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Started By
Message
The Voyager golden records have uranium on them to serve as clocks
Posted on 6/6/26 at 9:49 pm
Posted on 6/6/26 at 9:49 pm
The most useful thing you can give a hypothetical finder, along with the message, is an honest way to know how old the message is.
Electroplated onto the aluminum cover of each record is an ultra-pure sample of uranium-238. It sits in a small area about two centimeters across, and it is there to serve a single function. It is a clock.
The reasoning is straightforward. Uranium-238 decays into a chain of daughter products at a fixed, known rate. A finder who measures how much uranium-238 remains, against how much of the daughter material has accumulated, can calculate how long the decay has been running. That figure is the time elapsed since the sample was placed on the spacecraft. It tells the finder how old the record is.
The choice of isotope is the whole point. Uranium-238 has a half-life of about 4.5 billion years, meaning that after that span roughly half of any given quantity has decayed.
The uranium is not the only timekeeping device on the record cover. It is one of two, and the two are meant to be checked against each other.
Electroplated onto the aluminum cover of each record is an ultra-pure sample of uranium-238. It sits in a small area about two centimeters across, and it is there to serve a single function. It is a clock.
The reasoning is straightforward. Uranium-238 decays into a chain of daughter products at a fixed, known rate. A finder who measures how much uranium-238 remains, against how much of the daughter material has accumulated, can calculate how long the decay has been running. That figure is the time elapsed since the sample was placed on the spacecraft. It tells the finder how old the record is.
The choice of isotope is the whole point. Uranium-238 has a half-life of about 4.5 billion years, meaning that after that span roughly half of any given quantity has decayed.
The uranium is not the only timekeeping device on the record cover. It is one of two, and the two are meant to be checked against each other.
12
Posted on 6/6/26 at 9:52 pm to weagle1999
Records have uranium to measure time?
Posted on 6/6/26 at 9:53 pm to weagle1999
Too bad that once that thing is returned to Earth far into the future the Planet of the Apes that will then be here won't be able to read, write or count past ten.
Posted on 6/6/26 at 9:55 pm to weagle1999
Why the hell are we giving aliens a roadmap of how to come destroy us?
Be quiet in the dark forest night, lest the monsters hear you.
Posted on 6/6/26 at 10:45 pm to weagle1999
quote:Why the frick was it assumed that some alien race would look at it and know how to quantify the elapsed time by calculating the half life of uranium..
A finder who measures how much uranium-238 remains, against how much of the daughter material has accumulated, can calculate how long the decay has been running.
Posted on 6/6/26 at 10:51 pm to crotiger0307
quote:
Why the frick was it assumed that some alien race would look at it and know how to quantify the elapsed time by calculating the half life of uranium..
If they managed to get to space and collect the satellite there is an assumption that they are at least as smart as us.
There is no guarantee those who find it will be able to decode any of the information.
Posted on 6/6/26 at 10:52 pm to weagle1999
quote:
Uranium-238 decays into a chain of daughter products at a fixed, known rate.
Don’t tell the “Earth is 6000 yrs old” crowd this. They think facts and opinions are the same thing.
Posted on 6/6/26 at 10:54 pm to weagle1999
Could NASA possibly make those symbols any more abstract?
Posted on 6/6/26 at 11:03 pm to shutterspeed
Should have been in English and sent a phone with the Google translate app.
Posted on 6/6/26 at 11:06 pm to shutterspeed
quote:
Could NASA possibly make those symbols any more abstract?
Should've just written the instructions in plain English, eh?
Posted on 6/6/26 at 11:50 pm to AUFANATL
quote:
Why the hell are we giving aliens a roadmap of how to come destroy us?
Be quiet in the dark forest night, lest the monsters hear you.
The closest star to our solar system today is about 4.2 light years away. Voyager 1, the faster-moving of the two probes, will take over 70,000 years to travel that far.
On top of that, the RTG’s providing power to the probes will be long dead by then. They won’t be broadcasting anything. They’ll just be tiny pieces of space junk hurtling through interstellar space, occasionally passing several light years from a star.
By the time either of the voyager records pass close enough to a hypothetical alien civilization to actually be discovered, we’ll either be interplanetary (maybe interstellar) or we’ll be extinct.
The Voyager records aren’t meant as a means to establish communications. It’s more like burying a time capsule in hopes that someone might find it long after you’re gone.
Posted on 6/7/26 at 12:24 am to weagle1999
quote:
against how much of the daughter material has accumulated, can calculate how long the decay has been running.
Yeah but how do you calculate time in the middle of space?
This post was edited on 6/7/26 at 12:25 am
Posted on 6/7/26 at 2:52 am to weagle1999
We know over 4.5B years that decay stays absolutely fricking constant?
Posted on 6/7/26 at 5:55 am to SallysHuman
quote:
Records have uranium to measure time?
Go back to the knitting board.
Posted on 6/7/26 at 6:01 am to Champagne
quote:
Too bad that once that thing is returned to Earth far into the future the Planet of the Apes that will then be here won't be able to read, write or count past ten.
Unfortunately that read / write / count issue is already here.
Posted on 6/7/26 at 6:19 am to weagle1999
There's another method of timekeeping on Voyager.
quote:
The cover also carries a pulsar map, the same basic diagram used earlier on the Pioneer 10 and 11 plaques. It shows the position of the Sun relative to 14 pulsars, with each pulsar’s rotation period written in binary. Pulsars spin down slowly and predictably over time. A finder who knows how fast those 14 pulsars are spinning when the record is found, and compares that to the periods recorded on the cover, can also work out roughly how much time has passed
Posted on 6/7/26 at 6:52 am to crotiger0307
Why would we assume that aliens would know what uranium is?
Posted on 6/7/26 at 7:10 am to Champagne
quote:
Planet of the Apes that will then be here won't be able to read, write or count past ten.
Democrats?
Posted on 6/7/26 at 7:19 am to weagle1999
Would time dilation affect any of this?
Posted on 6/7/26 at 7:21 am to AUFANATL
quote:
Be quiet in the dark forest night, lest the monsters hear you.
They know we are here but we aren't a threat to them, yet.
My thoughts are that "First contact" will happen once we are able to achieve interstellar travel.
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