SETI@Home Publishes Skymap 317
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."
Re:Should we be concerned... (Score:4, Informative)
Re:SETI is a crock- here's why (Score:3, Informative)
As for the century long delay, just start talking. Wicked lag time, but eventually you'll get something said.
Re:Should we be concerned... (Score:5, Informative)
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).
Re:If the signal has INCREASED? (Score:3, Informative)
Perhaps the signal is from an object like a pulsar that is increasing in mass near its center and increasing its rate of spin a'la conservation of angular momentum? After all the first time a pulsar was discovered, it was thought to be "little green men".
Re:If the signal has INCREASED? (Score:1, Informative)
Re:Doppler Drift Rate "chirping" seems way redunda (Score:3, Informative)
Re:Trick? (Score:2, Informative)
cepstral terms (Score:5, Informative)
Re:SETI was not the first distributed project (Score:2, Informative)
Re:Proximity to a star? (Score:2, Informative)
However, to be more consistent with popular media science measurement systems, we would more correctly say that a sheet of interstellar space the size of a football field and the thickness of a human hair would contain about 3000 atoms.
Re:Proximity to a star? (Score:3, Informative)
N.
Re:SETI is a crock- here's why (Score:1, Informative)
Re:Proximity to a star? (Score:5, Informative)
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 (Score:5, Informative)
Let's look at the links in this article:
Re:Doppler Drift Rate "chirping" seems way redunda (Score:4, Informative)
Let's just look at the CPU. CPUs have millions of transistors (a Pentium 4 has ~42 million), and each transistor is an electronic switch. The transistor technology they use is Field Effect [physlink.com] or "FET". The most common would be "MOSFET". To maintain the state of the switch as ON or OFF, the device holds a small charge (positive or negative depending on the device) and the charge acts to "pinch off" the channel for current to flow, or to open the channel, as the case may be.
While a transistor is just sitting there in a particular ON or OFF state, it uses very little electricity. However, to change the state, you have to either charge or discharge the gate. When you charge or discharge it, this results in a small but finite amount of current flow, and there being resistance in metal and silicon, this results in power being consumed (at a rate of the current squared, times the resistance). So a transistor that is constantly switching will consume power, but a transistor not switching will consume very, very little.
So, if you home computer is just sitting there doing nothing, then it isn't using most of the chip, and the transistors just sit there waiting for the next instruction to execute. However, when you're running SETI @ Home, the CPU is constantly crunching numbers, and the transistors are constantly switching.
If you want to see this yourself, run a temperature monitor on the CPU while it's not doing anything, and then when you run SETI@Home or DOOM. You'll notice that the temperature spikes when it's doing something, and this is just used up energy. If you have electric heat in your house, and live in a cold climate all year long, you may not see the difference on your power bill, but I don't think that applies to most of us.
Re:Proximity to a star? (Score:4, Informative)
Re:Doppler Drift Rate "chirping" seems way redunda (Score:2, Informative)
Sorry, but cepstral techniques don't do what the SETI people need them to do. The de-chirping needs to happen coherently (i.e. without any loss of the phase information from the original data and signals that it might contain). The reason for this is that the signal-to-noise of a detected periodic signal is much less if you use an incoherent technique like the cepstrum rather than a coherent one. And since they are looking for very weak signals, they need every bit of S/N that they can get.
OTOH, I have developed a cepstral-like technique to detect binary pulsars in data almost identical to the SETI@home data. You can read about it here [harvard.edu] or here [lanl.gov] if you are interested.