
“Diagram of All Space and Time” by Carl Sagan (1960s?) - benbreen
https://www.loc.gov/resource/mss85590.084/
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oevi
"The X axis represents time [...] and the Y axis represents scale" \- Isn't it
the other way round?

~~~
lotto-win
Yes. Though I've done this before as well. It was always hard for me to name
them. It's like reading clocks, hard as well.

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thaw13579
Interesting to see that Seth MacFarlane established the collection, which has
more avaiable here:

[https://www.loc.gov/collections/finding-our-place-in-the-
cos...](https://www.loc.gov/collections/finding-our-place-in-the-cosmos-with-
carl-sagan/about-this-collection/)

~~~
wyldfire
It fits with his role as executive producer of "Cosmos: A Spacetime Odyssey",
it really seemed to me to be a part of preserving Sagan's legacy.

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deepsun
What is the lattice to the left of human experience?

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headcanon
it looks just like a random sketch, but I could be wrong.

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chvid
I don't get it? (Somebody please explain :-))

(Isn't the boundary just what is set by the speed of light?)

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gunn
My interpretation is that there are three boundaries - the big bang, the
planck length, and the one defined by the speed of light.

Within that there's a smaller area defined by the limits of the human senses.

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gdubs
Not saying Carl Sagan came up with this _particular_ diagram while high on
weed, but it’s not altogether irrelevant to the conversation to mention that
he privately smoked throughout his career, and credited cannabis for providing
insights, documented in an essay he wrote anonymously as “Mr X” for a book on
marijuana from the 1970s. [1]

Felt it worth mentioning on the day Congress took the small (yet meaningful)
step of legalizing industrial hemp production in the US.

1: [https://www.leafly.com/news/lifestyle/carl-sagan-
cannabis](https://www.leafly.com/news/lifestyle/carl-sagan-cannabis)

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CapmCrackaWaka
I believe what he is getting at is that there is a limit on certain space
times that are accessible to a given observer. Imagine an alien race (or a
point in space) that is 10M light years away. We want to obtain information
about the _current_ state of that point in space. Unfortunately, the next X
years of that section of space (I don't know enough relativity to calculate X)
is totally inaccessible to us. There is absolutely nothing we can do to obtain
information about the current state of that point until X years has passed.

~~~
swebs
There are points of space that will NEVER be visible to us as the rate of
cosmological expansion over sufficiently large distances outpaces the speed of
light.

~~~
tabtab
There's a galactic scam for you: sell beings real-estate that they can never
use nor inspect. "A Xerzigian Prince offered me a great deal on some used
galaxies..."

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stcredzero
PBS Space Time on the same subject:

[https://www.youtube.com/watch?v=1YFrISfN7jo](https://www.youtube.com/watch?v=1YFrISfN7jo)

Minute Physics SpaceTime Globe (The best tool for understanding relativity
I've ever seen.)

[https://www.youtube.com/watch?v=Rh0pYtQG5wI](https://www.youtube.com/watch?v=Rh0pYtQG5wI)

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lifeformed
Why is the "into the future" arrow pointing down? If increasing time is up,
shouldn't the future be that way too?

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function_seven
This graph is meant to show what is observable. The past is up, and distances
are along the _x_ axis.

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Aardwolf
The time scale for human experience is around a second or so to 100 years,
which makes sense for what we experience, but I also don't understand what
past and future mean in the diagram, the vertical axis seems to mean time
duration rather than a time in past or future...

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philipov
Observations take time. The y axis shows the duration of possible
observations. Durations shorter than the plank time or longer than the current
age of the universe are inaccessible; as are durations into the future, since
we can only make observations in the past.

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codezero
I may be wrong but I think the realm of human experience has grown quite
significantly since this was made, kind of awesome.

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briga
He wrote realm of "direct" human experience, which presumably means the
unaided human senses over a human lifetime.

~~~
codezero
Ah thanks. That makes sense.

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mcguire
" _The Seth MacFarlane Collection of the Carl Sagan and Ann Druyan Archive_ "

???

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wbrasky
Ann is Carl's widow. McFarlane has championed his work and was big driver (and
I believe financier) of the new Cosmos.

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0xdeadbeefbabe
It's a small world after all.

