Our Home

To my conservative friends and family,

I know we disagree on most everything, and these days virtually every one of us, whether we're liberal and conservative, feels like the other side has either 1) been grossly misled by our respective, biased media outlets, or 2) harbors deep antipathy towards the country or to some of the people in it who are not like us. So we have this vast political chasm between us, and it seems hopeless to bridge the gap. We all acknowledge that this is a sorry state of affairs but we just can't fix it. Even so, we remain friends and family, we love each other and we respect each other. We're not going to give up most of our firmly held political views, but we can attempt to listen to each other, trust that our friends and family aren't bad people or stupid people, and every now and then consider that our side maybe has it wrong on something. I certainly do that.

There are many political debates upon which there can be reasonable disagreement. But there can no longer be any rational defense of the position denying that the Earth is warming and that we are causing it. We can debate what is to be done about this situation, but that fact is simply undeniable. Anyone in public office or in the media who says otherwise is either willfully ignorant of the facts or is misleading the public in a way that I believe is truly criminal. And the motive for this could not be more clear: they are either shills for the corporations who fund their campaigns / television programs, or they are pandering to their constituents whose lives currently depend on the fossil fuel industry. While the latter is at least somewhat in line with their duties, the former is simply reprehensible.

We can and should debate the best way to go about mitigating the problem, to do it in a way that strengthens the economy and supports those who must transition to a new line of work. But that requires we all first acknowledge that there is a real problem that must be solved. And once we've done that, we have to keep our eyes on the big picture; transitioning to a clean fuel economy will take some adjustment, no doubt. But so much is at stake. Mass extinctions, permanently flooded cities here and around the world, enormously destructive storms, severe drought and wildfires, radical ecological transformations, major economic upheaval. It's all happening right now.

Under the two party system there can be any number of policy issues on which a partisan can disagree with his or her party. And so there must be Republicans out there who believe global warming is a real threat and want their politicians to stop denying science. Republicans now hold all the power in Washington, so it's up to those inside the party to stand up and do what's right. If you are a Republican who knows the party is wrong on this issue, I beg you to work from within to end this dreary charade.

And to those of you who do not yet believe in global warming -- because it will become even more apparent in the years to come -- I humbly ask that you look again at the weight of the evidence and reconsider your position. Just consider the possibility that it isn't a vast left wing conspiracy, that there are real people (scientists) who do their job diligently and faithfully follow the data wherever it leads. Consider the possibility that Sean Hannity and Jim Inhofe and Scott Pruitt have more to gain from lying to you than The Weather Channel does. Consider the possibility that we are perpetuating an environmental disaster that will make us all pariahs in the eyes of our children and grandchildren. 

We have just one planet to call home, to cherish from now until the extinction of our species. I pray that we have an ocean of time ahead for us. Let us be good stewards of this lovely world while it is ours to protect. Please.

Regarding our paper, "A Cloaking Device for Transiting Planets"

This week you may have seen articles about a paper Professor David Kipping and I wrote called "A Cloaking Device for Transiting Planets." If you feel so inclined I would encourage you to read the paper itself (rather than the somewhat accurate but largely incomplete coverage it's gotten in the press). As far as scientific papers go I think it's quite readable for a scientifically literate public audience. It was decidedly outside our main research foci but we whipped it up in very little time while we continued working on other projects. We had a lot of fun with it and I believe it is a worthwhile addition to the SETI literature.

On the whole I have been thrilled with the response that we've gotten. The paper has been discussed on Space.com, the BBC, Popular Science, Discover Magazine, Scientific American, and Gizmodo, to name just a few. The story blew up on Twitter, and our explanation video has garnered more than ten thousand views so far. We've reached readers all over the world, and for myself I think it is an unambiguously positive thing to get a non-scientific audience thinking about exoplanetary science, the search for extraterrestrial intelligence, and whether we ought to try to make contact or, by contrast, try to hide ourselves. For many people it takes something a little provocative to make them pay attention to science and I'm delighted our work got their attention.

Our paper explored the energy requirements of using lasers to distort a transit signal for the purpose of communicating with or cloaking one's presence from an observer in another star system. Crucially, we suggested that other civilizations could be doing this to their transit signal right now. We found the energy requirements to do this for the Earth were remarkably low, within the capabilities of today's technology, and we therefore made the case that an artificial transit profile is very easily achieved by other civilizations and could thus be detected in transit data. Importantly we made no statement about whether we ought to cloak or ought to broadcast our own presence, though many media outlets seemed to think we were advocating for the construction of such a device. We simply ran the numbers and put it out into the world for others to chew on.

Of course we knew that the most provocative aspect of our paper was the notion that we could build a cloaking device for our own planet, and the paper uses the Earth as a concrete example of how one might achieve a transit cloak. We opted to title the paper "A Cloaking Device for Transiting Planets" in part because we knew this aspect would get the most attention and that meant more readers. I suppose we could have called it "A Cloaking and/or Broadcasting Device for Our Planet or Other Planets", but I think the title we went with is the strongest.

I think in retrospect we could have stressed to journalists a greater emphasis on the idea that this is something other civilizations might be doing right now, that we might be able to see signals in the data that could tip us off to other intelligences out there. (Interesting to note: once we realized the main thrust of our paper was getting lost in the mix we doubled down on emphasizing it, but those quotes were routinely left out of the coverage). We see the paper as essentially a SETI paper, but clearly (and understandably) public attention has largely focused on building a cloaking device for the Earth. And while we as science fiction geeks share a kind of enthusiasm for futuristic concepts like a cloaking device for the Earth, I think it's safe to say that as scientists we share the skepticism about the necessity for building such a device on the Earth, at least right now.

Nasty comments about us and our work in the comments sections of the various articles were inevitable, and I certainly don't take them to heart because I stand behind our paper and I know that they've gotten an incomplete picture of our work. Many people lamented the waste of money, though we haven't spent a public dime on this paper. We haven't built anything and there are no plans to do so, and we are both paid through a private institution where we work on a variety of projects. Others suggested we had "a lot of time on our hands", but the truth is David thought up and wrote the core of the paper over the course of a single weekend (when most people are catching up on Netflix), and I'd estimate I spent maybe 10 hours on my part of the paper. We spend the vast majority of our time working on "serious" scientific projects that get much less attention. In any case I suspect that many people making these comments about our paper hold similarly dim views towards other high-profile science projects like the detection of gravitational waves with LIGO or the discovery of the Higgs boson at CERN -- both "serious" science projects that come with very hefty price tags.

I have been more surprised by the negative response from some astronomers, particularly SETI astronomers. I understand that astrophysicists roughly fall into two camps: those who think the search for life elsewhere is a major motivator behind our investigations of the Universe, and those who are really just interested in understanding the physics of the Universe. I of course fall into the first group, but to each their own. Even so I am puzzled by the negative response from those astronomers who actually work on SETI topics. You'd think they would share our enthusiasm for a new potential signal in the data. But I am almost certain that none of them actually read our paper before commenting on it. They may have read an article or two about it, and maybe got a skewed take on it from a journalist calling for a quote. (I've learned that the propagation of information in the media can sometimes be like a game of telephone... the second article borrows from the first, the third from the second, and so on... in the end the information can be wildly distorted). 

Perhaps those critical astronomers think that our paper is less science and more science fiction, but that same criticism is often levied at SETI projects. Or perhaps they think that a paper like ours detracts from "serious" science in the eyes of the public. But again, those in the public who might think our work is a waste of time would probably also balk at the money and time that goes into, say, studying the structure of the Cosmic Microwave Background, and we don't shy away from those investigations for fear of those who don't share our enthusiasm for learning about the cosmos.

The criticism has not be universal, thankfully; our paper has received support from a number of astronomers in the community, including some high profile scientists. I think Professor Avi Loeb at Harvard said it best in the Space.com article:

"If there is a literature of ideas like this one, ideas that people proposed for potential signals that are artificial -- the richer the literature is, the better it is. [...] The moment we find something artificial, it will change everything. It's good to have the imagination at work prior to seeing something unusual, so we are aware that there are possibilities beyond what we expect."

From the beginning we have believed that the question of how we might detect extraterrestrial civilizations, as well as the question about broadcasting or hiding our presence, is a worthwhile question to explore and is something we want the public and scientists alike to think about. Insomuch as our work has sparked that conversation around the world I think we have achieved our objective and then some. And I'll argue as much to any scientist or member of the public who thinks our work lacks merit. Public engagement with science is critical, and papers like ours engage the public imagination in a way many esoteric studies simply cannot. It's also imperative that we not shy away from exploring big questions even if some people fail to see the value. And as for the question of finding extraterrestrial intelligence out there, I continue to believe that such a discovery would be one of the most important of all time. If our work means we're playing even a small role in that process of discovery, I'll be very happy indeed.

"If there is a literature of ideas like this one, ideas that people proposed for potential signals that are artificial — the richer the literature is, the better it is," Loeb said. "The moment we find something artificial, it will change everything. It's good to have the imagination at work prior to seeing something unusual, so we are aware that there are possibilities beyond what we expect." - See more at: http://www.space.com/32423-laser-cloak-could-hide-earth-from-aliens.html?cmpid=514648#sthash.OkDcQDgN.dpuf

"If there is a literature of ideas like this one, ideas that people proposed for potential signals that are artificial — the richer the literature is, the better it is," Loeb said. "The moment we find something artificial, it will change everything. It's good to have the imagination at work prior to seeing something unusual, so we are aware that there are possibilities beyond what we expect." - See more at: http://www.space.com/32423-laser-cloak-could-hide-earth-from-aliens.html?cmpid=514648#sthash.OkDcQDgN.dpuf

"If there is a literature of ideas like this one, ideas that people proposed for potential signals that are artificial — the richer the literature is, the better it is," Loeb said. "The moment we find something artificial, it will change everything. It's good to have the imagination at work prior to seeing something unusual, so we are aware that there are possibilities beyond what we expect." - See more at: http://www.space.com/32423-laser-cloak-could-hide-earth-from-aliens.html?cmpid=514648#sthash.OkDcQDgN.dpufFrom the beginning we have believed that the question about broadcasting or hiding our presence, as well as the question of how we might detect extraterrestrial civilizations, is a worthwhile question to explore and is something we want the public to think about. Insomuch as our work has sparked that conversation around the world I think we have achieved our objective and then some. And I'll argue as much to any scientist or member of the public who thinks our work lacks merit. Public engagement with science is critical and we shouldn't be shy about exploring big questions even if some people fail to see the value. And as for the question of finding extraterrestrial intelligence out there, I continue to believe that such a discovery would be one of the most important of all time. If our work means we're playing even a small role in that process of discovery, I'll be very happy.

On the Occasion of New Horizons' Historic Rendezvous with Pluto

Image of Pluto captured by New Horizons on July 7th, 2015 at a distance
of ~5 million miles.

In a few short days the New Horizons spacecraft will arrive at Pluto. After a nine year voyage, traveling faster than any vehicle before it, the spacecraft's rendezvous understandably has the internet and the scientific community buzzing. Pluto has been a source of fascination since it was first discovered in 1930; the last outpost before you reach interstellar space, Pluto has been the doleful guardian at the edge of the solar system. Until very recently it was nothing more than a point of light in our most powerful telescopes, but in the last several months we have seen tantalizing images of the binary planetary system, and we are almost certainly in for some big surprises when we finally arrive. I can't wait to see the surface up close.

A great video was posted on the New York Times website a few days ago, highlighting the New Horizons mission and interviewing astronomers and planetary scientists about the meaning of the Pluto encounter. In the video the mission is framed as the end of an era, the final voyage to complete our 50-year reconnaissance of the Solar System. And in a sense it's true; we have visited all the major worlds, as well as a few minor ones, and Pluto is the last stop on the traditional tour.

All the same that felt funny to me saying we've completed our reconnaissance of the Solar System. I have always defended the 2006 IAU decision to reclassify Pluto as a dwarf planet... not because the definition isn't problematic, but because the classification begs the question, "why is Pluto a dwarf planet?" The answer of course is that there is a whole host of other worlds out there, equally real and equally exciting, that you just didn't get the chance to learn about in fourth grade because no one knew they were there! There is Eris, Orcus, Quaoar, Haumea, Makemake, and distant Sedna on its highly elliptical orbit-- to name just a few of the more prominent Kuiper Belt objects. Why should Pluto get all the glory? It seems to me that for many people nostalgia for the wonder they felt as a kid trumps the wonder of what is to come, the wonder of the unknown. But these worlds await our exploration! There is so much left for us to discover. And lest you think that if you've seen one, you've seen them all, consider the curious array of moons that orbit Jupiter and Saturn. There is an astonishing variety of worlds in our Solar System, and there is good reason to think that what we will find in the coming years in the depths of Trans-Neptunian space will be startlingly different than what's come before.

Still, even if this isn't really the end of our forays into deep space exploration, it is indeed the end of an era. This will be the last time for a very long time that we see a mission to the outer solar system. There was a thirty year gap between the launch of New Horizons and the launch of Voyager, the last spacecraft to venture out beyond Saturn, and there are no real plans in the works for anything to follow along these lines. Will it be another thirty years until we take another shot at exploring the vast depths of our own Solar System? If so we cannot expect any more close-up images of these worlds until about 2050 or so. So better soak it up while you can. Of course we can hope that next-generation telescopes, ones currently under construction or in the planning phases, will yield in the years to come imaging of the distant dwarf planet retinue spectacularly better than present technology, but even then we'll have to wait at least a decade or so for those to come online, and we cannot expect anything like the breathtaking detail that's in store for us with the Pluto flyby in a few days.

Astronomy tends to be that way: we're always looking at what's coming next, but we usually have to wait an awfully long time for it to come. It's the combination of budgetary restrictions, the limited supply of expertise, and the extensive planning involved that makes space missions and revolutionary telescope projects take so long. In science it often happens that scientists work for many years on a single project, and in some cases a scientist will die before he or she see the fruits of that labor. In a sense that's true of every scientist, as the work always outlives the man or woman behind it, and proves useful to the next generation long after they've gone. You might feel a bit sad to think about those scientists never getting to see what wonders may be wrought from their work, but for myself I find it to be humbling, and invigorating. We are all just a small piece of this puzzle, but we are part of a collective enterprise that will be making remarkable discoveries and improving our understanding the universe long after we've turned to dust. So long as we humans can preserve our way of life, the body of scientific knowledge will be ever increasing, and each little contribution lives on.

I will always be impatient for the next mission. I can't wait to see probes sent to Europa and Titan and Enceladus. I can't wait to see a manned mission to Mars. But the anticipation is also thrilling. It spurs the imagination and generates wonder in a new generation of scientists. We have to leave some mysteries for the future, after all.

For now, Pluto is the present we get to open in a few days. It's been a long time coming, and it's going to be spectacular.

-----------------------------------------

Thanks for reading, and staying with me during this rather long hiatus. I'm rarely moved to write much these days, but I remain active on Twitter (a much less demanding medium) so please follow me there if you feel so inclined. In any case, I hope to get back to writing more regularly, one of these days.

Mentors in Science -- Carl Sagan's Lingering Influence

Check out my appearance on WNYC's The Takeaway with John Hockenberry.  Loads of fun.  I was pleased to share the radio with Emily Rice (Astrophysicist at College of Staten Island and the American Museum of Natural History) and Seth Redfield (Professor of Astronomy at Wesleyan):

Answers for Creationists

Last night Bill Nye faced off with Ken Ham (of Answers in Genesis fame) in a lengthy debate over creationism and science.  I caught only the last half hour or so, and unfortunately I found it to be less-than-illuminating.  Perhaps it was the sheer exhaustion of such a long debate, but by the time I tuned in I found Nye's answers to be a bit rambling and failing to adequately address the implications of the questions (he gave an admirable explanation of the Second Law of Thermodynamics, for instance, but he failed to point out the fallacy of the question's crux).  Nevertheless, I admire Nye for his willingness to go into the lion's den and speak science to those who would ordinarily have no interest in it.  

This morning BuzzFeed provided a photo series of creationists with their questions for Bill Nye.  Obviously I am not Bill Nye, but as a scientist I thought I could try to answer them.  It's interesting looking at these photographs... none of these people strike you as unintelligent, back woods people with their heads in the sand.  They appear perfectly capable of listening to rational arguments, so it isn't necessarily a fool's errand trying to answer their questions.  Anyway, here goes:

1. Bill Nye, are you influencing the minds of children in a positive way?

Science education is unambiguously positive for children, even in cases where the science curriculum may be at odds with your personal beliefs.  We live in a complicated world, where people hold a wide variety of views, and it is no service at all to shield children from such disagreements.  As Carl Sagan once said, "science is more than a body of knowledge, it's a way of thinking."  The idea is, we look at the world and question it, try to make sense of it, refuse to take things at face value or blindly follow authority.  The great thing about science is, it's open to everyone.  If you think a scientific theory is in error, you have every right to test it and try to overturn it.  But for your work to be accepted by the scientific community, it must be rigorously tested, independently verified, and shown to be in good accordance with the facts.

Science is not about indoctrination.  Quite the opposite, in fact.  Skepticism is crucial for the process, so there is absolutely no problem at all with students who do not fully trust a science teacher simply because he or she says something is true.  The key is, though, this sort of skepticism must be brought equally to every assertion about the origin of our Universe, or the origin of species.  It is not good science to be skeptical of what is taught in the science classroom and then to turn around and not show equal skepticism of what is taught in the church.  If you are truly interested in finding the answers, you must question boldly even your most cherished beliefs.

Our Choice

It's common these days to hear global warming skeptics admit that climate change is real, but doubt humanity's impact on it.  The advocates of the do-nothing approach are these days no longer able to deny the fact of climate change, so they are forced instead to spin the remaining uncertainties.  In so doing they have set upon a classic bait-and-switch that aims to confuse those who are not well versed in the physics of the environment.  To admit global warming is real, and then to turn around and question the scientific consensus on its cause, is for some people a kind of reasonable middle ground, a halfway point that is appealing because it's conciliatory.  Unfortunately, it's just wrong.

Sometimes you will hear it said that the evidence is ambiguous.  It is not.  More than one hundred years of study, on perhaps the most pressing issue in science, points to a clear correlation between rising CO2 levels, rising temperatures, and the explosion of the human population in the last 150 years or so, coinciding with the industrial revolution.  For the entire history of humanity -- hundreds of thousands of years or so since the dawn of what we typically call a human -- the population was very low.  It was not until the mid-19th century that the population reached 1 billion people.  Today, it is more than 7 billion.

This exponential rise in the human populations begins at the beginning of the industrial revolution.  And as our lives improve, our population swells, and our technology enjoys an exponential growth.  In short order we are able to produce millions upon millions of machines that spew obscene amounts of carbon into the air.  This carbon remained below the Earth's surface for millions of years -- deposited over millions of years -- but today we are devouring it at an insatiable rate, dumping our waste products into the air and into the ocean.  There is no natural mechanism that could have released such enormous amounts of carbon into the environment all at once.  It required the human catalyst for rapid change.

Kicking the Gasoline Addiction

Even as the US economy seems to be turning a corner, gas prices are on the rise, and as Americans feel the pain at the pump President Obama's approval numbers are sinking.  Both sides have used gas prices as a political football in the past, blaming opponents for high prices and taking credit when prices are low.  In 2008, we'll recall, there was much talk about gas prices, and of course President Bush, supreme master of failure in the eyes of Democrats, was chiefly to blame.  Now it's Obama's turn to face the wrath of the gas-addicted public, and round and round we go.

The truth, as most economists will tell you, is that the president has little real control over gas prices.  Sure, he can tap the strategic oil reserve, and if we had a President Gingrich, we could open every square mile of offshore and wildlife preserves for drilling.  But such efforts would still have a small, and quite delayed effect, and of course they are short-sighted solutions to persistent, long-term problems.  The true fallacy of "drill baby drill" was that increased drilling could have precisely zero influence on the gas prices of 2008, or 2012 for that matter.  In reality, gas prices are controlled by the price of oil, and as this is an international market, the president has virtually no say in the matter.

In an excellent article at Business Insider,  USC marketing professor Ira Kalb argues that oil companies have been ingenious in their ability to hike prices to record levels, even in the midst of a struggling economy, all while raking in record profits, enjoying enormous tax breaks, and skirting their promises to invest in alternative energy sources.  The oil companies have convinced us, Kalb says, that they need subsidies from the government to help keep gas prices down, when in reality the price of oil is solely under their own control.  In essence, they invariably maintain an illusory shortage of their product to keep prices high, so that the money will keep rolling in and they can keep funding politicians who will protect their tax breaks.

But what can we do?  According to a 2007 study from the Department of Transportation there are approximately 254 million passenger vehicles in the United States.  The vast majority of these cars burn that sweet unleaded fuel.  And here in the US, much to the chagrin of utopians, public transportation is largely not a viable option to reduce gasoline consumption.  Sure, the big cities like New York get along quite well with a robust metro transit system, and of course public transportation seems to work well in Europe.  But we are not nearly as densely populated as Europe (for comparison, if the United States had the population density of Germany, we would have about 2.2 billion people living here instead of 313 million).  So while there are some places for which public transportation is effective, there are vast expanses of land where building trains or running buses is just not workable.

As the population expands we will need more energy.  This energy demand, short of some unimaginable global catastrophe, will never go away.  It's clear that fossil fuels, though still fairly abundant at present, are finite resources that will ultimately give out.  These resources can never be replenished on any reasonable timescale, and we are burning through millions of years' worth of carbon over the course of just a few decades.  The Earth is large, but just as a microscopic virus is capable of taking down very macroscopic creatures, so too can we have an outsized influence on the fate, and resources, of our planet.  There's no question that we are well on our way to depleting Earth of its fossil fuels. 

So why are we so reluctant to ween ourselves off this addiction that we all know has to be kicked?  We can blame myopia, inertia, vested interests in the status quo, and the comfort of the familiar.  We are like children who fail to understand that sucking a thumb, while perfectly normal as a toddler, will be totally unacceptable as an adult.  Just as children are incapable of fully understanding the world of adulthood that awaits them, so we are trapped by our own inability to see what the world will look like, say, 100 years from now.  Most of us have a rosy vision of the future, and perhaps we think it will simply appear without any effort by us or our children.  But the truth is, we build our future, and we have to start laying the foundation now.  The alternative is stark: perpetual reliance on OPEC and the like.  

You'll notice we've not even addressed the obscene effects on the environment caused by burning fossil fuels.  The tragic neglect of our planet is among the most pressing of human problems, and it must be addressed.  But a sizable portion of this country thinks climate change is a hoax.  So what will convince them it's time to get off gas?  Maybe the pain at the pump will do it.  We are slaves to the manipulated markets of oil.  Only by diversifying our energy sources can we hope to end the monopoly that eats into our pocketbook at a time when so many are struggling.  But of course you can't put a wind turbine on your car!  What's the solution?

God and the Science Classroom

In a recent interview with the Nashua Telegraph, Republican presidential candidate Rick Santorum was asked about teaching creationism in schools.  In a familiar tone, Santorum claimed that there is a fear, on the left and in the scientific community, of talking about God in the science classroom because of a kind of political correctness, and a sense that, in spite of its awesome explanatory power, the notion of a creator has been arbitrarily considered off-limits to inquiry.  Here's his exact quote:

There are many on the left and in the "scientific community," so to speak, who are afraid of that discussion because oh my goodness you might mention the word, God-forbid, “God” in the classroom, or “Creator,” or that there may be some things that are inexplainable by nature where there may be, where it’s better explained by a Creator, of course we can’t have that discussion. It’s very interesting that you have a situation that science will only allow things in the classroom that are consistent with a non-Creator idea of how we got here, as if somehow or another that’s scientific. Well maybe the science points to the fact that maybe science doesn’t explain all these things. And if it does point to that, why don’t you pursue that? But you can’t because it’s not science, but if science is pointing you there how can you say it’s not science? It’s worth the debate.

There is, of course, nothing surprising about Santorum's argument, he's made it many times before.  Science curricula are probably not terribly threatened by his candidacy -- he's polling in single digits at present -- but still, his views reflect those of a large section of our country, and the question is often posed.  Why, exactly, can't God be a part of the equation when it comes to science classes?

Why Search For Life?

The search for life elsewhere in the universe is among the most awesome of scientific endeavors.  For the first time in the 4.5 billion year history of our planet, creatures from the Earth are now plumbing the depths of space in search of our neighbors.  It is a daunting and frustrating job: the vast distances between our solar system and others, the sheer number of stars that must be surveyed, and the complicated set of circumstances required just to allow for the possibility of life on another world, make the work exceedingly difficult.  Even as we have become accustomed to the idea of extraterrestrials through the science fiction of our time, and have made the most breathtaking discoveries about the cosmos, there are those who deride the search for life as mere fantasy, a waste of taxpayer dollars.  Meanwhile, there are some enthusiasts who persist in the delusion that intelligent extraterrestrials are probably close-by; hiding on the Moon, perhaps, or on Mars.  Such 19th-century thinking may be responsible for some disillusionment when it comes to genuine searches for extraterrestrial life, slow and painstaking as they are.  In light of the fact that interstellar travel will almost certainly not happen in our lifetime, there is a kind of exploration defeatism.  If the aliens are not reachable in our time, so the thinking goes, is it even worth trying to contact them?

Juno sends us another Pale Blue Dot

The Juno spacecraft, recently launched on its 5-year voyage to Jupiter, just snapped this picture of the Earth-Moon system from a distance of 6 million miles.  What a lovely and vulnerable pair.

It's worth quoting Carl Sagan:

"That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known."

-------------------
You may have noticed a dearth of postings recently.  I'm afraid it's been a busy summer, and will likely be a busy fall.  In light of this, some postings will be shorter than has been typical of late, but hopefully I'll be able to write a little more often this way.  I hope you will continue to find the content satisfactory.  In the meantime, be sure to follow me on twitter.

Farewell to the Shuttle

Today the space shuttle launched on its 135th and final mission.  When the four astronaut crew of Atlantis arrive back on Earth just two weeks from now, a complicated chapter in human spaceflight will draw to a close, and then, for better or for worse, we will have plenty of time to ponder its place in history.

For the next several years, American astronauts will have to hitch a ride aboard Russian Soyuz rockets to visit the space station largely funded by US taxpayers.  In just two weeks, Russia will become the only nation on Earth in the business of launching humans into space on a regular basis.  But after a few more years, hopefully, Americans will be flying into orbit atop commercial spacecraft, and NASA will be well on its way toward the goal of sending human beings far beyond low-Earth orbit, to an asteroid, and eventually to Mars and its moons.

But the future of manned spaceflight is by no means written, and the legacy of the space shuttle's successes and shortcomings looms large.  Conceived during the Apollo era, finally launched for the first time in 1981, the space shuttle never quite lived up to its promise of routine spaceflight.  It was a technological triumph -- an elegant, reusable space plane capable of delivering large payloads and even retrieving spacecraft to bring back to Earth.  But in a way, the seemingly unadventurous nature of its work sapped the energy out of America's appetite for space exploration.  The higher-than-expected costs, and the tragic loss of two crews in 1986 and 2003, made us question whether the whole endeavor was really worth it.  Even as the shuttle's unique capabilities allowed us to service the Hubble Space Telescope five times in Earth orbit, and delivered many sections of the now magnificent International Space Station, the shuttle program came to be seen by many observers as a waste of time, a holding pattern of sorts.  We had made some daring ventures into the abyss, landing 12 men on the Moon, and then we spent 30 years orbiting the Earth, again and again and again and again.

To say that flying the shuttle was not a daring enterprise is a step too far.  Spaceflight of any kind is an extraordinarily complicated venture, where the slightest malfunction can result in catastrophic failure.  The Challenger and Columbia disasters are a testament to the true hazards of human spaceflight.  But with the advent of the shuttle program, NASA's mission slowly diverged from the dreams of its financiers, and in failing to hold the imagination of the public, what was arguably the main driving force behind human spaceflight -- the itching desire to explore the frontiers first hand -- withered with each successive flight.

By and large, in the 1960s America was not terribly interested in geological discoveries on the Moon.  The Apollo program was not really about science, and for most people, the science was probably of tertiary concern.  Politically it was about beating the Soviets, for sport and for security, but viscerally, we recognized its deeper meaning.  To walk on the Moon, that rock that has circled serenely above us for billions of years, never once lighted upon by creatures from the Earth, was truly a moment for the ages.  Never again would it be an untouched world, forever would it bear the footprints of humans.  It was arguably the crowning achievement of human technology.  But after only 6 successful landings, we pulled back to plan our next move.  The Russians were working on space stations, so we had to get into that game, too.  In a sense, the very thing that had driven us to such great heights in the age of Apollo  -- competition with the Russians -- drew us back to spend the next three and half decades orbiting the Earth.  Meanwhile, dreams of a rapid expansion of space exploration, with moon bases and Mars landings, largely evaporated.

Still, the space shuttle was and is the greatest vehicle ever built for low-Earth orbit operations.  But perhaps it was always doomed to live in the shadow of Apollo.  The splendid optimism of space exploration in the 1960s, the breathtaking speed at which we achieved our goals, the seemingly limitless possibilities, gave way to the static pessimism and cutbacks of the 1970s and 1980s.  Perhaps Apollo was just the high that we could never hope to achieve again.

In spite of all this, I will miss the space shuttle.  It has served us well, and the 355 brave astronauts who have flown on the shuttle have done important work -- conducting a host a valuable zero-gravity experiments, launching interplanetary spacecraft, repairing satellites, and ushering in a new age of international cooperation in space with the Mir and ISS programs.  But the shuttle's retirement is a necessary part of moving on to the next mission.  If there is something to lament, it should not be the end of a program that by any standard has gone on a bit too long; rather, it is the wide gap between STS-135 and the launch of the next manned American space vehicle.  That remains four or five years away, and the way forward is a little murky.  Funding for manned space flight is in limbo, though it always seems to be.  But as Congress wrestles with the White House over the money and the mission, we will cool our heels while Russia takes our astronauts up at $63 million a ride.  Perhaps we will feel the itch again in the meantime.

The so-called Commercial Crew program seems to be the right way forward.  If we are to make manned orbital flights truly routine, as we should hope they will be one day, commercial operations are the next logical step.  The resources at NASA are to be refocused on missions beyond the Moon, to an asteroid in 2025 and to Mars in 2035.  There's good reason to suspect those dates may slip, as firm deadlines don't seem to mean quite as much as they did in the 1960s.  We have set our sights on new horizons, but it will take sustained effort to meet those goals.  Spending the next four or five years languishing without a manned space program of our own may frustrate the public just enough to renew our desire to explore.

At first glance, the time frames involved with going to an asteroid and eventually Mars may seem terribly timid.  But we should not forget that going to an asteroid, let alone Mars, will be a spectacularly difficult exercise, for which we are just beginning to design serious plans.  The Mars landing, recently described by The Economist as the "El Dorado of space exploration," will require preparation and design of unprecedented sophistication.  We have not yet even managed a robotic sample return mission from Mars.  Sending astronauts across the interplanetary gulf separating Earth and Mars will be far more dangerous than crossing the mere quarter-million miles from the Earth to the Moon.  In fairness to NASA and the shuttle program, dreams of a Mars landing very shortly after Apollo were probably far too optimistic.

So, here we are.  Will we press on to greater voyages, sending out at long last our cosmic argonauts to plumb the depths of interplanetary space?  Or will we wait for the next generation to pick up the mantle we have borne just a little way from where we started?

Time will tell.  In the meantime, we say farewell to the space shuttle.  Good luck, Atlantis.

Still Here

Well, good news.  We survived the rapture.  Or rather, we survived saturday.

It turned out to be a pretty nice day, actually.  I was invited to three rapture-themed parties, and we all had a good laugh about the May 21st doomsday prophecy of Harold Camping, the 89 year old charismatic responsible for the apocalyptic prediction.  Between the throng of Camping's followers spreading the word around the globe, and the habitual jokesters of social media reveling in the absurdity of the prophecy, it made for quite a phenomenon.

But in the wake of this mirthful saturday, Camping's followers face a brutal reality.  Some have alienated their families, others have left their jobs, still others have liquidated their assets to warn the world of their imagined catastrophe.  Many of us have wondered what we might do if we knew the world were coming to an end.  In Camping's followers, we have some experimental evidence.  And the question now is, what's next for these disappointed followers?  Will they lose their faith in Camping?  Will they lose their faith in God? Or will they delude themselves into thinking that somehow the events of saturday (or more accurately, the non-events of saturday) are some kind of confirmation for their worldview?  No doubt reactions will be diverse, but it will be interesting to watch.  There have been many religious leaders who have predicted the end of the world, but few have gained so much traction as this one.  Where many apocalyptic groups have lived on secluded compounds, Camping has managed to foster a global following.

But how could such a prophecy capture so many minds?  Why are people so willing to trust in these sorts of far-fetched scenarios, when the same people are so dubious about scientific findings backed up by massive amounts of evidence?  That question may be too large to answer here, but we can tease out some explanations.

On Earth Day, Dreaming About The Future

Photo from the Galileo spacecraft, 1990.

I grew up with dreams of a dazzling future.  As children of the 20th century, I'm sure most of us did.  The future of my imagination had computers you could talk to, fabulous portable electronics, video phones, virtual reality, and people living in space.  Indeed, some of those dreams have become a reality.  In our time we have seen some remarkable technological advances -- the explosion of the internet, the dizzying leaps in computing power, the ubiquity of powerful personal electronics, and breathtaking discoveries in medicine, astronomy, and cosmology, for instance.  In spite of recent economic stagnation, there is the persistent sense that our best days are yet to come.  The future of our dreams holds untold technological wonders.

This future, of course, is predicated on the consumption of power.  Lots of power.  The technologically sophisticated lifestyles we have come to enjoy will require an unending supply of energy, on an enormous scale.  In 2005, the United States alone consumed about 100 quadrillion BTUs, roughly the energy contained in 800 billion gallons of gasoline or 3.6 billion tonnes of coal.  Annual world consumption is on the order of 450 quadrillion BTUs, and with the world population climbing ever upward, it's easy to see that the demand for energy will continue to swell.

But there's a problem.  Our power consumption is responsible for an obscene level of carbon emissions which threaten to alter the climate of the Earth, causing violent storms, coastal flooding, the destruction of ecosystems, the acidification of the oceans, and the widespread extinction of many species, which may have a profound impact on the food chain.  Fueled mainly by coal, oil and natural gas, this level of consumption is unsustainable at best, and extraordinarily reckless at worst. 

On Earth Day, much is made about the need for conservation.  Not only should we recycle and do what we can to minimize pollution, but we should also cut down on our energy consumption.  That's a great idea, and in 2011, that's what you must do if you're serious about saving the planet.  At a time when there is heartbreakingly little political will to make big changes in our energy economy, the only way to reduce our environmental impact is individual responsibility.  Earth Day is an important part of spreading that message, making sure people know what they can do to make a difference, but it may do little toward convincing the millions of Americans who are decidedly hostile toward environmentalism.  And so, even if every environmentalist in America were to minimize their carbon footprint, half of the population might persist in unchecked consumption. 

What is troubling about the energy conservation message, and what is understandably so unattractive to those on the right, is the austerity. 

The Clarity of Embarrassment.

Yesterday I sort of embarrassed myself in front of thousands of people in the twitterverse.  It might not have been such a big deal, but it was a lapse in critical thinking, and since this blog puts a lot of emphasis on skepticism, I couldn't help but feel like a fool.

Let me explain.  Yesterday, Richard Wiseman, author of an excellent blog featuring fantastic optical illusions and puzzles, posted a irresistible magic trick on his twitter page.  He invited readers to select one of five cards -- as he labeled them: 9C, 2H, 5C, 7D, and 10S -- and then he asked you to click on this link to see if he guessed it correctly.  Try it now... did it work for you?

Skepticism!

In case you were wondering, yesterday's post, "The Awesome Implications of Narwhal Telekinesis," was just an April Fool's joke.  I hope you enjoyed it.

The Awesome Implications of Narwhal Telekinesis.

In case you missed it, there's BIG news in the world of cetology.  Dr. Sven Sorensen of the Danish Research Institute for Whales, Dolphins, and Porpoises, has just announced a finding that will fundamentally alter our perception of our mammalian cousins in the sea.  NOAA is providing updates as they become available, be sure to follow them here.

Since 1988, Dr. Sorensen has been the world's leading expert on the narwhal, a tusked whale native to arctic waters, resembling something like a beluga crossed with a unicorn.  These fascinating creatures have remained somewhat of a mystery until recently, when Dr. Sorensen made a startling discovery.  You see, we've always known that whales are smart.  As mammals, they teach their young as we humans do, they engage in play and even problem-solving.  But no one could have expected what Dr. Sorensen has just discovered.

The MESSENGER Mission

Last night, as much of America was no doubt tuned in to the drama of NCAA basketball, I was pleased to be engaged otherwise.  I just couldn't miss the big event.  At 8 o'clock eastern time, NASA television carried live coverage of the MESSENGER orbit insertion maneuver (OIM), which was to be the first time any spacecraft has ever orbited the planet Mercury.  It was a critical moment for the mission -- perhaps the most critical of its 6 1/2 years in flight -- and there was only one chance to get it right.  Had the OIM burn failed, the spacecraft would have whizzed by Mercury, perhaps never to return.  Fortunately, the maneuver seems to have been a total success.

NASA television is pretty cool, really.  Their budget is clearly not incredibly high, but there are no commercials at all, and you get to enjoy an unfiltered look at our space operations.  There was, of course, no live television images broadcast from MESSENGER, so the coverage consisted of interviews, animations, slide shows, and a live feed from mission control.  It was all I needed to be content for the evening. 

The last time Mercury was visited by any spacecraft was in 1975, when the Mariner 10 spacecraft made the last of its 3 flybys.  Mercury is too close to the Sun to be observed by the Hubble telescope, so if we want to get a good look at it, we have to send a spacecraft.  But because it orbits in such a hostile region of space, any spacecraft bound for Mercury must be engineered to deal with extreme temperature fluctuations; there is an almost 1100 degree Fahrenheit difference between light and shadow.  Mariner 10 provided us with a lot of great science... among other things, it discovered that Mercury has a magnetosphere, totally unexpected amongst astronomers.  But due to the timing of its flybys, and the nature of Mercury's slow axial rotation, it was only able to photograph about 45% percent of the surface of Mercury.  The rest would remain a mystery.  There would have to be another mission -- an orbital mission -- to map the rest of the planet, and answer some of the questions that were raised by the tantalizing results of Mariner 10.

Examining Alternative Theories

The last several years have seen a shift in opposition to mainstream climate change theory.  For a long time, global warming was regarded by the skeptics as just a hoax... in the words of Senator Jim Inhofe back in 2003, "the greatest hoax ever perpetrated on the American people."  The skeptics said there was no evidence that the Earth was warming, that scientists were simply fear-mongering for the sake of fundraising, and sometimes they pointed to local phenomena, like frigid winter temperatures and brutal snowstorms, to back up their claims.  To be sure, this school of thought remains a major force in the anti-science community; Sean Hannity seems to have a particular affinity for using winter storms as evidence global warming isn't happening.  But increasingly there has been another argument advanced by the right -- that is, global warming is happening, but we humans are not causing it.  Instead, they say, there is any number of other factors causing global warming, and as such, we need not worry about it.  

There are a variety of alternative theories put forth by the skeptics in this camp.  Sunspots and sun cycles have been blamed for global warming, as have volcanic eruptions, cosmic rays, and various other astronomical causes (variations in Earth's axial tilt, the fluctuating eccentricity of Earth's orbit and the precession of equinoxes as relates to perihelion and aphelion, for instance).  Now, there is no question that these various factors do affect Earth's climate, and that can be seen clearly in the record of ancient climates.  We know that the Earth has seen periods of natural warming and cooling, and there is no doubt that these sorts of changes will happen again.  Nevertheless, these variables cannot explain the warming trend over the last 100 years or so nearly as well as anthropogenic factors, like the emission of enormous levels of carbon dioxide corresponding to the industrial revolution.

Skeptics of mainstream climate change theory may take to these other hypotheses in part because there is a sense that we humans are not capable of making big changes in our ecosystem.  Of course, history tells us otherwise.  Human beings have driven many species to extinction or to the brink of extinction by over-hunting and habitat destruction, and in the 20th century, with the advent of chlorofluorocarbons (CFCs), we put an enormous hole in our ozone layer.  Meanwhile, we continue to possess the power to cause a global nuclear winter.

To understand how humans are capable of making such profound changes to the climate, we have to understand the two main elements behind our increased impact on the environment: the industrial revolution and recent population expansion. 

Who Can You Trust on Climate Change?

Today's New York Times examines Virginia attorney general Ken Cuccinelli's one-man crusade against climate science.  Take a look at it here.

The ongoing battle over climate change highlights a central problem in a population that is under-educated in science.  The question is, who can you trust?  For those who have not gone to the trouble of educating themselves on climate science, you just have to trust what you're being told.  But for a subject as contentious as climate change, you're being told two radically different things.  One the one hand, you have a large majority of scientists, who have reached a consensus.  They tell us that climate change is real, and that human activity is the primary agent of global warming.  Some of the details remain to be nailed down (for instance, how fast is it happening, how extensive will the damage be, how high will seas rise, etc), but the main storyline is clear.  On the other hand, you have some politicians, media personalities, and a small minority of scientists, who cast doubt on the whole affair.  This group can be broken up into two main varieties: those who don't believe climate change is happening, and those who do believe it is happening but think we humans are not responsible for its creation or its resolution.

The population is left to decide who is right.  Who do you choose?

Why Should We Go to Space?

Sometimes I ask myself, "why should we go to space?"  It's a question I think many of us have probably asked ourselves.  I can tell you all sorts of reasons why our exploits in space are extraordinary, but that doesn't really answer the question.  It's a question that needs to be answered, though, and any advocate of space exploration should have an adequate response. 

Every year, as the United States has to draw up its budget, there are lots of considerations.  How much do we spend on defense?  How much can we afford to take care of the poor, the elderly, the children?  How much do we send abroad for humanitarian purposes?  And how much do we invest in education, and technological advancements here at home?  Each of these are very important, but when money is tight, we have to make some difficult decisions.  We have to get our priorities in order, and the composition of the government determines those priorities, sometimes but not always along party lines.

When it comes to making cuts, space exploration sometimes finds itself on shaky ground.  It can feel like a luxury item, like that cable sports package we like but don't really need.  Looking at the billions of dollars spent on manned space flight or space telescopes, for instance, it's easy to wonder how many children that might feed, or how many teachers that could pay (but of course, it's an equally valid question to ask how many fighter jets and warheads we could stand to do without).  No expenditure exists in a vacuum, though, so while we can easily imagine all the good that an extra 10 billion dollars might do for any single program, we have lots of commitments and we have to figure out how to spread the money around to cover all our bases.

Our ventures in space began with a decidedly defensive purpose.  When the Soviet Union launched Sputnik in 1957, it became clear that we were vulnerable to an unprecedented threat: intercontinental ballistic missiles.  As was typical of the Cold War, we set about the task of demonstrating our technological prowess.  It was a matter of national security, after all; the best way to deter the Russians from destroying us with ICBMs was to make sure everyone knew we could do the same thing to them.  But as a lovely side effect of that scary time, the United States began a preliminary reconnaissance of the solar system.  In a breathtaking achievement, the US landed a man on the Moon just 12 years after the first satellite was launched, and only 66 years after the Wright Brothers' first powered flight.  Since the beginning of the space age, we Earthlings have sent robotic emissaries to all of the major planets; investigated the myriad moons of the outer solar system; landed robotic spacecraft on Mars, Venus, and Saturn's moon Titan, with a few rovers exploring the Martian landscape; built an enormous space station in Earth orbit; connected the world through a dazzling array of communications satellites; and stared into the vast depths of space, peering 13 billion years into our remote past, and accumulating data that is impossible to collect from Earth's surface.

We are so incredibly fortunate to live in this age of great discovery.  The human species has spent its entire modern existence -- many thousands of years -- looking up at the stars and wondering what they are.  But it's only in the last 2 or 3 percent of that history that we have been able to work out some of the answers.

Ophiuchus! What now?

I woke up yesterday thinking I was an Aries, and went to bed thinking I was a Pisces.  Oh brother.  I guess it means that I'm "compassionate, gentle, artistic, mystical and highly intuitive."  All this time I thought I was "optimistic, independent, impulsive, playful, competitive, courageous, sometimes combative and always adventurous."  Gee, I'm sort of all those things sometimes. 

I really couldn't care less, you understand, but the big news yesterday in the twitterverse and elsewhere was the addition of a 13th sign to the zodiac, called Ophiuchus.  Of course, it's not really a new addition to the zodiac... The constellation of Ophiuchus has always been there along the ecliptic, we've just traditionally left it off the list of the big 12 astrological signs.  But it was widely reported that not only is Ophiuchus a new sign that we'll all have to learn to live with, but that the precession of the Earth's axial rotation has, over a few millennia, shifted our view of the sky so that the Sun is no longer in the same apparent position along the zodiac as it was thousands of years ago, when this version of astrology was concocted.  In other words, people with birthdays in late March have traditionally been considered Aries, but today the Sun is really in Pisces at that time of year.

This story is just so silly in a variety of ways.  For one thing, it wasn't actually news.  The Earth's axial precession doesn't happen overnight, and astronomers haven't just discovered it (read this discussion of the problem by Phil Plait way back in 2008)..  In the words of Sam Cooke, it's been a long time coming.  Then there was the panic and irritation that the traditional signs are all wrong (today HuffingtonPost cleverly examined the Earth-shattering consequences of this shift).  If you've got a tattoo of your astrological sign, tough luck buddy.  And then there was the inevitable backlash from those unlucky souls born in late November and early December, suddenly thrust into a brand new personality profile.  How would you feel to grow up thinking you're a Scorpio, and suddenly find out you're really an Ophiuchus?  The name sounds like a disease.   What's my birth stone?  And how am I supposed to know what kind of person I am?  No one has published my new attributes yet.

Then today, the astrologers came to the rescue.  Nothing to fear, they said.  The Ophiuchus shift only applies to Sidereal Astrology, not Tropical Astrology.  Most believers probably don't know the difference, but don't worry, we westerners typically believe in Tropical Astrology, which is unaffected.  On twitter I saw several people commenting in a similar, but tellingly inconsistent vein: "Ophiuchus only affects those who were born 2009 onwards. If you're born before 2009, the sign stays the same."  That's a relief.

Thoughts After a Tragedy

Take a look at this great new video, narrated by Carl Sagan:

In the wake of horrific tragedies like the shooting in Tuscon this past weekend, we are reminded that human beings are sometimes capable of terrible things.  But the events of the weekend also show that for one act of brutality, there are several acts of heroism. Such is, I believe, the nature of humanity.  For all our shortcomings, and the violence that perpetuates around the globe, we remain a hopeful and curious species.  Our intentions are heroic, and we long for peace.  We are not born with hatred in our hearts.  Our brains retain the vestiges of more violent epochs, but we have the capacity to temper our reptilian impulses of aggression, and triumph over all adversity.  We have evolved for cooperation.

One of my favorites lines from Contact sums it up well:

"You're an interesting species, an interesting mix. You're capable of such beautiful dreams, and such horrible nightmares. You feel so lost, so cut off, so alone.  Only you're not.  See, in all our searching, the only thing we've found that makes the emptiness bearable... is each other."

It is too early to know the true motive of the shooter.  It may turn out that his mental instability is chiefly to blame, that a toxic political discourse is only peripheral, and that there was little that could have been done to prevent his rampage.  Maybe he's just insane.  But every mass murderer could be considered insane compared with "normal" human beings.  Some atrocities, like this one, may be driven by incoherent beliefs, but many others are perpetrated in pursuit of very common political objectives.  Whether we are talking about suicide bombs or genocide, these actions have been carried out with at least tacit approval from a larger group of people.  The line between "normal" and "insane" is sometimes blurry.

But we humans have it within us to conquer hatred.  It is possible to knock down the barriers that stand to divide us.  We can do it, and we must do it.  We have traveled a long way to get here, and we have a long way to go.  We'll have to work together.  The world is just too wonderful.

The First Interstellar Missions

Check out this excellent paper from Marc G. Millis, arguing that interstellar space travel could be possible in as little as 200 years.   The paper calculates the amount of energy required for two types of interstellar missions, and uses estimates of world energy output growth to determine when the required energy might be available to such missions.  Millis bases his calculations on the fraction of energy made available to current space missions, accounting for various technological innovations and broader considerations that might accelerate or delay serious consideration of interstellar missions.  The math suggests that an interstellar spacecraft colony could be achievable in approximately 200 years, and a probe to Alpha Centauri could be launched within 500 years. 

Millis' estimate is both exciting and disappointing.  Space enthusiasts want desperately to see an interstellar mission in our lifetime, but of course most of us realize that's probably not in the cards.  At the same time, some scientists have said it may be a thousand years or more before we are capable of interstellar space travel (that is, fast interstellar space travel), so a few hundred years is actually good news.  The world is likely to be a far different place in a thousand years, but 200 years is only 10 generations or so.  The English we speak today will probably remain intelligible to those lucky people in 2211.  We are just barely missing the wonders that may be in store for the future, just as the great scientists of the 18th and 19th centuries barely missed the extraordinary breakthroughs that would come in the 20th century.  They laid the groundwork for our world, though, and now it is up to us to lay the groundwork for tomorrow.

But where are we going, and why?  Will we be diversifying our interests, spreading the seed of humanity beyond the solar system?  Or are we simply going to investigate our nearest stellar neighbor and radio back the results? 

Questions for Young-Earth Creationists

Last Wednesday, Kentucky Governor Steven Beshear announced that millions of dollars in taxpayer funds will be going to Ark Encounter, a planned Christian creationist attraction similar in theme to the infamous Creation Museum (also in Kentucky).  Both attractions are sponsored by Answers in Genesis, a particularly zealous creationist group that adheres to a Young-Earth cosmology as part of their belief in a literal interpretation of the Bible.  According to their beliefs, the Earth and the heavens are somewhere in the vicinity of 6,000 years old.

As you would imagine, this has sparked the usual debate over separation of church and state, and of course I'm inclined to agree with those who really don't want their money going towards such things.  But the Governor seems to have mostly diffused the controversy on economic grounds, noting that the attraction will generate millions in tax revenue and create hundreds of jobs.

In light of this rejuvenated debate, I thought it might be a great time to present my Questions for Young-Earth Creationists, which I promised several months ago.  Here goes:

Happy Thanksgiving!

Here's wishing you and yours a very happy, safe and relaxing Thanksgiving. We are truly fortunate to live in this time, when we as a species are coming to know the wonders of the universe for the first time in the history of our planet.

Above, a special greeting from crew members aboard the ISS.