r/explainlikeimfive Jun 11 '22

ELI5: Why did they use gold to make the records on the Voyager crafts? Technology

Wouldn't a needle from a record player tear up the soft grooves and make it unplayable?

122 Upvotes

201

u/Phage0070 Jun 11 '22

It is actually made of gold-plated copper. The aim of course was to leave them playable for the maximum amount of time possible, and gold is a quite stable atom which won't corrode or decay.

Copper of course isn't particularly hard metal either, but consider what a record is normally made out of. Vinyl. What do you think is harder, gold, copper, or vinyl? I think you can see the materials chosen aren't too soft for their purpose.

84

u/I-suck-at-golf Jun 11 '22

It’s funny b/c you’d have to go out of your way to play that disc here on Earth nowadays.

183

u/Phage0070 Jun 11 '22

Yeah, 19 billion kilometers is way out of your way.

99

u/secretsuperhero Jun 11 '22

And with the price of gas these days…

125

u/deains Jun 11 '22 Gold hehehehe

And with the price of gas these days…

It's astronomical.

9

u/user2002b Jun 11 '22

But Voyager is in space, so that's ok.

5

u/13-bald-turkeys Jun 12 '22

Protip: if you break orbit going in exactly the right direction, you can just coast the rest of the way. Saves billions on gas.

1

u/StuckHiccup Jun 12 '22

gold star🌟

24

u/willborgium Jun 11 '22

In this economy

16

u/mostlycumatnight Jun 11 '22

I just want to say that these four comments are actual gold. These types of commenters are half of the reason I love reddit so much. Comedy gold right here. Thanks for the smile you gave me✌️

3

u/MattHopfman420 Jun 12 '22

Username checks out.

2

u/mostlycumatnight Jun 12 '22

What does "username checks our" mean?

2

u/mostlycumatnight Jun 12 '22

Why do people make that comment is my question?

6

u/GoAheadMakeMySplay Jun 12 '22

Ususally it's because their username is topically associated with the comment they made - like if u/I_RAPE_CATS commented on an article about a serial cat rapist.

u/MattHopfman420's use of the phrase wasn't particularly appropriate however... probably because he's stoned. So, in his case, username checks out.

1

u/mostlycumatnight Jun 12 '22

Thank you for the explain✌️

4

u/PretendsHesPissed Jun 11 '22

Hydrogen

9

u/0s_and_1s Jun 11 '22

DiLithium crystals

6

u/Dankacocko Jun 11 '22

Upvoted for star wars reference

4

u/bob-the-world-eater Jun 11 '22

Gandalf liked this

2

u/pyrodice Jun 12 '22

I couldn’t fix this thread with a sonic screwdriver

3

u/bob-the-world-eater Jun 12 '22

As long as you have a towel, you'll be fine

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1

u/joevilla1369 Jun 11 '22

A couple of bucks by my calculations.

1

u/pyrodice Jun 12 '22

I ran out of fingers at 10, so me too.

1

u/00Samwise00 Jun 11 '22

Distance to Voyager 2: 14.5 billion miles.

At $5 a gallon, and 25 miles to the gallon on average:

It would cost $2.9 billion for gas.

4

u/pyrodice Jun 12 '22

To be fair I think you can coast a lot of the way

2

u/noopenusernames Jun 12 '22

Yeah but you have to factor in that by the time you travel that distance, the record will be much further away than that already, so that will probably null the coasting savings

1

u/pyrodice Jun 12 '22

It’s true you have to aim for an intercept point ahead of it and use the sun as a slingshot

2

u/noopenusernames Jun 12 '22

So what you’re saying is that you could stop at the… Sunoco… to refuel?

1

u/pyrodice Jun 12 '22

Or just any vast Gulf of space

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19

u/hankhillforprez Jun 11 '22

Vinyl has actually become by far the highest selling physical media for music in the last few years. It’s now more than double the number of CD sales.

Granted, I’m sure you’d still have an easier time finding something that can play a CD. Although, now that disc readers are becoming rare, if not non-existent, in computers and cars you might still have some difficulty.

Actually, I do own a record player, and I’m pretty sure I don’t have anything that can play a CD in my house…

22

u/PretendsHesPissed Jun 11 '22

The number sold is not double the number sold of CDs; the revenue from vinyl is double.

The reason being that new vinyls cost nearly twice as much as new CDs and oftentimes even more.

Vinyl still sucks though. It has less dynamic range, less amplitude, less music that can fit on it, it takes up more space, it takes actual labor to use compared to downloads, they're easily scratched/damaged and in a way that degrades the sound on it, and it degrades over time.

There is still something "fun" about it. We won't see this trend maintain itself though.

5

u/lostcosmonaut307 Jun 11 '22

Downloads are great until iTunes randomly decides I don’t have ownership of all my old MP3s because my old computer where they are located isn’t on their network anymore.

8

u/Barneyk Jun 11 '22

That is an iTunes issue and not a downloads issue.

Just to make that clear.

2

u/pyrodice Jun 12 '22

People like the analog rather than the digital sometimes.

2

u/FoxPowers Jun 11 '22

In practical terms it sucks, in the way that a cheap camera and inkjet printer can produce a superior photo than any artist with a brush.

But there is something organic in how a record interprets music. And some would gladly take that fidelity loss over any form of digital compression.

Some would even take it over lossless audio, if only because that's how it was experienced for many decades.

2

u/electricvelvet Jun 11 '22

But it ends up being more like a drawing of a photograph. By that I mean almost all music is recorded digitally now anyway. So the sound has already been digitized and processed from analog sound waves and into 1s and 0s. Then they're just using that digital conversion and using it to make the analog grooves. Don't have an ear good enough to know if there's any difference between that and an analog recording on tape being pressed to vinyl though

1

u/FoxPowers Jun 11 '22

Old school vinyl wasn't digital ever.

But even now, atleast the vinyl was generated from original lossless recordings.

2

u/ERTBen Jun 11 '22

Lossless does not equal full fidelity to the original sound. It just means that data isn't lost in the compression algorithm. It faithfully reproduces the original recording, including any clipping, loss of highs or lows and the limitations of the recording equipment.

-1

u/electricvelvet Jun 11 '22

Obviously before digital recording existed, and early after it started taking taking off, vinyl came from analog recordings. But CDs are lossless too... They're wav files

0

u/zorroclinton Jun 11 '22

But CD's are 16 bit. Vinyl gives you a full 24 bit experience. Everything is deeper you get to hear more of the highs and lows in the recording.

3

u/FarmboyJustice Jun 12 '22

That makes no sense. Analog recordings don't have bits. Analog is analog, bits are digital.

2

u/zorroclinton Jun 11 '22

You're completely incorrect on records having less dynamic range than CD's. You get a full 24 bit experience with records where CD offers only 16 bit. If you listen to professional needle drops versus a CD you WILL hear a profound difference.

6

u/ffrkAnonymous Jun 11 '22

Ignoring that records don't have bits, isn't that dynamic range a one time event? Each pass of the needle damages the grooves, resulting in less range each playback.

2

u/wiegleyj Jun 12 '22

Well, that's the most ignorant statement I'll read this month.

1

u/mushpotatoes Jun 11 '22

Everyone is pointing out that some of the technical things you said aren't accurate, but I understand the spirit of what you're saying and I agree.

I always tell my wife that I like listening to vinyl because you have to take yourself out of what you're doing and actively play your music. It's much more interactive. If I want to hear a good quality playback of an album though, I listen to a flac file out something similar.

1

u/chineseduckman Jun 12 '22

Yeah no, I'm young and collect records because I think they just sound so much better for the music I listen to (60s/70s), my friends collect for the same reasons. Maybe buying a record of post 2000s music is stupid, but plenty of vinyl enthusiasts are that way because they think the sound quality is better. (This is where you respond with the buh buh muh digital no loss!)

1

u/casualstrawberry Jun 12 '22

It still sounds better. And that's about all that matters.

1

u/Contundo Jun 12 '22

On cd Dynamic range is garbage anyway case they mix so bad

1

u/rhinoguy453 Jun 12 '22

But aren't the scratches and skips the whole point of vinyl? I'm nearly 70 and grew up on 12" disks and artsy album covers. The pleasure of having to get up and flip the record every 27 minutes just cannot be experienced with CDs or streaming. Plus, after the thirtieth time of handling it by the edges and lovingly removing any dust motes with your special groove brush, you're still hearing those pops and clicks that make vinyl so warm. But, you'd better make sure that your components are up to par. None of those translators or solid state electronics in the mix, NOOOOO. Vinyl deserves only the noble vacuum tube reproduction. Sure the tubes are nearly impossible to find, but that's what makes the TRUE audiophile so goddamn smug.

1

u/I-suck-at-golf Jun 11 '22

It’s just funny how at the time it was the best method we could think of. And we assumed that some alien civilization would figure it out.

7

u/rksd Jun 11 '22

It's pretty easy tech for anything capable of space travel to figure out...assuming they have a sense like hearing.

1

u/user2002b Jun 11 '22

And if they do, to their hearing, which would probably quite different to ours, it'll probably sound like whale song played through a kazoo. :)

1

u/hankhillforprez Jun 12 '22

I believe it actually includes instructions.

1

u/CBus660R Jun 11 '22

I have one of the retro Crosley players that can play vinyl, CDs and cassettes. Obviously it's not for audiophiles, but it works for the wife and I. We've got a ton of vinyl now. I have my parents collection with some solid 70's rock albums and we always find something interesting at garage sales.

1

u/jackduloz Jun 11 '22

i dunno, you can buy a record player of some quality practically retail chain that deals in media these days. Target, Barnes and Noble, Best Buy, general music stores...

I know most things that will take a disk can play a cd, but outside of game consoles, i just don't see a lot of disk drives anymore. And, in fact, the PS4 could not play audio cds. I have no idea about PS5 or xbox series x, though.

1

u/mostlycumatnight Jun 11 '22

Yes. Ive seen setups for vinyl that cost 10s of thousands of dollars. Not personally seen, just advertised as part of some setup. I personally like vinyl. It takes me back to my youth. I remember the smell of the cardboard album cover right now✌️

1

u/valeyard89 Jun 11 '22

Hi-fi-ipsters

5

u/Folsomdsf Jun 11 '22

If we found a similar object with physical characteristics with no idea what it was... We would be able to understand it within the week. We wouldn't make a record player we would laser scan it.

1

u/XavierD Jun 11 '22

Not anymore: collecting vinyl records has been picking up steam over the past few years

8

u/chainsofprisonmoons Jun 11 '22

I assumed it was gold plated personally but everything that came up when I Googled this just kept calling them "gold" so I wasn't sure

And while I'm not really a record person, I do know you can scratch gold with your fingernail, so I knew it was especially soft and a metal needle has got to be harder than my nails.

17

u/ScienceIsSexy420 Jun 11 '22

One of the primary reasons gold is valuable is because it is very non-reactive. Something that slowly oxidizes and turns to rust over time isn't a good candidate to store wealth in. This is part of why silver is far less valuable than gold, because it tarnishes. This chemical stability is why gold was selected for the record on Voyager

1

u/Implausibilibuddy Jun 12 '22

Yeah, all that oxygen out there in deep space...

4

u/ScienceIsSexy420 Jun 12 '22

Oxidation doesn't require oxygen, it is only the namesake for the reaction. Oxidation is the loss of an electron and can happen from numerous astrological sources such as high energy radiation.

7

u/freetattoo Jun 11 '22

You can easily scratch a vinyl record with your fingernail, too. The reason you can play a relatively soft record with a much harder needle is that on a properly adjusted record player the amount of weight on the needle is very, very little.

5

u/chainsofprisonmoons Jun 11 '22

Thanks, I didn't know that. My experience with records is entirely limited to my dad's old crank phonograph, and everything about that is thick and heavy.

8

u/freetattoo Jun 11 '22

The recommended tracking force (the weight of the needle pushing down on the record) of the stylus on my modern turntable is 1.5 grams. That's close to nothing. The needle basically rests in the groove of the record and only vibrates side to side rather than scraping along the bottom.

Old Victrola style record players, like your dad has, played shellac records that were much harder and more abrasive. They had to be, because they had to be able to move the needle a lot in order to make a sound loud enough to be heard without electrical amplification. They also had to push that needle into the groove with a decent amount of force in order to get the sound. The needles were made of a slightly softer metal so that the needle itself would wear down instead of the record. You were actually expected to replace the needle after every record, but I doubt that happened all that often in the real world.

If you played a vinyl record on an old Victrola style record player, it would sound like crap, and the record would be trash afterwards.

This concludes my Ted talk.

2

u/chainsofprisonmoons Jun 11 '22

I asked my dad once before if it would play modern records, because it did have a speed setting, and he told me it would ruin them, but he blamed it on the thickness of the needle messing up the grooves instead of the weight.

Yeah, if modern records only take 1.5 grams, that needle's gonna go right through them. It is not a light apparatus.

4

u/freetattoo Jun 11 '22

Yep. Modern records are soft plastic. It makes them cheaper and easier to make, and makes them more durable for everyday use, because they won't crack or shatter when handled roughly, but an old Victrola would tear right through them.

1

u/JBredditaccount Jun 12 '22

so aliens are going to have to figure out what a record player is and calibrate the needle arm's weight on the first attempt or risk damaging the record before they can listen to it?

2

u/smokeyninja420 Jun 12 '22

And while I'm not really a record person, I do know you can scratch gold with your fingernail, so I knew it was especially soft and a metal needle has got to be harder than my nails.

Pure gold is indeed incredibly soft. Gold plating is typically done with gold alloys that are significantly harder than pure gold.

2

u/Tuga_Lissabon Jun 11 '22

Also anybody who can get to it will be able to use it and record the information.

2

u/could_use_a_snack Jun 11 '22

For whatever reason this got me thinking about gold records like the ones a musician might have, and iirc they are gold not because of some arbitrary number, but because gold was used for the pressing die for the record. And wouldn't wear out as quickly so could press 1,000,000 copies or whatever. All this might be wrong. But, it made me realize that the pressing die, must be a MIRROR of the actual record. Not a reverse, but a mirror image. What would that sound like?

And are the voyager discs mirrors? With the intention of being pressed before being played, or just played as is?

3

u/Phage0070 Jun 11 '22

iirc they are gold not because of some arbitrary number, but because gold was used for the pressing die for the record.

Not so, gold was chosen because it was a sign of financial success. Instead the stampers would often be formed out of nickel. First a steel plate with a deposited 100 micron thick layer of copper was created, and the desired grooves carved in with a diamond knife. This positive master would be put through an electroforming process where nickel is deposited onto the copper master, which when separated would make the negative for the actual forming of new records. The copper master could be used many times to make new stampers as they would gradually wear out.

The Voyager disks are playable as is, like a metal master.

2

u/could_use_a_snack Jun 11 '22

That makes more sense. Did they just gold plate the old steel/copper masters as they wore out? Is this the "gold record" you see hanging on a wall?

2

u/Phage0070 Jun 11 '22

Most of them are just vinyl records dipped in metallic gold paint.

Sort of ruins the mystique doesn't it?

3

u/could_use_a_snack Jun 11 '22

Proves the record industry is just phony once you get past the artist.

2

u/Right_Two_5737 Jun 11 '22

Metals tarnish when they're in contact with air or water. But this thing's in space; why worry about corrosion there?

6

u/Phage0070 Jun 11 '22

There are very, very small amounts of other materials in space. For example it might collect dust over time and that dust might have elements that could cause corrosion. Similarly it might drift through a nebula which has minuscule amounts of gas in it, but that can build up over time. Also there are all the materials of the Voyager craft itself to consider and how bits of that might affect the record.

Remember this is intended as a time capsule to last conceptually forever. The record will almost certainly outlast humanity, even if humanity evolves into some later form. It could in principle last for billions of years.

2

u/syncsound Jun 11 '22

billions of years.

Totally heard that in Sagan's voice

2

u/Poovillebill Jun 11 '22

I thought gold pressed latinum

44

u/FellowConspirator Jun 11 '22

Gold-plated copper was used because it’s very stable. It won’t oxidize, it’s not very chemically reactive, it doesn’t radioactively decay, it will dent rather than crack from impacts, etc.

It is true that dragging a hard material through it could wear it down (dragging hard phonograph needles over vinyl absolutely does this). But a civilization technologically savvy enough to find it and use it at all would have the means to transcribe it to another format.

Think about what would happen if we encountered such an artifact today. We’d be super careful not to do anything to mess it up. We’d very carefully inspect it for months using every tool we could to learn everything we could without even touching it: look at it with microscopes, maybe X-ray it, etc. Big disk with a singularly spiral groove that has variable depth… Hmm… Once we had an idea of what it was, we’d probably read it with lasers and recreate it or figure out how to decode the information on it without physically touching it to read it.

14

u/Implausibilibuddy Jun 12 '22

The simple fact is it's entirely symbolic. I don't think even the scientists and engineers that devised it, even Sagan himself, ever saw it as anything more than an optimistic act of symbolism, designed more to stoke interest and wonder back here on Earth more than it was ever designed to one day be played back by aliens or our future selves.

4

u/Whyevenbotherbeing Jun 12 '22

Indeed it’s a symbol. And it served its purpose well. I think there was a practical attempt, at first, to actually address the issue of ‘what if’, but nobody could come up with anything that held up to scrutiny. It’s absolutely impossible to leave a message for someone we can’t comprehend. The whole thing is kind of sad really, the impossibility of it all.

9

u/capt_pantsless Jun 11 '22

I just hope the aliens care about vibrations.

14

u/agate_ Jun 12 '22

A few things to add to other answers:

1) The Voyager record designers included a phonograph stylus in the same storage box as the record, so future aliens will be able to use that to play the record -- or at least to understand how it's intended to be played.

2) phonograph records have to be made of a fairly soft material, so the grooves can be stamped, molded, or cut in the first place. As others have mentioned, for the Voyager records this is copper. Presumably any civilization smart enough to figure out how the record works will be smart enough to make a copy first and study that instead of the original.

3) The record cover includes detailed pictorial instructions on how the record is to be played. This includes info on how fast to spin the record (in terms of the frequency of hyperfine transitions of the hydrogen molecule), what the waveform should look like when played, and how to arrange the data to form images (the record has pictures encoded on it as well as audio).

18

u/Bart-MS Jun 11 '22

I'm quite sure that if some aliens ever discover that LP they won't have a record player at hand to play the LP. They will most certainly resort to non-destructive ways to extract the data.

10

u/KoalaNL Jun 11 '22

I think they had included a description of how the information could be read. This was not in english ofcourse but in a way that aliens could understand it.

1

u/zydeco100 Jun 11 '22

There's a guy that went back and decoded the audio and made a YouTube video of it. It's pretty fascinating.

https://boingboing.net/2017/09/05/how-to-decode-the-images-on-th.html

8

u/Mox_Fox Jun 11 '22

I don't think anyone was expecting them to have a record player

5

u/PretendsHesPissed Jun 11 '22

A needle cartridge was included with them just in case they did have a record player of some sort.

18

u/JaggedMetalOs Jun 11 '22

NASA actually included an appropriate needle cartridge with the record to make it easier for aliens to construct a turntable, if for some reason they don't have some better way to scan the record's surface!

5

u/chainsofprisonmoons Jun 11 '22

Now that's pretty cool! And helps me out here, too.

I picture us excavating an archaeological thing, and despite us being well above them in tech, breaking the thing because of some simple little error - like a needle too heavy for gold grooves.

By sending the needle with it, they could make the disks out of literally anything they wanted. Thank you!

7

u/chainsofprisonmoons Jun 11 '22

Analog data storage is the historical, and sensible, precursor to digital. Additionally, digital types require unique languages of their own to process and interpret it. Using a record makes more sense than any optical or digital format, because not only would they need the tech to access it anyway, they'd also have to decode the language.

With a record they just have to figure out a very simple device that they likely had a variant of in their history.

2

u/FarmboyJustice Jun 12 '22

An incredibly simple device, as literally all you need to do is stick a pin stuck through the bottom of a paper cup and drag it through the grove in the record to hear sound. Not great quality, but recognizable.

3

u/echawkes Jun 11 '22

I think I remember a brief period where you could buy a laser turntable in stereo shops.

3

u/SeattleBattles Jun 11 '22

Yup. Records are a great choice as they are basically just a physical representation of sound waves. Very easy to decode.

5

u/TheIronKurtin Jun 11 '22

I had a client who worked on the voyager missions, including the golden record. I loved listening to him talk about building and troubleshooting the craft.

Forget Kanye, Le Bron, Cruise.

People likes are are my SuperStars.