
Wikipedia to the Moon - chris_wot
https://meta.wikimedia.org/wiki/Wikipedia_to_the_Moon
======
johngossman
The FAQ is much more illuminatng then the main page:
[https://meta.m.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ](https://meta.m.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ)

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Sniffnoy
Non-mobile link:
[https://meta.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ](https://meta.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ)

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guelo
If an alien makes it all the way to the moon with the tech to read the disc
why wouldn't they hop on over to Earth where there would be much more data?
When Carl Sagan did it it was much more evocative because Voyager will be
traveling for thousands of years into deep space.

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Houshalter
Well hypothetically if the Earth was destroyed by grey-goo or something, the
disc would still be there.

But the other answer is that it's much easier to find. Where would you put a
ceramic copy of wikipedia on Earth to maximize it's probability of being
found? Anywhere you put it could get destroyed, buried, or stolen. Who knows
what will happen to it over the Eons.

This disc will be on the surface of the moon forever. Anyone surveying the
surface of the moon for unnatural objects will find it. Although that might
take some advanced technology, it would be easier than surveying the Earth.

And while they might find many artifacts on Earth, locating that single copy
of wikipedia out of all the other junk we've left behind is a bit improbable.
We haven't covered the moon with much junk.

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icebraining
_This disc will be on the surface of the moon forever._

Or until a meteorite hits it.

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Florin_Andrei
It's true. The surface of the Moon is a lot less peaceful than it seems. If
you process the image, you can tell the affected area from a single meteorite
strike is much bigger than the crater itself:

[http://www.astrobin.com/full/220884/0/](http://www.astrobin.com/full/220884/0/)

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gcr
Has anyone compared the surface of the moon over time? We can count how many
meteorites have hit the surface since we've been taking pictures of it, and we
can also probably assess the actual damage they've caused.

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Intermernet
NASA's Lunar Impact page is at
[http://www.nasa.gov/centers/marshall/news/lunar/#.VxmMxvl942...](http://www.nasa.gov/centers/marshall/news/lunar/#.VxmMxvl942w)

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tamana
How do "Earth-based observations of the _dark_ portion of the moon" work?

Is that the dark part of the light _side_ , where the sun won't overexpose the
video?

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Florin_Andrei
It's as easy as night versus day.

Flashes from bolide strikes are actually easier to see on that part of the
Moon where it's night. Where the Sun is above horizon on the Moon, the ambient
light is drowning out any light-producing events.

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JoeDaDude
They should team up with the Time Capsule to Mars project
([http://www.timecapsuletomars.com/](http://www.timecapsuletomars.com/)) which
ostensibly will use quartz storage technology to send millions of photos to
Mars. If the quartz memory is for real, it should be able to store Wikipedia.

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learc83
The deadline for the Lunar X Prize is next year, and according to wikipedia
one of the teams has a launch contract with SpaceX. Does SpaceX have a rocket
capable of making it to the moon?

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outworlder
Please note that the ability to "making to to <somewhere>" is all about
Delta-V. Which varies wildly with payload size.

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LeifCarrotson
To be precise, it varies according to the equation:

Delta-V = Exhaust velocity x natural log(mass full / mass empty).

As the "mass empty" is very dependent on the payload size, it will indeed
change a lot!

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maaku
See for example, New Horizons:

[https://en.wikipedia.org/wiki/New_Horizons](https://en.wikipedia.org/wiki/New_Horizons)

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dr_zoidberg
For those too lazy to go read: biggest rocket available + very light probe =
very fast travel

Another interesting read in this aspect is the Dawn Spacecraft, which had a
big delta-v because of its ionic thrusters:
[https://en.wikipedia.org/wiki/Dawn_%28spacecraft%29#Propulsi...](https://en.wikipedia.org/wiki/Dawn_%28spacecraft%29#Propulsion_system)

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RIMR
20GB? What kind of disc are they using? Why not use a 200GB MicroSD? That
would be way more efficient.

2 200GB MicroSDs would give you 400GB of storage weighing in at only 1 gram.

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yohui
[https://meta.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ#Ca...](https://meta.wikimedia.org/wiki/Wikipedia_to_the_Moon/FAQ#Can.E2.80.99t_we_use_some_other_medium_with_more_space.3F)

> _Can’t we use some other medium with more space?_

> _The conditions in space prove hostile to many data mediums. Traditional CDs
> or DVDs would be destroyed in space, because they are composed of layers and
> would come undone. It’s different with a medium made of ceramics. Also, you
> have to consider the dimensions and weight of your medium. The ceramic disc
> is light enough and resilient._

I'm guessing microSD cards are not radiation hardened.

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tracker1
Wonder how much lead you'd have to wrap an sd card & reader in for it to be
"safe" for space travel.

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dzdt
If you want as much protection as Earth's atmosphere provides, 25 inches. At
least that gives as much mass in between the card and space as the atmosphere
does. (1 atm is about 30in of mercury, lead is 11/13 as dense as mercury...)

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tracker1
But it isn't just about mass, there's density to consider... we aren't sending
up computing devices into space wrapped in 25 inches of lead... so I'm
guessing that far less is actually needed.

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gooseus
I wonder what the estimated cost per GB will be for this data transfer?

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whatever_dude
I bet they can get the data there faster than it'd take for me to upload it
anywhere using Time Warner Cable.

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sbmassey
How long would it survive there? The surface of the moon is a pretty hostile
environment, I would think.

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magnat
It's a ceramic disc. Since there is no wind erosion, if it doesn't get direct
hit, it should last quite some time. Footprints from first landing are still
there - and are expected to be for at least next 10 million years - so you can
expect finely-engraved piece of rock to last much longer.

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ivanb
There is still radiation erosion. It may corrupt the data if it is packed too
tightly.

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sparkzilla
Sending an archive of YouTube would be much more useful for any aliens that
happen to drop by. YT comes far closer to _The Sum of All Human Knowledge_
than Wikipedia.

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Houshalter
I'm not sure that's correct. Wikipedia contains detailed articles on many very
obscure subjects. Searching for such topics on YouTube usually gives
disappointing results.

Wikipedia is missing some material though. A better choice might be the google
book project or libgen, which contains a ton of obscure books and scientific
papers. But compressing it all to 20 GB would be difficult or impossible. Much
easier than compressing Youtube though.

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sparkzilla
That's my point: They're assuming the aliens want to know about detailed,
encyclopedic subjects. But what if they just want to know about Kim
Kardashian?

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morgante
[https://en.wikipedia.org/wiki/Kim_Kardashian](https://en.wikipedia.org/wiki/Kim_Kardashian)

That's more than anyone ever needs to know about Kim Kardashian.

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Houshalter
They have 20 GB? I downloaded the entire English wiki 4 years ago (just the
text of articles, not photos) and it was 12 GB.

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ooooo00000
Now it's ~55 GB uncompressed and as you said that's without images, audio, and
more.

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Houshalter
I meant compressed. Text compresses really well.

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danielvf
It does indeed. However compression may cause problems for future beings
discovering or understanding the data.

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jsmthrowaway
Keep in mind they have to understand the text and image encodings. The concept
of glyphs themselves, even. Words. Language. Bytes (why 8 bits). Bits.
Knowledge expressed as sentences. How to read the media. Compression would be
just another thing.

There's a pretty big hurdle to comprehension even without compression because
we are thinking in human terms. Imagine all of the prerequisite human
knowledge you overlook to even approach the concept of an encyclopedic article
describing something. Aliens might share knowledge by hitting each other with
telepathic darts for all we know, having a completely different understanding
and implementation of information, and words might require years of study on
their part to comprehend. Even the golden record carries a lot of assumptions.
What we know about the universe is not necessarily final, even with
rudimentary things like information theory.

In the end it's a bunch of bytes, numbers really, on a disc. What are numbers,
even? What if they have a totally different non-numeric system to quantify and
explain their existence?

Think about finding an extraterrestrial storage device like this from _our_
perspective. I'd safely predict 20 years before we even extract one byte of
data, and a lot of that time would be arguing over it, probably. Although
thinking about an alien Nobel ceremony for cracking the "extraterrestrial
ceramic Wikipedia" is a pretty amusing thought.

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Houshalter
One of my favorite short stories is _That Alien Message_ :
[http://lesswrong.com/lw/qk/that_alien_message/](http://lesswrong.com/lw/qk/that_alien_message/)

Its about humanity trying to reverse engineer a message from space that has
very few bits. One of the morals is that humans would be able to decode crazy
encodings provided enough time. And more data helps a lot. With 20 GB, even
compressed, common patterns could quickly be found.

I don't believe for a moment a race advanced enough to recover the disc
wouldn't understand it.

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jsmthrowaway
Me neither, to be clear. Just saying that compression is but one drop in the
bucket.

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fapjacks
Sneakernet on steriods.

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flashman
On asteroids.

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Ruud-v-A
Now I understand why they were begging for donations all the time

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coolspot
How to downwote comment on the HN? I only see "upvote" button.

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schwarrrtz
You need to be at a certain karma level to downvote.

