Dumusque said that he and his colleagues observed Alpha Centauri B more than 450 times over several years to get a handle on its behavior. After subtracting away the star's orbital motions as well as the presumed effects of starspots and the like, what remained was a tiny fluctuation—an alternating speedup and slowdown, attributed to the gravitational pull of a low-mass planet on a 3.2-day orbit. The planet's tug makes a tiny contribution of about 50 centimeters per second to the velocity of Alpha Centauri B, which is currently moving about 20 kilometers per second with respect to Earth.
"This is a really tough detection to make," Fischer says. "I know that the Swiss team is extraordinarily careful. I have a lot of confidence in them." The Geneva group was the first to discover an exoplanet orbiting a sunlike star, back in 1995, and has since found more than 100 new worlds. Another leading planet hunter, Geoff Marcy of the University of California, Berkeley, says that the evidence for the new planet appears strong. "If the existence of the planet is correct, and I suspect it is, this is an historic discovery," Marcy wrote in an e-mail. "You can spit a watermelon seed to Alpha Centauri."
Fischer notes that she and her colleagues recently completed a major upgrade to their own spectrograph in Chile, and they are now working to determine whether their own limited data might be able to help confirm the existence of a planet around Alpha Centauri B. Meanwhile, astronomers around the globe will no doubt turn to our nearest star system with renewed interest in the hopes of finding more planets there, and especially planets that might harbor life. "This actually makes me very optimistic. I'm super excited about this result," Fischer says. "I wish it was me that found it."
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Add CommentThe exoplanet mass spectrum is a key diagnostic clue for understanding these systems.
Reply | Report Abuse | Link to thisDiscrete Scale Relativity predicts that the exoplanet mass function will have a primary peak at 8 x 10^-5 solar masses, or about the mass of Neptune. There are not yet quite enough representative exoplanet mass data to fully test this prediction, but the Kepler mission has found that the thousands of candidate exoplanets it has identified have a radius function that is strongly peaked in the Neptune range. Also, the inferred mass spectrum for exoplanets with periods less than 100 days is strongly peaked at roughly the mass of Neptune [M. Mayor and D. Queloz, New Astronomy Reviews, 56(1), 19-24, 2012; Figure 7].
14 definitive predictions by Discrete Scale Relativity can be viewed at:
http://www.academia.edu/2021262/Predictions_of_Discrete_Scale_Relativity .
4 predictions have already been verified or are strongly supported by observational evidence.
Robert L. Oldershaw
Discrete Scale Relativity
http://www3.amherst.edu/~rloldershaw
I suspect that this planet, even though it is not habitable, would be the logical destination for our first trip to another star system. Of course this assumes that there are technological advances that would reduce the trip duration from the estimated 40,000 years or current technology would require to get there.
Reply | Report Abuse | Link to thisI am curious if any attempt has been made to identify any dim brown dwarf stars that may be closer especially in the direction of Alpha Centauri. I realize that it would be unlikely to have any inhabitable planets around those stars but they may be viable choices for any needed intermediary stops on the way to Alpha Centauri.
It is fascinating to think that mankind may be at the threshold of leaving our birth world for the stars. Maybe our grandchildren will see planets first hand that we can only dream of.
I can only dream that my existing grandchildren can survive and prosper here on Earth... Forget about other-worldly fantasies and focus on the existence of billions here where humanity must survive - the alternative is insufferable!
Reply | Report Abuse | Link to thisThose billions keep growing and are going to need space to continue to grow in.... Otherwise, we need to find ways to reduce the population to levels our world can sustain in the long term.
Reply | Report Abuse | Link to thisNo, these billions need to limit their growth to fit the resources available.
Reply | Report Abuse | Link to thisEuropean society was saved from self destruction several hundred years ago only by the discovery of America and it's resources - we're back! Unsustainable methods are, well, unsustainable! There is no 'New World' like a pristine America waiting for our immediate consumption! Get real, people!!!
As a child (circa 1955) I was told by my father that we would never, ever be able to see stars as anything more than mere points of light. His logic was simple; the angular displacement of stars was just "too small". So, don't even waste time thinking about exoplanets. And now we can "see" small planets that disturb star velocities by one part in 40,000 well enough to understand the planet's orbit. What "impossible" discoveries await the children of 2155?
Reply | Report Abuse | Link to thisActually we should probably be concentrating our efforts on finding non-occupied, potentially, habitable planets as close as possible to us so when our Sun finally expands and turns this planet into a smoking cinder we will have established our seed on at least one other planet because when our Sun does expand it will be “game over” for life, as we know it, on this rock. Also we should be planning on sending; large diverse DNA samples out into Space with the hope that they will be trapped in some Planet’s gravity-well and possibly plant our notion of Life in some Alien Sea. Or we should accept our existence and eventual extinction as just another small step up the Universal Evolutionary Ladder and just focus on keeping the beer cold.
Reply | Report Abuse | Link to thisIf that was all we had to worry about, we'd have nearly 5 billion years to drink beer, should we live so long... Actually, I think most Egyptians survived on a diet of bread & beer - Brilliant!
Reply | Report Abuse | Link to thisActually, in about a billion years the sun's output will be 10% greater than it is now and so the Earth's ocean's and atmosphere will slowly start to boil away. The Earth will likely be lifeless in 4 billion years, long before the sun expands and swallows us. Keep in mind that multi-cellular life has only been around about 1 billion years so the planet is still very young. We are our greatest threat to our own existence by far. Worrying about the natural end of the earth is like a suicide bomber worrying about hardening of the arteries.
Reply | Report Abuse | Link to thisRSchmidt Good comment, especially like the last sentence.
Reply | Report Abuse | Link to thisIf humanity wants to survive, we must get off this rock before the next major extinction event. We must have Moon, Asteroid, and Mars colonies, and, with advances in propulsion, the outer planets' moons. Beyond that, if we can't develop warp drive, the Kuiper belt objects and the Oort cloud will get us out to around a light year. From there, the Oort clouds of other systems will beckon. We may never even want to enter another gravity well by then and our bodies will continue to evolve.
It may take a million years to reach another system, but, as long as we are advancing, we have plenty of time. It is giving up that will be the end us.
Actually, do you have a reference source for that prediction and your conclusions? It's true that the Sun's luminosity will increase around 10% in a billion years, but its temperature will not be significantly changed. The energy the Earth actually receives may depend on the spectrum of radiation received. See
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Sun#Life_cycle
All this is moot. Since humanity's technological society has been in existence for only 200 years, there's really no basis for predicting a future for humanity beyond the end of this century.
How long did the most persistent earlier civilizations last - several hundred years? Even Egyptian civilization collapsed several times over a couple of thousand years.
Given current population levels and our effect on the environment and natural resources, there's little reason to be optimistic about our long term survival. Certainly there's absolutely no reason to be concerned now about our ability to survive into the next millennium or fantasize about another perfect planet to plunder.
The civilization of a planet the Earth is engaged in waste of time and money, sending radio signals in Space. These signals "travel" within the limits of Solar system tens hours. Civilizations of the Universe for communication use a kind of energy - which speed in the electromagnetic environment of Space, many orders is higher. By analogy (a sound / light / x-energy). Century back ocean waves also were used for communication, delivering bottles with notes from one continent on another
Reply | Report Abuse | Link to thisI heard it at a lecture but here are some references. As the sun converts hydrogen to helium it contracts which increases its temperature. Though "brightness" is not the best measure of the temperature of a star the brighter a star is in the blue spectrum, the hotter it is. Astronomers use the term "Luminosity" instead of brightness and that does correlate to temperate as it is the measure of the amount of energy being emitted.
Reply | Report Abuse | Link to thishttp://cseligman.com/text/stars/sunms.htm
http://www.astronomy.ohio-state.edu/~pogge/Lectures/vistas97.html
What are you smoking? Radio waves travel at the speed of light and that is as fast as you can go. I think you are mistaking science fiction for science fact.
Reply | Report Abuse | Link to thisThanks for the references. I'll take them at face value and presume that the Sun will be more luminous and hotter, although this seems to contradict the chart in my previous Wikipedia reference.
Reply | Report Abuse | Link to thisLuminosity is the measure of photons received. The total energy imparted depends on the wavelength of light received. Luminosity directly corresponds to the number of photons received over time; the energy received varies depending on wavelength. For example:
"Red giants... have radii tens to hundreds of times larger than that of the Sun. However, their outer envelope is lower in temperature, giving them an orange hue. Despite the lower energy density of their envelope, red giants are many times more luminous than the Sun because of their large size."
Please see:
http://en.wikipedia.org/wiki/Red_giant#Characteristics
"It may take a million years to reach another system" - Postman1.
Reply | Report Abuse | Link to thisThis is incorrect. Existing probes (Voyagers and New Horizons) would reach alpha Centauri in 75,000 years, and existing electric thrusters already in use (on commsats and the Dawn mission) could reach there in 30,000 years with very modest mass ratio (3:1). With plasma thrusters being tested in the lab and a more demanding mass ratio (10:1) you can reach 130 km/s, which results in a 10,000 year trip.
Unless you think that progress in technology will never advance beyond what is in the lab now, we can expect further improvements. Known but untested technology should lead to exhaust velocities of 250 km/s, which for a mass ratio of 10:1 gives a mission velocity of ~600 km/s and a trip time of 2,200 years. Beyond that we would have to await the development of fusion engines.
In general, when the pace of progress is greater than the inverse of the trip time, as is true now, it pays to wait and base your starship design on faster future technology.
I suppose it is only natural when we think of Space travel to think in terms of building ships which will accommodate our bodies for the duration of such trips, but I suspect that by the time we are technologically advance enough to construct efficiently automated ships that can reach velocities that will make such interstellar trips practical we will also have perfected, and become comfortable with the notion of packing such ships with either cryogenic units housing clones along with Data storage devices capable of being uploaded at the appropriate times, be that in the case of a detected emergency or at a predetermined appropriate time prior to reaching the final destination. Such ships would not have to be large enough to carry supplies to maintain us and therefore could be designed to maximize fuel load and hence minimize trip time. Think of it in terms of aviation where the airliners climb to an efficient cruising altitude and then descend in accordance with their target airport. In the case of interstellar travel you would reach for the maximally efficient cruising velocity in accordance with your target planetary system.
Reply | Report Abuse | Link to thisI'll bring the beer!
Reply | Report Abuse | Link to thisOne day we will reach the stars. We will probably encounter another civilization (or several) in one corner (or several)of the vast infinite universe. I hope no other civilization visits us before we are prepared for that. Everything seems to be written already. There is no way we can change it. There will probably be an interstellar Noah's Ark. Excuse me gentlemen for the interruption. Go on with your conversation. Good night!
Reply | Report Abuse | Link to thisSorry about leaving out the other part that was supposed to be in my previous post, but better late than never.
Reply | Report Abuse | Link to thisSo one other possible scenario would be to compile a vast store house of diverse DNA samples much like the storage of ancient seeds is done here on Earth and put that in Cryo. The Data storage component could consist of the quantum bits which would contain the necessary information to allow a sufficiently advanced civilization to activate the programs necessary to reconstruct the DNA. Of course such a civilization may simply dump the DNA in their garbage dump, or have it for lunch perhaps with their version of “ a nice Chianti”, but I suspect curiosity is a Universal component of intelligent Species so I do not believe that would happen. The exterior of such ships could be embossed with Pictographs which could be read by Alien Species along with a preprogramed signal of sorts to act as a homing beacon. Many such ships could be sent out in various predetermined directions toward likely candidate systems which may harbour intelligent life by the time such ships arrive on target.
Whether the Earth is rendered lifeless in a thousand, a million or several billion years is sort of irrelevant the point is it is inevitable and irrevocable and when it happens our part in the “Play” will be over, unless we do something to stack the game.
Re: And Then What ? Why do you think human DNA SHOULD survive after our sun burns out ? 99% of all creatures who have crawled or walked or ran or swam across planet earth are now extinct. Extinction is the natural order and the natural end game for all life forms. Extinction is NORMAL. Humans have completely destroyed planet earth. Many plant and animal species on planet earth have become extinct BECAUSE of the unethical and immoral behavior of humans. Humans DESERVE to become extinct. Sending human DNA 'seeds' to other solar systems and habitable distant planets is a BAD idea and would simply spread innate human avarice to the far reaches of the universe. The more noble path would be simply and purposely allowing humans and their evil DNA to fade into oblivion and hope new and different intelligent life forms evolve in the universe with NO resemblance to the severely flawed human species.
Reply | Report Abuse | Link to thisI have reflected on what you have said and your argument does have some merit, on some level, but I would ask you the following: Do you not agree that the process of Evolution works on the principle that those best suited to survive do so and those not so well equipped do not and if you do agree then is there not a case to be made for we Humans to struggle as hard as we can to survive as a Species and by so doing perhaps some small group of us may be found worthy, by the forces of Evolution, to advance forward and become something more than we currently are? Would we not be remiss if we simply judged ourselves unworthy because of our current state? Every dominant Species that has gone before us has lost the game of long-term survival either because of catastrophic events beyond their control or because of their failure to adapt to the changing environment around them. I personally do not know if we will survive but I think that it would be as much a mistake to take the “fatalist approach” and “write us off” because of our flaws as it would be to believe that we, at this current stage of our development, are the evolutionary pinnacle of life on this planet. We are what we are. What we may become in the future is up to us. If we are intelligent enough to make the right choices in the long-term we deserve to survive. If we do not then the forces of Evolution will correct the situation without any help from us. I prefer to be optimistic with regard to our chances and hence plan for the long-term just as I make the choice to get up and face each day’s challenges rather than quit and commit suicide out of despair.
Reply | Report Abuse | Link to thisThe obvious problem with worrying about the distant future is that we're not likely to survive the near term catastrophic threats smacking us in the face - population control, resource management and our environmental impact (climate change). Unless we address these issues immediately we can expect to be extinct before we face any, in effect, imaginary potential long term risks.
Reply | Report Abuse | Link to thisIn the history of the Earth, the human population never approached 1 billion people until 1800 CE. About two hundred years later there are >7 billion people on this planet. We may reach 10 billion by the end of this century - or perhaps zero... This is the principal challenge to our continued survival!
Remember Babylon 5? Maybe the Centauri will give us the jump gate technology once we get there and ask them for it!
Reply | Report Abuse | Link to thisOf course we may be eventually wiped out by some catastrophe over which we have no control and so I see no reason to spend a lot of time thinking about such an occurrence. I prefer to assume that we will survive for the foreseeable future since I have no control over the path of Asteroids or Comets along with my complete lack of control over geological events such as massive volcanic eruptions and gigantic Earthquakes that could precipitate our demise. I do not believe that we are in danger of starving to death, as a Species, although I do believe large scale Famine, and the wars that may come about as a consequence thereof, may eventually “thin out the herd” so to speak. One of the main things that most people do not allow for when they “future-cast” is the very real possibility of future “game changing” discoveries that could rapidly advance our abilities with regard to Space travel such as the advent of practical Quantum Computing and the discovery of, or the creation of, materials and procedures that provide technological “giant leaps forward”. This is strange since all one has to do is look at what has taken place over the last 100 years and then think back 150 years and try to imagine what the average person would have believed possible at that time. It may be that within the next 100 years we will have solved the riddle of Dark Matter and Dark Energy and are able to harness it to service our needs. I believe that in the next 50 years we will make technological leaps and bounds that will boggle the mind of the average person today not unlike how the controllable rocketry technologies that enable us to place Rovers on the surface of Mars today would astound the people of 150 years ago. It may be true that we are on a collision course with our extinction but I for one will continue to mentally “pull back on the stick” right up to the moment of collision.
Reply | Report Abuse | Link to thisFuture prognosticators most often rely on the continuation of long term trends, such as the incredible progress made in science and technology. Yet, even continued technological development may not be sustainable.
Reply | Report Abuse | Link to thisThe effects of overpopulation are much more far reaching than just famine. Please see
http://en.wikipedia.org/wiki/Overpopulation#Effects_of_human_overpopulation
Populations are not only increasing, but they are becoming more urbanized and globally interactive, increasing the risk of pandemics. In the 1300s Europe lost 1/3 of its population due to bubonic plague, leading to the period known as the Dark Ages.
Could modern civilization withstand the potentially sudden illness and death of more than 2 billion people, or would it collapse? I think complete collapse is a very real possibility in this century as a result of any of many potential risks directly related to our continuing overpopulation. No, I don't really think that humanity is likely to eliminated, but that our ability to sustain our technological social infrastructure could be.
The idea that the solution to humanity's self imposed dilemma is to move to another 'New World' is ludicrous, since ongoing resupply and support would be impossible, and a minimum population in the many thousands would be required to provide a sustainably diverse reproductive population. Moreover, how would that help the many billions left to suffer on Earth? The hope of finding another ideal 'New World' to provide for humanity's continued survival is the critical point of this discussion that I object to - such fantasies merely divert resources needed to find solutions to our very real, immediate survival needs.
We need to finally address population management much more than we need breakthroughs in science and technology. Relying on war, starvation and disease to control our population growth seems acceptable as long as you don't end up as part of the 'controlled' group. No matter what country you live in today, a comfortable future for you and yours cannot be assured without directly addressing global population issues.
A massive emigration in which we take all human population to another planet seems very unlikely. I agree that population growth should stop. Probably to stop growth is not enough. The population should start declining. But very probably this should be an automatic process. I have heard that China limits (or used to limit) the number of children in a family. That is a very drastic measure. Probably there are many factors outside of human control that can influence growth population moving humanity into periods of rapid population growth (baby boomers)and periods of population decline like in the 1300's in Europe. At this point probably some countries should try to decrease population growth. Among them probably most of the countries in America. No one can give the order. It is how all the factors combine to create a trend. There must be several (may be many) books written about what the future looks like.When the time comes to leave this planet the size of the population will be according to the circumstances that prevail and we can not rule out that we may perish with the planet. All life on this planet may disappear in an Apocalypses. If we take good care of this planet and try to keep population growth at check I would say we can live very comfortably (and travel far and wide in the Universe)for another (I guess)100 million years at least. There are many possibilities, we humans may disappear and another forms of life continue on the planet. I do not know what scientists (in this field) say about how long will this Earth support life. I guess at least a hundred years. We are living the infancy of human kind. It is quite complicated. There is also spiritual considerations. My point of view is that we will prevail and one day move to another star, and we will enter into contact with civilizations on other parts of the Universe.
Reply | Report Abuse | Link to thisCorrection to my previous commentary.
Reply | Report Abuse | Link to thisI tried to say "I do not know what scientists (in this field) say about how long will this Earth support life. I guess at least a hundred million years".
Probably a tool should be added to edit what we have written.
I think there should be a positive correlation between luminosity ( brightness) and temperature ( energy received). Both luminosity and temperature should be function of two factors i) Nos. of photons ii) Energy content of each photon which is related to frequency ( or wavelength)
Reply | Report Abuse | Link to thisAs such luminosity should also be dependent upon frequency of photons also apart from nos. of photons
During the past 200 years of technological history of humankind , so far only 3 persons have touched for a few days only some extra terrestrial body in space i.e moon which is only 386000 Km away from earth. In view of the current state of affairs, any wishful talk of mass migration of humankind to some exo -planet located trillion of KMs away from earth is not more than Science Fiction Story
Reply | Report Abuse | Link to thisYes and no, depending on whether or not the context of the discussion is astronomical - see
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Luminosity#Luminosity
"In astronomy, luminosity is the amount of electromagnetic energy a body radiates per unit of time. It is measured in two forms: apparent (visible light only) and bolometric (total radiant energy). A bolometer is the instrument used to measure radiant energy over a wide band by absorption and measurement of heating."
Please examine the inset Hertzsprung–Russell diagram.
The heating imparted by a red giant would be less than for a blue-white giant star at relative distances such that an observer receives the same number of photons per second from each.
"The heating imparted by a red giant would be less than for a blue-white giant star at relative distances such that an observer receives the same number of photons per second from each."
Reply | Report Abuse | Link to thisThat is what I stated in my comment 30. A blue-white giant star radiates more heat ( energy) than a red giant for equal nos. of photons since its radiations are at higher frequency implying each photon is more energetic. ( Higher the frequency , higher the energy content of each photon)
I think luminosity ( apparent) is a measure of the energy received in the visible spectrum only while heat ( energy) is measure of energy received in the entire spectrum. In this respect, bolometric luminosity and total energy received ( heat) should be equivalent.
Otherwise, how to distinguish between luminosity and energy ( heat)?
But that's what I said in my comment #15, which you responded to with your comment #30. Do you misunderstand me? What was the purpose of your comment #30? These are rhetorical questions - please do not respond.
Reply | Report Abuse | Link to this(In reply to 31)
Reply | Report Abuse | Link to thisIt is very understandable what you say.
We all humans on Earth may disappear long before the Earth is capable of sustaining life. It could be a natural catastrophe that we may not be able to avoid the way he dinosaurs supposedly disappeared, or it could be something produce by ourselves.
Entire self-destruction of human kind seems to me, very unlikely. But we can fall into another Dark Ages, and stay there for a long time.
Certainly mass migration to a stellar destination seems today pure science fiction.
But my feeling is that may be one day we will discover things that will allow us to do thing that at this moment seem utterly unlikely.