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Profile Maarten Meulendijks
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Message 84058 - Posted: 8 Mar 2005, 19:20:52 UTC

Hello,

I'm new to SETI@home, so forgive me if I ask stupid questions. Firt of all about the candidates. What I realy would love is to hear the candidate signals. Is there a website where I can actualy hear the two types of sounds (the usual 'empty' sound, and the candidate sound)? I would like to get more in touch with the work we are doing. So hearing it for ourselfs would be great.

Second: how does this listening actualy works? How can you listen to something in outer space from the surface of the earth? Wouldnt a very distant sound just be lost in the atmosphere of earth before it reaches the 'ear' disk?

third: what exactly are we doing at home? I mean: I guess we receive a packet of data and a set of calculations to perform on it, but what packets are we getting? Is it a packet of time? How much time? How long is such a signal, how complicated is such a signal? What does the packege 'sound' like?

Thanks in advance!

Maarten from Amsterdam
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Profile Byron Leigh Hatch @ team Carl Sagan
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Message 84067 - Posted: 8 Mar 2005, 20:01:49 UTC - in response to Message 84058.  
Last modified: 8 Mar 2005, 20:26:32 UTC

Maarten Meulendijks Wrote the following

=======================================
> Hello,
>
> I'm new to SETI@home, so forgive me if I ask stupid questions. Firt of all
> about the candidates. What I realy would love is to hear the candidate
> signals. Is there a website where I can actualy hear the two types of sounds
> (the usual 'empty' sound, and the candidate sound)? I would like to get more
> in touch with the work we are doing. So hearing it for ourselfs would be
> great.
=======================================

Hello , ___ Maarten

---- and wellcome to ___ SETI@home II


try here:


<B>http://setiathome.ssl.berkeley.edu/mx/</B>





<A><B>Hands-On Radio SETI Exhibit</B>[/url]

Radio SETI (Search for Extraterrestrial Intelligence) is an area of scientific study that listens to radio waves from other stars,

seeking evidence of life outside Earth. Examples of radio SETI projects include SETI@home and Phoenix.

Hands-On Radio SETI Exhibit (HORSE) is an interactive page that uses sound and animation to teach about radio SETI.



<A><B>System requirements:</B>[/url]

Version 4.0 or greater Internet Explorer; also works in Netscape 4.0 and greater, but not reliably.

Works best on Windows; also works on Macs and UNIX/X11 but the graphics and sound may be choppy.

Make sure that Javascript and Java are enabled in your browser.

Make sure that your volume control is turned on.

HORSE has variants for different monitor resolutions. Click on the highest resolution that will fit on your monitor:




go here:

<B>http://setiathome.ssl.berkeley.edu/mx/</B>




My Very Best wishes to everyone ......... and keep on crunching :)

from:

friendly and respectful
byron ... [/url]_Earth Flag

<B>S@h_ Berkeley's Staff Friends Club member m2 ©[/b]
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Message 84071 - Posted: 8 Mar 2005, 20:13:45 UTC
Last modified: 8 Mar 2005, 20:58:07 UTC

Hello Maarten,

welcome to Seti@home. You ask some very interesting questions that could take a very long time to answer. I will try to be brief.

1. The signals are not something that can be converted into sound that a human being could understand. There was a small application on the Seti@home classic pages that converted the data sent to you pc into an audio file, but all you could ever here was noise.

2. The signals we are looking for are very special. They are tiny radio transmissions (well very big when they start off) at a very precise narrow band of frequncies. This frequency is the one chosen by the very clever people at Seti who tell us that if we found something on or very close to that frequency it may be from something or somebody trying to communicate. The signals, being radio waves will be attenuated by the Earth's atmosphere, but then they have become millions of time smaller already after having travelled billions of km through space.

3. The dish at Arecibo feeds a receiver which converts the signals into a form our computers can understand. This is then split into smaller chunks called work units (know as WU) that are sent out to everybody on the project. Your computer is searching in each WU for patterns in the signals captured at Arecibo. This search is known as crunching. Once your pc has crunched a WU returns information about any patterns it found.

The Seti@home classic website has more detailed explanations at and can be found at http://setiathome.berkeley.edu/learnmore.htm

Good luck with your crunching,

Richard

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Profile Maarten Meulendijks
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Message 84306 - Posted: 9 Mar 2005, 7:43:46 UTC

Thanks for the answers so far. A couple more questions:

4) How big are the chunks of data that we crunch at home, and how much data is collected during a 'telescope session'. So how much data is there? And how often does SETI collects new data? (and I wander: isnt there lost a lot of crunching time with distributing the data over the net?)

5) I have seen that the search path of the telescope, (how do you call it: a radioscope?) is focused on candidate signals found in previous crunches. But I also see on pictures that the actual disk is attached solid to the ground. Then how do they focus the beam when the disk cant move?

6) What are the thoughts about the time difference between sender and receiver? If we do find a signal, it is from a very very long time ago, the Inteligence might not even exist any more. Or is the time difference only depended on light speed and does sound waves travel different. (well 'ordinary' sound travels very very slow but is also depended of air to form a wave)

7) Is there a way to stop the Boinc-Seti screensaver from moving all the time? (I want to look at it)

8) finaly (a minor question, not realy important): I see that tonight my pc has uploaded two first chunks of data. By the way: does it upload the complete downloaded file or just a report of the analysis?). But if I check my account at seti, I dont see any credit added. When does one get a credit point?

Greeting to all from a still nasty cold Amsterdam!

Maarten
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Message 84309 - Posted: 9 Mar 2005, 8:04:12 UTC - in response to Message 84306.  

Welcome Onboard! By now, you've successfully stowed SETI@Home2 onto your computer and noticed that you've managed to upload 2 credits to Berkeley, CA. Well done!

> 4) How big are the chunks of data that we crunch at home, and how much data is
> collected during a 'telescope session'. So how much data is there? And how
> often does SETI collects new data? (and I wander: isnt there lost a lot of
> crunching time with distributing the data over the net?)

Since we're still getting things from Arecibo, they receive tapes that are placed into the splitter that cuts it up into roughly 256 Work Units, of which it is then cut into 1024 or so results that are sent out to BOINC Users.(Each size packet of data that I get is around 353 KB in size, roughly.) SETI collects data everytime that the telescope is being used. How much data is unknown because we simply don't know how many results were generated but if you look at the external BOINC sites, SETI has seen arouond 1,054,000,000 or so results. At 353 KB, that's 372,062,000,000 KB of data.(Off the top of my head estimates.)

> 5) I have seen that the search path of the telescope, (how do you call it: a
> radioscope?) is focused on candidate signals found in previous crunches. But I
> also see on pictures that the actual disk is attached solid to the ground.
> Then how do they focus the beam when the disk cant move?

Arecibo is in the ground and can't move, correct. What it does is that the telescope uses the rotation of the Earth to "move" the scope into place and any fine tuning is done with the Gregorian Dome that is situated above the bowl-shaped floor. I think that's why there's a certain arch that they look for in signals, to show that there was a pattern that correlated to the rise and fall of the star in relation with the rotation of Earth.

> 6) What are the thoughts about the time difference between sender and
> receiver? If we do find a signal, it is from a very very long time ago, the
> Inteligence might not even exist any more. Or is the time difference only
> depended on light speed and does sound waves travel different. (well
> 'ordinary' sound travels very very slow but is also depended of air to form a
> wave)

Radio travels nearly at the speed of light so the only factor that we're concerned about is the actual distance to the origin of the signal itself. But there is a catch to SETI@Home. We're not concerned about the contents of the signal insomuch as we're concerned with FINDING the signal. Once we find it, the experiment is a success and it gives way to the followup "Now that we've found it, what does it mean?" phase.

> 7) Is there a way to stop the Boinc-Seti screensaver from moving all the time?
> (I want to look at it)

There might be, check in the preferences.

> 8) finaly (a minor question, not realy important): I see that tonight my pc
> has uploaded two first chunks of data. By the way: does it upload the complete
> downloaded file or just a report of the analysis?). But if I check my account
> at seti, I dont see any credit added. When does one get a credit point?

You won't get credit immediately. Each WU is sent to 3-4 people who are charged with crunching it. SETI takes your returned work, assuming it's valid, and generates "pending credit" based on roughly your computer speed, amount of time spent crunching, and overall workload on your CPUs. Once there's enough valid results, the validator takes the median credit score and gives it to all 3-4 people who returned valid work. The assimilator takes the validated info and puts it into the main DB for future reference.

> Greeting to all from a still nasty cold Amsterdam!

Another thing about BOINC/SETI. We all get to meet people from all over the world. Hope this 2 cent-spiff of mine helped shed some light.

Aloha Nui Loa~! from nice, breezy and somewhat Balmy Hawaii!
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Profile Maarten Meulendijks
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Message 85057 - Posted: 11 Mar 2005, 14:09:52 UTC

Okay, thanks again. I now have some credit, so that part is functioning fine aswell. But still: more questions.

9) the mentioned crunch package of 350Kb. Is that not a little small? Couldn't (for example) increase the size of the package after som positive uploads?

10) the temperature of the processor. It runs at 100% efficiency since Boinc is on. I do not expect problems with it, because it is built to run at 100% but maybe there are some thoughts about this. I have seen some patch or something to compensate, but not for Boinc I think.

11) The reports back. Are they readable? I would like to see what happened and what is reporting home. And if a candidate signal is found, is there a signal, a sound, a bleep, a message or anything to report to me: hey, you maybe found a candidate? That would be nice. The whole thing now is so abstract, we are not getting in touch with the research that is being done on our computers. The graphs I see in the screensaver are completely not understandable or to fast to analyse. (and I cant get them to hold still).

12) that 'old' software addition to convert the raw data to sound to hear what we are working on: does that still works with Boinc?

ah yes, one more:

13) I dont understand the Boinck Quickstart options. I turned it to 'run based on preferences', but I see that it runs always, not only when the screensaver is on. Sometimes I have to suspend it to get my processor back for some other big task. I would like it to run only if the screensaver is on, and not when I am working myself. What should I do for that and where?

Thanks again!

Maarten
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Message 85116 - Posted: 11 Mar 2005, 19:22:42 UTC - in response to Message 85057.  

> Okay, thanks again. I now have some credit, so that part is functioning fine
> aswell. But still: more questions.

Bring `em on!

> 9) the mentioned crunch package of 350Kb. Is that not a little small? Couldn't
> (for example) increase the size of the package after som positive uploads?

They keep it relatively small because of the way that the data's split at Berkeley. There was some ideas back in 2001 on Classic that they would up the WU size when the science apps would become more intricate and programmed to look at a larger swath of frequency. This was supposedly going to happen when the multi-beam receiver began operation and we would start crunching that data. With the start of data collection with MB this year, we might see a new SETI app. and larger WU file-size.

> 10) the temperature of the processor. It runs at 100% efficiency since Boinc
> is on. I do not expect problems with it, because it is built to run at 100%
> but maybe there are some thoughts about this. I have seen some patch or
> something to compensate, but not for Boinc I think.

All depends on localized cooling and the conduct of airflow for you. I run BOINC on my laptop and it works fine for me to have it at 100% all through the day and night. Granted, it's hot as hell near the 12 hour mark but it runs clean and all programs I use on top of it work fine.

> 11) The reports back. Are they readable? I would like to see what happened and
> what is reporting home. And if a candidate signal is found, is there a signal,
> a sound, a bleep, a message or anything to report to me: hey, you maybe found
> a candidate? That would be nice. The whole thing now is so abstract, we are
> not getting in touch with the research that is being done on our computers.
> The graphs I see in the screensaver are completely not understandable or to
> fast to analyse. (and I cant get them to hold still).

As with Classic, they don't have secondary plugins to tell you what goes on or if you indeed found a signal. SETISPY and BOINCSPY are some of the plugins that keep track of your WUs and could give you a popup letting you know that the signal you crunched is interesting. Some people say that if Berkeley receives an interesting signal that you submitted, they'll send you a notice that gives you a heads up. I doubt this is true but it might happen.

> 12) that 'old' software addition to convert the raw data to sound to hear what
> we are working on: does that still works with Boinc?

It might, I'm not sure

> ah yes, one more:
>
> 13) I dont understand the Boinck Quickstart options. I turned it to 'run based
> on preferences', but I see that it runs always, not only when the screensaver
> is on. Sometimes I have to suspend it to get my processor back for some other
> big task. I would like it to run only if the screensaver is on, and not when I
> am working myself. What should I do for that and where?

"Run based on Preferences" is a default setting that tells the BOINC app to run based on the General Preferences that you have set. If you want to change it, go to the SETI Homepage, click on "Your Account" and then go to the "General Preferences". What you can do there is set not only the cache size of your SETI app but also there's a queue asking you "Do Work while computer is in use?" and you can easily click on "No". Check this section out to see how you want SETI to handle it. After you save your changes, it'll say that your preferences have been updated and will update your client upon next communication with the server. Just go into "Projects" and update.

> Thanks again!
>
> Maarten

No problem. Gotta help out fellow crunchers, given some people's tendancy to gripe about "lack of marketing"...blah...

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