
The Space Doctor’s Big Idea - mackmcconnell
http://www.newyorker.com/tech/elements/the-space-doctors-big-idea-einstein-general-relativity?intcid=mod-latest
======
bitwize
Still not as good as "Einstein's Theory of Relativity in Words of Four Letters
or Less". Excerpt follows:

A few more of us got it, then. But most of us just said, "What are you two on?
Put down the bong and get real! This is way too wild to be true." But they
just said, "Just try and see if it isn't true."

So we came up with ways to test old Al's idea, and each time Al hit the gold.
His idea had the sun's rays a tiny bit more red than what Izzy said. They
were. His idea put Mars a tiny bit off from how Izzy had Mars. It was.

The big one, the one that got told over and over, was the one with the dark-
at-day time. You know, when the moon gets in the way of the sun. At that time
you can get a real good look at a star when it's up next to the sun. (Next to
it in the sky, that is. Not next to it for real. You know what I mean.) They
went off and got a good look at a star that was very near the sun, and then
they used a book to see just what spot that star was in. You see, the rays
from the star pass so near the sun that they get bent, on the way to us. Old
Al, his idea said just how much the rays get bent. With Izzy, the rays get
bent, too, but only by half as much. So they took a look at the star, and they
took at look at the big book, and ... well, I'll bet you can tell me as well
as I can tell you just how far off that star was.

A-yup.

And then all of us, we all just sat back and said: "Whoa."

[http://www.muppetlabs.com/~breadbox/txt/al.html](http://www.muppetlabs.com/~breadbox/txt/al.html)

~~~
euyyn
> With Izzy, the rays get bent, too, but only by half as much.

What does this refer to?

~~~
andars
Newtonian gravitational lensing (not sure if that is an actual term). Newton's
gravity could be applied to photons to get some lensing, but this predicted
was half of that predicted with general relativity

~~~
devb
Exactly half, as it happens.

> A naive application of Newtonian gravity can yield exactly half this value,
> where the light ray is assumed as a massed particle and scattered by the
> gravitational potential well.

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

------
ctchocula
I think you absolutely need mathematics to understand the theory of
relativity.

Freeman Dyson writes when he was a child "I had read some of the popular
literature about Einstein and relativity, and had found it very unsatisfying.
Always when I thought I was getting close to the heart of the matter, the
author would say, 'But if you really want to understand Einstein you have to
understand differential equations,' or words to that effect." Later on, he
goes on to say how he ordered Differential Equations by H. T. Piaggio with
over seven hundred problems, most of which he solved over Christmas vacation.
Then when he attempted Peter Eddington's Mathematical Theory of Relativity, it
came very easily after the differential equations practice.

~~~
Panoramix
If I'm not mistaken Dyson also learned Russian one summer as a kid, because he
wanted to be able to read certain book. What a guy.

~~~
duaneb
To be fair, "just" reading Russian isn't that hard. A grammar textbook and a
dictionary gets me through polyphonic greek lit and modern german lit. Try it!
You might be surprised at how easy your brain will pick it up.

------
jmilloy
I guess this comment probably comes up every time Munroe's common-word pieces
come up, but I can't help but feeling like you only really understand (or
care) about the article if you already know enough about relativity.

> The first idea is called the special idea

No, it's not. Relaxing the rules to use key words (especially proper nouns)
would go a long way. You can call it Special Relativity and still "explain
relativity using only common words", can't you?

The result is that instead of an article explaining relativity, you end up
with an article about relativity translated into a common-word subset of
English.

Of course, I do enjoy decoding into normal English in my head as I read!

~~~
lelandbatey
I find I really like the labels "the special idea", and "the big idea." I like
it because it introduces the nature of the theory quite approachably, where a
theory is at it's heart an idea or a concept. Then, by labeling one "special"
and on "big", the relationship between the two is immediately obvious; we see
that one idea is covering a smaller but more particular area, while the other
idea covers a larger but potentially less-special and more general area.

The piece isn't as "strictly accurate" as it could be, but that's the point.
By making something approachable you'll hook into many more minds than
otherwise, and the knowledge of the reader that "this is not all, there is
more to learn" is powerful bait for the curious.

~~~
dgritsko
Bill Gates recently reviewed Munroe's "Thing Explainer" (a book consisting
entirely of explanations written in this style), and in his closing paragraphs
states the following:

"If I have a criticism of Thing Explainer, it’s that the clever concept
sometimes gets in the way of clarity. Occasionally I found myself wishing that
Munroe had allowed himself a few more terms—“Mars” instead of “red world,” or
“helium” instead of “funny voice air.”

Of course, that would defeat the purpose of the book. And Munroe himself is
aware of the tension. In “Page Before the Book Starts”—a.k.a. the
introduction—he acknowledges that some terminology is inescapable. “To really
learn about things, you need help from other people, and if you want to
understand those people, you need to know what they mean by the words they
use. You also need to know what things are called so you can ask questions
about them. But there are lots of other books that explain what things are
called. This book explains what they do.”

And it does that beautifully. Thing Explainer is filled with cool basic
knowledge about how the world works. If one of Munroe’s drawings inspires you
to go learn more about a subject—including a few extra terms—then he will have
done his job. He has written a wonderful guide for curious minds."

[http://www.gatesnotes.com/Books/Thing-
Explainer](http://www.gatesnotes.com/Books/Thing-Explainer)

I completely agree. Things written in this style occasionally start to feel a
bit clumsy, but the fact that my curiosity has been piqued to delve deeper
into a given topic is more than worth it.

------
koenigdavidmj
See also 'Uncleftish Beholding', a text about atomic theory using English as
it might be without borrowing so much from Latin and friends:
[https://groups.google.com/forum/message/raw?msg=alt.language...](https://groups.google.com/forum/message/raw?msg=alt.language.artificial/ZL4e3fD7eW0/_7p8bKwLJWkJ)

~~~
archangel11235
That was fun. Thanks.

------
suprgeek
A fun exercise in 'constrained' writing about a complex topic. However making
that claim that it 'explained' Relativity is not valid in any reasonable
sense.

I found the reliance on keeping to the 1000 most commonly used words to be
actually fairly painful to read thru to the end and even harder to understand.

Perhaps "Relativity as explained to a 6 year old" might make it more
accessible. A 6 year old has a vocabulary of ~5000 to 10000 words (for
reference) and being able to take these "verbal shortcuts" aka words would
make for better understanding.

~~~
btilly
I disagree.

I have never before seen a popularized attempt to explain things like light
bending that managed to get things right. He even took time to mention that
the popularized image of a sheet of rubber with a ball in it is an incomplete
way to think about things.

If it does not match your previous understanding of the topic, I'd suggest
reading it again. The only better explanations that I've seen involve tensor
calculus.

~~~
Steuard
I read the previous comment not as saying that this explanation was _wrong_ ,
but that it's just unlikely to be truly enlightening to someone who didn't
already know the subject reasonably well. I'm on the fence about whether I
agree: the cognitive load of interpreting the odd phrasing certainly does
compound the cognitive load of understanding the deeply non-intuitive physics.

This is quite a good presentation of the topic (or, parts of it), but if
clarity of understanding were the primary goal you could probably do
substantially better by translating it at least partway back into ordinary
language. (But then, fewer people might be intrigued or entertained enough to
read that version. So I'm not really complaining.)

------
KenoFischer
It is worth pointing out that only about 10% of Mercury's parahelion shift is
due to the effects of general relativity. The other 90% are due to
gravitational influence of the other planets. It is really quite remarkable
that astronomers of the 1800s made precise enough observations to be able to
tell that the parahelion shift was not entirely explained by known objects in
the solar system (since the effect is on the order of 10%, you have to know
the mass and position of every other major object in the solar system to about
that accuracy to be able to tell).

~~~
Jtsummers
[https://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet)](https://en.wikipedia.org/wiki/Vulcan_\(hypothetical_planet\))

I believe this was posted recently, or linked like I'm doing now in a comment.
Scientists in the 1800s tried to explain that 10% with a hypothetical 10th
planet within Mercury's orbit.

------
trequartista
I ran the entire text of this article through XKCD's simple writer tool
([http://xkcd.com/simplewriter/](http://xkcd.com/simplewriter/)) and it
pointed out that "movement" is not among the 1000 most common English words.
The word "movement" is used exactly once in this article.

So I guess this should be Theory of relativity explained using the 1000 most
common English words and one additional word :)

~~~
XaspR8d
True, though Munroe has been quite liberal about word derivations, and '-ment'
is a somewhat salient morpheme in English, despite not being very productive.

But still I'm surprised the article didn't pass the updated validator. Perhaps
an editor actually made the change?

------
zuck9
He wrote a book called Thing Explainer that is going to be published in a
week, which uses 1000 words to explain lots of things.

It was reviewed by Bill Gates recently:
[http://www.gatesnotes.com/Books/Thing-
Explainer](http://www.gatesnotes.com/Books/Thing-Explainer)

This article is likely an excerpt from that book.

~~~
mhb
Discussion of book and Gates' review:
[https://news.ycombinator.com/item?id=10546194](https://news.ycombinator.com/item?id=10546194)

------
andy_ppp
I for one hope that Thing Explainer is converted into Spanish[0]; it'd be a
quick win to learn the 1000 most used words in Spanish in context!

[0] May also apply to other languages.

------
emddudley
By Randall Munroe. If the pictures didn't already make it obvious.

~~~
benten10
...and the byline?

~~~
corin_
Personally I wouldn't always check the byline of an article, so were it not
for the pictures I'd have appreciated it being pointed out to me :)

------
jbob2000
This was really hard to read. I feel like I'm reading a redacted science text
book, with all the important bits removed.

~~~
kbenson
I found it very easy to read (as in understand), but very hard to read (as in
finish), because I'm a bit sleep deprived at the moment and it was putting me
to sleep.

It would be interesting to compare explanations like this[1] to mostly
equivalent explanations as they would traditionally be presented for learning
on a few topics I'm not familiar with to see if the concepts conveyed came
across better.

1: With footnotes for specific terms so the jargon can be linked.

------
ben0x539
Inspired by
[http://www.muppetlabs.com/~breadbox/txt/al.html](http://www.muppetlabs.com/~breadbox/txt/al.html)
?

~~~
vanderZwan
Didn't Guy Steele's "growing a language" also start with the 1000 most common
words?

~~~
pcmonk
IIRC he started with one-syllable words, but same idea.

~~~
oneeyedpigeon
If I am right, I think he did but just with words with just one sound.

FTFY ;-)

------
swiley
So this is why what-if hasn't been updated.

------
andor436
Excellent. I also enjoyed Brian Greene's visuals on the Late Show recently:
[https://www.youtube.com/watch?v=0jjFjC30-4A](https://www.youtube.com/watch?v=0jjFjC30-4A)

------
drcode
I'm tempted to read this story to my 4 year old daughter and see what her
opinion is of this "space doctor".

~~~
ismail
I just did. Her question was: "what does a space doctor checkup"

~~~
drcode
Which shows part of the problem of this approach: The word doctor is in the
top 1000 words in its usage for "medical doctors" but it's not in the top 1000
words in its usage as a reference to PhD graduates.

------
SilasX
Note: Munroe did the same thing in an xkcd for explaining the Apollo rockets
(I think that's what it is):

[https://xkcd.com/1133/](https://xkcd.com/1133/)

~~~
JumpCrisscross
Close! The Apollo programme used the Saturn V rocket [1].

[1]
[https://en.wikipedia.org/wiki/Saturn_V](https://en.wikipedia.org/wiki/Saturn_V)

~~~
jrockway
But his comic _is_ about Saturn V.

------
scott_karana
Is this a typo, or just a misunderstanding on my part? These two quotes seem
to be diametrically opposed in their explanation of Special Relativity in two
parts of the article.

> When you go fast, he said, the world around you changes shape, and time
> outside starts moving slower.

> Since the boats are going fast, the space doctor’s special idea says that
> their watches will run a little slower than the ones on Earth.

Shouldn't time outside start moving _faster_ in the first quote?

~~~
Strilanc
It's not a typo. When two ships are moving fast relative to each other, they
_both_ determine the other's clocks to be ticking slower.

[http://casa.colorado.edu/~ajsh/sr/paradox.html](http://casa.colorado.edu/~ajsh/sr/paradox.html)

------
buzzdenver
That was funny, but it would be easier to digest if he used a few extra words.

~~~
drcode
If you improve on it with a modified approach, buzzdenver, I'm sure many of us
on HN would be happy to give you feedback.

~~~
benten10
Idea: pull requests, but for essays.

~~~
chmullig
Wasn't that sort of what medium was pushing originally?

~~~
benten10
Was it? Not sure. It's too new-agey and commercialized for me, so I never
checked. Blogger and Jekyll-github all the way! Perhaps if someone leveraged
those technologies well, you actually would have source control for essays.

------
Albright
Thank you, Mr Munroe, but I still can't wrap my feeble mind around it. It's
still just too weird.

~~~
bosdev
Ah, so you understand it perfectly.

------
kodis
He's also done a similar piece explaining how rockets work using only the
thousand most common words in English. The one detail that I remember is that
apparently "thousand" is not one of the thousand most common words, as it was
rendered as "ten hundred".

------
gp7
For a layman's mathematical understanding of relativity I recommend "Why does
E=mc^2" by brian cox and jeff forshaw, which explains both the theory and why
the equations used to describe the theory, well, describe the theory. It does
it all with a nice just-so narrative that builds on physics from galileo all
the way through to einstein and ends up at particle physics. It's just a very
good book.

------
0898
There's an XKCD-inspired writing tool that only lets you use the most 1,000
most-common words in English:

[http://splasho.com/upgoer5](http://splasho.com/upgoer5)

~~~
oneeyedpigeon
Also, the official one:

[http://xkcd.com/simplewriter/](http://xkcd.com/simplewriter/)

------
MarcScott
The prose remind me of the writings of Kurt Vonnegut, particularly of
Breakfast of Champions.

~~~
krazydad
And so it goes.

* * * _

------
axg
Title should be "Theory of relativity explained by xkcd author Randall
Munroe".

~~~
dang
The original title has its charm. Not everything should be fully explained,
and on HN it's better if readers occasionally have to work a little.

------
rbanffy
Brilliant, as always.

------
webwielder2
tl;dr: Numbers.

------
rubyrescue
"If you’re in a car, you see watches outside the car go slower. They only go a
little slower, so you wouldn’t notice it in your normal life; it takes the
best watches in the world to even tell that it’s happening. But it really does
happen."

He said it backwards...

~~~
Steuard
The crazy thing about special relativity is that from the perspective of the
observer in the car, they're sitting still and everyone _else_ is moving. That
means that the observer in the car will see the watches of people on the
sidewalk ticking slowly, at the same time that the people on the sidewalk will
see the car's clock ticking slowly.

Everyone sees everybody else's watch ticking slowly (unless they appear to be
at rest). And yet it all hangs together in a beautifully consistent way. The
catch is that moving observers don't just disagree on whose watch is running
slow, they _also_ tend to disagree on whether distant clocks are correctly
synchronized or not. The disagreements about which clock is ticking too slow
always perfectly balance out the disagreements about which clock chimed noon
earlier.

~~~
btilly
In the path from special to general you have to give this point of view up.

More exactly, special relativity starts with the assumption that there are
special inertial frames of reference, here is what they look like, and here is
what they look like relative to each other.

General relativity starts with arbitrary coordinate systems, and ways of
expressing physics such that whatever was measured in one coordinate system
can be translated into what should have been measured in another. These
coordinate systems can have any mixture of weird effects.

The physics involves something called a metric. General relativity is what
falls out if you insist on the following statements:

1\. "Locally" things behave like special relativity.

2\. Given only low velocity and low mass, things behave like Newtonian
gravity.

3\. The terms of the metric satisfy a first order differential equation whose
definition is independent of the chosen coordinate system.

This gives you general relativity up to an arbitrary constant of integration
(the cosmological constant). And in the presence of mass it gives you the
prediction that no truly inertial frame of reference exists over any region
with matter in it. (The effects of gravity are all due to stuff being non-
inertial.)

From that prediction we find that the point of view and understanding from
special relativity is only a local approximation. You can't really describe
any interesting system that way.

