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SETI@home Science :
At Least 100 Billion Planets
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ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
Put this into your view of the Drake equation: NASA: Study Shows Our Galaxy Has at Least 100 Billion Planets Our Milky Way galaxy contains a minimum of 100 billion planets, according to a detailed statistical study based on the detection of three planets located outside our solar system, called exoplanets. ... ... The survey results show that our galaxy contains, on average, a minimum of one planet for every star. This means that it's likely there is a minimum of 1,500 planets within just 50 light-years of Earth. The study is based on observations taken over six years by the PLANET (Probing Lensing Anomalies NETwork) collaboration, using a technique called microlensing to survey the galaxy for planets. ... I suspect that the upcoming Kepler results will explode that number to something much greater... Keep searchin', Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
tullio Send message Joined: 9 Apr 04 Posts: 8797 Credit: 2,930,782 RAC: 1 |
Troppa grazia, Sant'Antonio. is an old Italian proverb. How can we monitor billions of planets? Tullio |
SciManStev Send message Joined: 20 Jun 99 Posts: 6652 Credit: 121,090,076 RAC: 0 |
As there are only 63 stars within 50 light years of earth, 1500 planets would mean some stars would have a lot of them. Steve Warning, addicted to SETI crunching! Crunching as a member of GPU Users Group. GPUUG Website |
Len Send message Joined: 15 Mar 10 Posts: 52 Credit: 11,725,173 RAC: 86 |
As there are only 63 stars within 50 light years of earth, 1500 planets would mean some stars would have a lot of them. Are we really sure about the low figure of 63? Having not spent any time counting them myself, I am loathe to state anything as fact; but a quick search of previous counts and estimates from scientific sources places the 1500 figure on the conservative side. 1600 to over 2000 being the predominant range that I found. Len I think I am. Therefore I am. I think. |
SciManStev Send message Joined: 20 Jun 99 Posts: 6652 Credit: 121,090,076 RAC: 0 |
As there are only 63 stars within 50 light years of earth, 1500 planets would mean some stars would have a lot of them. I have this. http://www.solstation.com/stars3/100-gs.htm Steve Warning, addicted to SETI crunching! Crunching as a member of GPU Users Group. GPUUG Website |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
The discrepancy is probably due to stating the number of Sun-Like stars which are Main sequence stars that are non binary. At one time I thought that there was a count of only 600 such stars out to 1000 light years |
musicplayer Send message Joined: 17 May 10 Posts: 2430 Credit: 926,046 RAC: 0 |
If a thought signal of extraterrestrial origin is supposed to be able to reach 300 light years out into space from its starting point, how many stars of type G, especially main sequence stars, would then lie within such a sphere? Could the Drake equation be adjusted for specific types of stars within a given distance, or is the spectral class for a given star enough? Our sun is spectral class G2 V, in comparison. Some stars getting old are evolving into subgiants and giants, changing their spectral types during this process and making possible existing life less likely near these objects. Procyon, having spectral class F5 IV-V is such an example. An even more evolved star, Arcturus, is a Population 2 star. Its spectral class is K1.5IIIFe-0.5, according to http://en.wikipedia.org/wiki/Arcturus . In between, we of course find Aldebaran (Alpha Tau) having a spectral class of K5III / M2V (meaning it has a red dwarf companion). This star I may guess is still a Population 1 star in comparison. Stars like Sirius are main sequence stars of type A. A1 V to be exact when it comes to Sirius. They are hotter, bluer and more luminous than our own sun, but maybe not totally unsuitable for life forms given possible planets with atmospheres and liquid oceans orbiting such types of stars. Also I came across the following web-page tonight: http://stars.astro.illinois.edu/sow/sowlist.html . |
Johnney Guinness Send message Joined: 11 Sep 06 Posts: 3093 Credit: 2,652,287 RAC: 0 |
100 billion planets, that really is a massive number. You have to really think about that number to get your head around it. How many of those planets have trees, and birds that fly in the Sky's, and flowing streams and rivers, and dinosaurs roaming freely across the plains. And great civilisations of people living out their lives. I bet hundreds of thousands of them have life on them just like here on Earth. John. |
skildude Send message Joined: 4 Oct 00 Posts: 9541 Credit: 50,759,529 RAC: 60 |
While you have an interesting argument against intelligent life the shear numbers say that it's more likely than not. I'd hate to think that we are the only self aware beings in this galaxy let alone the universe In a rich man's house there is no place to spit but his face. Diogenes Of Sinope |
john3760 Send message Joined: 9 Feb 11 Posts: 334 Credit: 3,400,979 RAC: 0 |
The number of planets with birds,dinosaurs or any other type of life we recognise on earth ,is definately a lot rarer than planets(which we havent even discovered yet) that can contain even the most basic forms of life. Another planet with dinosaurs is theoretically probable,but almost certainly non existant. john3760 |
Len Send message Joined: 15 Mar 10 Posts: 52 Credit: 11,725,173 RAC: 86 |
A planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has "cleared its neighbourhood" of smaller objects around its orbit. If we were to substitute "the sun" with "its star", I think we have a working definition of planet, surely? I think I am. Therefore I am. I think. |
Len Send message Joined: 15 Mar 10 Posts: 52 Credit: 11,725,173 RAC: 86 |
As there are only 63 stars within 50 light years of earth, 1500 planets would mean some stars would have a lot of them. Hmm. I have three apples and four oranges. However there are seven pieces of fruit. If one were to re-define fruit as "non-citrus fruit", then my statement that I had seven fruits would be wrong by the new definition of fruit, but where would that leave apples? Are they no longer fruit?. The original poster mentioned "stars". Not spectral type "G" stars. Of those there appears to be 64, granted. But the limit as to a specific spectral type was never given by the original poster. I think I am. Therefore I am. I think. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
The point is that sheer numbers do not guarantee anything. The Drake equation ignores perhaps two dozen requirements for the evolution of intelligent life similar to ours (in terms of being able to compare with homo sapiens in it's current state of evolution.. These are things like temperature, stable orbits, non crushing gravity, a magnetic field, tides, a moon to tidally lock and stabilize spin, an outer gas giant to protect from excessive asteroid/comet hits. sufficient water, dry land, non-poisoness atmosphere, an ozone layer, etc. Perhaps not all of these are absolutely essential and there are probably a dozen more that I or others don't even know about. if there were say only a dozen of these parameters and they were each only 20% likely then there would perhaps be a few hundred likely planets in our galaxy. On average they would be too far away to ever know if life existed. I think that there may be only a handful of such planets in our galaxy. I could believe that life such as ours exists somewhere in the universe-I also believe that it is likely that we will never know. The fact that recent searches may prove me wrong in my assumptions keeps me interested in the ongoing search. If the numbers predicted by Frank Drake and others were valid the Galaxy would be colonized by now and we would be enjoying the chatter rather than listening to a bunch of thermal noise. We would have been visited long ago. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
Hmm. I have three apples and four oranges. If you wanted to make an apple pie you would have exactly three apples. |
Bob DeWoody Send message Joined: 9 May 10 Posts: 3387 Credit: 4,182,900 RAC: 10 |
What I wonder is, will it make any difference in the long run. The possibility exists that travel back and forth between the stars will never be realized and therefore we may never make contact with our neighbors even assuming they are there. Bob DeWoody My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events. |
ML1 Send message Joined: 25 Nov 01 Posts: 20265 Credit: 7,508,002 RAC: 20 |
The point is that sheer numbers do not guarantee anything. The Drake equation ignores perhaps two dozen requirements for the evolution of intelligent life similar to ours... The observations and numbers continue to reinforce the view that our solar system is nothing 'special'... The development of our form of life here might be peculiar and 'rare', but the circumstances are nothing special. Note also that life might be widespread in various forms... I could believe that life such as ours exists somewhere in the universe-I also believe that it is likely that we will never know. At the moment, we are playing a game of numbers and possibilities, That is what the Drake equation attempts to add up. If there is already life in the universe that multiplies and travels, then to quote a famous phrase from Carl Sagan: "Where are they?" The observation that we haven't seen anything yet, might suggest that we might be the first at least for our galaxy... Keep searchin', Martin See new freedom: Mageia Linux Take a look for yourself: Linux Format The Future is what We all make IT (GPLv3) |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
it was Enrico Fermi who said ."where are they" We have a somewhat average star but nobody can claim that the conditions on Earth are replicated anywhere else. Some think that this is abundantly likely. I feel that there is a very sparse sprinkling of such planets in our Galaxy. Time will tell. right now these are all opinions. The uncertainty in the Drake equation and my musing that there are maybe a dozen or so necessary parameters for intelligent life that are possibly only 20% likely is infinite. Can intelligent life survive without Ozone, a tidally locked moon, a magnetosphere, a near circular orbit etc ?. I don't think so and the Drake equation does not address them. As we investigate more planets these percentages may become more exact. The reason for my hot air on the subject is to caution against the "Billions and Billions of planets teeming with life" given by Professor Drake and Carl Sagan. Perhaps there are Billions in the entire Universe but I doubt any big numbers in our Galaxy. |
ahj Send message Joined: 24 Sep 02 Posts: 11 Credit: 110,418 RAC: 0 |
But more than likely we are being ignored until we have the capability of FTL speed, or at least until we have spacecraft that have the ability to take off and land on their own. I think Mr. Einstein would like a word with you |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
It is in fact information that cannot travel faster than light. Try to explain how you could send a message using quantum entanglement and you will see what I mean. |
William Rothamel Send message Joined: 25 Oct 06 Posts: 3756 Credit: 1,999,735 RAC: 4 |
it is the distance between objects that is accelerating. A photon has no rest mass. it has energy given by e= plank's constant times it's frequency. It has this mass equivalency but no rest mass as it is a disturbance in the electromagnetic field in free space. Remember, a wave has energy but nothing actually travels longitudinally; only up and down. |
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