 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1
1 1 1 1 1 1 1 1 11
11 1 11 1 1 1 1 111
11 11 111 11 11 1 11
1 11 1 11 11 11 1 11111 11111 11111 11111
1 1 1 11
1111 11111 11 11 111 11 1
1 1 11 1 11 111 11 1 11111 11111 11111 11111
1 11 1 11 1 11
111111 11 11111 11 1 1
1 1 11 1 11 11 1 11 1 11
11 11 11 1 11 11 11 1
1 1 1 1 11 1 1 11 1 1
1 1 1 1 1 1 11 11
11 1 111 1 11 1 1 1 11111
1 1 111 1 1 11 11 1 111 1 1111111 111 111 1
1 111 1 1 111 11 1 1 1 111111 1 1 1 11
1 11 11 111 1 1
11 1 1 1 1 1 1 1 1 111 1 1 1 1 1 1
11111 111111111 111 111 11
11 11 1 1 11 11 11 11 11 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1111 11111 1 1111
This is the bare minimum what a sufficiently intelligent extraterrestrial being should do.
The sibling configuration, 73 rows by 23 columns, seems to provide a hint, let's delve deeper.
00000010101010000000000
00101000001010000000100
10001000100010010110010
10101010101010100100100
00000000000000000000000
00000000000011000000000
00000000001101000000000
00000000001101000000000
00000000010101000000000
00000000011111000000000
00000000000000000000000
11000011100011000011000
10000000000000110010000
11010001100011000011010
11111011111011111011111
00000000000000000000000
00010000000000000000010
00000000000000000000000
00001000000000000000001
11111000000000000011111
00000000000000000000000
11000011000011100011000
10000000100000000010000
11010000110001110011010
11111011111011111011111
00000000000000000000000
00010000001100000000010
00000000001100000000000
00001000001100000000001
11111000001100000011111
00000000001100000000000
00100000000100000000100
00010000001100000001000
00001100001100000010000
00000011000100001100000
00000000001100110000000
00000011000100001100000
00001100001100000010000
00010000001000000001000
00100000001100000000100
01000000001100000000100
01000000000100000001000
00100000001000000010000
00010000000000001100000
00001100000000110000000
00100011101011000000000
00100000001000000000000
00100000111110000000000
00100001011101001011011
00000010011100100111111
10111000011100000110111
00000000010100000111011
00100000010100000111111
00100000010100000110000
00100000110110000000000
00000000000000000000000
00111000001000000000000
00111010100010101010101
00111000000000101010100
00000000000000101000000
00000000111110000000000
00000011111111100000000
00001110000000111000000
00011000000000001100000
00110100000000010110000
01100110000000110011000
01000101000001010001000
01000100100010010001000
00000100010100010000000
00000100001000010000000
00000100000000010000000
00000001001010000000000
01111001111101001111000
Upon a digit clearance, a clear pattern emerges.
1 1 1 1
1 1 1 1 1
1 1 1 1 1 11 1
1 1 1 1 1 1 1 1 1 1
11
11 1
11 1
1 1 1
11111
11 111 11 11
1 11 1
11 1 11 11 11 1
11111 11111 11111 11111
1 1
1 1
11111 11111
11 11 111 11
1 1 1
11 1 11 111 11 1
11111 11111 11111 11111
1 11 1
11
1 11 1
11111 11 11111
11
1 1 1
1 11 1
11 11 1
11 1 11
11 11
11 1 11
11 11 1
1 1 1
1 11 1
1 11 1
1 1 1
1 1 1
1 11
11 11
1 111 1 11
1 1
1 11111
1 1 111 1 1 11 11
1 111 1 111111
1 111 111 11 111
1 1 111 11
1 1 1 111111
1 1 1 11
1 11 11
111 1
111 1 1 1 1 1 1 1 1
111 1 1 1 1
1 1
11111
111111111
111 111
11 11
11 1 1 11
11 11 11 11
1 1 1 1 1 1
1 1 1 1 1 1
1 1 1 1
1 1 1
1 1
1 1 1
1111 11111 1 1111
At this point, we have the decoded Arecibo message.
Here's the infamous flamboyant epistle we advertised.
-
Numbers 1 to 10: The numbers 1 to 10 in binary notation (white).
-
Human figure form: The atomic numbers of hydrogen, carbon, nitrogen, oxygen, and phosphorus, which compose DNA (purple).
-
DNA formula: The formulas of sugars and nucleotide bases of DNA (green).
-
Nucleotides and graphic representation of DNA: The number of nucleotides in human genome and the graphic representation of DNA's double helix structure (white and blue, respectively).
-
Average human height and population: The average height of a person (in white and blue on the left), a graphic representation of a human (red) and the human population, at the time 4 billion (white on the right).
-
Solar system: A representation of the solar system, including the obliterated Pluto, indicating the planets and our highlighted position (yellow).
-
Radio telescope representation: A huge graphic representation of the radio telescope (purple) and the dimensions of the transmitting parabolic antenna (blue and white below).
Brilliant, much of it is immediately deducible. Some fragments seem hazier and could be optimised.
-
Presenting numbers 1 to 10 is a cultural facet, we count from 1 to 10 merely because we recently built a numeral system that reflects our pentadactyl anatomy. Number ten is no special over other numbers.
-
There's only one rocky planet in the habitable zone, the others can hardly harbour complex life, let alone a communicative technological civilisation, so it's unnecessary to point out the solar system schematic.
-
The transmission frequency was 2,380 MHz, so the wavelength is This information can be obtained from the waves themselves, which makes the transmitting antenna schematic a blatant, redundant information.
-
The diagram pictures humans and their population, but this alone is of lesser importance compared to other relevant information we could have included.
Elaborating an assertive, succinct, expressive message, culturally neutral, summarising the major information blocks is quite much of a challenge, especially due to the lack of a defined protocol and the need to rely on universal –or self-contained– references, such as the frequency and wavelength of the message.
A New Galactic Telegram
We structure the information into four basic blocks presenting the main aspects.
-
Galactic position: Where we are in the galaxy.
-
Atmospheric composition: Indicates what our planet's surface is like, which obviously must be rocky, contain water and orbit in the habitable zone.
-
Formula of life: The structure of DNA that forms life as we know it, the chemical elements we're made of and how they unite.
-
Energy consumed: Indicative of civilisational technological evolution degree, how far we've come developing and consuming energy.
Long story short, pre-final telegram looks like
173 Hz 510
218 Hz 3,800
339 Hz 3,600
245 Hz 2,300
-------------------
C-N-O-Ar N2
O2
CO2
Ar
-------------------
H-C-N-O-P
C5OH7 PO4
C5H4N5 C5H5N2O2
C4H4N3O C5H4N5O
-------------------
Sol Terra
333,000 1
58,800 1
The Arecibo matrix couldn't accommodate our message in its original dimensions, so the frame was widened and shortened to 61 x 29.
Until this message finds a destination, it may be distorted along the way. A simple, practical technique is to use the edges to create a self-verification code. If the row sum is odd, we note 1 in the last cell and vice versa with zero, columns logic follows suit.
Galactic Position
Precisely pointing where we are in a tangle of hundreds of billions of stars is challenging.
Just like planets rotate around the Sun, our solar system also rotates around the centre of the galaxy.
At the galaxy's centre, there's also a giant body, akin to our Sun. This body is so large, so dense, and with such gravity that nothing escapes from it, not even its own light, therefore it doesn't shine: a supermassive black hole, which isn't a hole at all, and we call it Sagittarius A*.
Solar systems orbit Sagittarius A*, just like planets here orbit the Sun, just as electrons orbit an atom's nucleus. Beautiful architecture, isn't it?
Solar system's orbit takes around 225 to 250 million years. The last time we passed nearby, Pangaea was the only continent, flora was full of conifers and ferns, there were no flowers or grass, the first dinosaurs were small reptiles, and the closest things to mammals were the synapsids, presumably the smartest things around.
Sending a message to the other side of the galaxy won't consume even 1% of the 250 million years for galactic orbit. Stars will be practically in the same places, no need to worry about their dynamics or whereabouts. Even if it took longer, stars are insipid and predictable.
There are various ways to locate ourselves, however, most methods convey a strong cultural component. One creative way that comes to mind is using the brightest stars to orient ourselves, like Sirius, Antares, and Betelgeuse. But how?
A smarter way is using pulsars.
A pulsar is a very special and fascinating star. Picture a giant star that reached the end of its life, exploded, and whatever remained transformed into something very dense and compact called a neutron star. Now, when this brand new neutron star spins rapidly emitting regular beams of radiation, that's a pulsar.
Think of a pulsar as a rotating lighthouse. This lighthouse emits beams of light and radiation (like radio waves, X-rays, or visible light) in specific directions, spinning very fast and incredibly regularly —they're so regular they function as a cosmic clock. In fact, the galaxy doesn't have that many pulsars and it shouldn't be too difficult to find them.
How about building our own galactic GPS made of pulsars?
A GPS is an apparatus simpler than it seems. It only needs the distance to three references (satellites) to make circles around the satellites. The first circle is made at the centre of the first satellite opening the compass at the radius of the distance, following the same logic in the others. The intersection of these circles indicates the precise location.
Since the galaxy is in a three-dimensional plane, we need one more pulsar. Therefore, instead of three circles, we draw four spheres, following the same logic as before, and their intersection will point to our position with considerable precision.
In the message, then, we indicate four pulsars and their distances. Below are some improvised, very precise pulsars, which will be our lighthouse-clocks for space navigation. Distances are in light-years and the frequencies in Hertz.
| Pulsar | Distance (light-years) | Frequency (Hz) |
|---|---|---|
| PSR J0437-4715 | 510 | 173 |
| PSR J1713+0747 | 3,800 | 218 |
| PSR J1909-3744 | 3,600 | 339 |
| PSR J1744-1134 | 2,300 | 245 |
Turns out the potential recipient doesn't know what a light-year is - a light-year is our cultural artifact, an invention that indicates the distance travelled by light while Earth revolves around the Sun. Frequency, however, is easier to guess. Well, when transmitting, we can adjust the radio telescope to modulate every 1 second, giving the dimension of 1 Hz.
This completes our location system.
Finally, let's label it Burnell GPS in honour of the brilliant PhD student Jocelyn Burnell for her finesse in identifying pulsars and her investigative dedication, even though her egocentric professor (alluding geocentric) outcasted her from the final work, soon earning him an unworthy Nobel in Physics.
Atmospheric Composition
Now we list the most abundant atoms and chemical compounds in Earth's atmosphere. As mentioned above, surface must be rocky and provide conditions for liquid water. Compounds naturally follow a Pareto distribution, indicating that items aren't evenly distributed, instead they are quite disproportionately distributed.
-
Nitrogen (N₂): 78%
-
Oxygen (O₂): 21%
-
Carbon Dioxide (CO₂): 0.04%
-
Other gases: Argon (Ar), water vapour (H₂O), methane (CH₄) and ozone (O₃).
In this section, we present atomic numbers of C, N, O and Ar and the compounds, N₂, O₂, CO₂, Ar, in order of abundance.
Formula for Building Life
Here's about DNA, ignoring RNA. This block houses two layers of information: atoms involved and molecules. In the original Arecibomessage, this section is adequately expressed and we can reuse it.
Recapping, the first part, in purple, has five numbers, in binary notation, indicating the atomic number of the atoms used:
| Atomic Number | Atom | Symbol |
|---|---|---|
| 1 | hydrogen | H |
| 6 | carbon | C |
| 7 | nitrogen | N |
| 8 | oxygen | O |
| 15 | phosphorus | P |
Right below, in green, we have nucleotides and they need some context. Two types of nucleotides exist: sugars and bases. Picture DNA as a ladder. Sugars and phosphates form the sides of the ladder. Bases bind in pairs to form the rungs that unite the two sides of the ladder. Each base pair is like a perfect-fitting rung. Together these pieces carry the information necessary for cell function and reproduction —and life as we know it.
The sugar making this connection is deoxyribose —hence the name DNA, (D)eoxyribo(n)ucleic (A)cid. Sugar binds with another sugar through phosphate bridges, forming the backbone of DNA. Their formulas are C₅OH₇ and PO₄.
The bases are compounds we call adenine (A), thymine (T), cytosine (C) and guanine (G). They're always connected to each other: adenine only connects to thymine (A - T) and cytosine only connects with guanine (C - G). Pairs are then fitted into the ladder, connecting in a visual format of |sugar-pair-sugar|. This binding between bases is what keeps the two strands of DNA united, forming the famous double helix.
| Base | Formula | Presence |
|---|---|---|
| Adenine | C₅H₄N₅ | DNA and RNA |
| Thymine | C₅H₅N₂O₂ | DNA |
| Uracil | C₄H₄N₂O₂ | RNA |
| Guanine | C₅H₄N₅O | DNA and RNA |
| Cytosine | C₄H₄N₃O | DNA and RNA |
Authors depicted the double helix, including a vertical white bar in the middle —this bar indicates the number of nucleotides known at the time, in binary notation, about 4.2 billion. Today we know 3.2 billion base pairs distributed mainly along 23 pairs of chromosomes in the cell nucleus.
It is up for debate whether we should mention the 23 chromosome pairs. Fern, for example, has hundreds of billions of base pairs distributed along 720 chromosome pairs. On the other hand, a certain bacterium doesn't even have 1 million base pairs housed in a single chromosome.
The information isn't meant to replicate life on the other side, but to provide a generalised notion of what we understand as life.
Section explained, let's move forward.
Energy Consumed
There are different ways to indicate the level of technological evolution. In retrospect, if we were capable of transmitting a message to space, that's because we unravelled science to such a point we were able to devise an electrical contraption transmitting modulated waves into space, by the way, very telling.
Technological innovation is oftentimes linked to how much energy we use, whether electrical now, or coal, or animal traction. Ultimately, all activities are permeated using apparatus powered by electricity, adapted for efficient consumption.
By saying "we consume x% of the energy that the Sun emits" is a way of indicating how much we've progressed on this scale and reflects the capacity to perform work on a large scale through tools, feed productive processes, and provides an idea of the developed infrastructure.
Earth receives about 5.6 million exajoules (EJ) per year, while humanity consumes 600 EJ only, or 0.000017% of the total, or, still, one part in 58,800 of solar incidence.
Reducing everything in the universe to mass and energy, let's present a simple schematic of the Sun and Earth spoused by these numbers. Sun to the left, depicting its mass and emitted energy; Earth to the right, depicting its mass relative to the Sun along with energy consumed respective to solar incidence.
Mistaking relative mass with relative energy is no big deal, these are reasonably close numbers, 333 thousand times versus 58 thousand times. Moreover, energy demand is ever increasing.
Final Encoded Message
Four sections separated by horizontal bars (in grey):
-
Galactic position: to the left, pulsars identified by their frequencies (in pink); to the right, distances in light-years (in purple).
-
Atmospheric composition: to the left, atomic numbers of C, N, O, Ar (in cyan); to the right, the most abundant compounds in the atmosphere N₂, O₂, CO₂, Ar (in blue).
-
DNA: to the left, atomic numbers of atoms in DNA (in light green); to the right, formulas of sugars and bases (in dark green).
-
Technological evolution: to the left, drawing of the Sun with its relative mass and energy (in shades of yellow); to the right, Earth and the units of mass and energy (in shades of blue).
The self-verification codes are in red.
Thus we conclude our brief account of existence.