One of the amazing things about WISE is the sheer amount of data it generates: something like 7,000 images per day.  This translates to about 50 Gigabytes of data, each day, every day, for 9 months.  It also means that we are finding hundreds of millions of sources. You can imagine that the task of finding, say, new asteroids in all of those sources is a bit like trying to find the proverbial needle in a haystack, if the needle were moving and the haystack were on fire (well, okay, maybe not THAT bad, but you get the idea).  Needless to say, sorting through all of this involves a large team of people who are outstanding software engineers and astronomers who specialize in this sort of high volume data reduction.  The folks at the WISE Science Data Center at Caltech are real pros at this. But eventually, Joe or Jane Astronomers like me want to take the data products and start working with them.  For me, this means learning the WISE data formats and specifications.  So I have been spending a lot of quality time lately with my laptop!

A lot of astronomy these days is done by working with these massive data sets, looking for trends, unusual objects, and comparing data from differerent surveys and telescopes.  That translates to programming. As a physics major in college, I studied mechanics, quantum theory, electromagnetism, optics, electronics, etc.  In graduate school, I took classes in star formation, high energy astrophysics, galactic structure, the physics of radiative transfer, telescope and camera design, and so forth.  But I never took much in the way of college-level programming classes.  This means that most of the programming I’ve learned has been by practice rather than theory.  Consequently, my code tends to veer into brute force all too often instead of elegant solutions, because I’m usually in a big hurry to get the job done rather than spend the time to make the code nice.

"The files are IN the computer?...It's so simple!"

Of course, the great thing is that to program, you don’t really need to bother with niceties like wearing matching socks.  I find that I do my best work parked on the couch with everything I need within about a one arm-length radius of me: cups of tea in various states of thermodynamic equilibrium with their surroundings, warm socks, food, phone, glasses, etc.  The great thing about tea is that if you wait long enough, it turns into iced tea (I learned that trick while writing my thesis in graduate school).  Good times!

Finally, here is your image of the week, a cosmic flower in time for spring:

A new infrared image from WISE shows a cosmic rosebud blossoming with new stars. The stars, called the Berkeley 59 cluster, are the blue dots to the right of the image center.

I just got back from my first trip since WISE launched, to the Lunar & Planetary Science Conference in Houston, Texas.

I was invited to give a talk there on initial results from WISE. There is so much to do it’s unbelievable. We just keep thinking of new science projects to do with the torrent of data that keeps blasting down from space. We eat, sleep, and breath science now.

We’ve discovered about a couple thousand new asteroids now, including over a dozen new near-Earth objects and 4 new comets. Someone asked in my last post about the typical schedule for an astronomer. For those on our team, right now it’s about like this: Morning: get up, check email, work. Work, work, work, meetings, meetings, meetings, forget to eat lunch, meetings, finally remember to eat, meetings, meetings, work, meetings, work, work, work, work, work, go home, work, work, dinner, work, work, sleep. Repeat. We keep saying it’s going to slow down, but realistically, I don’t think it will, not for a while. We run the moving object processing pipeline every 2-3 days, which brings a new burst of observations to report, and new follow-up observations to coordinate and interpret. Observers from around the world are helping to follow up our targets, both amateurs and professionals. You can watch the action in real-time each day and night at this website.

All the objects that are designated W00-something-or-other are WISE detections. We can see the measurements that other people are contributing by watching the reports that come in under the “observations” section for each object. Each observer gets a unique identifier code issued to them by the Minor Planet Center at the Smithsonian Center for Astrophysics. So we can see who is contributing what, and when. We greatly appreciate all the fine and extremely dedicated folks who have contributed observations – our hats are off to you!

Also, we’ve started posting the “image of the week” on our WISE website.  Here’s this week’s - I hope you find it as lovely as I do.  For more info on it, click here.

A mosaic of images from WISE in the constellation of Cassiopeia. Visible in this image are two nearby galaxies, Maffei 1 and Maffei 2, normally obscured by dust.

We’ll start close to home, with a visit to a nearby comet that’s passing through the inner parts of our solar system right now: Comet Siding Spring.  This comet is zooming in from the frozen, desolate outermost reaches of the solar system from what’s called the Oort Cloud into the warmer, more hospitable region near the Sun.  This comet is on what’s called a hyperbolic orbit, meaning that it’s only going to pass this way just this once in the foreseeable future; after it swings by the Sun, it’s going to be gone for good, most likely.  The warm sunlight is causing particles and gas to stream off from the comet, forming a spectacular long tail that extends roughly ten million miles or so.  We took five snapshots of it with WISE over about an eight hour period, and we made a little movie of them (please click on the link since I don’t have time to resize the video so it will embed correctly).

You can see that just like the comet we just discovered, Comet WISE, Comet Siding Spring looks like a splash of red paint in these images because its dust is much cooler than the stars in the background:

Next, we’ll head outward from this next-door neighbor to our Sun’s local neighborhood.  This is a cluster of massive, newborn stars called NGC 3603 that is spewing out radiation, including ultraviolet, visible light and charged particles into the surrounding environment.  You can see from the inset a picture of the cluster that was taken by Hubble.  The advantage of having WISE becomes apparent when you look at how much of an effect those stars are having on the surrounding gas and dust from which they were born; the WISE image covers 2,500 times more area than the Hubble picture.  With Hubble, you can see great detail, and with WISE, we can see the big picture.  This is a cluster of forming stars similar to the one from which our Sun and solar system were born.  It’s a messy, chaotic process, as you can see from the photo.

Now let’s meet our own galaxy’s nearest big neighbor, the Andromeda galaxy: 

The blue colors show where the older stars in the galaxy are; just as on Earth, the bluest flames are hottest.  The red colors represent the longer wavelengths that are produced by dusty star formation regions just like we saw in NGC3603.  You can use the WISE data to see where the construction zones are in Andromeda, so to speak - the regions where active star formation is taking place. The other cool thing about this photo is that you can see the disk of Andromeda is bent on the left-hand side, like a hubcap that’s been in an accident.  This tells us that another, smaller galaxy probably crashed right through Andromeda at some point in the past.  The WISE photo covers a huge area, more than 100 times larger than the full moon appears in the sky, and with it, we can see all the little satellite galaxies that are orbiting Andromeda.

Finally, let’s journey to a galaxy cluster similar to the one our own Milky Way belongs to.  Our local cluster is called (somewhat unimaginatively) the Local Group.  This picture shows another, similar galaxy cluster some 20 million light years away called Fornax. 

Most of the cluster consists of old stars that appear blue to WISE, but can you guess which is building the most new stars?  Yep, you got it - it’s the little barred spiral on the lower right, which has the telltale red of cool dust that indicates star formation, just like in NGC3603 and Andromeda.  So we can use WISE to trace the history of star formation far away, and therefore back in time.

We hope you’ve enjoyed your journey with the WISE spacecraft, so please put your seat backs and tray tables up, and come fly with us again soon!

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UPDATE: Last night we discovered another comet!  It has just been officially announced via Minor Planet Circular.  It’s also known as Comet WISE, or P/2010 D1 (WISE).  Woot!  It was an exciting find - we saw the image the spacecraft had taken only a day ago, and one of our team members was able to jump right on it with a ground-based ’scope in Arizona and follow it up within a half an hour of finding it in the WISE images.  Instant gratification like this is rare in astronomy. 

We’ve all been working like crazy people on WISE.  I can’t even keep track of how many hours we work each day, but it’s paid off - we just discovered our first comet, our first potentially hazardous near-Earth asteroid, plus a whole host of other asteroids in the Main Belt.

Our new comet is now known officially as P/2010 B2 (WISE), or Comet WISE.  Here’s a pic of it: it’s the red, fuzzy dot in the center of the frame.

Cosmic dustball: Comet WISE

The fuzz is the dust and gas surrounding the nucleus of the comet.  Comets are basically like snowballs that are mostly filled with rocks - just like the mean kids in the neighborhood used to throw.   You can see how it compares to an asteroid, which is the other red dot in the frame to the upper left of it.  The asteroid isn’t fuzzy at all, and that’s how we found the comet - the fuzz was a dead giveaway.  Plus, we noticed that the fuzz actually points in the direction opposite the Sun, which is what you’d expect for a comet.   It got followed up by a hardy crew of professional and amateur astronomers, allowing it to be formally discovered. Thanks, folks! As Jon Stewart would say, “Nailed it!”

Our next fun find is now known as 2010 CO1, although we call it Banjo (that’s ’cause its original WISE designation was W008anj - get it?).  Banjo is what’s known as a potentially hazardous asteroid, which sounds scarier than it really should, in my opinion.  The day we got the discovery officially announced, I was grinning and excitedly telling one of my colleagues, “We found our first potentially hazardous asteroid!”  He looked at me like I’d said I’d found a cockroach and said, “Uh, that’s great, I think.”  He shouldn’t have worried because that classification just means (more or less) that the asteroid gets within 0.05 astronomical units (or 4.6 million miles) of the Earth’s orbit around the Sun.  As I’ve said before, that doesn’t mean it’s going to hit the Earth since the asteroid and the Earth will probably never be at the same place at the same time. Here’s a handy diagram of its orbit, courtesy of JPL’s Near Earth Object Program. This nifty tool lets you type in an object’s name, and you can play a little movie of its orbit - totally useful.  I’ve advanced the movie forward in time to a point where the asteroid crosses the Earth’s orbit, but as you can see, the Earth is pretty far behind it, so there is no danger of collision.

Orbit of 2010 CCO1

I finally managed to take a little time off today and actually go outside as I was starting to feel a little like Gollum (if I start calling it Comet Precious, that’s bad). Our team has been working doggedly ever since launch.  While the work is exhausting, it’s exhilarating.  I’ve waited so long to get these data, and as tired as we all are, we are so excited to see what new surprises are in store in each image.  It’s like surfing on a tidal wave of data.  In spite of the fatigue, it’s been wonderful to be able to immerse myself in learning all of these new things.

********

UPDATE: We have just announced the reclassification of an asteroid as a comet!  Another group found the object, known as 2009 WJ50, and reported it to be an asteroid.  However, last Wednesday, we saw in the WISE images that it was clearly a comet - it was fuzzy and had a tail!  Other observers confirmed the activity.  The object has now been redesignated as a comet.  Yee haw!  Just goes to show you that the heavens are far from unchanging…

I found the golden ticket!

Our first “golden ticket” is now known as 2010 AB78, although we’ve nicknamed it Boingo after my parrot.  It’s an asteroid that is roughly 1 kilometer in diameter, so it’s fairly large.  Of course, unlike Charlie, finding the golden ticket wasn’t a matter of luck, but rather a search strategy that more closely resembled this:

An asteroid-finding factory!

Near-Earth Objects are asteroids and comets with orbits that get close to Earth’s orbit.  That doesn’t mean they are going to hit the Earth, of course.  It’s sort of like driving on a busy street; just because there are a lot of cars zipping by on either side of you, it doesn’t necessarily mean your car is going to hit one.  They would have to be at the same place at the same time for that to happen, so even though the paths each car has travelled might get close, there is no collision.

WISE finds asteroids by using a sophisticated piece of software called the WISE Moving Object Processing System, or WMOPS (nested acronyms - we get bonus points for that!). We adapted this piece of code from a couple of other projects.   When we first get a set of images from WISE, we have software that automatically searches the images for all the sources in them, be they stars, galaxies, or asteroids.  The software records their positions and how bright they are.  WMOPS goes into that source list and figures out which sources are moving compared to the fixed stars and galaxies in each frame.  Then, it figures out which sources are actually the same object - just observed at different times.  So it’s a pretty smart piece of code.  The whole system has to be highly automated, since when the WISE survey is done, the source catalog will contain several hundred million sources!  You can imagine trying to sort through all of these to find individual objects would be very challenging without a boatload of computers and a nifty program like WMOPS.

We are currently putting the finishing touches on the calibration of our data reduction pipeline software, a process which requires that we acquire at least a couple of weeks of data taken in regular survey mode.  While we have carefully characterized the WISE instrument on the ground, some things can only be finalized once we are in orbit, and we need a fair amount of survey data to build our models of its performance.  Once the calibration is done, we will begin scooping up solar system bodies en masse.

Here is our newest addition to the approximately 6600 Near-Earth Objects that are currently known:

Infra-asteroid: 2010 AB78 is the red dot smack in the center of the frame!

2010 AB78 shows up like a red ember at the center of the image, because it’s glowing brightly in infrared light with a wavelength of 12 microns.  The stars appear blue, because they’re much hotter, and they emit proportionally less of their energy at these long wavelengths.  The color of the asteroids to WISE is an important feature we use to distinguish them from other stars and galaxies, in addition to their motion.  As you can see, at the longer infrared wavelengths, there aren’t a whole lot of other objects in the frame.

The other object is called 2010 AG79 (nickname: Steve Majors.  It’s a long story.)  It is a smaller asteroid, about several hundred meters in diameter.

With this first two asteroid discoveries, we are flexing our muscles in preparation for the heavy lifting we’re about to start.

Tens of thousands of images a day, tens of Gigabytes, millions of stars, asteroids, and who knows what else have made for a busy week.  We are finally, officially out of our 30 day in-orbit checkout phase, and we have started the survey!  We’ll pause for a moment to pop the Champagne, but now it’s time to get to work.

One of our many data quality checking pages displays snapshots of each image that you can scroll through.  Rotating through the sky, the heavens wheel past as you flick the mouse.  It’s a strange feeling to be sitting in an ordinary-looking office in a plain little building, watching a skyful of blazing stars freshly hauled in from  our spacecraft. When I eventually go outside to look for food, I feel like I’ve just arrived from another planet!

Here’s a little movie to give you some idea of the advance in sensitivity and resolution that we’re seeing.  Even though other telescopes like the Spitzer Space Telescope have vastly improved sensitivity and resolution, they have only surveyed about 1% of the entire sky in detail.  So if you want a look at most of the sky in infrared wavelengths, you’re stuck with using data from the Cosmic Background Observer (COBE) spacecraft’s DIRBE instrument, launched in 1989, and the Infrared Astronomical Satellite (IRAS), launched in 1983.  The IRAS telescope was actually bigger than WISE - 60 cm in diameter vs. our 40 cm - but IRAS had 62 pixels; WISE has 4 million.  You can see what a difference modern electronics make!  Sorry the embedding has messed up the page formatting, but I don’t want to take any more time trying to fix it.  :P  If I’m going to mess around with the computer, it’s going to be for working on WISE data!

Starry-eyed surprise

If an ordinary picture is worth a thousand words, this one is worth at least a thousand stars!

From the press release:

“This infrared snapshot of a region in the constellation Carina near the Milky Way was taken shortly after NASA’s Wide-field Infrared Survey Explorer (WISE) ejected its cover. The “first-light” picture shows thousands of stars and covers an area three times the size of the moon. WISE will take more than a million similar pictures covering the whole sky.

The image was captured as the spacecraft stared in a fixed direction, in order to help calibrate its pointing system. The mission’s survey will be done while the satellite continuously scans the sky, and an internal scan mirror counteracts the motion to create freeze-frame images. The team is working now to match the motions of the spacecraft and the scan mirror precisely.

This eight-second exposure shows infrared light from three of WISE’s four wavelength bands: Blue, green and red correspond to 3.4, 4.6, and 12 microns, respectively.

Image credit: NASA/JPL-Caltech/UCLA”

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More soon, including a comparison of this new WISE image vs. the old catalogs it will replace: COBE and IRAS.

“What is it?”

“It’s beautiful.”

There is so much to see.

Sorry I haven’t updated this blog in a few days. Like the rest of our science team, I’ve been glued to the computer screen almost the entire time

It’s like Christmas and Hannukah and New Year’s and my birthday and the Fourth of July all rolled into one! While most of Pasadena watched the Rose Parade, we watched the stars. This was definitely the most spectacular New Year’s I’ve ever had. We’ve been giddily flipping through the images. It’s amazing - there is SO MUCH data. It’s funny, I’ve known that WISE takes a 4 megapixel image every 11 seconds for six years now, but to see it in action is really mind-blowing. Pictures pile up so fast that my poor laptop can’t possibly keep up, but that’s why we have a huge room full of computers and hard disks crunching away downstairs.

Something wonderful.

We are busy working on the last calibrations before we can start the survey. We use a little mirror to rapidly click from one part of the sky to the next, and we have to match the rate at which we scan the telescope to the rate that the mirror moves. The process is similar to focusing a pair of binoculars - you run the focus knob from one end of its range to the other, and you choose the setting that gives you the sharpest image. We are also tuning up our pipelines for reducing the data and looking for moving objects like asteroids and comets.

This is why I always wanted to be a scientist - to explore the universe and to better understand our place here, for one of the greatest joys in life is learning.

Happy New Year!

The cover floated away to cheers, hoots and high-fives in the control room.  At a command from the Ace, we saw the temperatures drop into place, and we could see the small bump in the telescope’s pointing - the kick-back from the cover flying away.  Now it’s somewhere in a lower orbit, waiting to slowly burn up in Earth’s atmosphere.  Yippee!!!!

I have to admit that this whole in-orbit checkout process is a bit like race horses on a steeplechase course - we have a series of hurdles to jump, although we’re almost done now.  Just a few more bars to leap over.

So we’re all huddled in the control room anxiously awaiting the first pictures from WISE to make it to Pasadena.  The first images have been transmitted from space already, so they’re on the ground, at the White Sands ground station facility in New Mexico.  They’re wending their way through the wires to California…very soon, we should have our first look at what WISE can see!

Right now I’m sitting at Caltech downloading a fresh load of images from WISE. This weekend, we switched on the WISE camera for the first time, and we are now cranking through many, many gigabytes of data!

The sequence began at 2:15pm on Saturday. The entire ops team gathered in front of the monitors in the control room as the Ace (that’s what we call the mission controller) called out the commands over the voicenet to activate the payload for the first time on orbit. We watched the telemetry screens anxiously for confirmation that the four detectors had powered on correctly, and that their temperatures would stabilize as we expected. Scripting commands scrolled up the Ace’s screens. Talking to a spacecraft is a little like talking to your imaginary friend, or a ghost - you send a message into the ether, wait for a while (feeling a little like you’ve been talking to yourself), and suddenly a flood of replies come back seemingly out of nowhere. It’s an improbable-seeming chain of events that has to take place to make this happen: At a command from the Ace, radio waves are blasted from New Mexico up to the spacecraft, which thinks about it, obeys the directions, then sends more radio waves to another satellite (NASA’s Tracking and Data Relay Satellite System). This messenger satellite turns and passes the answer back to New Mexico - all while both spacecraft are whipping around the Earth at 17,000 miles per hour. The signal wends its way back through cables to Caltech and JPL, and our monitors light up. So many things have to right just to send a simple message: Power is ON. It’s truly amazing that any of this works.

Over the course of the next hour, we got back the replies we’d been hoping for: all four detectors were alive, their temperatures had stabilized at the expected frosty levels, and our scan mirror moved as expected. The knot of tension in my stomach eased up a little. Time to start taking pictures! In the control room at JPL, we couldn’t see the results immediately, since even though WISE transmits at a blindingly fast 100 Megabits per second, it still took a few hours to get the first 2 GB of data we collected down to the ground due to the security protocols. Plus, all the image data comes directly to Caltech rather than to the JPL control room. We could see the flash memory on board the spacecraft filling up, though - but what was WISE seeing? Were all four detectors okay?

A few of us from the science team waited nervously at Caltech for the first image data to show up on the servers. Finally, by 8:45 I heard a cheer from our lead software engineer downstairs, and we got the link to the files from him. Typing as fast as I could, I grabbed the files and popped open the first images. Success!!! All four detectors showed exactly what we’d expected: the same pattern of stripes and blocks that we’d observed on the ground. This is because we haven’t ejected the telescope’s cover yet, so we’re looking at the inside of the lid. WISE has yet to open its eyes.

So for the last few days we’ve been poring over this dark data, studying the detectors to see if they really behave the same in space as they did on the ground. I’m happy to report that everything is looking great so far, and we’re on track to eject the cover Tuesday afternoon at 2:30pm Pacific time! The sleeper is almost awake.

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