SETI public: Searching for ETI in the ecliptic plane

• Previous message: LARRY KLAES: "SETI public: Predicting low-frequency radio fluxes of known extrasolar planets"

Searching for ETI in the ecliptic plane

For release: Wednesday, June 4, 2008, 9:30 a.m. CDT

Contact:
Dr. Richard C. Henry
Johns Hopkins University
1-410-516-7350
henry_at_jhu.edu

TEAM HOPES TO USE NEW TECHNOLOGY TO SEARCH FOR ETS

A Johns Hopkins astronomer is a member of a team briefing
fellow scientists about plans to use new technology to take advantage
of recent, promising ideas on where to search for possible
extraterrestrial intelligence in our galaxy.

Richard Conn Henry, a professor in the Henry A. Rowland
Department of Physics and Astronomy at Johns Hopkins' Zanvyl Krieger
School of Arts and Sciences, is joining forces with Seth Shostak of
the SETI Institute and Steven Kilston of the Henry Foundation Inc., a
Silver Spring, Md., think tank, to search a swath of the sky known as
the ecliptic plane. They propose to use new Allen Telescope Array,
operated as a partnership between the SETI Institute in Mountain View,
Calif., and the Radio Astronomy Laboratory at the University of
California, Berkeley.

Comprising hundreds of specially produced small dishes
that marry modern, miniaturized electronics and innovative
technologies with computer processing, the ATA provides researchers
with the capability to search for possible signals from
technologically advanced civilizations elsewhere in our galaxy – if,
in fact, such civilizations exist and are transmitting in this
direction.

Employing this new equipment in a unique, targeted search
for possible civilizations enhances the chances of finding one, in the
same way that a search for a needle in a haystack is made easier if
one knows at least approximately where the needle was dropped, said
Henry, who is speaking about the proposal at the American Astronomical
Society annual meeting in St. Louis.

According to the researchers, the critical place to look
is in the ecliptic, a great circle around the sky that represents the
plane of Earth's orbit. The sun, as viewed from Earth, appears
annually to pass along this circle. Any civilization that lies within
a fraction of a degree of the ecliptic could annually detect Earth
passing in front of the sun. This ecliptic band comprises only about 3
percent of the sky.

"If those civilizations are out there – and we don't know
that they are – those that inhabit star systems that lie close to the
plane of the Earth's orbit around the sun will be the most motivated
to send communications signals toward Earth, " Henry said, "because
those civilizations will surely have detected our annual transit
across the face of the sun, telling them that Earth lies in a
habitable zone, where liquid water is stable. Through spectroscopic
analysis of our atmosphere, they will know that Earth likely bears
life.

"Knowing where to look tremendously reduces the amount of radio
telescope time we will need to conduct the search," he said.

Most of the 100 billion stars in our Milky Way
galaxy are located in the galactic plane, forming another great circle
around the sky. The two great circles intersect near Taurus and
Sagittarius, two constellations opposite each other in the Earth's sky
– areas where the search will initially concentrate.

"The crucial implication is that this targeted search in a
favored part of the sky -- the ecliptic stripe, if you will – may
provide us with significantly better prospects for detecting
extraterrestrials than has any previous search effort," Kilston said.

Ray Villard of the Space Telescope Science Institute,
who is joining the team in their observations, said that in November
2001, STScI publicized Hubble observations of a transiting planet and
"it occurred to me that alien civilizations along the ecliptic would
likely be doing similar observations to Earth. Once they had
determined Earth to be habitable, they might initiate sending
signals."

Shostak of SETI notes that the Allen Telescope Array is
ideal for the team's plans to search the entire ecliptic over time,
and not just the intersections of the ecliptic and galactic planes.

The team's presentation at the AAS meeting also explores
possible scenarios for the appearance of civilizations in our galaxy.

"These models are nothing but pure speculation. But hey …
it is educational to explore possibilities," Henry said. "We have no
idea how many – if any – other civilizations there are in our galaxy.
One critical factor is how long a civilization – for example, our own
– remains in existence. If, as we dearly hope, the answer is many
millions of years, then even if civilizations are fairly rare, those
in our ecliptic plane will have learned of our existence. They will
know that life exists on Earth and they will have the patience to beam
easily detectable radio (or optical) signals in our direction, if
necessary, for millions of years in the hope, now realized, that a
technological civilization will appear on Earth."

Images from the team's presentation are available here:

http://henry.pha.jhu.edu/seti.html

Digital photos of Henry are available. Contact Lisa De
Nike at 1-443-287-9960 or Lde_at_jhu.edu.

• Previous message: LARRY KLAES: "SETI public: Predicting low-frequency radio fluxes of known extrasolar planets"

This archive was generated by hypermail 2.1.6 : Wed Jun 04 2008 - 20:31:24 PDT