E.T., Don’t Phone Home; Drop a Line Instead
September 01, 2004
NEW BRUNSWICK/PISCATAWAY, N.J. – Were E.T. really interested in getting
in touch with home, he might be better off writing than phoning,
according to Christopher Rose, professor of electrical and computer
engineering at Rutgers, The State University of New Jersey.
Rose contends that inscribing information and physically sending it
to some location in deep space is more energy-efficient than pulsing it
out on radio waves, which disperse as they travel.
“Think of a flashlight beam,” Rose says. “Its intensity
decreases as it gets farther from its source. The same is true of the
beam of a laser pointer, though the distance is much longer. The
unavoidable fact is that waves, both light and radio, disperse over
distance, and over great distance, they disperse a lot.”
Rose and Gregory Wright, a physicist, are co-authors of a paper
titled, “Inscribed matter as an energy-efficient means of communication
with an extraterrestrial civilization,” which appears on the cover of
the September 2 issue of Nature. The paper grew out of Rose’s work at
the Wireless Information Network Laboratory (WINLAB) at Rutgers’ School
of Engineering. “Our original question was, ‘How do you get the most
bits per second over a wireless channel?’” Rose says. This led him to
consider distance, and the “energy budget” required for sending a
signal. The budget increases with distance, Rose contends, and the
detectability of the signal diminishes. The less detectable a message
is, the lower its speed.
In addition, Rose says, when waves pass a particular point,
they’ve passed it for good. Potential recipients at that point might be
unable to snag a passing message for any one of many reasons. They
might not be listening. They might be extinct. So someone sending such
a message would have to send it over and over to increase the chance of
its being received. The energy budget goes up accordingly. A physical
message, however, stays where it lands.
Rose is in favor of listening for that close encounter, but he
thinks researchers should have their eyes open, too. Rose speculates
that “messages” might be anything from actual text in a real language
to (more likely) organic material embedded in an asteroid – or in the
crater made by such an asteroid upon striking Earth. Messages – and
Rose suggests there might be many of them, perhaps millions – might
literally be at our feet. They might be awaiting our discovery on the
moon, or on one of Jupiter’s moons. They might be dramatic or mundane.
A bottle floating in the ocean is just a bottle floating in the ocean –
unless, upon closer inspection, it turns out to have a message in it.
Rose concedes that this idea may be hard to accept, but this
difficulty arises from our concern about time. If the sender isn’t
concerned about reaching the recipient and getting an answer in his own
lifetime, inscribing and sending is the way to go.
“If haste is unimportant, sending messages inscribed on some
material can be strikingly more efficient than communicating by
electromagnetic waves,” Rose says.
Of course, E.T.’s choice of medium might be affected by how
much he had to say. “Since messages require protection from cosmic
radiation, and small messages might be difficult to find amid the
clutter near a recipient, ‘inscribed matter’ is most effective for
long, archival messages, as opposed to potentially short ‘we exist’
announcements,” Rose says.
Contact: Ken Branson
732/932-7084, ext. 633
|About This Image:
Photo by Joseph Blumberg, manager of science communications.
Permission is granted to reproduce this image in connection with news coverage of this story. All other rights are reserved.
To download the high-resolution picture,
click on the "Go to Larger Image" link above.
A larger image file will appear on your
File Specifications: JPG, 153K, resolution 230 dpi.