Archive | March 2012

Technical difficulties resolved, for now.

Early this morning Jane Jordan diagnosed the problems (resulting from an improper termination of our observations yesterday) and fixed them.  I’ve now added that ‘fix’ to my cookbook so in the future I can be more effective at supporting the observations.  Why mention any of this here?  Just to request your continuing patience as we modify our real-time software to enable SETILive and incorporate your assistance.  Thanks.


We are experiencing technical difficulties …

Tonight (it’s all relative to where you are, and I’m in California) something unusual is going on with our SonATA observations. Since we started up a bit before midnight local time, Jon Richards and I have been babysitting the automatic SonATA (that’s SETI on the ATA) observing system. It started up on time from the observing cron files, but something is non-standard. Jon and I have spent the past few hours trying to figure out what’s going on – what changed – what might the error messages we’ve been receiving really mean???? For those of you familiar with software coding and embedded error messages, you can understand that error message XXX_XXXX doesn’t necessarily tell you what the REAL problem is. Jon (as brilliant as he is) and I haven’t been able to decipher tonight’s messages. Data are being taken and decisions are being made and we are continuing with our observing. However, when Jane Jordan, the particular wizard best suited to solving this puzzle, looks at the logs on Monday; she may tell us that tonight’s data are compromised and we should reobserve all of these targets/frequencies. Why wait until Monday? Why don’t we get Jane out of bed right now and have her tell us what’s really wrong? Our SETI team is tiny, and our observations take place EVERY day. We need to move forward with new ideas while we enable our ongoing observations. So at the risk of having to inform you, and the team, that tonight’s observations aren’t valid and will need to be redone, we are letting Jane sleep so she can be awake to help us improve SonATA and SETILive. Tonight, the SonATA system tells me that we are observing three targets simultaneously, but when I try to classify signals at, I am being presented with only one beam, not three. Welcome to the world of real observational science, and please accept my apologies for any “do overs” we need to do to get the job done.

Three beams, 50% more fun!

We’ve enabled the third (and final) target beam at the ATA, so that means you’ll be classifying three Kepler targets and that will make it more likely that a signal you mark in only one beam is actually a “signal of interest” and worth making the ATA go back to that Kepler target for a followup measurement. This will become the norm (if all goes well). We don’t think you’ll have any problem marking that third target image in the same 60 seconds you’re used to and with a third image, that’s 50% more Kepler targets to classify each time, so you might just enjoy it 50% more than usual. Let us know here or even better, on Talk if you have anything to say about it.

With two beams, a weak signal appearing in only one target beam can mean that instead of coming from the target ET star system, it was a satellite or other interference but just a little too weak in the second beam for you to see. The sensitivity to interfering signals coming in from the side (in the ATA’s “peripheral vision”, instead of in the direction of the target) varies enough between the beams so that this can happen. With three beams “voting”, it’s less likely that one beam is that much more sensitive than both of the others and the interfering signal is more likely to show up in two of the beams.

Again, let us know if you have any comments here or even better, on Talk.

Something new, some things to come

We’ve been live in this initial phase for over nearly two weeks now and the number of people joining the search and your genuine excitement for the project has been downright awe-inspiring and very gratifying for the entire SETILive/Zooniverse team.
By getting involved with SETILive you’re joining a truly live experiment and the most ambitious project the Zooniverse has ever built from both a technical (taking live data from the ATA) and user-interface standpoint. Building an interface that will allow us to spot potentially interesting signals has been our main focus thus far and following some very helpful feedback from the SETILive community we’re updating the signal-marking interface today to make it more flexible and descriptive, and we’re expanding the tutorial resources.
The immediate goal of marking signals in SETI Live is to work out what signals are terrestrial interference so we can trigger a followup observation at the ATA for promising signals. As you probably know, we’ve had some start up issues with web sites and maintaining live data connection with the ATA and that is now becoming stable. With the general stability improving and with these improvements to the interface, we’re in good shape to start fully closing the loop and over the next week or so we’ll be working to fully and consistently enable the followup requests to the ATA. We’ll also be working on introducing artificial ET signals now and again to the signals and of course, will indicate to you when that happens right after you finish marking the observation. This will allow us to get our evaluation of this experiment off and running in the coming weeks.
We’ve changed the marking process to make the “Describe the Signal” a two-step process, which should reduce some confusion. We still have the basic tutorial introduction and that should still be enough to get you right into it, but we’ve expanded the tutorial resources for you if you want more guidance or background information. There’s now a live video showing how to mark a range of examples.We’ve also enhanced our Signal Gallery, still showing information on what might be producing the signals , but when you move your mouse over the image, you get marking advice both visually and in the text.
So, welcome to the next phase of SETILive! We’ve taken a few small, but significant steps in making this work better for you and therefore, better for the quality of the science we eventually produce together. We all hope that will be finding a truly promising signal, but it could be analyzing the implications of NOT finding one, or quantifying the possibilities of applying your collective intelligence in this way to this type of problem. Any of these outcomes will be scientifically important.
In the discussions, there’s a lot of interest in more background on what it is you’re seeing and what to expect an ET signal to look like. In the near future, look on this blog for more background information on the science of SETI and the nature of signals both terrestrial and extraterrestrial.
In the background, we’ll also be looking at subtle changes in the way we present the data to you that could help you see weak signals better and more consistently. Of course, we have to be very careful about any changes to what you’ve already got better and better at using. We’ll also be evaluating alternate visualizations that involve color, but that is a tricky business and we won’t change anything that dramatically without some careful evaluation.
Thanks to all of you for getting us off to such a great start and for helping us to make it better.

Everything you do will help us

I’m Jill Tarter, the Director of the Center for SETI Research.  Since we launched at TED last Wednesday, I’ve been reading what you’ve been writing.  There have been a bunch of comments on SETILive about not knowing what to do or what to mark or whether you are getting it right. We’ll work on making the tutorial more accessible and more informative as you’ve suggested, and over time we will implement some better marking tools as you’ve requested – but the ‘getting it right’ part is a bit more dicey.  That’s because we really don’t know yet exactly what ‘right’ is.

As Lou Nigra (thanks, Lou!) and the tutorials have described, the SETILive data that are coming from the ATA originate in the crowded bands; small portions of the terrestrial microwave window that we have historically skipped over.  That’s because our SonATA system gets confused there – it detects LOTS of signals, but it cannot finish clustering them, and classifying them by comparing them to signals that are detected in the other two (or maybe one as is now the case) beams on the sky being observed simultaneously, or finish looking them up in a database of all the signals that have been tagged as RFI in the past week.  Rather than conduct our observations with non-uniform sensitivity, or continuously restart software modules that have given up in exhaustion, we have chosen to ignore these crowded bands – at these frequencies we’ve been blind and deaf.  Ultimately that might turn out to be the best strategy – after all, why are those bands crowded?  They are crowded because they have been allocated to different types of terrestrial communications services.  We are the ones making all those signals.  Or are we?

IF (of course it’s a huge if) there is a technological civilization near enough to us – its distance in light years is less than half the time over which our technology has been transmitting at a particular frequency band – perhaps that civilization has noticed that the Earth is very ‘radio bright’ at certain frequencies. Perhaps it has transponded back a reply at the same frequencies, knowing that we would have receivers that work there.  A bit more speculation suggests that their message may be crafted to be detectable against this background of terrestrial transmissions.  With this scenario in mind, we could try to code and implement all sorts of clever, non-linear anomaly detectors that inter-compare the signals received from the multiple beams on the sky – but remember we are trying to do this in near-real-time.  The detector has to finish this task significantly before the observations move on to the next frequency band, because the system still needs to match whatever the detector has found against recently detected RFI from other directions on the sky.  We don’t know what we are looking for, but we do want to invoke logical constraints that insure that the signal is only coming from one direction on the sky and not many.

Before we throw a whole lot of new computing resources (that we actually don’t happen to have) at this problem, we should take a look at what’s actually going on in the crowded bands as a guide to what might be the most effective strategy – that’s where you come in!  We are hoping to use the amazing pattern recognition of your eyes and brains to look for signals (patterns of some sort) that appear in only one beam and not in any of the others.  We hope you can help us set up a sort of rogues’ gallery of signal patterns detected over the past week (fortnight, month, 3 days ??) that can be collectively ‘remembered’ to assess whether this particular signal pattern has been seen before from other directions on the sky. That’s why we want you to mark the RFI in multiple beams as well as any pattern that only shows up in one beam.  And then if enough of you mark the same single-beam pattern (so we are fairly confident it’s real, not noise), we’ll decide that it’s an interesting candidate signal and follow up on it immediately.  That means that instead of moving on to the next frequency in the observing sequence, we will reobserve in the same directions, at the same frequency.  SonATA is still blind, so you will have to tell us whether the pattern persists – is it still there?  Is it still only in one beam?  If so, the next observation will observe at the same frequency, but looking at different directions.  Is the pattern still there? Well, that’s too bad, it means it really was some form of interference and isn’t associated with the target we were pointing at on the sky. BE PREPARED – WE THINK THIS WILL HAPPEN A LOT.  Just like your eyes have peripheral vision, a radio telescope has ‘sidelobes’ into which signals can scatter and be confused with signals entering from the direction the telescope is pointing.  The sidelobes are complicated in the way they cover the sky; it may appear that a signal is coming from only one beam out of three, but moving ‘off source’ can reposition the sidelobes so that the interference is once again detectable.

But what if the signal/pattern persists when we reobserve ‘on source’, and disappears when we go ‘off source’? That’s getting interesting! We’ll start up a cycle of ‘ons’ and ‘offs’ that will stop when the signal fails to be detected, or not be detected, at the right time, or when we’ve completed five cycles.   If the system successfully completes five cycles, then the team at the Center for SETI Research will be alerted and we’ll be right there with you using our eyes and brains to figure out what to do next.  Since we’ve begun SETI observing on the ATA this has not happened in the less crowded bands that SonATA has been exploring automatically.  Now that we are trying to probe the crowded bands, we’ll have to see how it goes.

By now I hope you are convinced that your efforts can only help us.  There’s a slight chance that you just might discover a signal from another technology buried underneath all the terrestrial interference and we will all celebrate.  But at the very least you’ll help us better understand what it is that humans are doing as they manage to look at complex patterns and isolate sub-patterns that are unique to one of multiple samples.  There may well be neurologists or psychophysicists out there who already know that answer, but my team doesn’t.  If we can learn from you, we can be better equipped to train future automated detectors.  And if it turns out that this is not a task at which humans are particularly adept, well we haven’t lost anything.  After all, our previous strategy was to ignore the crowded bands.  There is only an up side to your participation.

Thanks for being willing to help out, and good luck!

Science in the Moment

I’m Lou Nigra and have the good fortune to be Project Scientist for SETI Live and I’d like tell you about what we’re doing and why.

The SETI Live project’s goal is to take the Search for Extraterrestrial Intelligence (SETI) into the large chunks of radio frequency spectrum previously made mostly useless by the human-made Radio Frequency Interference (RFI) that crowds them from sources like GPS satellites and mobile phone networks. We’ll do this by showing you radio frequency signals direct from the SETI Institute’s Allen Telescope Array (ATA) as they are received while looking in the direction of stars that according to the Kepler telescope (and sometimes our sister project, Planet Hunters) have planets where liquid water is likely and so have the best chance of hosting an ET civilization producing radio signals of their own. Not only that, we’ll be putting you “in the loop” – if enough of you see a potential ET signal in the same data, then within minutes, the ATA will be interrupted and sent back to take a second look. This is already pretty exciting on several levels – you’ll process SETI data fresh off the telescope, the telescope will be pointed at stars with promising planets, and if you identify something ET-like, it could trigger a follow-up measurement. Now, this is basically what the ATA computers normally do, so why bring a bunch of citizen scientists into the loop?

Cleverly conceived computer algorithms used by the SETI Institute are extremely good at identifying potential ET signals in the presence of simple forms of RFI or small amounts of it. They become confused and unreliable when too much RFI begins to make the data too complex and chaotic. This is where you come in. Maybe it’s because humans evolved in a basically chaotic world that our sight (and other senses) are so good at picking out of that chaos the patterns that are important to us at the moment. Because of this, we believe that the human eye… well actually the human brain, will be much better suited than a computer algorithm to finding the weak, but orderly engineered signals we expect to intercept from a distant ET civilization amidst the complex and sometimes chaotic background of RFI.

Aside from the very important contribution to SETI science of opening up new frequency spectrum to the search, there are other scientific results we expect to get from SETILive. For one thing, we don’t know just how weak an ET signal you’ll be able to identify. So, we’re going to evaluate this by occasionally inserting data with an artificial ET test signal and collecting statistics on the results. Don’t worry, we will tell you immediately after you’ve classified one of these that it had a test ET signal and whether you caught it or not. We also don’t yet know the best ways to visually present this data to users that will make it easiest to pick out ET-like signals. We expect this to evolve as the project progresses and we’ll evaluate how successful you are with different visualizations. We expect to publish the results of both of these studies so you will be contributing to some important signal analysis science. Some of this may also lead to improving SETI computer algorithms.

We’ll start with a simple display that is widely used and very effective throughout radio astronomy: The “waterfall” display. Here the data is shown to you in a set of images, each of which shows all the frequencies in a particular bit of spectrum coming from a particular Kepler target’s direction, the strength of each frequency, and also how this changes with time. We’ll also give you some graphical tools to identify signals with frequency patterns that could be of interest.

Welcome to this unique Zooniverse project! I’m very excited to be a part of it and I look forward to working with you all.

What We Do With Your Classifications

What Data Do You See?

On SETI Live you are looking at ‘live’ data from the telescope.  Every second, SonATA (SETI on the Allen Telescope Array) reports the power measured in individual frequency channels that are 1 Hz wide.  While the SonATA system is dealing with more than 20 million such channels, for each beam on the sky, SETI Live is concentrating on only a few bands of channels that are crowded with signals.

Each waterfall plot displays the power in each of 533 channels horizontally, with each vertical row being a new time sample.  The most recently sampled data is at the top of the plot.  The brightness of the pixels represents how strong the signals are.

There are two or three separate waterfall plots for each observation, because the SonATA system looks at different target planetary systems at the same time.  If a signal is really coming from one of the targets, it should be in only one of the plots – this is the sort of signal that might be from ETI.  If the same signal can be seen in multiple plots, then it is some sort of interference of RFI that is entering into what we call the telescope sidelobes.  Your eyes have peripheral vision, and so does a telescope – that’s what we call sidelobes.  It is hard to distinguish a loud signal in the sidelobes from a weak signal in the telescope beam.  Looking at multiple targets at the same time helps us figure this out.

How Does the Crowd Find ET?

During the initial observations, signals that you identify as being in only one beam, having some non-zero drift rate, and never having been seen before, become interesting candidates to be real ET signals.  So when the current cycle of data acquisition ends, SonATA will retune the telescope’s frequencies and look back at the same target and frequency to try to reacquire that signal again.  But SonATA is still blind to the crowded bands and so you will have to help with this follow up.

If the candidate signal you found was changing frequency over time, SonATA will predict the frequency where it should now be found, and generate waterfall plots for you to observe.  Is the same signal still there?  Is it in any other beam?  If the answer to the first question is yes, and to the second question is no, this candidate remains of interest. Otherwise it will be classified as being due to chance noise, or interference.

A candidate that’s still interesting automatically generates an observation ‘off-source’ in the next data acquisition cycle.  These new data will be presented to you.  Is it still possible to see the signal?  If so, it is coming from somewhere other than the target we were looking at and is therefore interference.  If it isn’t seen ‘off-source’ than the next observing cycle will look back at the target.

This automated on/off cycle will continue 5 times, or until the signal is identified ‘off-source’ or fails to be seen again while pointing on the target.  After 5 cycles, SETI scientists are alerted and humans take over the logic of where to point the telescope next – this is a rare, but very exciting occurrence!  You are still critical because you’ve been classifying this signal up to now and are the experts on recognizing it.  We’ll all look together to figure out how to proceed and what other questions to ask.