Aliens Even More Likely Now To Be Out There ~ Average star has two potentially Earth-like worlds

Boffins in Australia have applied a

hundreds-of-years-old astronomical rule to data from the Kepler

planet-hunting space telescope. They’ve come to the conclusion that the

average star in our galaxy has not one but two Earth-size planets in its “goldilocks” zone where liquid water – and thus, life along Earthly lines – could exist.

“The ingredients for life are plentiful, and we now

know that habitable environments are plentiful,” says Professor Charley

Lineweaver, a down-under astrophysicist.

Lineweaver and PhD student Tim Bovaird worked this

out by reviewing the data on exoplanets discovered by the famed Kepler

planet-hunter space scope. Kepler naturally tends to find exoplanets

which orbit close to their parent suns, as it detects them by the

changes in light they make by passing in front of the star. As a result,

most Kepler exoplanets are too hot for liquid water to be present on

their surfaces, which makes them comparatively boring.

Good planets in the “goldilocks” zone which is

neither too hot nor too cold are much harder to detect with Kepler,

which is a shame as these are the planets which might be home to alien

life – or alternatively, home one day to transplanted Earth life

including human colonists, once we’ve cracked that pesky interstellar

travel problem.

However there exists a thing called the Titius-Bode relation

– aka Bode’s Law – which can be used, once you know where some inner

planets are, to predict where ones further out will be found.

Assuming Bode’s Law works for other suns as it does

here, and inputting the positions of known inner exoplanets found by

Kepler, Lineweaver and Bovaird found that on average a star in our

galaxy has two planets in its potentially-habitable zone.

That doesn’t mean there are habitable or inhabited

planets at every star, of course. Even here in our solar system,

apparently lifeless (and not very habitable) Mars is in the habitable

zone.

Even so, there are an awful lot of planets in the

galaxy, so some at least ought to have life on them, and in some cases

this life ought to have achieved a detectable civilisation. Prof

Lineweaver admits that the total lack of any sign of this is a bit of a

puzzler.

“The universe is not teeming with aliens with

human-like intelligence that can build radio telescopes and space

ships,” admits the prof. “Otherwise we would have seen or heard from

them.

“It could be that there is some other bottleneck for

the emergence of life that we haven’t worked out yet. Or intelligent

civilisations evolve, but then self-destruct.”

Of course, humans – some approximations of which have

been around for some hundreds of thousands of years, perhaps – have

only had civilisation of any kind in any location for a few thousand of

those years. Our civilisation has only risen to levels where it could be

detectable across interstellar distances very recently.

There may be many planets out there inhabited by

intelligent aliens who either have no civilisation at all, or only

primitive civilisation. There may be quite a few who have reached or

passed the stage of emitting noticeable amounts of radio or other

telltale signs, but those emissions either will not reach us for

hundreds of thousands of years – or went past long ago.

It would seem reasonable to suspect that there are

multitudes of worlds out there where life exists in plenty but has never

become intelligent, as Earth life was for millions of years before

early humans began using tools really quite recently.

But the numbers are still such that the apparent

absence of star-travelling aliens could make you worry about the

viability of technological civilisation if, like Professor Lineweaver,

you learn your astrophysics out of textbooks and lectures (and publish

your research, as we see here, in hefty boffinry journals like the Monthly Notices of the Royal Astronomical Society).

But if movies, speculofictive novels and TV have taught us anything here on the Reg

alien life desk, it is that in fact the galaxy is swarming with

star-travelling aliens (and/or humans taken secretly from planet Earth

for mysterious purposes in the past, or perhaps humans from somewhere

else etc). The reason we don’t know about them is that they don’t want us to.

Source Article from http://feedproxy.google.com/~r/AscensionEarth2012/~3/pC4_LLpRxyw/aliens-even-more-likely-now-to-be-out.html

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Aliens Even More Likely Now To Be Out There ~ Average star has two potentially Earth-like worlds