SETI@Home Publishes Skymap

An anonymous reader writes "The skymap of where in the night sky to find the most promising SETI@Home signals is reported today, along with the research plan for the March Stellar Countdown project. The dedicated use of the Arecibo Telescope to revisit these spikes, pulses, and steady signals, focused on 166 star candidates. Those 166 were pruned from the five billion signals that have been found since 1999, depending on the signal's persistence, closeness to a known star, and frequency. The next step is particularly fascinating, if a signal appears to have increased since the first observation put that star on the checklist."

Comments

Re:Should we be concerned...

[Anonymous Coward]

I'd like to point out that it's the green/orange squares that are candidate systems. The blue bell curve is the Milky Way distorted because it's an inverse sphere laid onto a square.

Re:Should we be concerned...

[Anonymous Coward]

actually the "bell curve" effect is the effect of the "plane" of the milky way intersecting with a cylinder (distorted on either end in this projection). The cylinder is "unwrapped" , thus the plane appears as a sinusoid due to the intersection angle of the galactic plane.

It is also interesting that the radio telscope can only tract objects in a band across the sky, due to physical limitations of a ground based radio telescope. This "can" mean that there are as many as ~4 times as many potential signals out there (since they don't line up with the galactic plane we can assume they are nearby star systems which are scattered about the plane).

cepstral terms

[js7a]

John W. Tukey ... is of course best known for his (re)invention, with IBM's Jim Cooley, of the fast Fourier transform, (FFT) which changed the topography of digital signal processing (never mind that Gauss had the FFT 150 years earlier). Tukey was also a great wordsmith: he coined the terms bit, byte, software and cepstrum, (the Fourier transform of the logarithm of the Fourier transform). But some of his cookier coinages, like quefrency (for cepstral frequency) and saphe (for cepstral phase) didn't catch on.

I first heard about the cepstrum from John, which he had invented to distinguish underground nuclear explosions from earth quakes in connection with the US-Soviet test ban negotiations. It became immediately clear to me that the cepstrum was ideally suited for extracting the fundamental frequency (the pitch) from speech signals -- a difficult task for distorted telephone signals. The cepstrum was an ingenious idea and today, 40 years later, it remains the best method for separating long delays (travel times of seismic waves in the earth's mantle or times intervals between the puffs of the human vocal cords) from short-delay and resonance effects (of the human vocal tract).

-- Memories of John Tukey

The seminal work coining the terms is:

B.P. Bogert, M.J. R. Healy and J.W. Tukey, "The Quefrency Alanysis of Time Series for Echoes: Cepstrum, Psuedo-Autocovariance, Cross-cepstrum and Saphe Cracking", in Proceedings of the Symposium on Time Series Analysis, edited by M. Rosenblat, 1963 (New York: Wiley), pp. 209-243.

Re:Proximity to a star?

[UnknowingFool]

The Drake equation computes the number of theoretical civilizations we can possibly contact. The first two factors are heavily dependent on proximity to stars.

R* is the rate of formation of stars suitable for the development of intelligent life. These stars are neither too hot (too close) nor too cold (too far) for life to form. This happy middle ground is also known as the Goldilocks zone.

Fp is the fraction of those stars with planets. Planets normally form only around stars. Some solar system have no planets and hence very little chance of having life as we know it.

All life is dependent on energy is some form or another. For most life on this planet, that energy is the sun in the forms of light and heat. While other forms of energy have been found to sustain life like chemosynthesis in the deep ocean trenches, this phenomenom will be nearly impossible to detect from earth. It is far easier to detect stars, but that doesn't mean locating a signal will be a breeze.

Link text: my pet peeve

[p3d0]

Please don't get too creative with what text you put in your hyperlinks. It makes it hard to tell where the links go. Hint: look at the Related Links box, and if it's totally nonsensical, your links need work.

Let's look at the links in this article:

• "skymap" points to the astrobio article
• "most promising" points to the skymap
• "project" points to a past slashdot article about SETI@home
• "these" points to a description of the signals SETI@home looks for

Here's my suggestion:

"An Astrobiology Magazine article today presents the skymap of where in the night sky to find the most promising SETI@Home signals, along with the research plan for the March Stellar Countdown project that produced it. The dedicated use of the Arecibo Telescope to revisit the most promising spikes, pulses, and steady signals, focused on 166 star candidates. Those 166 were pruned from the five billion signals that have been found since 1999, depending on the signal's persistence, closeness to a known star, and frequency. The next step is particularly fascinating, if a signal appears to have increased since the first observation put that star on the checklist."