small logo Editorial

The Secret of 70 Virginis
by Dr. H. Paul Shuch, Executive Director

One of the persistent rumors circulating on the Internet, a myth that just won't go away, is the allegation that SETI has received signals from the direction of 70 Virginis. 70Vir is a Sun-like star which we now know to have at least one planet, possibly in the habitable zone. It's claimed that we're hiding this knowledge from the public. In the interest of dispelling that myth, I reproduce below the entire email dialog between myself and an interested, though skeptical, SETI League member:

Someone in England said "SETI has received some radio signals from Virginis70". Is there anything to this statement?

            That British news quote was a prime example of something taken out of context, by journalists who don't fully understand the science they're reporting. The short answer is "no." The long answer is:
            When the planet at 70Vir was discovered, Dan Werthimer of U.C. Berkeley SERENDIP project commented (it was at the January 1996 AAAS meeting in Baltimore, as I recall) that SERENDIP had already looked closely at 70Vir at 435 MHz, and that all the signals detected were statistically consistent with background noise. "Aha!" must have thought the journalist, "signals HAVE been detected!" That's what got reported, and keeps surfacing. No signals, folks, just noise. (But that doesn't mean we shouldn't keep looking).
            BTW, when I've related this incident at conferences, I've been labeled "part of the Government coverup"!

What UK publication broke the Virginis/SETI story? Mainstream?

            A mainstream newspaper, NOT a tabloid. Sorry, I don't recall which one.

Does Dr. Paul Butler, U.C. Berkeley, have input into the SETI agenda in conjunction with the search for extrasolar planetary search? How does this work? Does SETI ever cue Dr. Geoff Marcy and Dr. Paul Butler to look in regions where anomalous signals have been detected? Which comes first, the signal or the planet?

            The planet, where there's any coupling whatever, but the two generally operate independently. SETI candidate signals usually cannot be associated with a single, specific star; the beamwidths of the antennas are too broad. (Even the Big Ear radio telescope at Ohio State University, one of the narrowest, has about five stars within its field of view at any given time). Since interesting signals can generally be narrowed down only to a general region, we don't provide much input to the planet hunters. And since they already know which nearby stars are most Sun-like and of the right age, mass, temperature combination to form planets, they don't really need our input. As it happens, the star catalogs used by the targeted search SETI folk and the planet hunters have a good deal of overlap anyway.
            On the other hand, when confirmed planets are announced, we do one of two things:

  1. review data for past observations of the region of the sky containing that particular star,
  2. absent such past observations, we take a look.
            "We," in this case, is those doing targeted searches. The SETI League is engaged in an all-sky survey. See for an explanation of the two complimentary strategies.

Note (not yours, I realize) from: soon after the planets' discovery was announced, seti (the search for extra terrestrial intelligence) ran a quick check on their records, and discovered a number of anomalous signals coming from the direction of 70 virginis. (joe mcnally - fortean times magazine)

            They failed to print the rest of the sentence: "which were consistent with noise!" I love it when things are taken out of context, don't you?

What is Dan Werthimer's role; ie, what is the mission of SERENDIP?

            Dan works for the Space Systems Laboratory at the University of California, Berkeley, and along with principle investigator Dr. Stuart Bowyer helps to coordinate SERENDIP. See for an overview of SERENDIP's mission.

Does SERENDIP work hand-in-hand towards finding remote planets?

            No, SERENDIP is a parasitic SETI program (see their website), so they don't get to choose their targets.

You indicate that SETI will continue to scan 70 Virginis. What is the objective, or why the additional curiosity?

            SERENDIP IV at Arecibo runs at a different frequency than SERENDIP III, so repeat looks at previously scanned targets would be standard procedure.

As reported by NASA at

The planet, designated 70 Vir b for short, was discovered by very slight periodic shifts in its colors. Defining characteristics of this planet include that it is at least eight times the mass of Jupiter, it's orbit is much smaller than Jupiter's, and it's temperature allows water to exist in liquid form - like on the Earth. Life on Earth is based on liquid water - could life exist here too?
How are such details such as size, mass, temperature, possibility of water, etc., determined about a world so distant? Did SETI data influence these amazing observations?

            For a complete description of the technique, see SETI cannot claim any credit for the technique; it's purely optical.

And last but most important: where have anomalous signal been found? Many of us are still trying to deal with "teasing information" dating back as far as Project OZMA. After all you indicate: "We Know We're Not Alone!" What do you know?

            Little more than you do. See for some of what we've heard so far. It's interesting (and not at all counterintuitive) that most of the 40 or so tantalizing candidate signals detected since 1960 have been concentrated in the galactic plane (after all, that's where all the stars are, isn't it?)
            As for the "teasing" information from OZMA, Frank Drake figured out on about the eighth day that his Epsilon Eridani hit was a fast-moving, high-altitude aircraft. No such aircraft "existed" at the time (Powers' U2 notwithstanding), so he was not at liberty to say more. Ditto the Trevor Unsworth hit depicted on The SETI League's web site. I know a bit about the classified military satellite which caused the interference, but if I told you, I'd have to kill you.
            Let me assure you that SETI scientists have no incentive whatever to cover up any meaningful discoveries which may result from our research. We're not funded by the government anymore, and (in the case of The SETI League) we're a grass-roots, international effort. (Our search now involves over 500 members in 30 countries on five continents, growing toward 5,000 participants someday -- let's see any Gov't try to squelch that!)

How are anomalous signals CONSISTENT with noise? I don't understand. What is the usual, what isn't?

            OK, one last try, and then I really have to get back to work.
            Everything that's at a temperature above absolute zero generates radio signals. These are natural signals (noise), NOT artificial, or created by intelligent beings. You can see such thermal noise by turning on your TV, to an unused channel -- it looks like a snowstorm. You would receive such signals from any star. (In fact, if you watch satellite TV, you will notice that twice a year, at the equinoxes, you receive interference from our own Sun, as it aligns with the geosynhcronous satellite belt. That signal is surely not intelligently generated.) You do statistical analysis on all signals to see if there's anything artificial buried in them. In the case of 70Vir, there wasn't.

Can you give me a better description of what was received from 70Vir? Who interpreted the data? Do you have any visual graphics of the signal such as you portray on your website?

            I don't have any graphics of 70Vir specifically, and I doubt the SERENDIP people do; it's all probably just raw computer data. A computer interpreted the data. But I can give you an example. Take a look at the "Wow!" signal, as depicted at Everything to the left of time 22:14:30 is consistent with noise. So is everything to the right of 22:18:00. What's in between is statistically different from noise, hence assumed to be a signal of some sort.

            Now I had intended to put this myth to rest, not make a career of it, so this will have to suffice. Thanks for your interest.

Click to email the Webmaster
| Home | General | Memb Svcs | Publications | Press | Technical | Internet | Index |
entire website copyright © The SETI League, Inc.
this page last updated 4 January 2003
Click for top of page
Top of Page