Shallow Thoughts : : science

Making "Citizen Science" compelling

I had the opportunity to participate in a focus group on NASA's new "citizen science" project, called Moon Zoo, with a bunch of other fellow lunatics, amateur astronomers and lunar enthusiasts.

Moon Zoo sounds really interesting. Ordinary people will analyze high-resolution photos of the lunar surface: find out how many boulders and craters are there. I hope it will also include more details like crater type and size, rilles and so forth, though that wasn't mentioned. These are all tasks that are easy for a human and hard for a computer: perfect for crowdsourcing. Think Galaxy Zoo for the moon. The resulting data will be used for planning future lunar missions as well as for general lunar science.

It sounds like a great project and I'm excited about it. But I'm not going to write about Moon Zoo today -- it doesn't exist yet (current estimate is mid-March), though there is a preliminary PDF. Instead, I want to talk about some of the great ideas that came out of the focus group.

The primary question: How do we get people -- both amateur astronomers and the general public, people of all ages -- interested in contributing to a citizen science project like Moon Zoo?

Here are some of the key ideas:

Make the data public

This was the most important point, echoed by a lot of participants. Some people felt that many of the existing "citizen science" projects project the attitude "We want something from you, but we're not going to give you anything in return." If you use crowdsourcing to create a dataset, make it available to the crowd.

Opening the data has a lot of advantages:

• People can make "mashups", useful sites that display your data in useful ways or combine it with other data. This can generate more interest in your project and more contributors.
• School groups can work on class projects or science fair projects, probably contributing more data along the way.
• It might help the next generation of scientist get started.
• It shows openness and good faith: witness the recent blow-up over the leaked IPCC emails and the debate over how much climate data has been kept private.

Projects like Wikipedia and Open Street Map, as well as Linux and the rest of the open source movement, show how much an open data model can inspire contributions.

Give credit to individuals and teams

People cited the example of SETI@Home, where teams of contributors can compete to see who's contributed the most. Show rankings for both individuals and groups, so they can track their progress and maybe get a bit competitive with other groups. Highlight groups and individuals who contribute a lot -- maybe even make it a formal competition and offer inexpensive prizes like T-shirts or mugs.

A teenaged panel member had the great suggestion of making buttons that said "I'm a Moon Zookeeper." Little rewards like that don't cost much but can really motivate people.

Offer an offline version

They wanted to hear ideas for publicizing Moon Zoo to groups like our local astronomy clubs.

I mentioned that I've often wanted to spread the word about Galaxy Zoo, but it's entirely a web-based application and when I give talks to clubs or school groups, web access is never an option. (Ironically, the person leading the focus group had planned to demonstrate Galaxy Zoo to us but couldn't get connected to the wi-fi at the Lawrence Hall of Science.)

Projects are so much easier to evangelize if you can download an offline demo.

And not just a demo, either. There should be a way to download a real version, including a small data set. Imagine if you could grab a Moon Zoo pack and do a little classifying whenever you got a few spare minutes -- on the airplane or train, or in a hotel room while traveling.

Important note: this does not mean you should write a separate Windows app for people to download. Keep it HTML, Javascript and cross platform so everyone can run it. Then let people download a local copy of the same web app they run on your site.

Make sure it works on phones and game consoles

Lots of people use smartphones more than they use a desktop computer these days. Make sure the app runs on all the popular smartphones. And lots of kids have access to handheld web-enabled game consoles: you can reach a whole new set of kids by supporting these platforms.

Offer levels of accomplishment, like a game

Lots of people are competitive by nature, and like to feel they're getting better at what they're doing. Play to that: let users advance as they get more experienced, and give them the option of doing harder projects. "I'm up to level 7 in Moon Zoo!"

Use social networking

Facebook. Twitter. Nuff said.

Don't keep results a secret

Quite a few scientific publications have arisen out of Galaxy Zoo -- yet although most of us were familiar with Galaxy Zoo, few of us knew that. Why so secretive? They should be trumpeting achievements like that.

How many times have you volunteered for a survey or study, then wondered for years afterward how the results came out? Researchers never contact the volunteers when the paper is finally published. It's frustrating and demotivating; it makes you not want to volunteer again. Lots of us sign up because we're curious about the science -- but that means we're also curious about the results.

With citizen science projects, this is particularly easy. Set up a mailing list or forum (or both) to discuss results and announce when papers are published. Set up a Twitter account and a Facebook group to announce new papers to anyone who wants to follow. This is the age of Web 2.0, folks -- there's no excuse for not communicating.

I don't know if NASA will listen to our ideas. But I hope they do. Moon Zoo promises to be a terrific project ... and the more of these principles they follow, the more dedicated volunteers they'll get and that will make the project even better.

Tags: science, astronomy, open source, crowdsourcing
[ 19:25 Feb 06, 2010    More science/astro | permalink to this entry ]

Pluto Visits the States

This is a reprinting of an article I wrote for my monthly planet column in the SJAA Ephemeris:

Is Pluto a planet, or not? Maybe you caught the news last month that Illinois, birthplace of Clyde Tombaugh, has declared Pluto a planet. It joins New Mexico, Tombaugh's longtime home, which made a similar declaration two years ago.

When I first heard about the New Mexico resolution, I was told that they had declared that Pluto would be a planet within the state's boundaries. That made me a bit curious: would Pluto even fit inside New Mexico? I looked it up: Pluto has a diameter of 2300km, while New Mexico is about 550km in longitude and a bit more in latitude. Not even close (see Figure 1). Too bad -- I liked the image of Pluto and Charon coming to visit and hang out with friends. Though at Pluto's orbital velocity (it takes it just under 248 years to complete its 18 billion kilometer orbit, meaning an average speed of 23 million km/year or 63,000 km/day) and its current distance of about 32 AU (4.8 billion km), it whould take it about 207 years to get here.

But it turns out that's not what the resolution said anyway. Both states' resolutions said roughly the same thing:

BE IT RESOLVED BY THE LEGISLATURE OF THE STATE OF NEW MEXICO that, as Pluto passes overhead through New Mexico's excellent night skies, it be declared a planet and that March 13, 2007 be declared "Pluto Planet Day" at the legislature.

RESOLVED, BY THE SENATE OF THE NINETY-SIXTH GENERAL ASSEMBLY OF THE STATE OF ILLINOIS, that as Pluto passes overhead through Illinois' night skies, that it be reestablished with full planetary status, and that March 13, 2009 be declared "Pluto Day" in the State of Illinois in honor of the date its discovery was announced in 1930.

So the law applies to anyone (though it's probably not enforceable outside state boundaries) -- but only when Pluto is overhead in New Mexico or Illinois.

But wait -- does Pluto ever actually pass overhead in those states?

New Mexico stretches from 31.2 to about 37 degrees latitude, while Illinois spans 36.9 to 42.4. Right now Pluto is in Sagittarius, with a declination of -17° 41'; there's no way anyone in the US is going to see it directly overhead this year. Worse, it's on its way even farther south. It won't cross into the northern hemisphere until the beginning of 2111. But how far north will it go?

My first thought was to add Pluto's inclination -- 17.15 degrees, very high compared to other planets -- to the 23 degrees of the ecliptic to get 40.4°. Way far north -- no problem in either state! But unfortunately it's not as simple as that.

It turns out that when Pluto gets to its maximum north inclination, it's in Bootes (bet you didn't know Bootes was a constellation of the zodiac, did you? It's that 17° inclination that puts Pluto just past the Virgo border). That'll happen in February of 2228.

But in the Virgo/Bootes region, the ecliptic is 8° south of the equator, not 23° north. So we don't get to add 23 and 17; in fact, Pluto's declination will only be about 7.3° north. That's no help!

To find the time when Pluto gets as far north as it's going to get, you have to combine the declination of the ecliptic and the angle of Pluto above the ecliptic. The online JPL HORIZONS simulator is very helpful for running data like that over long periods -- much easier than plugging dates into a planetarium program. HORIZONS told me that Pluto's maximum northern declination, 23.5°, will happen in spring of 2193.

Unfortunately, 23.5° isn't far enough north to be overhead even from Las Cruces, NM. So Pluto, sadly, will never be overhead from either New Mexico or Illinois, and thus by the text of the two measures, it will never be a planet.

With that in mind, I'm asking you to support my campaign to persuade the governments of Ecuador and Hawaii to pass resolutions similar to the New Mexico and Illinois ones. Please give generously -- and hurry, because we need your support before April 1!

Tags: science, astronomy, pluto, humor, writing
[ 19:09 Apr 01, 2009    More science/astro | permalink to this entry ]

For Ada Lovelace Day: Vera Rubin

For Ada Lovelace Day I'm honoring Vera Rubin.

In 1948, when she applied to Princeton as an aspiring astronomy grad student, they wouldn't let her in because women weren't allowed. (They finally started admitting women in 1975.) Fortunately, Cornell was more accommodating.

For her thesis, she worked on a project that seemed useful and uncontroversial. She took other people's data on the redshifts of galaxies, and catalogued them to see how fast they were all moving away from us.

Except something unexpected happened. She found that galaxies in one direction weren't moving away as fast as galaxies in the other directions. The universe was supposed to be expanding evenly in all directions -- but that's not what her data showed.

In 1950 she presented her results to a conference of the American Astronomical Society. The results were not promising. Famous astronomers she'd read about but never met stood up in the audience to ridicule her paper and say it couldn't be true. No one would publish her master's thesis. It wasn't a good start to her career. She decided to try to find something less controversial to study.

Her husband finished at Cornell and moved to Washington, D.C.. Rubin and her new baby moved with him, and she enrolled as a PhD student at Georgetown. They had two children by now; her parents watched the kids while she took night classes.

She hooked up with George Gamow at Georgetown. He called her to ask her about her research -- but said they'd have to talk in the lobby, not in his office, because women weren't allowed in the office area of the building.

After Rubin finished her PhD with Gamow in 1954, Her experience trying to present her 1950 paper made her leery of confrontation. She's said, "I wanted a problem that no one would bother me about." Working with Kent Ford at the Carnegie Institute in Washington, she helped design a super-sensitive digital spectrograph, and they set out to make a huge catalog of data on boring "normal" galaxies no one else was looking at. They started with the Andromeda galaxy, M31, the closest large galaxy to us (and the easiest one to see with the naked eye, if you go somewhere away from city lights).

And right away they found something weird. Normally, you'd expect the outer parts of the galaxy to be rotating a lot slower than the inner parts. Think of our solar system: Mercury goes around the sun really fast (a Mercury year is only 88 days), Earth goes not quite as fast, and when you get all the way out to Pluto, it takes 247 years to go around the sun once. It's not just that it has farther to go to make a circuit around the sun; it's that the sun's influence is so weak way out there that Pluto goes a lot slower in its orbit than we do.

Galaxies should be the same way: stars in the center should just whiz around in no time, while stars at the outer edge take forever.

But Rubin and Ford found that Andromeda wasn't like that. When they started looking at the stars farther out, they were all going about the same speed. If anything, the stars at the edge were going a little faster than the stars in the center.

That made no sense. It didn't follow any normal model of gravity or galaxy formation. They published their results in 1970, but no one took them seriously. They decided that maybe something was wrong, or their equipment was faulty. They decided to try studying a simpler problem: just measure the redshift of some faint galaxies and make a catalog of those.

That went well for a while -- except that pretty soon, they ran into the same thing Rubin had discovered as a graduate student back at Cornell. Galaxies in the direction of Pegasus were moving away from us at a different speed from galaxies in other parts of the sky. She and Ford tried again to present that, but the reaction wasn't any more positive this time.

Discouraged, they went back to trying to measure galaxy rotation, hoping Andromeda had just been a fluke. But every galaxy they studied looked the same as Andromeda, with the stars far out near the edge of the galaxy rotating as fast, or faster, than the stars near the hub.

There were only two possible explanations. Either the law of gravity doesn't work the way we think it does ... or there's a lot more matter inside a galaxy than what we see with a telescope.

When they tried to present this result, no one believed it, so they kept measuring more galaxies, always with the same result.

By 1985, they had enough evidence that people finally started paying attention. As their results got talked about more and taken more seriously, they came up with a name for the extra mass that makes the galaxy rotation flat: "dark matter". Yes, the dark matter you hear about that apparently makes up more than 90% of all matter in the universe. Not a bad discovery for someone who was just trying to lay low and catalogue a lot of data that might be useful to other people! (Rubin's first graduate project, on the rotation of the universe, has also since been vindicated.)

Vera Rubin is still working at the Department of Terrestrial Magnetism. Her intellect, hard work and perseverance are an inspiration, and I salute her on Ada Lovelace Day. (You can read other people's Ada Lovelace Day posts in the Ada Lovelace Day Collection.)

Tags: AdaLovelaceDay09, chix, astronomy
[ 19:12 Mar 24, 2009    More science/astro | permalink to this entry ]

Upheaval Dome: New research confirms impact theory

Kurt Fisher wrote to draw my attention to the latest Lunar Photo Of the Day (LPOD), a lovely shot he made of one of my favorite places anywhere, Upheaval Dome in Utah's Canyonlands National Park.

Upheaval Dome has long been strongly suspected to be a massive, eroded impact crater, but the LPOD highlights a study that finally puts this (non-)controversy to rest, Elmar Buchner and Thomas Kenkmann's Upheaval Dome, Utah, USA: Impact origin confirmed, documenting shocked quartz grains in the Kayenta sandstone of Upheaval's outer ring.

It's about time -- it's been pretty clear for many years that this structure was an impact formation, not a collapsed salt dome (the relative lack of salt in the core might have been a clue) but the park service doesn't seem to have gotten the message, giving equal weight to the salt-dome theory in all its Canyonlands literature and signs. Perhaps the Buchner and Kenkmann paper will finally convince them.

Reading about this gave me the push I needed to update my own Upheaval Dome page, adding links to the latest research and to the excellent Upheaval Dome Bibliography Kurt has put together. My page also badly needed a bigger view of the crater itself, so I stitched together a quick panorama of the view from the rim that I'd shot on a trip several years ago but never assembled.

Tags: geology, astronomy, trails, impact crater
[ 12:15 Nov 29, 2008    More science/geology | permalink to this entry ]

Bright naked-eye comet: 17/P Holmes

I finally got a chance to take a look at Comet 17/P Holmes. I'd been hearing about this bright comet for a couple of days, since it unexpectedly broke up and flared from about 17th magnitude (fainter than most amateur telescopes can pick up even in dark skies) to 2nd magnitude (easily visible to the naked eye from light-polluted cities). It's in Perseus, so only visible from the northern hemisphere, pretty much any time after dark (but it's higher a little later in the evening).

And it's just as bright as advertised. I grabbed my binoculars, used a finder chart posted by one of our local SJAA members, and there it was, bright and obviously fuzzy. Without the binoculars it was still easy to see, and still noticably fuzzy.

So I dragged out the trusty 6" dobsonian, and although it has no visible tail, it has lots of structure. It looked like this:
It has a stellar nucleus, a bright inner area (the coma?) and a much larger, fainter outer halo. There's also a faint star just outside the coma, so it'll be fun (if we continue to get holes in the clouds) to see how fast it moves relative to that star. (Not much motion in the past hour.)

It's nice to have a bright comet in the sky again! Anyone interested in astronomy should check this one out in the next few days -- since it may be in the process of breaking up, there's no telling how long it'll last or what will happen next. Grab some binoculars, or a 'scope if you have one, and take a look.

Tags: science, astronomy
[ 21:51 Oct 28, 2007    More science/astro | permalink to this entry ]

Traffic Science

NPR this morning had a program on speeding. One of the "experts" they brought in was Richard Retting, senior transportation engineer with the IIHS (that's the Insurance Institute for Highway Safety, a group funded by auto insurance companies).

Early on they asked him why speeding was bad. He said there were three reasons. The first two were straightforward: when you're going faster, you (1) travel farther before you can react to something, and (2) take longer to stop. No problem there, and I waited for the third reason, presuming it was going to be kinetic energy.

Well, almost. The third reason, he said, was energy. "Remember that equation E = mc² from high school?"

Wow! If I drive faster than the speed limit, I'm converting my mass into energy? For those who haven't studied physics recently, he was probably confusing Einstein's equation relating energy, mass and the speed of light with Newton's formula for kinetic energy, KE = mv²/2. The host responded incredulously "The speed of light?" but Retting didn't seem to notice, and pressed on: "When you're going faster, your energy is disproportionate and exponential."

Okay, you're talking on the radio and you have a brain-o. I'm sure we've all said silly things when we knew better, like reciting the wrong equation then not noticing the gaffe. But he also seems confused about what "exponential" means, perhaps because of that "exponent" of 2 in the equation. An exponential curve is when you have something like 2^X, not X². Admittedly, the dictionary of "exponential" includes vague definitions like "Pertaining to exponents", and I suppose there is an exponent of 2 involved. But really, folks: kinetic energy increases as the square of speed.

A little later in the program, someone called in to mention studies showing that higher speeds don't necessarily correlate with accidents, and Redding chastised him for doing google searches for studies: "That's not how we do science in this country." Hey, Mr. Retting -- it might pay to be a little more careful with your own science if you're going to be dismiss callers with remarks like that.

Tags: science
[ 17:37 Jun 07, 2007    More science | permalink to this entry ]

The Fibonacci Spiral and the Nautilus

or, don't believe everything you read

I've been working on a short talk on Fibonacci numbers for a friend's math class.

Back when I was in high school, I did a research project on Fibonacci numbers (their use in planning the growth of a city's power stations), and for a while I had to explain the project endlessly, so I thought I remembered pretty well what sorts of visuals I'd need -- some pine cones, maybe some flower petals or branching plants, graphics of the golden ratio and the Fibonacci/ Golden Spiral, and some nice visuals of natural wonders like the chambered nautilus and how that all fits in with the Fibonacci sequence.

I collected my pine cones, took some pictures and made some slides, then it was time to get to work on the golden spirals. I wrote a little GIMP script-fu to generate a Fibonacci spiral and set of boxes, then I went looking for a Chambered Nautilus image on which I could superimpose the spiral, and found a pretty good one by Chris 73 at Wikipedia. I pasted it into GIMP, then pasted my golden spiral on top of it, activated the Scale tool (Keep Aspect Ratio) and started scaling.

And I just couldn't get them to match!

No matter how I scaled or translated the spiral, it just didn't expand at the same rate as the nautilus shell.

So I called up Google Images and tried a few different nautilus images -- with exactly the same result. I just couldn't get my Fibonacci spiral to come close.

Well, this Science News article entitled Sea Shell Spirals says I'm not the only one. In 1999, retired mathematician Clement Falbo measured a series of nautilus shells at San Francisco's California Academy of Sciences, and he found that while they were indeed logarithmic spirals (like the golden spiral), their ratios ranged from about 1.24 to 1.43, with an average ratio of about 1.33 to 1, not even close to the 1.618... ratio of the Golden Spiral. In 2002,John Sharp noticed the same problem (that link doesn't work for me, but maybe you'll have better luck).

As the Science News article points out,

Nonetheless, many accounts still insist that a cross section of nautilus shell shows a growth pattern of chambers governed by the golden ratio.

No kidding! Google on fibonacci nautilus and you'll get a boatload of pages using the chambered nautilus as an illustration of the Fibonacci (or Golden) spiral in nature. It's not just the web, though -- I've been reading about nautili as Fibonacci examples for decades in books and magazines. All these writers just pass on what they've read elsewhere ... just like I did for all those years, never actually measuring a nautilus shell or trying to inscribe a golden spiral on one.

Now do a Google image search for the same terms, and you'll get lots of beautiful pictures of sectioned nautilus shells. You'll also get quite a few pictures of fibonacci spirals. But none of those beautiful pictures will actually have both the nautilus and the spiral in the same image.

And now I know why -- because they don't match!

(Happily, this actually may be a better subject for my talk than the nautilus illustration I'd originally planned. "Don't believe everything you read" is always a good lesson for high schoolers ... and it's just as relevant for us adults as well.)

(Slides from the talk I wrote start here: The Rabbit, the Nautilus and the Pine Cone.)

Tags: science
[ 21:15 Feb 08, 2007    More science | permalink to this entry ]

On the Twelfth Day of Christmas, My True Love Gave to Me ...

At dinner last night, amid the ubiquitous miasma of egregious Christmas music which is inescapable in public places starting in mid November, during "The Twelve Days of Christmas" Dave got a faraway expression in his eyes. My mother asked why, and he explained that he was thinking about the mathematics of the song: how many items of each type have been given by the end, and which items are more numerous?

There are two ways to interpret the song.

On the second day of Christmas, my true love gave to me
Two turtle doves
And a partridge in a pear tree.

So by the second day, you have two turtle doves, and you have the original partridge -- but do you also have a second partridge, as a literal interpretation of the song implies? Or is the song simply repeating all the previous gifts, not implying that they're given again?

Most people seem to assume the latter, but let's take the song literally and assume that on the third day, you get three french hens, plus two more turtle doves (that makes four) and one new partridge (for a total of three).

My first thought was that at time step T, you double what you had in step T-1 (you're getting all the same stuff yet again) and add T for the new gifts. But that's not right: you get a new load of each item (one partridge, two doves, three hens, and so forth) but you don't double all the accumulated extras who are now crowding your back yard. Time to start writing down the sums.

At each time T, the quantity you have of the Jth item is:

	T
NJ,T =	Σ J
	i=J

That's easy: it's just N_J,T = J*T- J*(J-1) (pretend you've given J of the Jth object at each time step; but since you didn't give it before timestep J, subtract all the ones up to timestep J-1).

N_J,T = J * (T - J + 1)

If all you want to know is how many of each item you have at the end (on the 12th day), plug in T-12:

N_J,12 = J * (13 - J)

A quick sanity check: that means you'll have 12 of item 1 (partridges in pear trees), because you've gotten one new one each time, and 12 of item 12 (drummers drumming), which you got in one big noisy box on the last day. Likewise, you'll have 22 each of items 2 (turtle doves, of which you got two every day except the first day) and 11 (pipers piping), which you got on day 11 and again on day 12.

So the curve which interested Dave is an inverted parabola; you get the least number of the first and last gifts, and the largest quantity of the two middle gifts: six geese a'laying and seven swans a'swimming. How many geese and swans do you get in the end? Here's the surprising answer:

N_6,12 = N_7,12 = 6 * 7 = 42

Douglas Adams fans will immediate recognize this as the solution to the ultimate question of Life, the Universe, and Everything. Now you know what the question was!

One last question: how many items, total, of all types will you have by the end of the twelfth day?

Since you already know how many of each item you have, just add them all up:

	12		12		12		12
Ntot =	Σ j * (13-j)	=	Σ (j * 13 - j2)	= 13 *	Σ j	-	Σ j2
	j=1		j=1		j=1		j=1

Fortunately, we know that

A
Σ i	= A (A + 1) / 2
i=1

and

A
Σ i2	= A (A + 1) (2A + 1) / 6
i=1

so we can use those identities to figure out how many total items we'll have:

Ntot	= { 13 * (12 * 13) / 2 } - { 12 * 13 * 25 / 6 }
	= 364

So it turns out that true love packs a present for just about every day of the year into those twelve days!

(And I found an excuse to play with using HTML tables to display equations.)

Tags: science
[ 11:59 Dec 21, 2006    More science | permalink to this entry ]