APOD: A Message from Earth (2020 May 03)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: A Message from Earth (2020 May 03)

Post by APOD Robot » Sun May 03, 2020 4:06 am

Image A Message from Earth

Explanation: What are these Earthlings trying to tell us? The featured message was broadcast from Earth towards the globular star cluster M13 in 1974. During the dedication of the Arecibo Observatory - still one of the largest single radio telescopes in the world - a string of 1's and 0's representing the 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 featured 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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RocketRon

Re: APOD: A Message from Earth (2020 May 03)

Post by RocketRon » Sun May 03, 2020 5:05 am

And the explanation of the colors ?
I'm guessing they don't transmit very well via radio...

We'd also wonder how this 'compares' to the messages on the Voyagers.
Will those elusive galactic dwellers out there who receive these assume there were 2 ** quite different
messaging services, or 2 quite different technologies emanating from the same Solar System.

** or more, if you include TV transmissions, other stray microwave, radar, radio, light signals, etc.
Or even atomic blast morse code, if you allow the signals were relatively few and far between...

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Re: APOD: A Message from Earth (2020 May 03)

Post by JohnD » Sun May 03, 2020 9:52 am

It may be an interesting exercise for lockdown to interpret the picture.

Ignore the key above, you are an alien who has received the message and worked out that the series of binaries are to be displayed on that grid, a hopeful assumptions but you get nowhere otherwise. What does it all mean? Top line, one to ten? In what base? It's not binary! Then the Purple square(ish) and Green box, what? The Blue squirls could be seaweed, and that Red arrow pointing up, could be a fish? AH! that last purple outline - its One of Us! As a message to aliens it made a lot of assumptions!
John

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Re: APOD: A Message from Earth (2020 May 03)

Post by orin stepanek » Sun May 03, 2020 11:35 am

What was it; 40,000 yrs. to nearest star? So if star''s planets are inhibited; and inhabitants do indeed find the probe? wow; thats rarer than finding a penny in the deepest sea! :shock: 👽
Orin

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Re: APOD: A Message from Earth (2020 May 03)

Post by neufer » Sun May 03, 2020 12:36 pm

orin stepanek wrote: Sun May 03, 2020 11:35 am
What was it; 40,000 yrs. to nearest star? So if star''s planets are inhibited; and inhabitants do indeed find the probe? wow; thats rarer than finding a penny in the deepest sea! :shock: 👽
  • It taint really for "THEM."
https://en.wikipedia.org/wiki/Kilroy_was_here wrote: <<Kilroy was here is an American symbol that became popular during World War II, typically seen in graffiti. Its origin is debated, but the phrase and the distinctive accompanying doodle became associated with GIs in the 1940s: a bald-headed man (sometimes depicted as having a few hairs) with a prominent nose peeking over a wall with his fingers clutching the wall.

The phrase may have originated through United States servicemen who would draw the picture and the text "Kilroy was here" on the walls and other places where they were stationed, encamped, or visited. An ad in Life magazine noted that WWII-era servicemen were fond of claiming that "whatever beach-head they stormed, they always found notices chalked up ahead of them, that 'Kilroy was here'".

According to one story, German intelligence found the phrase on captured American equipment. This led Adolf Hitler to believe that Kilroy could be the name or codename of a high-level Allied spy. At the time of the Potsdam Conference in 1945, it was rumored that Stalin found "Kilroy was here" written in the VIP bathroom, prompting him to ask his aides who Kilroy was.War photographer Robert Capa noted a use of the phrase at Bastogne in December 1944: "On the black, charred walls of an abandoned barn, scrawled in white chalk, was the legend of McAuliffe's GIs: KILROY WAS STUCK HERE.">>
Art Neuendorffer

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Re: APOD: A Message from Earth (2020 May 03)

Post by neufer » Sun May 03, 2020 12:49 pm

https://en.wikipedia.org/wiki/Scytale wrote:
<<In cryptography, a scytale (rhymes with Italy; Ancient Greek: σκυτάλη skutálē "baton, cylinder") is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message. The ancient Greeks, and the Spartans in particular, are said to have used this cipher to communicate during military campaigns.

The recipient uses a rod of the same diameter on which the parchment is wrapped to read the message. It has the advantage of being fast and not prone to mistakes—a necessary property when on the battlefield. It can, however, be easily broken. Since the strip of parchment hints strongly at the method, the ciphertext would have to be transferred to something less suggestive, somewhat reducing the advantage noted.

Suppose the rod allows one to write four letters around in a circle and five letters down the side of it.
The plaintext could be: "I am hurt very badly help".

To encrypt, one simply writes across the leather:

Code: Select all

_____________________________________________________________
       |   |   |   |   |   |  |
       | I | a | m | h | u |  |
     __| r | t | v | e | r |__|
    |  | y | b | a | d | l |
    |  | y | h | e | l | p |
    |  |   |   |   |   |   |
_____________________________________________________________
so the ciphertext becomes, "Iryyatbhmvaehedlurlp" after unwinding.

To decrypt, all one must do is wrap the leather strip around the rod and read across. The ciphertext is: "Iryyatbhmvaehedlurlp" Every fifth letter will appear on the same line, so the plaintext (after re-insertion of spaces) becomes: "I am hurt very badly help".
History

From indirect evidence, the scytale was first mentioned by the Greek poet Archilochus, who lived in the 7th century BC. Other Greek and Roman writers during the following centuries also mentioned it, but it was not until Apollonius of Rhodes (middle of the 3rd century BC) that a clear indication of its use as a cryptographic device appeared. A description of how it operated is not known from before Plutarch (50-120 AD):
  • The dispatch-scroll is of the following character. When the ephors send out an admiral or a general, they make two round pieces of wood exactly alike in length and thickness, so that each corresponds to the other in its dimensions, and keep one themselves, while they give the other to their envoy. These pieces of wood they call scytalae. Whenever, then, they wish to send some secret and important message, they make a scroll of parchment long and narrow, like a leathern strap, and wind it round their scytale, leaving no vacant space thereon, but covering its surface all round with the parchment. After doing this, they write what they wish on the parchment, just as it lies wrapped about the scytale; and when they have written their message, they take the parchment off and send it, without the piece of wood, to the commander. He, when he has received it, cannot otherwise get any meaning out of it,--since the letters have no connection, but are disarranged,--unless he takes his own scytale and winds the strip of parchment about it, so that, when its spiral course is restored perfectly, and that which follows is joined to that which precedes, he reads around the staff, and so discovers the continuity of the message. And the parchment, like the staff, is called scytale, as the thing measured bears the name of the measure.
    —Plutarch, Lives (Lysander 19), ed. Bernadotte Perrin.
Art Neuendorffer

Z00mer

Re: APOD: A Message from Earth (2020 May 03)

Post by Z00mer » Sun May 03, 2020 2:13 pm

It is about a 25,000 year one way trip to the target. At the time did the senders at Aricebo have enough data in order to 'lead the target'?

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Re: APOD: A Message from Earth (2020 May 03)

Post by Chris Peterson » Sun May 03, 2020 2:49 pm

Z00mer wrote: Sun May 03, 2020 2:13 pm It is about a 25,000 year one way trip to the target. At the time did the senders at Aricebo have enough data in order to 'lead the target'?
The target will move an insignificant distance in such a short time, and the beam is not all that narrow in the first place.
Chris

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Re: APOD: A Message from Earth (2020 May 03)

Post by neufer » Sun May 03, 2020 3:57 pm

Chris Peterson wrote: Sun May 03, 2020 2:49 pm
Z00mer wrote: Sun May 03, 2020 2:13 pm
It is about a 25,000 year one way trip to the target. At the time did the senders at Aricebo have enough data in order to 'lead the target'?
The target will move an insignificant distance in such a short time, and the beam is not all that narrow in the first place.
The 2V/c radian angle between where an object appears to be and where where a signal should be sent does come up in lunar laser ranging.

The primary concern there was not so much in 'leading the target' (which is quite easy to do) as it was in the fact that retro reflectors sent the signal back to where it came from rather than where the Earth telescope should be after the 2.5 second two way trip. As it turned out, the beam was just wide enough for this not to be a problem.
Art Neuendorffer

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Re: APOD: A Message from Earth (2020 May 03)

Post by tmcdanel » Sun May 03, 2020 7:52 pm

Apparently the author did not know that SETI@home has already shut down. March 31 was there last processing until further notice.

https://twitter.com/BerkeleySETI/status ... 8726928387