DOES OUR GALAXY HAVE REGION OF “OLDER” LIFE?
by Terence Dickinson, SkyNews Editor

The idea that there must be life on other planets in the universe is more than two thousand years old, but it is only in the last half century that scientific research journals have contained even a few words on the subject.

The breakthrough came in 1959 with the publication an article by physicists Giuseppe Cocconi and Philip Morrison on searching the skies for radio signals from possible extraterrestrial intelligent life on planets of distant stars. Until then, any speculation on life on other worlds was simply taboo, and could compromise a promising career.

Cocconi and Morrison did not suffer career damage. In fact their idea was embraced by many--though not all--scientists. Since then, dozens of articles have appeared on the possible nature of alien communication, speculations on the types of planets upon which alien civilizations could arise, calculations of the number of planets with extraterrestrial civilizations, and so on.

The articles, “papers” as scientists call them, have appeared in virtually all the top research publications such as Nature, Science, and the Astronomical Journal. However, so much has now been said on the subject that new papers cause hardly a ripple either in the mainstream news media, or the scientific press. A recent article, which appeared in the journal Science last year, was an assessment of what the authors called “the galactic habitable zone.” The paper was titled, “The Galactic Habitable Zone and the Age Distribution of Complex Life in the Milky Way.”

The three Australia-based authors, an astronomer, a biologist and a supercomputer specialist, looked at whether some sections of our galaxy might be unsuitable for life as we know it. They first assumed that life would arise on a planet something like the Earth, then theoretically tracked the evolution of such planets in various parts of the galaxy.

Three dangers repeatedly cropped up. One was a nearby star blowing up as a supernova. The blast could sterilize the planet of life. In certain environments where supernovas are regularly erupting, such as the central regions of the galaxy, life probably would not evolve.

A second hazard is ordinary stars swinging close to the planet’s sun, which would stir up clouds of comets that would rain down on the planet. Repeated episodes could be devastating on a world with life evolving.Both of these scenarios, the researchers say, eliminate environments anywhere around the central sector of the Milky Way Galaxy, which includes more than half of the stars in the galaxy.

The third factor the authors finger is the recent discovery of the prevalence of Jupiter-sized planets in other solar systems in the same locations where smaller Earth-sized planets are in our solar system.

When they crunched the numbers, the researchers found that a habitable ring of stars (and their planets) began to emerge in the galaxy about 8 billion years ago at roughly the sun’s distance from the galactic centre. On average, these stars and planets are one billion years older than the Earth, which, the authors suggest, means the average civilization in our galaxy would be relatively nearby and one billion years older than us.

However, this idea, like so many others that revolve around the possibility of extraterrestrial life, were thoroughly hashed through more than a generation ago during the 1960s and 70s when some of the world’s leading scientists regularly gather for international conferences to discuss intelligent life on other worlds. It was a more optimistic era, a time when Carl Sagan, a regular at the ET-life conferences could be heard presenting statistics to support his suggestion that civilizations could inhabit a million planets in our galaxy alone.

No one takes those estimates seriously any more. In fact, astronomers in the 21st century seem to have evolved toward a more sober outlook on alien intelligence. Speculations about possibilities or probabilities now stir little reaction. If there is intelligent life out there, we remain as utterly unaware of its existence as we did when Cocconi and Morrison’s article first appeared nearly half a century ago.

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Now Appearing In Your Night Sky
by Todd Carlson, Assistant Editor

On May 30 a close grouping of the crescent Moon, Mars and Saturn can be seen in the western sky shortly after sunset. The four-day old Moon will be between orange-coloured Mars and the star Pollux. Binoculars will enhance detail on the Moon and will also reveal the Beehive, an cluster of stars 550 light-years distant, slightly above Saturn.

On June 17, Mars and Saturn will be within half a degree of each other. However, don’t wait until that night to take a look. Each night, until then, the distance between the pair is decreasing—from our perspective.

Imagine crouching down and viewing a billiard table edge-on with one yellow ball placed in the centre and a red ball slowly rolling the length of the table. From this vantage point it is difficult to determine the distance between the two balls as one passes the other.

This is akin to Mars and Saturn as we view them from Earth—the planets appear to be close but are actually separated by a vast distance. On May 30, the two planets are more than one billion kilometres apart. However, on June 17 when they seem to be next to each other, Saturn is 1.13 billion kilometres beyond Mars. Although it may be difficult to envision due to the lack of depth perspective, there are vast distances between all celestial objects visible in the night sky.

The motion of Mars against the background stars can be discerned even after a few nights. Note how the position of Mars relative to Saturn and the stars of Gemini changes each evening, culminating with the conjunction on June 17.

Diagrams, showing the position of each object for the events occurring on May 30 and June 17 can be found HERE.

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SkyNews Observer's Guide
Do you have an interest in astronomy but don't know how to begin? Are you considering buying a telescope for the first time? Visit the SkyNews Observer's Guide for tips and advice from editors Terence Dickinson and Alan Dyer.

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