A Neptune Kid, Waiting to Always-Already Know Pluto

If you’ve ever wondered what it means to always-already know something, you’re about to get a powerful demonstration, along with the rest of the planet. If all goes well with the NASA New Horizons mission, in a few weeks, you will always-already know what Pluto looks like. At crater-level detail.

As of June 29th, these low-detail teaser images of the Pluto-Charon system, based on the latest New Horizons update, are as good as it gets:



Savor the moment. Those born after around 2010 (I assume 5-year-olds are too young to appreciate the moment) will never know what it was like to not know what Pluto looks like. And those of us who do know will find it hard or impossible to re-experience that mental state of not knowing.

Moments like this, just before a significant collective mind-expansion, are rare. The last time we experienced something like this was in 1989, when Voyager 2 arrived at Neptune. That event changed my life.

Degrees of Knowing Pluto

Let’s stay with Pluto for a moment, before I tell you my Neptune story.

Several billion people going from not knowing something to always-already knowing something is not just a private mental experience or a student learning moment. It is a collective experience. The sort of collective experience that makes even a die-hard individualist like me use the pronoun we for a group larger than a handful, and mean it.

Until New Horizons got sufficiently close, this interpolated Hubble false-color image circa 2010 was our collective experience of knowing Pluto.


You couldn’t get a better image by talking to a more knowledgeable person or looking in libraries. A teacher couldn’t enhance your visceral experience of knowing Pluto by telling you more bald facts about it’s orbit, mass and temperature.

While not quite as bad as those “artist’s renditions” some people seem to like (I don’t, they inexpertly squat on an empty space in my head I’d rather leave empty), there’s something strangely unsatisfying about bits-stretched-thin enhanced images. Still, when I saw the image above in 2010, I did experience minor goosebumps. Because it was an improvement over this, our best previous collective image of Pluto, a 1996 effort from a less technically sophisticated period of Hubble’s life.


In this picture, the little inset raw images are somewhat satisfying, but the interpolated larger images, while scientifically justified, are not as satisfying to me. Our minds can tell when information is being stretched too thin to fill a larger hole-of-unknowing than it reasonably can. It’s a lesson you learn early as an amateur astronomer: higher magnifications with a lower-power telescope are not satisfying. The sharper images at lower magnifications are more satisfying. They tell a more conservative”truth” in some sense, given the raw bits of information collected.

It is surprisingly hard to find online historic photographs of planets from before the era of Hubble, Voyager-like missions, and the recently inaugurated era of adaptive optics. But this 2007 image, the current best ground-based picture of Pluto (from the Keck telescope on a particularly good night), approximates humanity’s experience of pre-Hubble Pluto (though it is much too good — I doubt anyone in the 1980s saw anything even close to this):


I can’t tell you what your mind will be like once the first detailed pictures of Pluto are released, but if you have the right kind of sensibility to really appreciate what’s in store for us, I can tell you the story of a similar mind expansion.

Halley, Uranus, Neptune and Me

The story of my fascination with Neptune begins with Halley’s comet visit in 1986. I was in sixth grade, and I went to an observing session put on by my school’s astronomy club (using an antique brass telescope that was already over half a century old at that point). The comet was an unimpressive sight, thanks to the poor conditions and equipment, and it was apparently not a very impressive Halley encounter by historical standards. But it was enough to awaken my astronomical consciousness, so to speak, and gradually transform me into a dedicated amateur astronomer over the course of my remaining school years.

That same year, Voyager 2 did its Uranus flyby.

Overnight, with most of the planet, I went from never really having thought about Uranus to always-already knowing what Uranus looked like.

Uranus-before-1986 was really an unknown-unknown rather than a known-unknown for me, since it had never been more than a name to learn in a formulaic way for tests, like a state capital. It didn’t mean anything and I didn’t care to make it mean anything. For me, the Uranus flyby was not a particularly powerful experience because my astronomical consciousness had been too-recently awakened. It had not developed enough enough for me to have experienced Uranus-as-a-mystery. It just jumped straight from whatever, I’m done with that test to oh, cool picture, what’s for lunch? 

So I have no real memory of what it was like to consciously not know, but care what Uranus looked like. But I expect the 1986 encounter was as life-changing for some older people as Neptune was to be for me.

What made the encounter particularly powerful for humanity as a whole is that Uranus was the first true space mystery unveiled in detail by a space probe.  While Voyager 1 had visited and sent back stunning photos of Jupiter and Saturn, those planets (being closer, much larger, and with plenty of fascinating ground-observable detail) had never been mysterious the way Uranus had been before Voyager 1. Neither had Mars, Venus or Mercury. Those five planets had also been known to all civilizations since antiquity, and there is even a satisfying-to-some theater of bullshit — astrology — associated with them. But Uranus went from newly discovered to mysterious to mystery resolved in just over 200 years. Newer mysteries were also revealed of course.

Neptune had a similar emergence in the human consciousness, with the added drama of a mathematical prediction leading to discovery, but it took less time: just short of 150 years.

And unlike the Uranus story, for me, the Neptune story was personal. Personal in a way the Pluto story (85 years from unknown to mystery-revealed) is going to be for a lot of teenagers.


I have very strong memories of consciously-not-knowing-but-caring what Neptune looked like. Halley’s comet and the Uranus encounter had awakened my Neptune-consciousness, and it had three years to develop.

As I suspect it was for other astronomy buffs in the 1986-89 period, Neptune was like a slowly growing hole in my head. I spent a lot of time poring over old Sky and Telescope issues from my school’s astronomy club library, but I can’t recall any pictures of Neptune better than a tiny blurry star.

Sometime during those 3 years (1988 I think), I did a science report for school, where we had to pick a planet to profile. I picked Neptune, and for the cover, drew it as a greenish ball rather like Uranus, since back then they were thought to be near-twins (they’re not; Neptune is more bad-ass).

My cover picture was not an artist’s impression of Neptune. It was an artist’s impression of a hole-in-my-head.

The closest approximation I can find online, to what “knowing Neptune” must have meant in 1986, is this modern photo by an amateur, Damien Peach, using the best modern amateur gear.


I doubt the best pre-Hubble telescopes, such as the pre-adaptive-optics 200″ Hale telescope at Mt. Palomar, did much better than this. Atmospheric turbulence, which modern adaptive optics help conquer, is particularly harsh on planetary observations. If you can find pre-1989 pictures of Neptune, I’d greatly appreciate a link in the comments or an email. I personally can’t recall seeing a picture this good back then, but then I had limited access to material in India, so I suppose they must have existed.

Anyhow, between 1986 and 1989, like I said, Neptune was a hole in my head. Uranus images had created an expectation of a certain scope and size. One that small blurry images and technical specifications of orbits, masses, number of moons could not fill.

In a way, such holes-in-the-head are the very essence of the scientific sensibility. When you a) know for sure that there is something big to know, b) don’t actually know the thing itself, but c) do expect to find out soon, the result is a very peculiar mental state. It is the philosophical big brother of everyday anticipation. The universe’s natural equivalent to a whodunit, with some existential restlessness added.

We don’t have a word for this feeling or state.

I do know many people have never experienced it, and are possibly incapable of it. Oliver Wendell Holmes partially captured the quality of hole-in-the-head incompleteness with his line, “A man’s mind stretched to a new idea never goes back to its original dimensions.”

But it is not just a new idea that will do the trick. A well-defined expectation of a new idea will do as well.

Some like the term “scientific curiosity,” but that makes the state sound like casual stimulation seeking. There’s nothing casual about it.

Phrases like “sense of wonder” (or awe or sacredness) fail for a different reason: they focus attention on the emotions of a few poetic and sensitive types — often the kind who can’t tell astronomy and astrology apart — rather than the external realities that evoke them. For sense-of-wonder people, new mysteries being slowly unveiled serve merely as dispensable emotion-provokers.

“Religious yearning” comes close, but while there are several physiological commonalities, the hole-in-the-head feeling is basically the opposite mental state. Religious yearning is also marked by a sense of something missing, but it’s a very different beast.

Religious yearning is often described as seeking a sense of connection or belonging to larger realities. Seeking a sense of yourself as being more significant than you think, by virtue of your connection to something bigger. When you find the missing piece, so the theory goes, you will feel complete.

Hole-in-the-head-ness is the sense that you’re going to find out you are less significant than you think, by virtue of your increasing disconnection to something increasingly bigger.

And of course, there’s the bigger difference. Religious yearning is never actually satisfied, though there are plenty of proxy missing pieces that keep you hoping. The seeking state itself is the terminal, fetishized state.

Neptune-like hole-in-the-headness, by contrast, is a transient state. You do find out  things, resolve old mysteries and move on to new ones. Your sense of being less significant than you think is validated with each new discovery.  If religious seeking, perennially unsatisfied, constantly reinforces anthropocentrism, hole-in-the-head-ness, repeatedly satisfied, constantly weakens anthropocentrism.

This, despite how dark it sounds, is a good feeling. A liberating feeling. A feeling that you can do anything because in a larger scheme of things, what you do probably matters less than you think. Because the universe repeatedly turns out to revolve less around you than you think.

And with each discovery, one hole in the head is filled, but a bigger one, representing a bigger set of mysteries, is created. Your mind expands, but the new hole occupies more of it than the filled space.

It is a feeling you have to develop an appetite for, and feed regularly. As the hole-in-the-head grows, your sense of yourself shrinks. If the earth shrinks to a pale blue dot as you look from a spacecraft speeding away, your identity shrinks to a pale-you-dot within your head, much of which is now occupied by a growing void.

If you live long enough, and pay close enough attention, you become aware of a Moore’s Law like decline in your sense of your own significance as the size of the universe expands in your head. I wish my identity halved in size every 18 months, but the rate is a little slower than that.

In 1989, the hole in my head was filled by a planet-sized new thing. Along with everybody else who had carried that hole for three years, I found relief with the Voyager 2 pictures of Neptune. The first photos (I don’t recall seeing these at the time) looked sort of like our early Pluto pictures are looking right now, blurry little appetizers before the main course:


The main course followed in the form of the spectacular detailed imagery that arrived a little later. I remember staring at these with an insane gleam in my eye for days.


In an anti-religious way, we had finally seen a long-anticipated anti-god, in rich enough detail to temporarily satisfy us. An ice-giant anti-god. An anti-god with a Great Dark Spot whose significance we discussed excitedly (it vanished a decade later).

It is a feeling the religious-but-scientifically-incurious will never properly experience. A sense of suddenly increased disconnection from a universe that has suddenly become larger than it had been a moment ago. A universe that had a gigantic, improbable, lightly striped blue ball in it, something nobody on earth had imagined existing a mere 150 years earlier.

A universe that, paradoxically, feels better than the one you just left, despite making you feel more insignificant.

In 1989, I was ridiculously and unreasonably pleased that Neptune existed and that I knew what it looked like. It was much more than mind-candy. It was a hat-busting 7-course mind feast.

Now in 2015, thanks to Hubble and adaptive optics on 10-meter telescopes, Neptune is a familiar part of our collective mind, no artist’s conception required.  An entire generation has grown up after me, never having experienced the mystery that was once Neptune, and the feeling of collectively having that mystery resolved and replaced with bigger ones. The ultimate I was there when that happened feeling.

Including, it pleases me to remind myself, people much richer than me in other ways, such as Mark Zuckerberg (born: 1984, aged 5 during the Voyager 2 encounter, almost certainly too young to remember what it was like to not-know Neptune).

Just for fun, here are recent Hubble pictures of Neptune:


And here is a ground-based adaptive optics image (from Hale I think, a false-color infrared image): image quality that was unimaginable in the eighties.



Philosophical Hunger

Reflecting on my Neptune story, I think I do have a term for the hole-in-the-head-feeling. It’s not curiosity or awe. It’s a sort of hunger. I think philosophical hunger is the right phrase.

“Science”, however you define it, is the primary (and perhaps only) means of feeding it. I suspect science is best defined  as the behaviors which successfully manage to feed and grow this appetite; an appetite that is ultimately an appetite for life itself. Other things might look similar, but they don’t have this telltale effect of progressively shrinking your identity and creating a growing void of philosophical hunger that demands fulfillment.

Once you’re on the philosophical hunger path, you grow increasingly hungry, but are always feeding at a sufficient rate to not starve. It’s just that your hunger grows faster than your ability to feed it. It is this state of increasing ambiguity, uncertainty, and not-knowing that you come to value, rather than the state sought by religious yearning, of increasing certainty and knowing.

While the hunger for certainty can (and does) easily become toxic, turning into psychosis and delusion-construction that ultimately traps you, the hunger for ambiguity, I think, puts you on a slow, difficult path of indefinitely increasing sanity. Increasing insanity, of course, is a death-limited process. But increasing sanity is a process that does not have a necessary terminal state. I am still insane of course, just like the rest of you, but I like to think I’ve grown slightly less insane in the past few decades, thanks in large part to our collective 1986 encounter with Neptune.

An aside: it seems strange to me that we normally view sanity as a fixed, idealized state and insanity as a set of complex departures from it. It seems to me exactly the other way around: all varieties of insanity are simpler states. They approximate the timeless, unchanging state of death to greater or lesser degree. Sanity by contrast, is not a state, but the achievement of escape velocity from that attractor. Sanity is perhaps, fundamentally the decision to live. A decision provoked by what-does-Neptune-look-like type holes in the head. So you decide to live long enough to find out, then you stay in the game to fill another hole, and another. And so on.

And with each little Δv thrust, you escape a little more. 

I think people fail to recognize this because they confuse sanity with rationality. Sanity is not rational. The decision to keep living for another chapter, then another, then another, is not rational. It is not even in any sense the right decision or even a single decision. It is just a decision it is possible to make, repeatedly, and thank yourself for making after, each time. Sanity is repeatedly realizing, I’m glad I stuck around for that. 

Repeatedly succumbing to philosophical hunger is of course, not the only way to keep on living, but it is the most satisfying way I have personally found.

I am, you might say, a Neptune kid. My philosophical appetites were awakened, first fed, and shaped, by the Neptune encounter. Next month, Pluto is going to be quite a treat and will keep me happy for quite a while. Then it will be something else. Then something else. But I’ll always identify as a Neptune kid.

We humans like to mark our place in the universe with reference to highly local human events in time and space. Presidents and Prime Ministers are popular, as are decade boundaries. There are people for whom the archetypal image evoked by “President”, whether it is the face of Reagan, Clinton or Obama, is the image that defines who they are. There are people who think of themselves as 70s kid or 80s kid or 90s kid (I suspect there are people out there who, if they think of Neptune at all, think of it as a “Victorian” planet because it was discovered in 1846). 

I do that sort of thing too because it is socially convenient. “Prime Minister” for me was Indira Gandhi first. “President” for me was Reagan first. I am an Indira-Gandhi kid, a Reagan-and-Gorbachev kid, and an 80s kid. These identities are familiar ones I wear often.

But my primary personal identity is probably Neptune kideven though I don’t wear it that often in public. In the staircase of mind-expanding collective moments we experience, Voyager 2’s encounter with Neptune marks my own first step up. The first significant decision to live, to my recollection, that was driven by a hunger for life rather than a fear of death.

For those about to become Pluto kids, it’s an identity that only a tiny fraction will ever even notice, let alone embrace, but they’ll be Pluto kids all the same, just as they’ll be Bush or Obama kids whether they are interested in politics or not.

But for those who do become aware of their Pluto-kid identity and allow it take charge of their future, life will never be the same. It will be a life full of hunger for itself, but also a life full of treats that will, for brief periods, satisfy that hunger.

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About Venkatesh Rao

Venkat is the founder and editor-in-chief of ribbonfarm. Follow him on Twitter


  1. Ben Mahala says

    As someone who’s always been interested in physical theory, I’ve been trying to think back to my first moment of satisfied philosophical hunger, and I just can’t seem to find one. I was too young and uninterested in theory in 1998 when the accelerating universe / dark energy was discovered. And that was more of a “huh” moment (unknown unknown -> known known) then a moment of philosophical hunger satisfaction ( known unknown -> known known). The greatest current philosophical hunger for any physical theorist is quantum gravity of course. However that is both currently unsatisfied and has been unsatisfied for so long that by now many question that they’ll live to see the day it will be. (I wonder if I-never-thought-I’d-see-the-day-ness is an extreme form of philosophical hunger satisfaction or something else?).

    The most recent satisfaction was the discovery of the Higgs Boson. More of an experimental satisfaction then a theory one, although it was extremely satisfying to watch a whole class of theories that had predicted the lack of that discovery explode in brilliant fire. (I had nothing personally against these theories, but explicit falsification is a fundamental joy for any theorist, since it means if nothing else you can finally move on). The slow falsification-by-exhaustion that SUSY seems to be going though is the opposite of this. Sort of the difference between finding the dead body of a relative vs. them having disappeared and been missing for 20 years.

    I wonder if the health of a field can be parametrized by the number and extent of successful moments of satisfied philosophical hunger, and if a field is not fed for long enough, it goes though a sort of decay. The science part of it dissipates and you’re left with the sort of pseudo-philosophical-pseudo-theological shell that a lot of fundamental physics seems to have devolved into. Until the next discovery, where it burst into light and the dead matter burns away.

    • Ben Mahala says

      A quick addendum: Feynman seems to have experienced the same thing in the field of general relativity before the 60s renaissance that field experienced. I can’t find the quote, but after Einstein and before the 60s the field was pretty much dead, with no new discoveries or expansions on the current theory.

      • The one I know is:

        “I am not getting anything out of the meeting. I am learning nothing. Because there are no experiments, this field is not an active one, so few of the best men are doing work in it. The result is that there are hosts of dopes here and it is not good for my blood pressure. Remind me not to come to any more gravity conferences!”

        From a letter to his wife during the Warsaw GR conference, 1962

    • I think at least the early triggers have to be purely visceral. You are most susceptible between 12-14 to having philosophical hunger awakened, but unless you’re a total prodigy, you can’t appreciate theoretical ideas like expansion and dark matter/energy. You need things like a Neptune flyby that makes such things real.

      Prodigies have other problems. They are so good at the doing, they never get a chance to develop the hunger. They can turn into robots, getting off on the social validation of “winning” in the game of physics competitively.

  2. My own personal “Neptune” was the Mars Pathfinder mission. And you’re right; it hit me squarely in the 12-14 age range. Each subsequent similar mission (say, the later Mars rovers or the recent comet landing) has left me a little sad because of how much less viscerally excited I was about it.

  3. Philalethes says

    Well, I guess I would qualify as a Sputnik kid. I was 14 years old when that event astonished the world, punching the first small hole through the envelope of Earth’s isolation.

    I had recently become an avid science fiction fan, beginning with devouring Robert Heinlein’s classic “juvenile” novel series, with their traditional depictions of Mars (desert with water canals and wise natives, hospitable if barely to human colonization) and Venus (swamp & jungle with wise natives, rather like the wettest equatorial regions on Earth, also hospitable to humans). These pictures of our nearest neighbors, of course, were shortly to be revised, drastically in the case of Venus.

    Of course, you will have always-already known that the surface of Venus is a hellish, howling desert – but many are still alive to whom it was pretty surprising news.

    I regret that my mother is no longer in this world; an amateur astronomer who used to host the planetarium shows at the local natural history museum, she would have loved to see these new pictures of Pluto.

    I am still a little jolted every time I hear Gustav Holst’s much-loved classic “The Planets”, and recall that when it was written (just a century ago) the existence of Pluto was unknown here on Earth. (I see that there is now a Pluto movement, composed by Colin Matthews, “an authority on Holst”, available on several recordings; I’ll have to check it out.)

  4. Avery Kimball says

    Your formulation of sanity as escape from the simpler (simplistic) known-quantity of death, contrasted with the popular conception that sanity is an ideal to adhere to with greater or lesser success, brings to my mind David Deutsch’s ideas about knowledge creation- that we are not, save a few minor refinements and adjustments, approaching a state of scientific knowledge that is nearly complete (a Platonic state of unified scientific knowledge); Instead, we are escaping from the perfection of ignorance into an ever Wilder West of newer and weirder knowledge.

    In fact, I find Deutsch’s work complements your own- and with as much weight as an internet stranger’s suggestion can have, I think a glance at his most recent book “The Beginning Of Infinity” would serve you well. If you are impressed by Official Qualifications, Deutsch is a Fellow of the Royal Society, and pioneered the field of quantum computing. I hope that offsets the new-agey cranktastic impression the above paragraph may have given.

  5. I remember having this hunger evoked when my father explained the theory of relativity to me as a 4th grader. I tried to
    explain what I learned to some of my classmates who just thought I was wierd.

    I remember being fascinated by the planets as a 7 year old in the late 70s, but it was almost an aesthetic thing, with a 50s era Time-Life book we had showing artists rendering of each of the planets , including a bizarre speculative picture what life on Venus’s surface might look like (this was before the Venera flights of course, where they found out it was just baking rocks.) The picture had air-ingesting flying fish flying around in Venus’ Atmosphere. .. Someone should link to THAT pic .. LOL . I’m going to google it after I finish this comment. I wanted to imagine each planet as being a specific color, much like the pictures.
    It seems that Mars really is red, from the pictures of its surface. To what extent is Nepture really “blue”? I figured the ‘color’ in alot of these photos is some artifact of light effects (like Mountains looking “blue” in mist from a distance) or the computer generating the image, maybe selecting the color that most highlights the contrasts on the surface.

    • I had that same Time-Life book as a kid and it was wonderful.

      • Yes, you are right. (A quick google images search did not turn up the flying air-fish picture.. I have the urge to go to a used book store to find it and scan it! )

  6. dazhuang2 says

    @vgr: Your claim that sanity is not rational reminds me of the logic that the death of a single individual is rational if it benefits others, the logical extreme of utilitarianism. The above course of logic can be used as an empirical proof of your claim but I find it far more interesting to use it to try to understand why individuals are individualistic and choose to live solely for themselves. I’ve concluded that the desire to be sane is driven by the opposing drives to remain sane in order to explore new things and the drive to stay sane simply to be alive. Since sanity is irrational, both the drives for curiosity and preservation are irrational. So maybe the drive for individualistic curiosity you so treasure ultimately is a random evolutionary quirk. Comments?

  7. Dave Foster says


    “Philosophical hunger” is a cumbersome term – just aesthetically, don’t know why, no offense – but your description is EXACTLY right. I had no term for it; I thought of the phenomenon – the drive, really – in terms of ratios. Because of this drive to know – an impetus, a calling, no idea the why or the origin, just baked into my brain and personality from the earliest recollections – every day I become aware of x, but can only partially learn/digest 1/100x (or whatever – in no way a linear relationship). So every day I get more stupid. It’s a little frustrating, the vague idea that there’s only so much time and but so much to partially know – and that’s in knowing that there are vast areas of inquiry that I (a) I don’t know about or (b) don’t care about (inc. astronomy. sorry, did like the Pluto-as-Death Star pics going around. Also, Pluto IS a planet, no matter what the international order of astrogeeks may have ruled.)

    But mostly, the thing is to always be very actively humble about one’s own knowledge. It’s not at all a bad sense, other than the tinge of pre-regret in having the finite lifespan. Rather, it is an amazing feeling, indeed an incorporeal hunger where it feels good to be hungry if not starving. The merriest, mostly private adventure.