Should there be a separate forum category for AstroPulse? There are separate categories at the SETI@home Beta Message boards: AstroPulse, SETI@home Enhanced.

Henri.

---

Manned mission to Mars in 2019 Petition <-- Sign this, please.

Now there are 13 sticky threads, which I consider is a bit too much. At least 4 of them are about Astropulse. Moving them and, of course, all the AP messages to a separate category would make this Number crunching category a bit clearer to follow.

Henri.

---

Manned mission to Mars in 2019 Petition <-- Sign this, please.

I suggest these names to new categories:
Number crunching - SETI@home
Number crunching - Astropulse

Henri.

---

Manned mission to Mars in 2019 Petition <-- Sign this, please.

I don't like the idea, on Beta there have been several posts made in the wrong board, here it would be chaos. It's bad enough here as it is people posting in tech news or the stickies when in should be in another board/thread.
We actually have too many boards as it is.

I agree.
Actually its all about number crunching.

regards

---

With each crime and every kindness we birth our future.

If the only problem is sticky's then why not combine a few of them?

---

Do you Good Search for Seti@Home? http://www.goodsearch.com/?charityid=888957
Or Good Shop? http://www.goodshop.com/?charityid=888957

It doesn't seem to be that much of a problem, So I'd leave It well enough alone.

---

The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's

If the only problem is sticky's then why not combine a few of them?

Yes, the Sticky's are annoying. They completely take up all the space in my monitor (yes, it's small).

---

- Luke.

They could tidy the stickies by putting all the FAQ's into a single FAQ Sticky and the Donation threads into a single Donation thread. That would half the number of stickies.

From how long distances deep in space can we catch a signal with the Astropulse project?
I think with the S@h we can catch a signal from maximum 3.000 Light years away.
Can Astropulse catch a signal from more long distances? for example from 10.000 or 20.000 Light years away?

---

SETI

The astropulse signal is richer (has more details) than the regular MB signal, and so takes more time to analyze. But I don't think it is correct to say that AP probes 'deeper' into space.

Remember that a light-year is merely a distance measure. We cannot tell how deep into space from which any signal eminates because we don't know when the signal was transmitted or how intense it was at its source. A radio signal will fall off roughly as 1/R^2 as it travels to us, with R being the distance between the Earth and the source. (Absorption by interstellar dust, and other loss mechanisms are ignored in the 1/R^2 estimate here for simplicity, but they represent small corrections.) So a strong signal from far away may have the same intensity measured on Earth as does a weak signal from nearby. Similarly, a signal created a long time ago from far, far away cannot a priori be distinguished from a signal of the same magnitude (measured on Earth) emanating from a body nearer to the earth created more recently.

One may expect to be able to estimate more about a signal's source distance by folding in other factors, such as how important the inter-stellar (inter-galactic?) absorption mechanisms are, how intense a signal would a 'normal' civilization may be expected to make, what the performance of our receiver and analysis system is, and so on. But such an estimate requires the convolution of many considerations and many assumptions. Obviously, this is a rich but difficult field of study!

The astropulse signal is richer (has more details) than the regular MB signal, and so takes more time to analyze. But I don't think it is correct to say that AP probes 'deeper' into space.

Remember that a light-year is merely a distance measure. We cannot tell how deep into space from which any signal eminates because we don't know when the signal was transmitted or how intense it was at its source. A radio signal will fall off roughly as 1/R^2 as it travels to us, with R being the distance between the Earth and the source. (Absorption by interstellar dust, and other loss mechanisms are ignored in the 1/R^2 estimate here for simplicity, but they represent small corrections.) So a strong signal from far away may have the same intensity measured on Earth as does a weak signal from nearby. Similarly, a signal created a long time ago from far, far away cannot a priori be distinguished from a signal of the same magnitude (measured on Earth) emanating from a body nearer to the earth created more recently.

One may expect to be able to estimate more about a signal's source distance by folding in other factors, such as how important the inter-stellar (inter-galactic?) absorption mechanisms are, how intense a signal would a 'normal' civilization may be expected to make, what the performance of our receiver and analysis system is, and so on. But such an estimate requires the convolution of many considerations and many assumptions. Obviously, this is a rich but difficult field of study!

If you have a look at the Astropulse (science) information page, there's quite a lot of information about this. Look for the section about 'dispersion': briefly, the shape of the pulses we're looking for will be different, depending how far they've travelled. So part of the complexity of the Astropulse search is coping with these dispersed pulses, and conversely the amount of dispersion will tell us from how far away they've travelled. So after we've caught a few pulses, we should be able to answer Petros' question.

They could tidy the stickies by putting all the FAQ's into a single FAQ Sticky and the Donation threads into a single Donation thread. That would half the number of stickies.

I'll run the idea by the Admin.

---

The astropulse signal is richer (has more details) than the regular MB signal, and so takes more time to analyze. But I don't think it is correct to say that AP probes 'deeper' into space.

Remember that a light-year is merely a distance measure. We cannot tell how deep into space from which any signal eminates because we don't know when the signal was transmitted or how intense it was at its source. A radio signal will fall off roughly as 1/R^2 as it travels to us, with R being the distance between the Earth and the source. (Absorption by interstellar dust, and other loss mechanisms are ignored in the 1/R^2 estimate here for simplicity, but they represent small corrections.) So a strong signal from far away may have the same intensity measured on Earth as does a weak signal from nearby. Similarly, a signal created a long time ago from far, far away cannot a priori be distinguished from a signal of the same magnitude (measured on Earth) emanating from a body nearer to the earth created more recently.

One may expect to be able to estimate more about a signal's source distance by folding in other factors, such as how important the inter-stellar (inter-galactic?) absorption mechanisms are, how intense a signal would a 'normal' civilization may be expected to make, what the performance of our receiver and analysis system is, and so on. But such an estimate requires the convolution of many considerations and many assumptions. Obviously, this is a rich but difficult field of study!

If you have a look at the Astropulse (science) information page, there's quite a lot of information about this. Look for the section about 'dispersion': briefly, the shape of the pulses we're looking for will be different, depending how far they've travelled. So part of the complexity of the Astropulse search is coping with these dispersed pulses, and conversely the amount of dispersion will tell us from how far away they've travelled. So after we've caught a few pulses, we should be able to answer Petros' question.

Yes, but...

A uniform plasma density is inherently unstable, both spatially and temporily. It will have density fluctuations on many length and time scales. Since this is probably not knowable, one must assume an average density distribution in space, at the time the pulse is transiting, in order to extract a distance estimate in this fashion. Hence, this is an example of the assumptions I was referring to.

@ Richard and Phon

Thank you both for your answers.

''The astronomers Duncan Lorimer and Matthew Bailes have already detected a millisecond transient radio pulse (one thousandth of a second), believed to originate 500 megaparsecs away.''-->http://setiathome.berkeley.edu/ap_info.php

If other Astronomers can detect a pulse from 500 Megaparsecs away then we can do it too i believe!

omg 500 Megaparsecs this is really huge distance!
1 Parsec = 3.3 Light years
1 million Parsecs => 3,262,000 Light Years => 1 Megaparsec
500 Megaparsecs => 1.500.262.000 Light years = > 1/2 Gigaparsec

This is exactly the technology we need to detect other civilizations !
With Astropulse we can detect pulses even out of our Milky Way!
If other civilizations use pulses to be detected from others then we are just one step away from the biggest discovery in the Mankind history!

---

SETI