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.
Endless space...the perfect environment for Hollywood liberals...it matches what's inside their heads.
For a budding space-faring race, Humans got dealt a folding hand. The biggest burn is the dead ball that orbits our planet. A living moon would have been critical to our chances. The next insurmountable barrier is that there are no other planets in our Solar System that can sustain life (get out of here, Io). Forget about travel to even the nearest star. All we could hope to do is seed another planet in a distant system with our genetic material.
I'd love for someone in the future to prove me a defeatist long after my death, but I think such endeavors such as SETI to be a tremendous excersise in futile masturbation.
I'm against conservation because it's akin to a starving family trying to save the last slice of baloney in an otherwise-empty refrigerator.
Drive SUVs, and drink to excess while it lasts.
Have a wonderful holiday weekend, RightWhale. :)
It's all what-ifs at the present.
There are 2 possibilities. Either there are others like us out there or there aren't. If there are, a lot of people will have to rework their way of thnking. If there aren't, a lot of people will have to rework their way of thinking. My uncle Frank won't have to rework his way of thinking since he already thinks it probably will have nothing to do with him anyway.
Even so, the volume of space to search in is likely pretty big. Anyone know the equation to find the volume of a torus? Now if these planets are plentiful enough, and relatively few of them have intelligent starfaring species on them, and the distances aren't too far between habitable worlds, then things will likely be relatively peaceful, with everyone having room to grow. On the other hand, if habitable planets are really scarce, I suspect that neutron bombs will be part of any terraforming package, to deal with the locals so we can take their real estate.
Yes, thanks, and to you, too.
It's not that the gas giants are the only ones out there, it's just that they are the only ones large enough to create a "wobble" that can be measured, with existing technology, in the star being observed.
I suppose you could erect solar panels on the uninhabited outside of each "hollow earth" to capture solar energy.
I figure that they'll go off instantly while pointing back down here. "Yup we detected earth. It's right over there"
I have the same problem with the stud detector that my wife bought me for Christmas. Everytime I pick it up it goes off
God Save America (Please)
The Fitzgerald translation of Omar is hopelessly bogus. Burn your copy. And have a happy and safe fourth.
Sure. It will work fine. But if you intend to go travelling in your hollow asteroid to other stars it won't do the job. For that something else is needed. I'll leave the tech design to others since I don't imagine I will be leaving the solar system.
GSA(P)
What this confirms is that the formation of planets is not a unique phenomenon and that we can expect a certain percentage of stars out there to have planets. Our galaxy is hardly the only galaxy in the universe. Even if only one star in a billion has a planet like earth, we are still talking about hundreds of billions of similar planets.
That doesn't suggest that there is life on any of them, nor does it suggest that there can't be life on every single one of them.
Right ascension 17 : 45.6 (h : m)
Declination -28 : 56 (deg : m)
Distance 28 (kly)
Our Sun, together with the whole Solar System, is orbiting the Galactic Center at the distance given, on a nearly circular orbit. We are moving at about 250 km/sec, and need about 220 million years to complete one orbit (so the Solar System has orbited the Galactic Center about 20 to 21 times since its formation about 4.6 billion years ago). The Galactic North Pole is at
Right ascension 12 : 51.4 (h : m)
Declination +27 : 07 (deg : m)
Considering the sense of rotation, the Galaxy, at the Sun's position, is rotating toward the direction of Right Ascension 21:12.0, Declination +48:19. This shows that it rotates "backward" in the Galactic coordinate system, i.e. the Galactic North Pole is actually a physical South Pole with respect to galactic rotation. The coordinate data given here were extracted from the online coordinate calculator at Nasa's Extragalactical Database (NED).
What I find amazing is, on a galactic scale, our solar system is barly old enough to drink a beer and play with stud detectors. (ya happy John O? I worked it in :)
Here's the Link:
Being an Art Bell time-shifter, he had a physicist was a different viewpoint on last year. Not about
intelligent life on other planets per se, but in a crowded bit of space, cataclysmic collisions with occur.
Bottom line is that he thinks SETI is looking in the wrong place.
No wonder. In 1950 there were 2.5 billion people on earth and in 2000 there were 6 billion. You ARE getting cramped.
Er, make that "he had a physicist on with...".
I got sidetracked getting the format for the formerly display submit screen example of posting links.
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.