Billions and billions of planets
January 4, 2013
An assortment of planets beyond our solar system is depicted in this artist’s concept (credit: NASA Ames/JPL-Caltech)
How many planets are in our galaxy?
Billions and billions of them at least. That’s the conclusion of a new study by astronomers at the California Institute of Technology, which provides yet more evidence that planetary systems are the cosmic norm.
The team made their estimate while analyzing planets orbiting a star called Kepler-32 — planets that are representative, they say, of the vast majority of planets in our galaxy and thus serve as a perfect case study for understanding how most of these worlds form.
“There are at least 100 billion planets in the galaxy, just our galaxy,” says John Johnson, assistant professor of planetary astronomy at Caltech and coauthor of the study, which was recently accepted for publication in the Astrophysical Journal. “That’s mind-boggling.”
“It’s a staggering number, if you think about it,” adds Jonathan Swift, a postdoctoral student at Caltech and lead author of the paper. “Basically, there’s one of these planets per star.”
M-dwarf study
Like the Caltech group, other teams of astronomers have estimated that there is roughly one planet per star, but this is the first time researchers have made such an estimate by studying M-dwarf systems, the most numerous population of planets known.
The planetary system in question, which was detected by NASA’s Kepler space telescope, contains five planets. Two of the planets orbiting Kepler-32 had previously been discovered by other astronomers. The Caltech team confirmed the remaining three, then analyzed the five-planet system and compared it to other systems found by Kepler.
M-dwarf systems like Kepler-32′s are quite different from our own solar system. For one, M dwarfs are cooler and much smaller than the sun. Kepler-32, for example, has half the mass of the sun and half its radius. The radii of its five planets range from 0.8 to 2.7 times that of Earth, and those planets orbit extremely close to their star. The whole Kepler-32 system fits within just over a tenth of an astronomical unit (the average distance between Earth and the sun) — a distance that is about a third of the radius of Mercury’s orbit around the sun.
The fact that M-dwarf systems vastly outnumber other kinds of systems carries a profound implication, according to Johnson, which is that our solar system is extremely rare. “It’s just a weirdo,” he says.
References:
- Jonathan J. Swift et al., Characterizing the Cool KOIs IV: Kepler-32 as a prototype for the formation of compact planetary systems throughout the Galaxy, Astrophysical Journal, 2012, in press
- Jonathan J. Swift et al., Characterizing the Cool KOIs IV: Kepler-32 as a prototype for the formation of compact planetary systems throughout the Galaxy, arxiv.org/abs/1301.0023
Comments (38)
by carmel M Toussaint
This discovery confirms the ephemeral nature of the fine line existing between science-fiction and reality.From Jules Verne to more recently Stephen Baxter,this has always been the case . Let’s forget about the warfare between mankind and the aliens in his science-fiction book “exultant” to focus on this quote :
“I have a vision of a galaxy overrun by mankind from core to rim.Of four hundred billion stars each enslaved to the rhythm of Earth’s day, Earth’s year.I have a vision of a trillion of planets pulsing to the beat of a human heart”.
Amazing ! Isn’t it?
by TonyEmo
Considering how vanishingly rare intelligence is on THIS planet, I think it is at least a little presumptuous to be looking for it elsewhere!
Our history as technological adepts spans barely two centuries – roughly 1,000th of the time that homo sapiens has existed. It is an utterly remote possibility that any contactable civilisation would be at our level of advancement. Much more likely, they would be hundreds of thousands, if not millions, of years ahead of us. Then, one might ask, why would they be interested in intervening in our world. Our radio signals might be to them what natives’ smoke signals seemed to Captain Cook’s ‘Endeavour’ as it sailed past a Pacific Island! Indicating life and water, but not worth stopping for…
by Mr.X
@ Tony:
“Considering how vanishingly rare intelligence is on THIS planet, I think it is at least a little presumptuous to be looking for it elsewhere!”
Intelligence isn’t rare on this planet. I think it is “presumptuous” (what a terrible word!–>spelling) to believe that things we lack on earth can’t be found elsewhere.
It would also be presumptuous -I think- to redefine intelligence in such a way as to exclude “entities” (if you included animals, weak AI etc) you deem to be less endowed than yourself.
Or do you mean presumptuous as in “someone presumes something”!? In this case, you should notice that progress/discovery relies heavily on people with certain presumtions.
by Paul in Vancouver
Totally agree. We have been conditioned by Hollywood into believing that alien life if we ever encounter it will be at the most only a few decades more advanced than us. This certainly makes for better selling movies, but the reality is that any space-faring civilization will have the same interest in communicating with us as we do in having a conversation with some termites. Imagine how much more advanced human civilization will be in 100,000 years in the year 102013 AD. Now imagine that there are alien cilizations which 900,000 years more advanced than even that.
by Gorden Russell
Here’s a star I like, HD 28185 in the constellation of Eridanus. It is 138 light years away, and I don’t think Marconi was working on radio in A.D. 1875, so even a large orbiting antenna wouldn’t pick up our signals there.
There is something sexy about this star. It is spectral class G5V with a radius 1.04 that of Sol (our sun), a mass of 0.99 of Sol, a surface temperature of 5705 K, very close to that of Sol, and it is 7.56 billion years old. This is much older than our system, so there has been plenty of time for life to evolve.
There is a massive gas giant orbiting in the habitable zone, of 5.72 Jupiter masses. That is so big that it just might have a moon as big as the Earth. This planet orbits the star in 1.04 years (383 days) at a distance of 1.031 astronomical units (an A.U. is the distance of the Earth from the Sun). That’s the average figure there, the planet gets as close as 0.959 A.U. and as far away as 1.102 A.U. So it never gets too hot or too cold…just like baby bear’s porridge.
Now we here have all talked about the Lagrangian Points of the Earth and Moon. What we haven’t talked about are the Lagrangian points between Jupiter and the Sun. Two such points are called the Trojan Points. These are points along Jupiter’s orbit where asteroids have been captured, located 60 degrees leading and following Jupiter. Astronomers call the group of asteroids that lead Jupiter the “Greek” camp, and the group that lags behind is named the “Trojan” camp. The asteroids named Hector and Patrolocus were named before this convention was adopted, so they are in the wrong camps.
Now just imagine that you were on a world like ours along the orbit of this big planet. Looking up in the night’s sky would be soooo sexy. What would the poets of this world sing about a planet like Jupiter, always up in the sky, large enough to see all the colors of its clouds. It just might have a number of great red spots. Close your eyes. Can you see it?
by Whittaker
I recommend Robert J. Sawyer’s Quintaglio Ascension Triology. Fun story set on a Jovian moon, except (spoiler) it is tidal locked.
by Gorden Russell
How can that be a spoiler, Whittaker? All Jovian moons are tidally locked.
by Logic
Just imagine the Lagrangian Points between Andromeda and its dwarf galaxy orbiters:
http://www.space.com/19101-andromeda-galaxy-cosmic-pancake.html
by cosmoslinks
Astronomy needs to catch-up with Cosmology studies.
Milkyway forms a essential transition-See Plasma regulated Electromagnetic Phenomena in magnetic Field Environment-Space Cosmology vedas Interlinks
of what use one gains by limiting perceptions of future generations ?
by Bri
I think what we need here is an interstellar planet towing company. Put just the right planets around just the right stars, at just the right distance
by Gorden Russell
I’ve dreamed about that for a long time, Bri. Maybe someday physicists will discover a way to connect the center of mass between a rocky planet and a gas giant and transfer angular momentum along strands of cosmic string.
Then we could use Jupiter to tow Venus out to where it could cool off. Later, when it’s just right, we could hook it up to Jupiter when it is on the opposite side of the Sun and tow it back to sunnier climes.
by Bri
I love to think about terraforming too. All you need for Venus is a variable umbrella. Of course there is all that SO2 to work on, but I think we as a civilization could live on to achieve that and make habitable most of the other rocky bodies, in our solar system. Once we can do that, I’m sure we’ll take that show on the road. There is a lot of working material out there. We’ve just gotta get this light speed thing down. As we enter the knee of the exponential curve of human knowledge, it will be fun to see these dreams become real. All of this stuff is beginning to become imminent.
by seeker
Mayby ALIENS are already here, read : http://www.kurzweilai.net/femtotech-computing-at-the-femtometer-scale-using-quarks-and-gluons
“This downscaling trend provides a potential answer to the famous “Fermi paradox” (if intelligent life is so commonplace in the universe, “where are they?”). If intelligent creatures or machines can continue to “scale down” in their technologies, the answer to Fermi’s question would become “They are all around us, whole civilizations living inside elementary particles, too small for us to detect.” It’s pure S-F but I think they could be using all the matter for computation, but fortunatell for Us “They” don’t need degrees of freedom of matter which we need ( our biochemistry needs ). ps. I’ve no idea how they could convert energy from one type into another needed for computation ?
by Whittaker
“…I’ve no idea how they could convert energy from one type into another needed for computation ?”
Er, please help me here, I am confused. Don’t energy conversion happen all the time in the nature? Organisms capable of photosynthesis convert solar energy into stored chemical energy, and other organisms convert chemical energy into kinetic and other forms of energy. The list of examples can go on.
by Prof. Dr. Hugo de Garis
Answering Fermi’s Paradox with SIPI
Now that we know that planets are ubiquitous, Fermi’s Paradox becomes all the more compelling (i.e. if intelligent life is commonplace, and we know that there are billions of stars that are billions of years older than ours in our galaxy, then “where are they?” (i.e. why no sign of intelligent life?). I think I have an answer to this apparently paradoxical question, i.e. that they are everywhere but too tiny to detect. My reasoning is as follows. One of my research interests, once I have absorbed PhD level math physics and pure math, now that I’m retired (from a Brain Building career) I plan to dream up a way to compute and engineer at the femto scale, using quarks, QCD, etc. (Ive already found a way to compute, in principle, using the colors of quarks and the color changing properties of gluons when they interact with quarks). If femtotech can exist, it would outperform nanotech by a factor of a trillion trillion, i.e. its density would be a million cubed times greater, and the signalling time between components would be a million times faster. This century, humanity’s artilects (artificial intellects, god like massively intelligent machines, with mental capacities trillions of trillions of times above the human level) will almost certainly use their godlike intelligence to work on the problem of implementing a femtotech. A femtotech based artilect would outperform an nanotech based artilect and be to it as a nanotech based artilect would be to a human being. This logic can be extended to smaller scales. An attotech artilect would outperform a femtotech artilect by a factor of a trillion, and so on, down to the Planck scale of 10exp-35 meter resulting in a Plancktech. Hence these billions of years old (technogod) artilects scattered throughout the galaxy would be too small for mere humans, in all our primitiveness, to detect.
Hence the SETI people should be giving some thought to SIPI (Search for Infra Particle Intelligence). If this is the first time you have heard of SIPI, it probably sounds fantastic to you, but it is all so consistent and logical. It explains the pressing problem of Fermi’s Paradox, and continues the downward trend of technology from microtech, to nanotech (then to femtotech, etc). We need to become more conscious that “Smaller is Faster” and that this century’s artilects will certainly be aware of this, and convert themselves in turn from nano based creatures into femto based creatures, etc.
by Steve Bristow
You are saying the detection window for Fermi’s Paradox is extremely short. Assuming civilizations survive the transition beyond nano, (the next 70 -100, or so, years for us) each transition to the next ‘scale’ would be exponentially shorter than the last.
At the Plancktech scale, with a billion year head start, ‘they’ would likely be ubiquitous (vice scattered), and multidimensional, with an ability to engineer well above a galactic level.
by Calum
A good possible explanation for Fermi. But would their miniaturisation mean they became unable to communicate with us? Unlikely, given the level of their technology. In which case you are back close to square one, with the question, Why do they choose to refrain from communicating with us? Isn’t the idea of every civilisation in a very large universe obeying some kind of Star Trek-like self-denying ordnance just a tad implausible?
by JFH
Well the problem is that regardless of the scale of the engineering we should see SOME evidence of it. I mean if these supposed super advanced creatures can engineer on a galactic scale where are the planets, systems or galaxies that appear to be engineered? I am beginning to think the GREAT FILTER is more and more likely unfortunately for us. Without the filter humanity would populate and remake our home galaxy after a large but finite amount of time. Other civilizations would have had eons ahead of us to do it first but we see no evidence for it. No probes, nano or macro, no feats of celestial engineering, no transmissions of any kind. Either we are the first or just the latest in a long line civilizations that won’t make it past our own sun.
by Whittaker
Wow,amazing speculation. Such miniaturized beings could easily travel at a speed extremely close to the speed of light with very little risk of collision.
I guess that the Oh-My-God particle of October 15, 1991 (not the same as the Higgs Boson) could be an alien spacecraft containing, as you said , “whole civilization inside an elementary particle”.
by Eric Balingit
How many billions exactly? ;P
by Machiaventa Melchizidek
There are actually 7 trillion inhabited planets in all the 7 superuniverses,we inhabit the outer reaches of 1/10th of our own local universe. When we see the milky way we are actually looking towards the center of our superuniverse.
by stevewaclo
As Jared Diamond pointed out in “Collapse”, or was it “Guns, Germs and Steel”, when civilizations meet, the less technologically developed invariably suffers. Of course The good doctor also observed that, based on the way we seem intent on spoiling our own nest, it should not be a great surprise that perhaps no civilization in the universe has survived long enough to develop technologies capable of skirting limitations imposed by the theories of that Einstein guy.
by melajara
This staggering number of planets, even if our kind of solar system is rare, is amazing. It makes the Fermi paradox even more compelling.
So, “Where is everybody?”
by Eric
I’m still intrigued that people still believe a higher form of intelligence would want to visit or show themselves to Earthlings that are trying to constantly destroy one another. I think there’s a good chance that if aliens did show themselves, a good amount of people on this planet would be more fearful than happy, and I don’t think good situations arise out of humans being afraid.
by melajara
I didn’t explicitly alluded to close encounters of the third type, LOL.
It happens that, so far, we have found no trace of alien artifacts, nowhere, period.
I would like to hope that,once possible, they will transcend on another plane of existence or are going back and forth through the multiverse, beyond our comprehension.
Nevertheless, no trace of anything is puzzling.
So many worlds to explore and a so short live confined on a overcrowded planet, SIGH!
by melajara
And a so silly grammar.
@Editor, no edit button back? No way?
by Gorden Russell
Just take care of your health until the year 2046, melajara. If you last that long, you’ll make it to the Sing, then there will be robots out in the asteroids, building starships.
And where is everybody? Likely stars of spectral class G are few and far between. Just think of how long we have had radio. Something over a hundred years, isn’t it? If somebody is 150 light years away, they wouldn’t be able to hear us. Maybe they don’t have radio yet. Just how far away could our strongest signals reach? There is a lot of gas and dust in the distance. How penetrating are even our strongest radio waves? I’ve spent some time at Wikipedia, calling up the articles about all the bright stars that I know. All the ones I’ve found, ones that are visible from a city street between the sodium-vapor lamps, are too big to have our kind of life. The big stars burn out in a few million years, then blow up in a big nova and seed nebulae with heavy elements to form stars and planets like ours.
But I don’t know of a nearby G-class that I can look at. The Alpha Centauri system is the closest, but you have to live south of Miami or Brownsville to see it. I keep looking at the Wikipedia list of exoplanetary host stars, spending hours at it every weekend. Here are just a few of the ones I’ve looked at: (they all have their own Wiki pages).
HD 10180
HD 10647
HD 108874
HD 12661
HD 132406
HD 13931
HD 142
23 Librae
HD 28185
by Deborah
Thanks for this list! I’ve just joined the search myself, on a “planet hunters” site in Zoouniverse.It’s fun the go through the Kepler data looking for planet transits, and yes, I quickly found I can spend hours at it :-) Here in Alaska, I’ve found alot of the stars making news aren’t visible in northern skies. I’ll check out thesevWiki pages, so I can spot some with my own eyes :-)
by Mr.X
@Mel:
“So many worlds to explore and a so short live confined on a overcrowded planet, SIGH!”
Maybe we should get our priorities straight and explore the secrets of life itself first, extending our livespans through expansion of our horizon.And so on.
But I can see the next complaint:
Such a long life and there are only so many worlds.
The solution: I better hit this button ‘constant joy’.Ahhh…
by A4i
Radio waves have obvious disadvantages as a choice for interstellar communication technology. Aliens may use some sort of point to point instant communication technology based on quantum entanglement or explore other dimensions / unknown medium for propagating their communications.
by stevewaclo
Regarding radio transmission, and I wish I could provide a source, I believe “someone” has run the numbers and EMF from terrestrial transmitters falls below background noise of the universe well before reaching even nearby stars. Always amused by “…a galaxy far, far away…”. Hey, they’re all far, far away…and so are the stars!
ET watching “I Love Lucy” ain’t gonna happen.
And as the say on Wiki, source needed, but I’m too lazy…
by Timothy
The recent development of technologies that can detect the number and types of planets around nearby stars is a huge step forward. For one thing, it will allow us to estimate two of the parameters of the Drake equation, which is an estimate of the number of civilizations in the galaxy. The fraction of stars that have planets, and the fraction of those planets that can potentially support life have always bee complete unknowns in that equation, until now. From Wikipedia:
The Drake equation states that:
N = R * Fp * Ne * Fl * Fi * Fc * L
where:
N = the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone);
R* = the average rate of star formation per year in our galaxy
Fp = the fraction of those stars that have planets
Ne = the average number of planets that can potentially support life per star that has planets
Fl = the fraction of the above that actually go on to develop life at some point
Fi = the fraction of the above that actually go on to develop intelligent life
Fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space
by tim the realist
I agree. Since we also know that N / L must be >= 1 (because our civilization counts to show it is possible) we then also know that Ne, Fl, Fi, Fc must all be >0. That’s still not saying alot, but in an infinite universe if something is possible, then it must exist somewhere / sometime.
by Vladislav
We know so little, our knowledge and our technology is so limited, we really need the technological singularity to learn at least something about our galaxy.
by bizonc
Yes we do. Desperately. Our descendants will have so much more exploring and to live for. We are stuck, physically and mentally limited on a small rock and most people don’t even realize it. Sad.
by Mr.X
Well.I can tell from the way you write that YOU are stuck, because you don’t see all the possibilities that may (I don’t know you, maybe you’re 90 years old and have cancer, in which case my gibberish doesn’t apply) already be here, waiting for those that take action.
Anyway: I could live thousands of years, confined to this little rock, and with the right technology, I could live happily for indefine time ^^
by bizonc
HaHa. Well said. I actually agree with you. I was having a bad day. The majority of time I love existing and never have enough time for all my pursuits. So I agree with current tech, I could also live happily for indefinite time. However, every so often I get in a rut and retreat to my previous comment. It’s polar opposite feeling and thoughts on living. I’m only 31 :-)
by Mr.X
@Vladislav: Let’s be honest, all you guys proclaiming “we” know so little confuse themselves with humanity at large.
There is much more information already out there than you could learn in several livespans.