Posted on 07/03/2002 9:03:47 AM PDT by RightWhale
Scientists estimate 30 billion Earths
By Dr David Whitehouse , BBC News Online science editor
Astronomers say there could be billions of Earths in our galaxy, the Milky Way.
Their assessment comes after the discovery of the 100th exoplanet - a planet that circles a star other than our own.
The latest find is a gas giant, just like all the other exoplanets so far detected, and orbits a Sun-like star 293 light-years away.
Scientists say they are now in a position to try to estimate how many planets may exist in the galaxy and speculate on just how many could be like the Earth. The answer in both cases is billions.
Virtually all the stars out to about 100 light-years distant have been surveyed. Of these 1,000 or so stars, about 10% have been found to possess planetary systems.
So, with about 300 billion stars in our galaxy, there could be about 30 billion planetary systems in the Milky Way alone; and a great many of these systems are very likely to include Earth-like worlds , say researchers.
Better grasp
The 100th new planet circles the star HD 2039. It was found by astronomers using the Anglo-Australian Telescope as part of the Carnegie Institution Planet Search Program.
The Jupiter-sized world circles its star every 1,210 days at a distance of about 320 million kilometres (200 million miles).
Astronomer Dr Jean Schneider, who compiles the Extrasolar Planets Catalogue, told BBC News Online: "The 100th planet is symbolic and important.
"The first discoveries concentrated on short orbital periods because of the limited timebase of observations. Now, we are learning more about the statistics of long orbital periods and know to what extent our own Jupiter is exceptional or not."
New telescopes
With the new world, astronomers say that they have just about finished surveying all the Sun-like stars out to a distance of 100 light-years from Earth.
Current planet detection technology - based on the "wobble" induced in the parent star by the gravitational pull of the orbiting planet - can only detect worlds about the mass of Saturn or larger. Earth-sized worlds are too small to be seen.
But even in this "biased" survey of giants, the smaller worlds predominate - which makes astronomers think that Earth-like worlds do exist. They may even be as common as Jupiter-sized exoplanets.
And if stellar statistics gathered in our local region of space are applied to our galaxy of 300 billion stars, then there may be 30 billion Jupiter-like worlds and perhaps as many Earth-like worlds as well.
Astronomers will have to wait for a new generation of space-based telescopes incorporating advanced detectors before they can detect Earth-sized worlds orbiting other stars.
Suggesting that there could be life out there and planets we might like is like telling Columbus that streets in America are paved with gold. Such an idea might cause exploration and the king to open the kingdom's coffers, but the reality will be far different. False hope. How is the King of Spain doing these days?
I hope you are not questioning the veracity of Captain James T. Kirk! No space bimbos? For Pete's sake keep it quiet or the space program is doomed...
If you like some more imagination pretend that the Stargate is real and some other race scattered the gene pool around the galaxy. Or possible by visiting a young planet and leaving behind some stray proteins that took over and began life.
Each of which must be 'saved' by environmentalists. I wouldn't be surprised to see some form of universe environmental protection legislation pushed by the enviro-lobby and introduced by the usual suspects by the end of next week.
We all are. Like rats in a box.
We don't actually need planets to live in outer space. Think about it: If we can build starships that take 1000 years to get anywere, we will have essentially built our own worlds. Don't need planets, it's a lame excuse for staying on this backwater mudhole of a planet.
If there's life on other planets then I'm sure that he must know,
And he's been there once already and has died to save their souls.
Get your terminology correct, you dunsel (g)
OTOH, I'd also like to see a few other worlds. Unfortunately, it's just too darn expensive to get there.
Out of the 100 SuperJupiters, they found 1 that has an orbit like the one and only original Jupiter. That 1 is a "possible" for small rocky planets similar to the inner planets. The rest are unlikely. That's 1 in 1000, not 1 in 10. The 30 billion is down to 0.3 billion. If you pick up 300 million grains of sand off a beach, what are the odds of even one jewel-quality diamond being in there? Could happen, but you could starve first.
Nice. And such a perfect fit for them.
I'll be borrowing that one :)
Getting there is the cheap part. Terraforming what we find there will be expensive.
I estimate too many scientists with too much time on their hands.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.