APOD: A Message From Earth (2012 Feb 19)

[APOD Robot]

A Message From Earth

Explanation: What are these Earthlings trying to tell us? The above message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of the Arecibo Observatory - still the largest single radio telescope in the world - a string of 1's and 0's representing the above diagram was sent. This attempt at extraterrestrial communication was mostly ceremonial - humanity regularly broadcasts radio and television signals out into space accidentally. Even were this message received, M13 is so far away we would have to wait almost 50,000 years to hear an answer. The above message gives a few simple facts about humanity and its knowledge: from left to right are numbers from one to ten, atoms including hydrogen and carbon, some interesting molecules, DNA, a human with description, basics of our Solar System, and basics of the sending telescope. Several searches for extraterrestrial intelligence are currently underway, including one where you can use your own home computer.

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[Beyond]

Digitallity, it's all Greek to me. But it does sound nice. And i can certainly relate to the waiting link.

[Ann]

Yes, that's a nice "waiting" link!

But we have learnt a thing or two since 1974. Back then it was thought that globular clusters were excellent places to search for extraterrestrial life. After all, there were so many stars in them that there had to be a multitude of planets there, too, and that had to increase the odds of finding life there.

Well, surprise. Astronomers now realize that the metal-poor nature of the stars in globular clusters means that it may well be harder for rocky planets like the Earth to form there. Admittedly it doesn't necessarily preclude the existence of rocky planets.

But worse, much worse, is the crowded environment of the globular clusters themselves. With so many stars orbiting a common center of mass, chances are that all the tidal tugs and pulls will make the planetary orbits "go haywire".

Another question, of course is whether or not the signal that was sent to M13 would have been effective at communication, assuming there was anyone in M13 to communicate with in the first place.

A third question is whether or not we should attempt to communicate at all. I believe there are scientists who think it would be folly to give ourselves away to a potentially more advanced alien species.

Ann

[alter-ego]

We'll have to send another message letting everyone know we have only 8 planets, not 9

[starstruck]

Looks a bit like a screen-capture from a Space Invaders game from the early 1980s. Let's hope they don't misinterpret our intended meaning!

Alternatively, it could be really frustrating if after 50 thousand years we get back a message saying the alien equivalent of "sorry, we didn't quite catch that, could you please repeat?, over..."

[Byork]

to all extraterrestrials

please retrieve and return to the earth the space probes / space craft indicated:

-voyager 1 (nasa)
-voyager 2 (nasa)
-pioneer 10 (nasa)
-planck (esa)
-herschel (esa)
-dawn (nasa)
-

-


thank you for your cooperation

[deathfleer]

even a university-educated person cannot understand the message. unless there is a civilized homo-sapiens double out there

[gravi]

During the trip, these radio waves do not undergo radiation fields? the message would not be canceled or changed?

And what about the Arecibo reply? there was some news of fraud in 2001, of people doing the crop circles?

[henrystar]

Yes, that's a nice "waiting" link!
But we have learnt a thing or two since 1974. Back then it was thought that globular clusters were excellent places to search for extraterrestrial life. After all, there were so many stars in them that there had to be a multitude of planets there, too, and that had to increase the odds of finding life there.
Ann

Even back then it was already well known that Globular clusters were "Pop II" stars (i.e., metal poor). The sending of the message was purely symbolic.

[orin stepanek]

We'll have to send another message letting everyone know we have only 8 planets, not 9

I think ET would count more than 9 it they searched our system because they would probably count all the rocks that were orbiting and were large enough to distinguish with their equipment! I don't think that man wants to be alone in the universe! That is why he is bored waiting!

Click to view full size image

[OverlordE]

I agree with starstruck in that I do not believe anyone would understand the message. Can someone point out the individual elements of the message? At least the voyager messages were understandable but this is beyond me.

[Chris Peterson]

I agree with starstruck in that I do not believe anyone would understand the message. Can someone point out the individual elements of the message? At least the voyager messages were understandable but this is beyond me.

The detailed explanation is hyperlinked in the image caption.

[Chris Peterson]

During the trip, these radio waves do not undergo radiation fields? the message would not be canceled or changed?

The radio signal is not altered during its trip. The energy spreads out according to the inverse-square principle, and therefore the signal-to-noise ratio deteriorates with distance. The ability of some distant entity to detect the signal and accurately reconstruct the message would depend on how effectively they could distinguish the signal from the noise. But the signal itself would not be altered.

[Chris Peterson]

even a university-educated person cannot understand the message. unless there is a civilized homo-sapiens double out there

I believe that a small group of well-educated, intelligent humans could readily decode this message in short order. It seems likely to me that any species with the technology to intercept this type of message would be able to do the same.

[bystander]

I agree with starstruck in that I do not believe anyone would understand the message. Can someone point out the individual elements of the message? At least the voyager messages were understandable but this is beyond me.

[From left to right]

1. The numbers one (1) through ten (10)
2. The atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up deoxyribonucleic acid (DNA)
3. The formulas for the sugars and bases in the nucleotides of DNA
4. The number of nucleotides in DNA, and a graphic of the double helix structure of DNA
5. A graphic figure of a human, the dimension (physical height) of an average man, and the human population of Earth
6. A graphic of the Solar System
7. A graphic of the Arecibo radio telescope and the dimension (the physical diameter) of the transmitting antenna dish

This pictograph of the message isn't what was actually sent, but if you are having trouble with it, try listening to this representation:

Click to play embedded YouTube video.

[Rick314]

The Wikipedia article is a good explanation of the intended content:
http://en.wikipedia.org/wiki/Arecibo_message

Something I noticed in comparing the IPOD image (rotated clockwise 90 degrees) with the Wikipedia image is that left and right are inverted. There are 8 ways to view the rectangle -- 4 90 degree rotations, flip it over, 4 more 90 degree rotations. I don't think getting the numbers forward or backward (left-right) matters, since once decoded only one would make sense. It makes just as much sense for us to read right-to-left as left-to-right. But up/down? I'm not sure anything in the image would lead the reader to know which way is "up". So might we be perceived as uni-pods with 4 arms and no head?

[Psnarf]

Knowing what each element of the message is supposed to represent doesn't help me. What were they thinking? Would a dolphin understand that anthropomorphic puzzle?
Space monkeys have been sending messages for quite some time. We call them pulsars, which are more accurate timekeepers than our best atomic clocks. [Ludicrous speculation deleted - Ed.]

[Chris Peterson]

Knowing what each element of the message is supposed to represent doesn't help me. What were they thinking? Would a dolphin understand that anthropomorphic puzzle?

I'm not convinced that it's anthropomorphic. Rather, I'd argue that it's technopomorphic. Dolphins wouldn't understand it, but they aren't equipped to receive it in the first place. On the other hand, it doesn't seem unreasonable that any entity that evolved to develop the same basic sort of technology we have wouldn't have sufficiently similar thought patterns to ours to be able to decode this- or at least some of it.

[Bob]

Are you sure it wasn't received?

Funny that the circle appears next to a satellite

http://www.astrosurf.com/univers/r%E9ponse.jpg

http://www.crop-circles.eu/images/crop- ... bolton.jpg

[Beyond]

ha-ha, i was looking for the circle, when it dawned on me that all crop circles are not circles. It does look as if you have a point there.

[NoelC]

Excerpt.jpg (10.03 KiB) Viewed 5868 times

Heh, after broadcasting into space that we have 9 planets, the IAU still felt it necessary to demote Pluto.

Ah well, the invasion force will probably just pass us by... "No, that's not them, there are only 8 planets there."

-Noel

[isny]

Why would you start the numbers with 1 and not zero? At least this confusing message will slow down the future alien invasion due to confusion about what we were trying to say.

[alter-ego]

Why would you start the numbers with 1 and not zero? At least this confusing message will slow down the future alien invasion due to confusion about what we were trying to say.

Regarding the numbers, I don't think the message is confusing. The most fundamental number set is in fact the natural numbers (i.e. counting numbers) and was likely viewed as the most important numbers for the message. Zero is not an element of the natural numbers. As simple as zero seems to us, it is actually a more abstract number which falls within the integer subset of numbers (edit: whole numbers contains 0, and is the next number subset above natural numbers). So choosing natural numbers seems to me to be a logical choice. Leaving out zero does define a specific class, or set, of numbers which ET would likely relate to. The fact that the number 10 is included may have been also meant to show we use / understand base 10.

Also, binary numbers consist only of 1s and 0s, so the concept of zero must be explicitly understood by default.

[neufer]

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.

Heh, after broadcasting into space that we have 9 planets, the IAU still felt it necessary to demote Pluto.

Ah well, the invasion force will probably just pass us by... "No, that's not them, there are only 8 planets there."

We could always just broadcast out:

http://asterisk.apod.com/viewtopic.php? ... ti#p108197

[Boomer12k]

50,000 years.....um....OK, wake me up when the alarm goes off....


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