Laughter

the human race has one really effective weapon

54 Years of Space Exploration

Leave a comment

50-years-of-explorationvia Cosmic Diary and the SETI Institute Facebook page:

National Geographic asked 5W Infographics to update its 50 Years of Exploration graphic, a classic that I use often in my talks to illustrate our space exploration program and its focus on the inner part of the solar system.

The updated version, renamed “Cosmic Journey“, is spectacular, better organized and easier to follow than its predecessor. It has been updated to include new missions sent over the past 4 years. The new color code includes the paths of failed, as well as successful, missions and also the nation that led them.

A high resolution version is available on the 5W Infographics website.

Advertisements


Leave a comment

Voyager 1 Is an Interstellar Craft

the_sun_flareHard to over-emphasize just how historic this is: it has been confirmed that Voyager 1 has pierced the heliosphere and entered into interstellar space. Back in June I posted about a “mysterious region” at the edge of our solar system, which had scientists a little confused about Voyager’s location. Evidently, that confusion has been cleared away.

From the University of Iowa’s IowaNow website:

“On April 9, the Voyager 1 Plasma Wave instrument, built at the UI in the mid-1970s, began detecting locally generated waves, called electron plasma oscillations, at a frequency that corresponds to an electron density about 40 times greater than the density inside the heliosphere—the region of the sun’s influence,” says Gurnett. “The increased electron density is very close to the value scientists expected to find in the interstellar medium.

“This is the first solid evidence that Voyager 1 has crossed the heliopause, the boundary between the heliosphere, and interstellar space,” says Gurnett, principal investigator for the plasma wave instrument.

At age 36, Voyager 1 is the most distant human-made object at more than 11.6 billion miles from the sun, or about 125 astronomical units.

“At that distance it takes more than 17 hours for a radio signal to travel from the spacecraft to one of NASA’s Deep Space Network antennas. The signal strength is so incredibly weak that it takes both a 230-foot and a 110-foot-diameter antenna to receive our highest resolution data,” Gurnett says.

That makes Voyager 1 the first human-made spacecraft to enter interstellar space. Though we can’t see or feel what that’s like, an instrument on the probe captured the sound of vibrating plasma there, and sent it back to Earth. You can listen to that here (or at the bottom of this post).

National Geographic explains how scientists know Voyager 1 crossed over in a little more detail:

Knowing exactly where the solar wind ends and where interstellar space begins has been an open question among space scientists for more than four decades, says Stone.

Since an instrument for directly detecting that transition died in 1980, the researchers have had to rely on indirect measures of magnetic and electrical activity from other instruments aboard Voyager 1 to find an answer.

One key to identifying this boundary is the difference in the density of charged particles between the solar wind and interstellar space, as it is about 50 times greater in the latter region.

Looking at a pair of solar storms that caught up to the spacecraft last October and then again last April, Gurnett’s team reported that measured changes in electrical activity around Voyager correspond to interstellar space.

As the storms passed the spacecraft, they triggered spikes in electrical and radio waves that uniquely corresponded in frequency to the spacecraft having entered the more densely charged interstellar space.

Based on that increase, the team extrapolated the entry date for Voyager 1 into interstellar space as August 25, 2012.

Voyager still has some life left in it too. The probe is not expected to completely lose power until 2025, though instruments on board will likely fail before that time. Remember, Voyager 1 was designed in the early ’70s and was launched on September 5th, 1977. As Suzanne Dodd—the Voyager project manager—points out, your average smartphone has approximately 250,000 times more memory than Voyager 1 does, which makes its continuing operation seem all that more miraculous. Also makes me wonder what we’re doing with all that extra memory in our pockets.


2 Comments

Speed Bump at the Edge of the Solar System

voyager_trajectoryI haven’t posted any science-y articles to the blog in awhile, but today two caught my attention.

Voyager I, now in space for over 35 years, is just approaching the very edge of our solar system. Astronomers have expected some very particular things to happen once it crosses over into interstellar space. Only, those things aren’t happening at all, and nobody can say why for sure.

From Wired.com:

The first Voyager sped out of the solar system in 1980 and it has since been edging closer and closer to interstellar space. The probe is currently out more than 120 times the distance between the Earth and the sun.

Scientists initially thought that Voyager’s transition into this new realm, where effects from the rest of the galaxy become more pronounced, would be gradual and unexciting. But it’s proven to be far more complicated than anything researchers had imagined…

…it’s almost as if Voyager thought it was going outside but instead found itself standing in the foyer of the sun’s home with an open door that allows wind to blow in from the galaxy. Not only were scientists not expecting this foyer to exist, they have no idea how long the probe will stay inside of it. Stone speculated that the probe could travel some months or years before it reaches interstellar space.

For the curious reader, 120 times the distance between the Earth and the sun is approximately 18.5 billion kilometers, or 11.5 billion miles. It’s hard to imagine such a distance, so think of it this way:  The speed of light is 299,792,458 meters per second. If you could travel that quickly, it would take more than 34 hours to go from the sun to Voyager I’s current position and back.

Or think of it in miles per hour: 300,000,000 meters per second is around 671 million miles per hour. You could get to Jupiter in about 40 minutes at that speed. Voyager I was launched on 5 September 1977, but its closest approach to Jupiter didn’t happen until 1979. It would take roughly a year to reach the Oort cloud.

It takes sunlight eight full minutes to reach the Earth.

Once you start to fix the distance in your head, Voyager I’s position becomes all the more amazing.

The other article that caught my attention concerns the formation exoplanets, and came via SETI’s Facebook page. It also puts our knowledge of the universe into perspective:

A team of researchers has discovered evidence that an extrasolar planet may be forming quite far from its star — about twice the distance Pluto is from our Sun. The planet lies inside a dusty, gaseous disk around a small red dwarf TW Hydrae, which is only about 55% of the mass of the Sun. The discovery adds to the ever-increasing variety of planetary systems in the Milky Way.

Planet formation far away from a small parent star is at odds with the conventional planet-making dogma. Under the most accepted scenario, planets form over tens of millions of years from the slow accretion of dust, rocks, and gas. That happens most easily close to the central star, where orbital timescales are short. Even under a disk instability scenario, in which planets can collapse quickly from the disk, it’s not clear such a low mass planet could form.

Carnegie astrophysicist Alan Boss, who works on disk instability models, said “If the mass of this suspected planet is as low as it seems to be, this presents a real puzzle. Theory would say that it cannot exist!”

But apparently it does exist. I’m excited by this kind of news because it demonstrates the versatility of planet formation in the universe. The more possible planets, the more places life could exist. And like lots of other people, I want to believe we’re not alone.

small portrait of Nietzsche from Wikipedia


1 Comment

Nietzsche Contra Science, Part I

blackboard with equations

Two weeks back I finished reading Nietzsche’s Beyond Good and Evil. As I read it, I was happy to find all the critical remarks Nietzsche makes about science, especially its relation to interpretation and truth. I’d forgotten about these comments in the nearly ten year break I’d taken from reading his work and the few memories I had left were of the “God is dead” variety. So it was with surprise that I found an already cleared path on which I could test some of my suspicions about the limits of science and its interpretive scope. My interest in this topic stems both from Nietzsche and from authors like Richard Dawkins and Christopher Hitchens, who I take to be very popular and of the opinion that scientific conclusions are both more true and more valuable than other truths, like those we find professed by various religions.

This post is not meant to be a refutation of their positions, however, and it’s not necessarily an endorsement of Nietzsche’s views either. The following commentary is just a series of notes, clarifications, reactions, and various suspicions aroused by Nietzsche’s attacks on science in Beyond Good and Evil. I hope to write further posts like this one, probably in short installments that will focus on just a few sections at a time. My aims are to clarify his positions for myself and to test some of my own thoughts on the subject. For the record, I read this Cambridge University Press edition, translated by Judith Norman.

Nietzsche begins his book with a brief but striking—and infamous—introduction. “Suppose that truth is a woman — and why not? Aren’t there reasons for suspecting that all philosophers, to the extent that they have been dogmatists, have not really understood women?… What is certain is that she has spurned them…”

Philosophers seek the truth and are turned away again and again. This is the idea he wants you to consider from the start. No matter how passionate the pursuit, philosophy is doomed to a life of unrequited love. But Nietzsche’s not just having fun at our expense. He continues, questioning why we seek truth in the first place and not something else. Nietzsche asks, “What in us really wills the truth? … why not untruth instead? And uncertainty? Even ignorance? The problem of the value of truth came before us, — or was it we who came before the problem?” (§1).

His answer is, in part, that individuals will a truth suitable to their own needs and personalities. In section five he writes, “[Philosophers] act as if they had discovered and arrived at their genuine convictions through the self-development of a cold, pure, divinely insouciant dialectic… while what essentially happens is that they take a conjecture, a whim, an ‘inspiration’ or, more typically, they take some fervent wish that they have sifted through and made properly abstract — and they defend it with rationalizations after the fact. They are all advocates who do not want to be seen as such.” We desire the truth in order to rationalize our beliefs, ideas, and actions. There’s none of the noble or heroic ideals about finding truth because it is the highest or best thing in life. At least, not here. What matters instead is the psychological element. Truth is a mutable thing, bent and sculpted into different shapes by different people with different purposes.

Nietzsche cuts even further into the idea of a firm and unchanging truth by attacking the idea of a “thing-in-itself”.  First he considers what it means for there to be a “thing-in-itself,” then he makes an important distinction between the value of truth and the nature of truth. As far as the “thing-in-itself” goes, Nietzsche associates it with a tendency to divide the world into pairs of opposites. He states, “The fundamental belief of metaphysicians is the belief in oppositions of values. It has not occurred to them to start doubting right here at the threshold, where it is actually needed the most, even though they had vowed to themselves ‘de omnibus dubitandum’ (§2).

What does he mean by opposition of values?

I’ll use moral values to help figure that out. If we jump ahead to section 44, we find Nietzsche proposing that humanity’s worst qualitiesour disposition to violence, deception, even slaveryare valuable for human life. Maybe even more valuable than qualities like selflessness and honesty. Someone who isn’t too cynical might ask how that could be. Lying and selfishness are typically categorized as destructive or negative traits, selflessness and honesty as positive ones. Every kid knows that lying might help in a pinch, but that it can also come back to bite you in the ass. Selfishness is worse. We associate that with narcissism, parsimony, greed, and other reprehensible traits. So what could Nietzsche mean when he claims that even tyranny could be good for humanity?

We might think that he means “whatever doesn’t kill us makes us stronger,” and I think that’s at least partly right. But this isn’t just a matter of casting a positive light on difficult times. Nietzsche goes further.

In order to think of something as inherently good or inherently bad, in order for us  to think of paired oppositeslike self-interest/selflessness, deception/honestyas opposite, it’s necessary for us to think of them as fixed concepts. If self-interest and selflessness were at all confused or muddled together, were we to find even the hint of one in the other, then the opposition they represent would fall apart. Think God’s laws as they appear in the Old Testament: they’re firm, clear, and distinct. They stand in clear opposition to other laws or rules we might formulate like “only the strong survive” or “jealousy is the sign of a healthy appetite.”

The problem is that the world we’re familiar with, the one made up of jobs and families, of social circles and private thoughts, is always in flux. Knowledge, on the other hand, is supposed to be fixed and unassailable. Because of this, a space opens up between the world and the knowledge that is supposed to help us move through it. Moral laws like “don’t kill,” or even physical descriptions, like general relativity, are the kinds of things we expect to stay the same no matter what the case. But when we look around the world we find that there isn’t much that’s standing still. Everything is constantly changing, from the global level right down to the atomic.

This is, I think, at the root of Nietzsche’s attack on both philosophy and science. Both hope to describe or explain the world in fixed terms and, what’s more, they hope to show that their descriptions and explanations constitute the truth, exclusive of other explanations.

But Nietzsche’s claim isn’t that these explanations and descriptions are just false; it’s not that we have the wrong moral laws or bad physical descriptions and need to change them. His claim is that all truths derive their strength from a lie about the existence of opposites. So what if selflessness turned out to be the product of a twisted self-interest? What if truth were possible only because of a lie? What if the philosopher and the scientist didn’t find truth so much as construct it with bits and pieces of fiction?

Nietzsche makes that claim in section four:

§ 4

We do not consider the falsity of a judgement as itself an objection to a judgement; this is perhaps where our new language will sound most foreign. The question is how far the judgement promotes and preserves life, how well it preserves, and perhaps even cultivates, the type. And we are fundamentally inclined to claim that the falsest judgments (which include synthetic judgments a priori) are the most indispensable to us, and that without accepting the fictions of logic, without measuring reality against the wholly invented world of the unconditioned and self-identical, without a constant falsification of the world through numbers, people could not live—that a renunciation of false judgments would be a renunciation of life, a negation of life…

Just like most philosophy, science seeks absolute truth. Reproducible results, precise measurements, rigorous logic, the elimination of doubts and of superstitions, unconditional results—these are its hallmarks. Nietzsche seeks truth too, thinks truth is even necessary for life, but his contention is that no truth is unconditioned, which is to say that absolute truths are useful myths.

There’s a lot to unpack in that section, but what I notice first is the way Nietzsche frames his discussion. The promotion and preservation of life usurps everything else. If a perceived truth proves somehow fatal for life—a term Nietzsche will develop throughout the text—if it threatens the health of humanity as a species, then he will denounce it, preferring a falsification that yields vigor, strength, enthusiasm, originality. Nietzsche constantly elevates these kinds of athletic and artistic qualities above the more traditional ones, shifting the philosophical discourse from a desire for truth to a desire for cultivation, strength, and individuality.

This is a major shift, and it entails a deeper corollary: that all so-called truths are actually falsifications in disguise. So it’s not as if philosophers and scientists, through deeper thinking or scientific method, can discover more certain truths and discard the less certain ones. Re-read that section. All logic is a fiction. Apparently unconditioned truths are inventions—even numbers get tossed under the bus.

Consequently, calling any kind of information the truth is meaningless, because even if a particular truth is a functioning, life-affirming one, it’s still also a lie. Nietzsche’s suspicions about the “opposition of values” extends that far.  True and false—no two things could appear more distinct, but here Nietzsche draws them closer, asking what if?

Well, what if all oppositions are illusions? What if all knowledge is built on a lie? What does that mean for philosophy and science?

One of science’s great seductions is that it works. It’s produced penicillin and manufactured jet engines, explained the motions of the stars and described the variety of life on this planet; it shot man into space and made photographing Saturn’s moons possible. How could something that so plainly works be the product of falsification and fabrication? Nietzsche’s contention that some truth could be unappealing or even life-defeating isn’t unusual and it isn’t contradictory. We’ve all heard that “the truth hurts” and anyone who thinks about it long enough might question whether science, as technology, has had a positive or a negative effect on humankind.

To think that Nietzsche would deny the practical results of good engineering, however, seems somehow crazier.

At least, crazier at first glance. When I think about it, I can imagine a scientific explanation that produces practical results, but does not produce an unconditional, universal truth. Modern medicine, for instance, has made it possible to treat illnesses that were once impossible to treat, and this because it has access to more information about what causes illness, how chemicals react in the body, how cells mutate, and so on. Treat the right cause and the effect disappears.

But does this mean that the practice of medicine—and all the associated research—has unearthed some fundamental and unconditional truth?—about biology, chemistry, compounds, atomic elements? Or has it added just another descriptive level to an already complex nexus of data and events that includes everything from feelings of illness to social stigmas about the sick? That one cure works and another doesn’t… that anything works while another doesn’t—is that enough to claim sole ownership of the truth?

The more I consider that possibility, the more ludicrous it becomes. That view reduces truth to a game of identifying causes and predicting effects. We take the predictive power of science to be an indication that we’ve understood something fundamental about a particular subject, which may be true.  But then we extrapolate on that indication and apply the lessons we’ve learned in one subject to numerous other subjects. By that means, we make conclusions about the existence of God using the laws of physics, or we model our understanding of societies on models of the atom. And by this I don’t just mean that we use images from one field to help describe ideas in another. I mean that we take the physical description of the universe as being the fundamental, all-encompassing description over and above all others merely because the physical description produces empirical results that we can measure and use for our own satisfaction. 

And satisfaction is exactly where this post started. “They are all advocates who do not want to be seen as such.” They might be philosophers, artists, or scientists. No matter who proposes it, we can see here how a truth might be built on a lie. Why should we presume that the physical model of the universe is sufficient for describing all phenomena? What rationale do we have for applying the lessons of one science to the questions of another? Is it a lie that such a leap is even possible? Could cause and effect itself be a lie? As a side note, that something good and true could be founded on a lie isn’t an idea original to Nietzsche. Plato either wrote or recorded such an idea roughly 2000 years earlier, in Book Three of The Republic.

I can hear someone asking, “What other kinds of truth, beside the scientific, might there be?” Religious and cultural truths are the first that come to mind. They are not without their own rationale, and some are even based on simplistic empirical observations. Philosophy produces its own truth too. Within it there are many different perspectives about what constitutes truth and even some dispute about whether or not the truth—along with virtue—is something we can learn.

In my next post I plan to look at section 21 and the way it connects with Nietzsche’s view of nature, which is basically that it is unlawful and without order. He calls it “profligate without measure.” His contention in that section, that the notion of cause and effect is itself a convenient fiction, tosses science, along with philosophy, into an even deeper mire.

(Please leave comments if you’ve found this even remotely helpful, or if you think I’ve gotten something terribly wrong. My intent in writing these is not to pontificate, but to work through the book actively.)

the death of socrates


2 Comments

Describing Reality: Philosophy vs. Science

The difference between scientific and philosophical explanations is something I’ve been thinking a lot about in the last couple of years. The popularity of authors like Richard Dawkins and Christopher Hitchens is partially responsible, but I’m also interested in the limits of scientific and philosophic inquiry. Is it possible for neuroscience to tell us something about free will that philosophy can’t? Do the laws of physics tell us more about reality than the study of language or metaphysics?

To answer these questions, we might first ask what philosophical inquiry does that’s different from scientific inquiry. To that end, I’d like to point everyone to The Partially Examined Life—one of the best podcasts on the Internet and a great place to explore different philosophical ideas. Anyone that hasn’t checked it out should change that now.

About this time last year, Wes Alwan wrote a small essay called What Is a Philosophical Explanation? Sounds like a simple enough question, but appearances can be deceiving. Wes does a great job of distinguishing between philosophical explanation and scientific investigation, which is helpful if you’re wondering whether, for instance, physics can tell us more about human behavior than theology. His remarks about conceptual clarity are especially helpful:

In the case of the scientific model the phenomena are clear: Bohr’s atomic model, for instance, explains the frequencies of light produced by hydrogen gas after it has been heated and subsequently loses energy during cooling. The phenomena being explained are not themselves conceptually unclear: if we were unclear as working scientists about what “emissions spectrums” meant or looked like, we’d have to clear that up in order to do our work successfully…

Further: when we develop an atomic theory, we do not have to query atoms about what spectra they’re giving off and wait for them to report back to us; nor do we have to know what it’s like to be an atom or give off spectra. The situation is radically different for psychology and philosophy. My concept “light” does not implicate me in it to the same degree as my concept “sadness.” If I had to get another human being to understand the former, our joint attention to a few cases would be sufficient. But in the case of sadness, pointing to someone crying, or crying myself, would not in itself be a demonstration unless the person to whom I were demonstrating it a) had already experienced sadness and b) knew how to interpret the outward behaviors of others in terms of that experience (i.e., to empathize).

I’ve been meaning to link to this forever, but now that I’m thinking about the difference between science and philosophy, and specifically about the proper limits of the sciences, it is especially relevant. This idea of being “implicated in a concept” applies, I think, to the test I posted about a few days ago, in which scientists hope to discover whether or not the universe is in fact a simulation. Built into that question are all kinds of concepts—like consciousness, reality, and simulation—that may or may not be describable via mathematical means. And yet, I encounter this belief again and again, that science—especially math and physics—gets us closer to reality than, for instance, philosophy or religion. I don’t doubt the value of science, but I do wonder at its application and misuse.

I’ll be writing more about this, but I wanted to get these initial thoughts on the page, and to point everyone to one of my favorite websites. I encourage everyone to check it out.

Rene Descartes


28 Comments

Weird Science: Testing Brains in Vats

I don’t know how seriously other scientists will take this, but according to this article at Phys.org, physicists at the University of Bonn believe they can develop a test that will accurately measure whether or not we are a bunch of brains in a vat. Or just one one brain in a vat. The test would depend upon our understanding of something called quantum chromodynamics, a field of study concerned with the way elementary particles are bound together by different forces.

Anyone with a thorough understanding of high energy physics can check the paper out on the arXiv website. If you can make anything of it, please don’t be afraid to leave a comment. In the meantime, I have to wonder at the idea that this is testable at all. As the Phys.org article notes,

… any conclusions resulting from such work would be limited by the possibility that everything we think we understand about quantum chromodynamics, or simulations for that matter, could be flawed.

The data this test would return would have to be checked against a simulation, unless I’m missing an important fact and there’s something else to check the data against. If that’s the case, we run into the same problem everybody else has run into when pondering this question: how do I know my experiences or my data adequately represent whatever “reality” is “out there?” And if the answer is something like “we have mathematical models that tells us what we should find,” how do we test whether those mathematical models are accurate or reliable?

If all I’ve experienced is this thing that we’re calling a simulation, what can I know about an existence that isn’t a simulation? These are pretty elementary philosophical questions—but none of them have been answered, which is why this article had me raising my eyebrows.

The conceptual setup here is another reason I’m skeptical. It’s not that I don’t understand the concepts (I think I do to a small degree), it’s that I don’t think they’re very clear. That may be the article’s fault more than the scientist’s, but I’m still left wondering how they’d get around some pretty fundamental problems. For instance, what are the simulations they are using simulations of? If I devise a simulation for reality that demands particular results, and then I find that those results match what I see in reality, why should I conclude that reality is a simulation? Why not conclude the opposite and say that I’ve devised a very good simulation of what’s “real?” I get the feeling a lot of this could be cleared up by someone who understands the kinds of simulations they’re talking about, but until I can get a grasp on that, I’m left to wonder.

There’s also a problem of consciousness. My existence is so caught up in the concepts of reality and simulation that I can’t imagine a way to untangle the two. What I mean is that the idea of simulation only seems meaningful from a conscious subject’s point of view. Is it possible this test somehow accounts for consciousness? Is it even possible to think about the difference between reality and simulation without a clear sense of what a conscious subject is?

I know I’m jumping all over the place, but this little article brought up all sorts of questions, and I haven’t thought about these kinds of problems in a long time. As it stands, I can’t help but be skeptical. Not about my existence, but about that test.

from 2001


Leave a comment

The Hubble Extreme Deep Field

By Ethan Siegel, over at Scienceblogs: The Deepest View of the Universe. EVER. – Starts With A Bang. Thinking about it for just a few seconds will make you dizzy:

If you assume that the XDF is a typical region of outer space, you can calculate how many XDFs it would take to fill the entire night sky; it’s about 32 million. Multiply by the number of galaxies you find in the XDF, and that’s how you arrive at about 200 billion galaxies in the Universe.

We’re taking a region of space that has very few nearby galaxies, or galaxies whose light takes less than a few billion years to reach us. We’ve selected a deliberately low-density portion of the nearby Universe. The XDF has found many more galaxies whose light has traveled between 5 and 9 billion years to reach us, which are relatively dim galaxies that the HUDF simply couldn’t pick up. But where it really shines is in the early Universe, at finding galaxies whose light has been on its was for more than 9 billion years, finding the majority of new galaxies there.

But even the XDF is not optimized for finding these galaxies; we’d need an infrared space telescope for that, which is what James Webb is going to be. When that comes around, I wouldn’t be surprised to find that there are maybe even close to a trillion galaxies in the Universe; we just don’t have the tools to find them all yet.

You can find multiple resolutions for the XDF image, along with more technical information and a brief explanation of what you can see in the image, by visiting Hubblesite.

Hubble XDF image

Credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team