Blogs / Cosmic Variance

There is a struggle going on for NASA’s soul. Is NASA all about sending human beings into space? Or is NASA about elucidating the secrets of the cosmos? The former is, of course, best embodied by the Apollo missions: pure, unadulterated rocket science. The latter is probably best associated with the Hubble space telescope (although NASA’s contribution to our understanding of the Universe goes far beyond Hubble). Of course, spacewalks and science are not mutually exclusive (as Hubble has demonstrated). But a singleminded focus on the former has led to significant weakening of the latter.

At present, it looks like there will be two more space shuttle launches. That’s it. Within a year, our nation will no longer have the capability to launch humans into space. For some this is a sure sign that America is sliding into mediocrity. Both the first and the last man to step on the Moon testified before Congress last May, speaking out against the Obama plan to shut down the Constellation program (video). Their testimony was reminiscent of a past age, where we proved our worth by beating the Russians to the Moon, and the natural next step is to now prove our worth by beating the Chinese to the Red Planet. The jingoistic associations are unsettling, and these arguments gloss over the staggering costs involved. To quote none other than Neil Armstrong: “If the leadership we have acquired through our investment is allowed simply to fade away, other nations will surely step in where we have faltered. I do not believe that this would be in our best interests.”

It is certainly amazing that we’ve had continuous human “inhabitants” in low-Earth orbit. Rocket science is, indeed, rocket science, and this should never be taken for granted. Launching people into orbit is a massive endeavor, and having them survive in the incredibly inhospitable environment of space is even more impressive. But the simple truth is that the contributions to basic science from the space station have been entirely negligible (especially in comparison with the staggering costs). Furthermore, I would argue that the Hubble space telescope has done significantly more to awe and inspire the world than the International Space Station.

A year ago we discussed an Academy report which criticized the direction of the manned space program, and recommended profound changes. Subsequently the Academy released a separate report sharply criticizing the scientific underpinning of NASA, and recommending similar changes. Two months ago the Obama administration outlined a new vision for NASA, in line with these reports, including the cancellation of the Constellation program (which was the new and improved version of the Apollo program). Given the immense sums of money involved, especially to influential states such as Florida and Texas, Congress has taken the liberty of trying to do an end-run around the White House, and fund Constellation despite the lack of a request for funding. In a triumph of politics over common-sense, money will be poured into building more rockets, rather than funding a broad portfolio of technological development (including better ways to get humans into orbit and beyond) and basic research (including unmanned probes and satellites elucidating the mysteries of the Universe). In the latest salvo, fourteen Nobel laureates, and a few astronauts for good measure, issued an open letter supporting Obama’s strategy, and advising Congress against throwing all of NASA’s eggs in the “heavy lift rocket” basket.

One thing is clear: for better or worse, the shuttle program is at an end. There is no clear successor, and it will likely be many years before another astronaut is launched into orbit by the United States. If you want to experience the thrill of sending humans into space (and it is an incredible, indescribable rush), you’d better hustle on down to the Kennedy Space Flight Center. The next-to-last launch is currently scheduled for November 1, 2010.

Yes, I know, I’m not very good at this hiatus thing. But there is important news that needs to be promulgated widely — the news of calculus. No more will innocent citizens cower in fear at the thought of derivatives and integrals, or flash back in horror to the days of terror and confusion in high-school math class. Because now there is a cure for these maladies — The Calculus Diaries: How Math Can Help You Lose Weight, Win in Vegas, and Survive a Zombie Apocalypse.

Yes, you read that subtitle correctly. Let’s be clear: this book is probably not for you. That’s because you, I have no doubt, already love calculus. You carry a table of integrals in your back pocket, and you practice substituting variables to while away the time in the DMV. This isn’t the book for people who already appreciate the austere beauty of a differential equation, or even for people who want to study up for their AP exam.

No, this is the book for people who hate math. It’s for people who look at you funny and turn away at parties when you mention that you enjoy science. It’s for your older relatives who think you’re crazy for appreciating all that technical stuff, or your nieces and nephews who haven’t yet been captivated by the beauty of mathematics. The Calculus Diaries is the book for people who need to be convinced that math isn’t an intimidating chore — that it can be fun.

Know anybody like that? Any gift-giving holidays coming up?

Now it’s true, I know the author. In fact, I appear as a character in the book (to a certain degree of comic effect). I’m the one who gets soaked when we ride Splash Mountain at Disneyland, but also the one who maximizes his winnings at craps by clever betting in Vegas. You get the idea: this isn’t a textbook, it’s a tour through the real world (and occasional fantasy worlds), pointing out that math is all around us, and that perceiving it is kind of cool.

When you understand math, how you think about the world changes. Every day, we all change position by accumulating velocity, or do informal optimization problems when making a decision. But most people don’t know about the wonderful insights that math can add to these processes. You know, because you are a mathphile. But you are outnumbered by the mathphobes. You have a secret that they don’t know, but now there’s a way to share it. What are you waiting for?

Speaking of video goodness, we’d be remiss not to remind everyone that Sunday is the premiere of Phil Plait’s new mini-series on Discovery, Bad Universe.

It will be a lot like Armageddon, with Phil instead of Bruce Willis in the role of the balding hero figure. And science instead of complete nonsense. Improvements all around!

I gave a tech talk at Google headquarters on the arrow of time, which was a lot of fun. Must be what all of Silicon Valley was like back in the boom days — pool tables, free food, volleyball, and lots of smart people everywhere. Rather than a lecture hall, the talks are held in a big lobby space where people are regularly walking through, so that passers-by can become intrigued and start listening. Also, it became clear during the questions that at least one Google employee is concerned about how to preserve intelligent life past the 10¹⁰⁰ year mark when our universe will be nothing but empty space. Glad they’re thinking long-term!

Here is the talk, which is basically at a popular level, although I felt empowered to use the word “logarithm” without explanation. I’ve also tried to collect other talks by me onto one page, for those who just can’t get enough. (Hi, Mom!)

This past week has seen a lot of news stories about a “Manhattan-sized” plume of oil found in the Gulf of Mexico by researchers near the site of the BP Deepwater Horizon well. This sent my BS detector into the yellow zone, so I have been trying to get a better idea of just how much oil remains in the Gulf from this disaster. It’s definitely not gone.

So I went to Wikipedia. There, you can find a reference to a New York Times article from the beginning of August, where the total volume of the leak was estimated to be 780,000 cubic meters of oil. Now, that’s clearly in the category of “reasonable guess” – no one knows for sure. But it is very unlikely to be a factor of two larger or smaller than that, so let’s just use that for now. There are a lot of other uncertainties, for example the amount of natural gas (methane) that came out with the oil, how the flow rate changed with time, and so on. But again, let’s just ignore those.

How big is 780,000 cubic meters? Simply taking the cube root of this number, this is the volume of a cube 92 meters on a side. It would look something like this next to the Pentagon:

I can imagine two reactions to this comparison: 1) Damn, that’s a lot of oil! 2) That’s tiny compared to the volume of the Gulf of Mexico! (I bet one’s political views might play a role in which reaction comes first…)

If we were to take this volume and spread it out in a layer 1 millimeter thick, it would cover an area of 780 million square meters, which is a square about 28 kilometers on a side. The satellite images of the oil slick showed affected regions much larger than that, from which I conclude that the thickness of the surface layer must have been much less than 1 millimeter at those times. (But check my math, somebody!)

If all the oil were dissolved uniformly into the Gulf, which has a total volume three million billion times the size of the leak, the concentration would be about one third of one part per billion. That’s an interesting number all by itself, and not at all as small as it seems. But not all the oil leaked is in the Gulf – much of it evaporated and a good deal has been consumed by bacteria. But the rest of it went somewhere, right?

Now to the underwater plume. In the abstract of the Science Magazine paper that led to all the news stories, the authors said “Our findings indicate the presence of a continuous plume over 35 km in length, at approximately 1100 m depth that persisted for months without substantial biodegradation.” I cannot find the word “Manhattan” anywhere in their article, and so I have to conclude this was some mainstream media (WSJ?) person’s rather inept attempt at putting the size of the plume into perspective. It was parroted endlessly in the media as if it had meaning. In fact it’s quite misleading – clearly the term “Manhattan-sized” conjures up images of the whole island of Manhattan along with all the tall buildings…but as we have seen the total volume of oil leaked into the Gulf is about the size of one of those buildings.

So what is this plume? The authors define it as “a discrete spatial interval with hydrocarbon signals or signal surrogates (i.e., colored dissolved organic matter or aromatic hydrocarbon fluorescence) more than two standard deviations above the root-mean-square baseline variability.” That is, a place in the water where there is clearly oil present at detectable levels. It can be at quite low concentrations and still be detectable. One of the article’s main findings was that “Gas chromatographic analyses for only monoaromatic hydrocarbons of several water samples gathered using survey guidance confirm benzene, toluene, ethylbenzene, and total xylenes (BTEX) concentrations in excess of 50 μg L^–1 within the plume at 16 km downrange from the well site.” This is all bad stuff we don’t want in the water or getting into the food we eat.

I assume a lot more scientific research will need to be done to know the actual damage that the presence of these oil components will do to marine life, the fisheries, and the food chain. The authors took a stab at making an estimate of how much oxygen depletion was occurring due to biodegradation of the oil, concluding that “it may require many months before microbes significantly attenuate the hydrocarbon plume to the point that oxygen minimum zones develop that are intense enough…to threaten Gulf fisheries.” That’s good news for marine life, I assume, but means that the subsurface oil will take quite some time to be bioegraded, which is bad in the longer term. So why hasn’t the media talked about that aspect of the article?

There is no question that this was a huge amount of oil leaked into the Gulf and that the impacts will be felt for many years to come. It is an epic disaster by any measure and may have consequences no one has considered yet. But we have to be rational about the real impacts of the disaster, and rational about the real risks involved in deep water drilling. The only way is to continue vigorously the kind of research we saw in the Science Magazine article, and debate the findings openly. BP needs to release publicly everything it knows about the spill.

The recent US Decadal Survey (Astro2010) contains a conundrum.

As part of the report, the Decadal Survey committee identified three key “scientific objectives” on which they felt the community should focus. These were:

1. “Cosmic Dawn: Searching for the First Stars, Galaxies, and Black Holes”
2. “New Worlds: Seeking Nearby, Habitable Planets”
3. “Physics of the Universe: Understanding Scientific Principles

(For the record, I think this is a completely reasonable list, filled with the kinds of things that make splashy magazine covers. It’s arguably tilted a bit far from more traditional but critically important aspects of astronomy — for example, we don’t actually know how stars form, or how they explode, and yet the only bit of stellar physics that’s covered under this list is the fossil record of the absolute lowest metallicity stars. However, the committee had to narrow things down, and these are certainly the most “sellable” aspects of our field, as far as congressional committees and the general public is concerned.)

Now, these key questions are supposed to be partial guides to the project prioritization that the committee carried out. And yet, when you look at the list of recommended space- and ground-based investments, there really is precious little that is deeply connected to #2. As many have commented here and elsewhere, where is the investment in exoplanets?

While I agree it appears to be a glaring conflict, I think it’s actually completely sensible. The search for extrasolar planets is by far the hottest new area of astronomy. However, because it’s so new, the scientific landscape is wide open and barely explored. Is the most interesting question the mass function and radial distribution of planets? Are the subset of habitable planets the most compelling targets? Is the study of atmospheres and exoplanet weather the big breakthrough issue? What about the theory of stability of planetary systems? Do we know the physics controlling how all these planetary systems form? Every single one of these questions is awesome, but it would be nuts to take bets now on a billion dollar flagship facility dedicated to just one of these topics.

I’m guessing that what the committee did was essentially try to earmark some of the explorer-class space and ground missions for exoplanets. They made exoplanets an unambiguous scientific priority, and then they did their best to protect pots of money for faster timescale moderate-sized experiments (2nd ranked for both ground and space). Thus, when an exoplanet mission is proposed for an Explorer satellite, they get the huge boost of saying that their satellite will help answer one of the key questions from the Decadal Survey. (Edit: They also called out for investment in “New Worlds Technology” (i.e., things like a steerable sunshade) that would reduce the price of a mission to study habitable planets in the future, putting an exoplanet-optimized flagship mission at a fundable price point in time for the next decadal survey.) This strategy is smart — we’ve got Kepler up right now, JWST in the nearish future, and on-going ground-based work across the world. The field is evolving so rapidly, that it’s almost certainly better that the experimental response be kept as nimble as possible. So, reading the tea leaves, I think exoplanets did just fine in this report.

The big news this week in astrophysics is not the discovery of a new planet. Nor is it the first glimpse of a galaxy on the other side of the Universe. It’s much more important: the arrival of the latest Decadal Report. It all started over a year ago, and fellow blogger Julianne has been a major participant.

The full report is an excellent description of the entire field, both where we are now, and where we’re likely to be headed. If 200+ pages is a bit much to swallow, the report contains a 5 page Executive Summary (with 5 tables laying out the project rankings and costs). Probably the best place to start, however, is Julianne’s discussion of the report: post 1, post 2, and post 3.

For those with no attention span whatsoever, here is my 6 bullet-point summary:
1. Surveys rule the roost. The next decade is about survey telescopes. The #1 space priority is an infrared survey telescope (WFIRST) (a successor of SNAP/JDEM). The #1 ground priority is a wide-field optical survey telescope (LSST).
2. Another golden decade of cosmology (and planets). Both the top space and ground priorities originated as dark energy/cosmology missions. They turn out to be excellent planet missions as well.
3. Bang for the buck. Smaller, diverse, rapid-response programs provide excellent science return. The “Explorer program” and the “Mid-scale Innovations Program” are the #2 priorities for space and ground, respectively. Specific missions within these programs are unspecified.
4. The birth of gravitational-wave astronomy. We are (hopefully) entering the decade of gravitational-wave astrophysics. The Laser Interferometer Space Antenna (LISA) is the 3rd ranked space mission. This is a big deal: gravitational-waves have yet to be seen, but the astronomical community nonetheless recognizes and prioritizes the role they have to play in exploring our Universe.
5. Clash of the Titans. The 3rd priority for ground-based astronomy is a huge (30 meter) optical/infrared telescope. There are two projects well underway (GMT and TMT). The report encourages the NSF to pick one for federal investment.
6. Etcetera. Other things that are discussed include an X-ray telescope (IXO), a high-energy gamma ray telescope (ACTA), a submillimeter telescope (CCAT), and a number of smaller missions and projects (including full funding for NASA’s Astrophysics Theory Program). Note that the Hubble Space Telescope’s successor, the James Webb Space Telescope (JWST), is not extensively discussed in this report, since it is already funded and is on track for launch in the next few years.

I’m excited about all of these facilities. I’ve written papers related to many of them (JDEM, LISA, and LSST), and I am convinced they will all profoundly deepen our understanding of our Universe. The Decadal report represents a tremendous investment by the astro community, involving hundreds of scientists making extremely painful and difficult choices. At the end of the day, a clear ranking has been produced, and a strong case has been articulated. Now the task it to convince the full astronomy community, Congress, and the taxpayers that we have done our homework, and that these missions are worthy of major public investment. We have an incredible decade ahead of us!

On to the ground-based (i.e. NSF funded) recommendations (for large, new projects — i.e., not including on-going investments in ALMA; there are a number of interesting medium scale projects recommended, but I probably won’t have time to get to them).

First priority was the Large Synoptic Survey Telescope (LSST) — a survey for a multi-color, multi-cadence survey of the sky with an 8m class telescope. As my colleague and LSST Project Scientist Zeljko Ivezic puts it, “LSST will make a movie of the sky,” which, you have to admit, is pretty cool. When you think about discovery space in astronomy, the largest gains come when you move into new regimes. We’ve largely run out of new wavelength regimes, but the time-variable regime has not yet been explored in a large scale systematic way (although PanSTARRS and the Los Cumbres Observatory will certainly be making headway). In addition, the co-adds of all the epochs will produce an 8m telescope version of the 2.5m Sloan Digital Sky Survey (SDSS) imaging, which is a good thing. All data is non-proprietary, and can be used by anyone.

Second priority is a “Mid-Scale Innovations Program” — basically, a ground-based equivalent of the NASA Explorer program. The decadal survey committee reviewed a wealth of scientifically compelling medium size projects. These don’t rise to the level of building giant new facilities, and are typically seeking funding for an instrument and a decidated multi-year survey on existing facilities. The report recommends that there be a review and funding mechanism for such projects, which have the capability of responding nimbly to scientific and technological changes.

Third priority is contributing to the development of a 30m class ground-based optical/nearIR telescope (a “Giant Segmented Mirror Telescope”; GSMT). Such a telescope would be essential for carrying out spectroscopy of the sources found at the limits of 8m-class telescope imaging; basically, if you detect a source in an image, when you want spectra, you’re spreading the light over much larger areas, requiring bigger apertures to reach the same signal-to-noise as when all the wavelengths are being imaged together. There are currently 2 large US programs that are well underway (TMT and GMT), using private funding. For these programs to have enough money to be built and operated, an investment of Federal money is required. This money would also guarantee some degree of access for the larger US community, but probably significantly less than 50%. The report recommends that involvement should be at least a 25% share. However, they argue that there is only money enough to invest in one, and the community had better pick one as soon as possible, rather than letting both go forward.

The fourth priority is participation in the “Atmospheric Cerenkov Telescope Array” (ACTA), to detect and characterize the highest energy cosmic rays. Recent years have seen the detection of TeV cosmic rays, which places strong constraints on particle acceleration at the highest energy scales; a new array would greatly expand the chances of fully understanding the origin of these high energy events. Rather than funding a separate US initiative, however, the report recommends joining into an existing European project (CTA), in spite of the fact that the US would be a minor partner.

Reactions to the Ground-Based Recommendations:

Perhaps the biggest surprise was the drop in the GSMT from (1) its prioritization in the previous report, and (2) its prioritization in the actual optical/IR subcommittee (See Table B.1). The justification was that LSST was a much lower risk in terms of cost and technology, and, as in the space recommendations, pragmatism ruled the day. The committee was quite strong in their support for GSMT as a project, and pointed out that the combination with LSST is highly synergistic — LSST provides the targets, and GSMT tells you what they are. However, the pie was simply not big enough to give everyone a slice. In addition, if you can only dish out one slice of pie, you want it to feed the most number of people — LSST made a strong case that a much larger fraction of the US community could make use of the data.

Personally, I’m very sympathetic to this view. There are scientific advances that come because you have new facilities pushing into new territory, and GSMT has this in spades. However, there are also scientific advances that come about because you have the largest number of very clever brains thinking about how to exploit a given data set. Taking SDSS as a model, a ridiculously large fraction of the ridiculously large number of SDSS-related papers had absolutely nothing to do with anything in the “black book” of science justifications used to obtain funding for SDSS. You take good data, you let smart people work with it, and you’ll get science you never anticipated. I’m optimistic that LSST could work the same way, with the caveat that the scientific impact may well be blunted without a wide scale investment in spectroscopy (which SDSS had, and which LSST lacks). I very much hope that a 30m gets built, but not to the point where I’d be comfortable leveraging all public large ground-based investment over the next 10 years for a 25% share of a telescope. (Full disclosure: I am not at an institution that would have private 30m access, and am at one that has made early and ongoing investments in LSST. So, my perspective is undoubtedly shaped somewhat by viewing GSMT projects as a potential “outside” user. I do my best to be fair, but I’ve pretty much shaped my scientific research around the premise that I won’t have exclusive access to large aperture telescopes.)

I am also really pleased to see the “Mid-Scale Innovations” recommendation. I think this is a smart way to make sure we can take advantage of rapidly changing fields. When something like dark energy or extrasolar planets shows up on the scene, it’s great to have a mechanism in place to take advantage of new opportunities. In addition, it’s a smart way to skim the low hanging fruit, so that larger missions have a better understanding of what the scientific requirements really are — for example, you’d design a very different dark energy mission if you know that w is nearly equal to -1, than if you had no idea of its value.

The other noticeable lack here is a call for US participation in the Square Kilometer Array. (The panel did recommend some radio projects in the medium scale category.) However, if you look at Figure 4-8 (which I found fascinating and surprising) fewer than 10% of the members in the American Astronomical Society (ASS) categorize themselves as “Observational Radio” astronomers. I’d presume this would grow in response to investment in ALMA, but the community is clearly not enormous.

So, my take on the ground-based recommendations, is that they did pretty well at making hard choices. And the choices were indeed hard, and are going to be rightfully hard to swallow in many cases.

So, the Decadal Survey (”Astro2010″) results are out. I missed the webcast (which I heard was of pretty sketchy quality), but read Roger Blandford’s slides, and have skimmed or read a reasonable fraction of the preliminary report. Here’s my summary and first reactions, broken down by regime. Steinn has also been blogging a running commentary of his reactions here.

Space Missions:

The top recommendation for a space mission is “WFIRST” — basically a 1.5m wide-field IR imager in space, with low-resolution spectroscopy capabilities. This concept is the latest realization of what was previously known as “JDEM” (for “Joint Dark Energy Mission”, which itself was an expanded and reconstructed version of “SNAP”, the Supernova (SN) Acceleration Probe). The goal would be to use some combination of high redshift SNe, baryon acoustic oscillations (BAO), and weak lensing to constrain the parameters of dark energy. The committee recommended that the mission allow for a general observer (GO) program (thank goodness) and have a component dedicated to exoplanet discovery through microlensing (really? not really something I follow, but this isn’t something I’ve heard much about. UPDATE: from the comments, Andy Gould has a white paper pointing out that the weak lensing requirements are essentially identical to what’s needed for a microlensing-based planet search. Basically, you get it for free if you decide to pursue weak lensing. However, they did not take Andy’s recommendation that the dark energy mission not pursue 3 independent techniques in one satellite.).

The next recommendation is for a mixed portfolio of smaller satellite missions. These “Explorer”-class missions have historically been hugely successful — WMAP, GALEX, etc — but have been squeezed out recently by funding limitations and pressure from flagship mission development (JWST) and operations.

The third recommendation is for continued development of LISA, an orbiting interferometric gravitational wave detector. LISA is a really nifty project — one that I was not inately that interested in, but that became more and more compelling the more I learned about it. Co-blogger Daniel has thought a lot about LISA, and maybe we can get him to talk some more about it.

Reactions to the Space Recommendations:

Overall: These were hard choices, and reading the report, it’s clear that a huge amount of weight was given to cost, feasibility, and competitiveness. IXO, the next generation flagship X-ray mission, dropped compared to its previous ranking, largely because the committee found it to be technologically and financially risky (”The Survey Committee also found IXO technologies to be too immature at present for accurate cost and risk assessment”). They instead flagged IXO as ripe for money for “technological development”, so that it’s ready to go for the next report. The Space Interferometry Mission (SIM, or SIMlite) dropped completely out, in large part due to cost vs scientific return.

The real bummer about these recommendations is that entire subfields of US astronomy are pretty much shut out of the only environment where they can operate. X-ray, UV, and high-resolution astronomy (outside of IR and radio) are fundamentally space-based enterprises, and when Chandra and HST shut down, there will be nothing left, and nothing in the pipeline for a decade or more. The good times are continuing to role if you’re an infrared astronomer — (considering the series of Spitzer, WISE, JWST, and now WFIRST), but entire communities are going to be gutted. I do think that IXO will eventually get a start, because it’s a strong mission, but are there going to be any X-ray astronomers left when it starts getting data?

WFIRST: It will be interesting to see how this plays out, because two of the three dark energy techniques are going to making a fair bit of progress over the next decade, even without this mission — two of the three new gigundo Hubble Multicycle Treasury programs will have a significant high-redshift SN component, and ground-based BAO surveys like BigBOSS are viable candidates for completion within a 10yr timescale. I’m sure discovery space will be left, but it will be interesting to see where we are in 10 years. There is also a highly ranked ESA mission with very similar capabilities. The only way it makes sense to go forward with WFIRST is if the projects somehow merge.

Explorer Missions: There will definitely be broad community support for this recommendation. For certain wavelength regimes, this will be the only game in town. UV astronomers can probably make some real progress here, because there are huge gains that can be made by increases in detector efficiency, rather than by larger apertures, which are expensive to build and launch. High-resolution questions can’t be addressed through the Explorer program, since you really need large baselines that are inaccessible at this cost limit (large baseline = big mirrors or interferometry = expensive). Not sure what can be done in the X-ray, but hard to go from Chandra or XMM down to what’s available through this approach.

LISA: I think LISA is pretty cool. I would have thought that the technological challenges for LISA are comparable to those that IXO faces, but I’ll sensibly assume that the committee spent infinitely more time evaluating this issue than I have. Of the two, LISA probably has more pure discovery space potential. We at least know something about x-rays from space, but we know close to nothing about gravitational radiation from space.

Ok, I gotta try to do some actually science today before I tackle the rest of the recommendations…more later

The US astronomical community is anxiously awaiting tomorrow’s press conference on the release of the “Astro2010 Decadal Survey”. Now, the astronomical community has press releases all the time, but almost all are about communicating scientific results or images to the general public. Tomorrow’s is different. What we learn will shape the next ten years of investment in astronomical infrastructure, and set the course of much of scientific innovation in the ten years after that.

For close to half a century, the astronomical community has gone through an extremely productive exercise in navel gazing, producing exhaustive reports once a decade to lay out our priorities as a field. These reports are the result of a year long process of consultation, analysis, and lobbying. Through the National Academy of Sciences, the community organizes a series of committees to evaluate every aspect of US astronomical research. They try to identify scientific areas that are ripe for breakthroughs, and then to match these areas with specific technological investments in astronomical tools (primarily telescopes, but also increasingly computational and theoretical resources). The committees then do their best to rank these investments into a prioritized list.

The process of making a prioritized list is relatively horrific, since it involves choices between extremely different, non-overlapping projects. For example, if you’ve spent your life understanding optical and near-infrared spectra of galaxies, you’ll be rooting for a gigantic ground based telescope — most competing projects will be of little utility for your research. However, as a field, we are forced to face up to the fact that sometimes the best way to move forward on an astrophysical topic is not necessarily where we, as individuals, have chosen to do so. We also have to recognize that what may interest us personally may not be the most important question in the field. For example, I’m a nearby galaxy kind of girl, but I’d be a fool not to recognize that extrasolar planets are far more “ripe” for dramatic results. Finally, accepting these facts is not equally easy for all individuals, and many people are willing to go the mattresses for their preferred outcome. One hopes for good behavior, but people will be people.

The reason the process is so high-stakes is that the ranking that comes out of the Decadal Survey is taken very, very seriously. The upper administration of NASA and the National Science Foundation take these recommendations as commandments (i.e. don’t bother seeking funding for the satellite telescope that was ranked 15th). Ever more seriously, congressional staffers read these reports, making Congress extremely unlikely to finance anything but a top ranked project. (The few times that earmarks have been laid out for specific projects, it’s been Seriously Frowned Upon by the community, and by any administrator who has based their planning on the ranked list). Frankly, this is great, even if it’s hard. We wouldn’t want anyone else to make these decisions but us, as hard as it is to sometimes see your favorite project nudged out by something you are far less interested in.

So, the big things to look for in the news tomorrow are the first ranked ground-based project (i.e. NSF funded) and the first ranked space-based project (NASA funded). In the current funding climate, and with the growing costs of building competitive facilities, the community is unlikely to get more than one major initiative rolling — if that. This decadal report is unlikely to make the mistakes of the last one, which can best be described as being equivalent to asking a 3 year old whether they’d prefer a bathtub full of ice cream or a pony. This round, there was much more attention paid to cost, so that the committee could make realistic decisions.

Frankly, it’s a bit of a scary time. The situation reminds me a bit too much of the Superconducting Supercollider. The funding levels needed to make big advances are at a point where we really can’t afford more than one major initiative a decade. That puts us in the unfortunate position of having a single point failure. Say we back one big project. Suppose that the one big project goes over budget (as cutting edge facilities frequently do) to the point where it gets cancelled, 10-15 years from now. Then, we’re left with nothing, and young astronomers start looking for jobs in Europe.