How Many Planets Are In The Universe?

“Stuff your eyes with wonder, live as if you’d drop dead in ten seconds. See the world. It’s more fantastic than any dream made or paid for in factories.” -Ray Bradbury

It wasn’t all that long ago — back when I was a boy — that the only planets we knew of were the ones in our own Solar System. The rocky planets, our four gas giants, and the moons, asteroids, comets, and kuiper belt objects (which was only Pluto and Charon at the time) were all that we knew of.

Image credit: NASA's Solar System Exploration, http://solarsystem.nasa.gov/planets/index.cfm.

But these were just the worlds around our Sun, which houses (according to current definition) eight planets. Our Sun is just one of an estimated two-to-four hundred billion stars in our Milky Way galaxy, and looking up towards the night sky, one can’t help but wonder how many of those stars have planets of their own, and what those worlds are like.

Image credit: Free Roaming Photography, by Mike Cavaroc.

There are a vast variety of stars out there in our galaxy. Our Sun is just one example — a G-class star — of seven different main types.

Image credit: Wikipedia user Kieff; annotations by me.

We may think of our Sun as being typical and on the relatively dim side, since a disproportionate number of stars visible to our eyes in the night sky are O, B, and A-class stars. But in reality, the Sun is more massive and intrinsically brighter than 95% of stars in our galaxy. The red dwarf stars — M-class stars — which are no more than 40% the mass of our Sun, make up 3 out of every 4 stars that are out there.

What’s more than that, our Sun exists in isolation; it is not gravitationally bound to any other stars. But that is not necessarily how stars exist in the galaxy, either.

Image credit: VISTA infrared survey, ESO / J. Borissova.

Stars can be clustered together in twos (binary stars), threes (trinaries), or groups/clusters containing anywhere from hundreds to many hundreds of thousands of stars.

My point is this: if you want to accurately estimate how many planets there are in our galaxy, you can’t just take the number of planets we find around our star and multiply it by the number of stars in our galaxy. That’s a naïve estimate that we’d make in the absence of evidence. But just for fun, that’d give us somewhere around two-to-three trillion planets in our galaxy. And as we know from our own Solar System, there’s a great variety of what the surfaces of those planets could look like.

Image composite: credit Mike Malaska. For individual image credits, see lower left.

But over the past two decades, we’ve been looking. We’ve been looking with a few different methods, in fact, and the two most prolific are the “stellar wobble” method, where you can infer the mass-and-radius of a planet (or set of planets) around a star by observing how it “wobbles” gravitationally over long periods of time:

Image credit: European Southern Observatory.

And the transit method, where the light coming from a distant star is partially blocked by the disk of a planet in its solar system passing in front of it.

Image credit: ESA / NASA's Solar And Heliospheric Observatory (SOHO), 2006.

It’s important to recognize, when we do this, that we will not see the vast majority of planets that are out there. Take NASA’s Kepler Mission, for instance, which has discovered hundreds (if not thousands) of planets by looking at a field-of-view containing around 100,000 stars. But that does not mean that there are only a few planets-per-hundred-stars. Consider the following: if Kepler were looking at our Solar System, and our Solar System was oriented randomly with respect to our perspective, these are the odds that the alignment would be good enough to observe a transit of our star by one of our planets.

Planet Degree Range (out of 180) % chance of good alignment
Mercury 1.37 degrees 0.76% chance
Venus 0.738 degrees 0.41% chance
Earth 0.533 degrees 0.30% chance
Mars 0.320 degrees 0.18% chance
Jupiter 0.101 degrees 0.056% chance
Saturn 0.0556 degrees 0.031% chance
Uranus 0.0277 degrees 0.015% chance
Neptune 0.0177 degrees 0.0098% chance

Now you may think those are not-so-good odds, but you don’t even know the half of it. Mercury and Mars are too small, meaning they don’t block enough of the Sun’s light, to be detectable with Kepler, and the four outer planets, despite their large sizes, take too long to orbit for Kepler to observe more than one transit, a necessity for a planetary candidate.

So this means that if Kepler were looking at 100,000 stars identical to our own, it would have found 410 stars with a total of 700 planets around them.

Illustration credit: NASA / Jason Rowe, Kepler Mission.

But as of today, Kepler has found over 11,000 stars with at least one planetary candidate, and over 18,000 potential planets around those stars, with periods ranging from 12 hours up to 525 days. In other words, there are:

  1. a huge variety of planetary systems out there, most of which are very different from our own,
  2. orbiting a wide variety of stars, including binary and trinary systems,
  3. and we are only seeing the ones that are large enough, orbiting their stars close enough, that also have unlikely, fortuitous alignments with respect to our line-of-sight.

You may have read this week that there are at least 100-to-200 billion planets in our Milky Way, and that’s true, but that’s not an estimate; that’s a lower limit. If you instead were to make an estimate, you’d get a number that’s at least one (and more like two, if you’re willing to make inferences about outer planets) orders of magnitude higher: closer to ten trillion planets in our galaxy, alone!

Image credit: ESO / M. Kornmesser.

In other words, based on what we’ve seen so far, most stars are likely to have planets, and based on what we’ve seen in the inner solar systems of the ones that do, a large fraction of them are likely to have more rocky planets in their inner solar systems than even our own has, to say nothing of the outer solar system!

Image credit: J. Pinfield / RoPACS network / University of Hertfordshire.

This doesn’t even include orphan planets (without a parent star), which we know exist, even if we don’t know their numbers yet. Over time, we’ll continue to learn more and refine our estimates, but right now, there are at least about as many planets as there are stars in our galaxy, and quite possibly many, many more than even eight times that number.

Our solar system may turn out to be average, slightly above average, or somewhat below average; we’re still not sure. But regardless of which way it goes, we’re talking about trillions of planets in our galaxy alone. And remember, our galaxy isn’t alone in the Universe.

Image credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team.

With at least 200 billion galaxies out there (and possibly even more), we’re very likely talking about a Universe filled with around 1024 planets, or, for those of you who like it written out, around 1,000,000,000,000,000,000,000,000 planets in our observable Universe.

That number’s only going to get more accurate, but I’m tired of people giving the lowball-estimate when it’s eminently likely that there are so many more. Let’s keep looking, for not just planets, but for water, oxygen, and signs of life. With all of those chances, we’re bound to get lucky if we persevere and look hard enough!

Comments

  1. #1 kim
    January 5, 2013

    ouch!…it hurts my head but it’s so good! Thanks Ethan again

  2. #2 GB
    United States
    January 5, 2013

    Fermi’s Paradox doesn’t seem like much of a paradox to me.

    However, I sometimes wonder if the irony might be that we live in a universe (potentially filled with life) that can’t ever be visited by any member of that universe just due to the laws of physics of that universe.

    If travel at some fraction of the speed of light is an absolute limit and if the closest star/planet is too far away for us to ever reach it then whether the universe has abundant life or not is almost a moot point if we can never observe it.

  3. #3 killy
    Earth
    January 5, 2013

    Thanks for the post!
    More people should read it to understand we are a very small part of the universe.

    What a exciting time are we living!!

  4. #4 Tony P
    Providence, RI
    January 5, 2013

    Looking at it statistically there has to be life on more than just the Earth. Think about it, the elements we’re made from are common throughout the galaxy! We are after all star dust.

    And it can’t be just our little G2V star that has life circling around it.

  5. #5 OKThen
    Planet Earth
    January 5, 2013

    Very nice summary.
    I did not know a lot of the things you explained and put in perspective.
    Thanks.

  6. #6 Skywalker
    Switzerland
    January 6, 2013

    Fascinating “mind opener”. Thank you dear Ethan.

  7. #7 theTentman
    Approaching the Asteroid Belt
    January 6, 2013

    Wonderful post. Thank you.

  8. #8 Phil Shaffer
    Columbus, Ohio
    January 6, 2013

    For a while, I have been wanting to get some sort of visualization tool for the #’s of “things” in the universe. I was thinking of the # of grains of sand on a beach compared to the # stars, galaxies, etc. Your post today was a prod to do it.
    Assume – beach 30 meters wide, 1 meter deep. Sand – 8 grains/cubic MM (http://www.6footsix.com/my_weblog/how-many-grains-of-sand-i.html)

    So, with a little rithmetic, we can get the length of a beach corresponding to these things:
    1) number of galaxies – 0.83 meters. – OK, I can visualize that, and it is a lot
    2) Number of stars in our galaxy – 1.66 meters.
    3) number of stars in the observable universe – the beach would be 333,333,333 Km long. (207,100,000 miles for those of us mired in the English system) Now things are getting out of hand
    4)(gulp) # of planets in the universe. – the beach would be 4,166,666,667 Km (2,588,750,000) miles long. This is pretty close to the distance to neptune.
    Well, that was interesting, at least to me.

  9. #9 uncleMonty
    January 6, 2013

    Until recently I had imagined that the stellar wobble method for finding exoplanets would involve measuring the visible change in a star’s position as viewed from the earth, for example right-to-left and back again. I learned just last week in the book store that this isn’t the case, though, and that you can get much more accurate measurements from the redshift and blueshift of the star’s light as it moves in the plane towards us and away from us.

    This made me think that just as the transit method requires a system be edge-on to us, the Doppler method would require that a system not be oriented so that we view it directly, or almost directly, from above or below–since this would mean the star didn’t move, or hardly moved, in a Doppler-detectable direction.

    So: how big would this blind zone of star system orientations be, what percentage of systems would we expect to fall into it, and is it a factor in counting/estimating the number of planets?

    I don’t think anything has ever fired up my imagination the way the search for exoplanets does! I would quite happily die tomorrow if I could spend the time until then poring over a photo album of gorgeous, strange scenes from other planets in our galaxy.

  10. #10 Wow
    January 6, 2013

    There’s a transverse effect to the dopler shift.

    Smaller. But there.

  11. #11 uncleMonty
    January 6, 2013

    Huh, so I wonder how you tell the difference between a small Doppler effect that’s due to a large planet in a “bird’s eye” system, versus the same small effect that’s due to a (relatively) small planet in an edge-on system… can we tell which plane a sun-sized star is spinning in?

  12. #12 Phil Shaffer
    columbus, Ohio
    January 6, 2013

    So , using doppler shift, if we are looking directly in the plane of the solar system, we will see a particular red shift. If we are at 90 degrees, we should see no redshift (I see above the transverse red shift, but I don’ understand this, so I am ignoring it – Call it poetic license.
    Now in the intermediate case, say 45 degrees, the redshift will be present, but half of what you would expect in the edge on case.
    Now – here is my question – since the degree of redshift depends on the angle at which we view it, how is it possible to correct for this when trying to calculate the mass of the planet?
    Also, in the pure situation of one large planet, the redshift method is clear, but let’s say there are 4 large planets. The redshift will be a very complex curve. How does one compute the number and mass of each planet.

    (i’m waiting for the answers here to start work on the data I gathered last night ;)

  13. #13 uncleMonty
    January 6, 2013

    Phil as I understand it when there are more planets you have to decompose the complex curve into its constituent parts, much as you decompose a soundwave into its constituent (pure sinusoidal) partials, by e.g. Fourier transform.

    You had the same question as me above about decoupling the mass effect from the angle effect, but it’s not a problem if we can detect how the star is rotating–then we know how much to correct by. And it seems, after a little more searching online, that there are methods for finding a star’s rotational velocity and direction. At least, I’ve seen it’s possible for some stars though I haven’t yet seen explicit confirmation that it’s possible for sun-like stars.

  14. #14 uncleMonty
    January 6, 2013

    Oh and it’s not hard to imagine the small Doppler shift in a system seen from above: a pure sideways motion, as seen from earth, will mean the star is very slightly further away at the endpoints of its lateral motion. Imagine a very long equilateral triangle with the earth at the skinny part and the other two corners the extreme points of the star’s apparent excursion. When the star is at the center of its motion, forming a right-angled triangle with the earth and either extreme, a little trigonometry will give the difference in length between the two long sides.

  15. #15 uncleMonty
    January 6, 2013

    sorry, I meant isoceles triangle, not equilateral, of course.

  16. #16 Sinisa Lazarek
    January 6, 2013

    Even if only 0.000001% of 150 billion have life on them, that’s still 15000 planets with life in our milky way! And if only 1% of those have intelligent life, that’s 1500 planets with different races.. amazing :) Starfleet here we come ;)

  17. #17 Sinisa Lazarek
    January 6, 2013

    sorry… last number should be 150 not 1500

  18. #18 Wow
    January 6, 2013

    even at 1500 planets, that makes an average distance between them of around 6000 light years between each system.

    To be honest, that’s why sci fi ALWAYS has FTL travel. The reality, without FTL travel, is that you leave one planet to colonise another and never heard from again.

    Even if you were a creature living 10 million years, you wouldn’t bother with a conversation that took 12,000 years for each message/response.

  19. #19 Dr. Rod
    minnesota
    January 6, 2013

    I’ve concluded, as GB seems to say, that in spite of all the intelligent life there likely is, we’ll never meet. The distances are too great. Contrary to GB saying “filled with life”, the galaxy is an immensely huge void with tiny specks of life scattered very far apart.

  20. #20 Mark McAndrew
    United Kingdom
    January 6, 2013

    Dr Rod, the galaxy might be mind-bogglingly huge, but it’s also mind-bogglingly old – so old that there could be (and I’d bet there are) civilizations* out there that watched their home star burn out before ours even formed. They’ve had more than enough time to fully explore the galaxy.

    They’ll also be technologically immortal, so it doesn’t have to be restricted to von Neumann self-replicating space probes either (which could do the job, travelling no quicker than 0.1c, in just half a million years: http://www.rfreitas.com/Astro/ComparisonReproNov1980.htm )

    *unless it’s just the one… First civ to get out there basically claims the lot. Civs 2+ will be so far behind (odds of similar tech levels meeting are tiny), that the oldest will be galaxy-spanning before the second one gets off its planet.

  21. #21 Michael Kelsey
    SLAC National Accelerator Laboratory
    January 6, 2013

    @uncleMonty: The “radial velocity method” (those are the right Google keywords) uses the main Doppler shift, not the transverse. The magnitude of the shift (often translated into velocity) is fit to a Keplerican (orbital) oscillation with the planet’s mass and the orbital inclination both unknown.

    The result gives you the planet’s mass in the form “M sin i”, where sin(i) is the sine of the inclination angle: 0 degrees is edge on, and 90 degrees is face on.

    The fit is more complicated with a multiple-planet system, but you can do it where the “sin i” is common to all terms. That may not be strictly true (it isn’t exact for our Solar System), but it’s close enough to get decent fits, as well as to rule out spurious signals (like stellar oscillations).

    As Ethan wrote, the transit system is limited to essentially edge-on systems (sin i ~ 1). When you can apply both methods to the same star, you can derive “exact” masses for the planets.

  22. #22 Tihomir
    January 7, 2013

    Ethan, based on these numbers, what would be the latest value (estimate) of the Drake equation?

  23. #23 Joe Barsugli
    Colorado
    January 7, 2013

    In response to Phil S. about visualization…

    I once had a book called “One Million”. It consisted of one million dots printed several thousand to a page. Every once in a while, a dot was singled out with an annotation: “Number of Hindus in Brazil”, “Telephones in China”, “Days since the founding of Rome”, and at the end of the book “Number of dots in this book”.

    Using grains of sand (or anything on the mm^3 scale) to visualize “billions” is pretty nice. If you took that stretch of beach that corresponds to the number of stars in the Milky Way galaxy and scattered the sand into a scale model of the galaxy, with the average grain (0.5 mm diameter) corresponding to the Sun’s diameter (1.4e9 m), the model of the galaxy (1.1e5 ly, or 1.04e21 m) would extend about 7.4e11 sand grains, or 370,000 km — roughly the distance from the Earth to the Moon.

  24. #24 Waterbergs
    South Africa
    January 7, 2013

    One point we all seem to be missing is the huge uncertainty in one element of the drake equation (an equation that lays out the factors that multiplied together determine the probable number of detectable extraterrestrial civilisations out there). The really big unkown is fl – the fraction of potentially habitable planets that go on to develop life. We simply have no idea what this number should be. It could be close to unity, or on the other hand it could sit at the ten to the power minus 100 and above level. We don’t know because we are still pretty much in the dark about how the first life evolved on our planet. Until we have a good understanding of that we will simply be guessing wildly at this key number. And it makes a huge difference – put in 10 to the minus 100 and even with Ethan’s 10 to the 24 planets the probablitiy of life out there is essentially zero. We must simply admit that based on planet numbers etc at this moment we have no idea if there is likely to be life out there.

  25. #25 Wow
    January 7, 2013

    Heck the surface of the earth can be described as that wrt people.

    Just imagine if there were no telegraph and no transport beyond legs or swimming.

  26. #26 progician
    London
    January 7, 2013

    GB:

    Don’t despair! Actually, the laws of physics does allow to reach many of the surrounding worlds, even to the point, that there’s the theoretical possibility to coast around a good bit of the observable universe. It’s all in the laws of relativity.

    First of all, the only theoretical speed limit we’re aware of is that of the speed of light. While there’s a lot of reason why we can’t reach even fraction of that speed today in respect to the rest of the universe, none of us can really predict what we will be capable of doing within let say 200 years. We certainly have come a long way since 1813 the steam locomotive was only spanking new invention just about the change our idea of mass transport. We already have theoretical design for interstellar spacecraft, and the most likely design that would eventually enable to travel interstellar distances in human life time is going to be something similar to the Bussard ramjet (http://www.askmar.com/Robert%20Bussard/Catalytic%20Nuclear%20Ramjet.pdf).

    In short the idea is to provide constant acceleration by the help of the interstellar medium. While the interstellar medium is scarce, as the spacecraft gains relativistic speed, the collection rate would increase.

    With relativistic speed (in respect to the rest of the material universe) one will encounter with time dilation which in turn would resolve the problem of reaching vast distances within reasonable time. When you reach around the 88% of the speed of light, you’ll start experience serious time dilation (that’s where it reaches around the factor 2). As you get closer and closer to the speed of light of course, the time dilation will cut you off from the human race on earth or even in the solar system because the time dilation gets so high that perhaps no one will be alive by the time you decelerate and come to rest in respect to you destination star system.

  27. #27 uncleMonty
    January 7, 2013

    @Michael: you wrote “@uncleMonty: The “radial velocity method” (those are the right Google keywords) uses the main Doppler shift, not the transverse.”
    Thanks, that’s what I believed in the usual cases but I wondered how it worked for a system whose star we view from one of its poles. In that case there is a tiny Doppler effect, since as the star appears to wiggle from side to side it must also change its distance from us (I think this is what Wow meant), but my back-of-the-envelope makes the effect much too small to do the job. Is that right?

    It’s too bad that the same systems that are best suited for Doppler methods are also the ones most likely to involve transits.

  28. #28 Bernard
    January 7, 2013

    Ethan,
    Have you ever come across someone’s knowledgeable power spectrum estimate of masses in our galaxy, from blue giant to brown dwarf to super-Jupiter to dwarf planet?

    And, thanks again for yet another informative piece,
    -Bernie

  29. #29 CB
    January 7, 2013

    @ Mark McAndrew:

    It does no good for a meet-and-greet with alien lifeforms if they already passed through our neck of the galactic woods hundreds of millions of years ago. The age of the universe cuts both ways — yes it’s more than old enough for a hypothetical alien civilization to have explored all of the galaxy, but that doesn’t make it any more likely that they’ll be right here during the incredibly brief moment we’ve been around and able to notice and record the fact.

  30. #30 crd2
    January 8, 2013

    Cool piece. How about a write up on hot jupiters!

  31. #31 Sinisa Lazarek
    January 8, 2013

    @Progician

    “Don’t despair! Actually, the laws of physics does allow to reach many of the surrounding worlds, even to the point, that there’s the theoretical possibility to coast around a good bit of the observable universe.”

    while you are correct that laws of physics allow, the rest is just bollocks. Just because something is allowed by current laws doesn’t mean it’s either practical or doable. There is nothing in the laws that prevents i.e. humans evolving wings and flying. There is nothing in the laws that prevents us from building a spaceship powered by a black hole or bad news for that matter. That still doesn’t make it real or feasible. And the paper linked is just someone’s daydream… Besides, interstellar space is a much greater vacuum than what we have on earth. To “extract” hydrogen from such a vacuum is a joke, even the author realizes it doesn’t work so he put’s in some nebula in there…. And he somehow fails to address where does the energy for fusion come from.. what powers the ship before it starts “vacuuming” the interstellar hydrogen? All in all.. bullocks.

  32. #32 Sinisa Lazarek
    January 8, 2013

    p.s. while thinking more on the subject of hydrogen powered fusion reactor.
    It would be much more logical for it to be powered by astronaut piss than interstellar hydrogen. Much more hydrogen atoms in one cup of piss than any that can be scooped up by a ship from the vacuum of space. Wonder why the author didn’t think of that…. rofl.

  33. #33 Greg
    January 8, 2013

    A read mind bender. Funny how we enjoy the universe from our stationary planet named earth.

  34. #34 Stefan Stackhouse
    January 8, 2013

    Plug this into the Drake equation, and all you can get so far is that the answer might still possibly be non-zero. With so many planets out there, the odds pretty good that at least some of them are hospitable at least for extremophile bacteria or things like those. The three really big unknowns, though are still:1) getting life (of any type) started on a planet in the first place; 2) getting something like a Cambrian explosion; and 3) making the leap to self-aware intelligence. The combination of these three contingencies might be so rare as to still assure that we are alone.

  35. #35 birdfish
    January 8, 2013

    WRONG YOU SO CALLED SCIENTISTS WILL BURN IN ALL ETERNITY FOR TORMENTS BECAUSE THERE IS ONLY ONE PLANET EARTH WITH PEOPLE THAT OUR LORD AND SAVIOR JESUS CHRIST LIVED ON AND TO SAVE THE SOULS OF HUMANKINDS HE GAVE HIS LIFE AND ALL THIS TALK OF PLANETS IS NOT IN THE BIBLE AND TRUELY IS FROM THE DEVIL HIMSELF TO BLIND AND DECIEVE THE GOOD PEOPLES OF CHRIST

  36. #36 Steve
    Chandler, AZ
    January 8, 2013

    There are as many planets, galaxies, stars, as the power of a telescope can see. I believe that if our telescopes could see infinitely far, we’d see infinitely more celestial bodies out there. Its absurd to try to estimate the that number when we have no idea how big the universe is. We could be seeing only a small portion of it, or it could infinitely big.

  37. #37 knightEknight
    Florida
    January 8, 2013

    Thank you Ethan for another outstanding article!
    I would be very curious to hear your ideas about Andrei Lebed’s theory presented here: http://www.dailygalaxy.com/my_weblog/2013/01/-einsteins-emc2-may-breakdown-in-outer-space.html#more

  38. #38 Ethan
    January 8, 2013

    knightEknight,

    I have a longstanding policy (for about four years) of not plucking a bad science article from obscurity to tear into it and talk about the problems with it.

    So it’s unlikely I’ll be sharing my ideas about Lebed’s theory; better to leave it alone and let it languish in obscurity where it belongs.

  39. #39 knightEknight
    January 8, 2013

    Thank you! That is actually very helpful! :)

  40. [...] How Many Planets Are In The Universe?  Lots.  As in, lots and lots. Excerpt: [...]

  41. #41 luminiferousethan
    January 9, 2013

    Amazing post! Where do you get all the amazing pictures for your post? You always have the best pictures, and I always end up changing my desktop background when I read this blog.

    I haven’t read all the comments, but a common opinion I see is that even if there is life out there, the distances are too great, and we will “never” be able to reach them. I’m currently reading a book (The Stardust Revolution, which I highly recommend) and in the first few chapters, one person, I forget exactly who, in the 17th or 18th century was certain, absolutely certain, that we would “never” be able to know the composition and chemical make-up of the stars. They’re simply too far away. It was less then a century later that spectrography was invented. So, while I won’t tell anyone that faster than light travel is certainly possible, I will absolutely keep an open mind, and not underestimate the scientists of the future! Especially looking at how incredibly fast our technology is advancing, and the new doors to the universe it is opening up.

  42. #42 Wow
    January 9, 2013

    ” that we would “never” be able to know the composition and chemical make-up of the stars.”

    And they were right.

    We had to get spectroscopy before that could happen, since it’s far too far to walk, and we’d die from heat stroke if we tried.

    “I will absolutely keep an open mind”

    You seem to be preening yourself on this.

    However, Captain Obvious, nobody is closing their mind to it. Hell, I’ll quote you one that you probably never really read, just read the words you thought would be there:

    “The reality, without FTL travel, is that you leave one planet to colonise another and never heard from again.”

    So even if you want to insist FTL WILL happen, without it, you leave one planet to colonise another and never hear from again.

  43. #43 jay
    seoul, korea
    January 11, 2013

    gotta be ‘100-to-200 billion stars not planets in the Milky Way’

  44. #44 tom campbell-ricketts
    January 18, 2013

    Presumably, the stellar wobble technique suffers from higher false negative rates, the more planets there are orbiting a given star. It seems intuitive that the more planets there are, randomly positioned (ie not all pulling in the same direction), the closer the system’s centre of mass will be to the centre of the star. Has this been analyzed?

  45. #45 Susan Dos Santos
    Florida
    February 3, 2013

    Thank You.

  46. #46 skydiamond
    nola
    February 10, 2013

    My journey in spirit brings me to the matter that makes up the Universe and the lessons in written word and physical solutions and equations that join me in the matter bring me to this place and space in journey.
    So…..that being stated….without knowing Math or Science as well as the books teach…..I would like to just hear thoughts on the hypothesis that as we continue to evolve in this time and space , we can know the past and see the future. Eventually , we will be not only genetically altered and modified but our advancements with travel will advance to use a method that can travel dimensionally…..to the past universes in which our present selves occupy….and at this time in space…..our life may be altered so much so, as will our universe and planet….we will need to travel back to acquire the only minerals that we would now use for energy and food….(this future may not have agriculture from what we have done to it and the bodies could be technically and so genetically altered …..our food could consist on the same minerals that furl our energy. So ….if we can indeed see the future…..out there….but we can not yet travel to it……Don’t you think the future life(whatever it may be) would maybe even want to warn us of the godless hell we are allowing to take shape??! Symbols, messages, equations, letters, creation and the lessons are everywhere…..it is our CHOICE to see and use for selfless , Love , positive energy to create and live…..for positive spirits to rise…… we KNOW THE FUTURE…..and it is almost here…..FAITH has continued to prove itself……without my asking.

  47. #47 Wow
    February 11, 2013

    “Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them; and no man ever had a distinct idea of the trinity. It is the mere Abracadabra of the mountebanks calling themselves the priests of Jesus.”

    ― Thomas Jefferson

  48. #48 Putting aside the blinders
    February 15, 2013

    [...] think about us at the level of human beings in the universe. We inhabit a single planet, only one of a trillion planets in our galaxy. Sounds like a lot, right? But there are more than 200 billion galaxies in the known [...]

  49. #49 beam
    phillipines
    March 9, 2013

    wow grabe its so wonderful i kant explane mt happiness when i see those pictures that was really awesome god is really braive because hi did that

  50. #50 Ruby
    Philippines
    March 14, 2013

    Awesome!!! That’s all I can say. God is great for all He works…

  51. #51 Wow
    March 14, 2013

    Would it be acceptable to come along to your church and in the sermon start pointing out all the fallacies in the bible?

    Really, what you godbotherers are doing is EXTREMELY rude.

  52. #52 Andrew Dodds
    March 15, 2013

    Some random thoughts..

    As far as bacterial/simple life goes, I would expect it to be widespread. The logic runs this way:

    – Life appears in the geological record on Earth basically instantly – the moment it’s possible to detect life in rocks, we see it. If life appeared as an extreme-low-probability event there would be no reason to expect this.
    – The idea of life emerging as a result of random chemical interactions is essentially impossible. Additionally, there is no conceivable stable state which is a ‘half-way house’ between simple inorganics and life. You cannot, for example, postulate complex-but-not-self-replicating RNA hanging around for millions of years. Not in liquid water.
    – Hence I would postulate that life emerges quickly – probably in a pretty energetic environment such as a black smoker – when conditions are correct. If so, that would imply that simple life would emerge virtually everywhere.

    However, I’d also observe that for at least 60% of the history of our planet, it was microbes-only. There are good reasons for this – the lack of free oxygen being a major one. And this will probably hold more generally – the complexity of life will be limited by the complexity of the environment and the available energy flow. Earth, for example, has an extremely varied and complex environment, and the availability of oxygen and sunlight mean that there is a high energy flow. Whereas life under an icecap will have little diversity of environment and low energy flows; it may stay stuck at bacteria forever.

    As far as intelligent life goes.. it could be argued that it’s been possible ever since the mammal-like reptiles emerged >200 million years ago. So these could really be the rate-limiting steps to the Drake equation – changing the redox state of the planet to allow oxygen, followed by the dumb-intelligent transition.

    An interesting observation is that around a red dwarf star, the first of those steps could quite possibly take 10s of billions of years. On the other hand, around a star hotter than the sun, it may be faster, but not fast enough before the star went bang. So we could be amongst the first.. and the ‘golden age’ of civilizations emerging from red dwarfs in their thousands lies many billions of years in the future..

  53. #53 Wow
    March 15, 2013

    - Life appears in the geological record on Earth basically instantly

    Well, within a few million years, which is about as close to instant as the resolution of dating methods to that age get.

    - The idea of life emerging as a result of random chemical interactions is essentially impossible.

    That means you think life itself is essentially impossible. Something has to live to create something, but something can’t live unless it’s had a creator, is what you’re saying. But that creator is essentially impossible since it had to emerge as a result of random acts itself.

    Additionally, there is no conceivable stable state which is a ‘half-way house’ between simple inorganics and life.

    RNA.

    And, since our definition of “organic” is “carbon based”, any carbon-active catalyst is a half-way house between the two.

    E.g. clays.

    You cannot, for example, postulate complex-but-not-self-replicating RNA hanging around for millions of years. Not in liquid water.

    RNA do replicate, though.

    Your assertions seem based entirely on your incapability at biology. This is possible to rectify if you wish to. However, most “Creation MUST happen!” acolytes don’t wish to.

  54. #54 Andrew dodds
    March 15, 2013

    Wow – I’m not a creationist ( or panspermia advocate). Would you like to reconsider your reply?

  55. #55 Wow
    March 15, 2013

    Yeah, and Stalin wasn’t a despot. He said so.

    Would you like to reconsider your assertion I replied to?

  56. #56 Dam smd
    March 18, 2013

    How many planets are there

  57. #57 Wow
    March 19, 2013

    Several.

  58. #58 Andrew Dodds
    March 20, 2013

    Ok, late reply. Although if any statement I make is automatically a lie if it tries to make you think it could be tricky.

    The concept of an ocean full of complex organics giving rise to higher complexity is something I am arguing against, on extremely firm grounds – even the highest reasonable estimates of concentrations give a situation where hydrolysis rates would exceed any replication rate by many orders of magnitude.

    Indeed, such arguments also rule out any notion of the ‘long middle ground’ of life formation. Which is good news for both astrobiology and any hope of replicating abiogenesis in the lab; there is simply no chance that a ‘complex but nonliving soup’ could persist for a noticeable amount of time, geologically speaking, so not only must abiogenesis be fast (again, geologically speaking) but it must follow a fairly set pathway.

    The best hypotheses I’ve seen thus far revolve around the conditions at hydrothermal vents, which contain things like redox gradients, Fe-S complexes and clay minerals to promote mono-isomerism. Yet these environments persist for perhaps 10,000 years or less. Interestingly, any planet with substantial oceans on a silicate crust, even under an ice layer, will have ‘black smokers’ at some point.

    So – unless the mechanism for abiogenesis relies on a very Earth-specific process (which I haven’t even seen suggested) – then the chances are that it is both fast and near-ubiquitous.

  59. #59 Sinisa Lazarek
    March 20, 2013

    @Andrew
    “Yet these environments persist for perhaps 10,000 years or less.”

    why is it so hard to do some research before posting data?

    from wiki: Strontium, carbon, and oxygen isotope data and radiocarbon ages document at least 30,000 years of hydrothermal activity driven by serpentinization reactions at Lost City, making the Lost City older than known black smoker vents by at least two orders of magnitude

  60. #60 Wow
    March 20, 2013

    “even the highest reasonable estimates of concentrations give a situation where hydrolysis rates would exceed any replication rate by many orders of magnitude.”

    Which is why the complexity was probably on the shores, not the deep ocean.

    Please, stop arguing against strawmen, it’s tiresome.

  61. #61 Wow
    March 20, 2013

    So what is your alternative theory? That some god-like-but-not-god-honest being waved their magic^Wscience wand and created^Wdesigned life on earth?

  62. #62 Andrew Dodds
    March 20, 2013

    Sinisa –

    I was going from memory. Say < 100k years. On geological timescales, near-instant..

    Wow –

    Calm down. As I said, I lean towards the black-smoker hypothesis (The idea of tidal pools is interesting, but you have to ask where the chemical gradients are in such a scenario).

    My actual argument is this:
    – The early appearance of life on earth points to rapid abiogenesis.
    – It's also reasonable to argue from a chemical perspective that the process is rapid. Slow processes are actually harder to envisage.
    – Therefore one should expect microbial life to be extremely abundant, assuming that the process operating on Earth was not a freak one.

    I don't think that this is controversial. I would use it to predict life on Europa, IF Europa has a genuinely liquid water ocean in contact with a silicate mantle. Mars as well.. at least at some point in the past.

  63. #63 Wow
    March 20, 2013

    My actual argument is this:….$LIST

    Then your opening statement was a complete waste of EVERYONE’S time.

    - The idea of life emerging as a result of random chemical interactions is essentially impossible.

    Is what you had as your bullet point in your opener.

    Seems your argument as you are willing to say now never included that statement. If your actual argument was NEVER “the idea of life emerging as a result of random chemical interactions is essentially impossible.”, then why the hell did you say it?

    Just trolling?

  64. #64 Sinisa Lazarek
    March 20, 2013

    actually.. the sentence “- The idea of life emerging as a result of random chemical interactions is essentially impossible.” and ” The early appearance of life on earth points to rapid abiogenesis” are totally opposite.

  65. #65 Wow
    March 20, 2013

    Which is why it might have been entirely troll.

    Or it could be some IDer who found they weren’t going to get any traction and have backed down and changed everything so they can then complain they’ve been done so bad by those mean religious scientistics.

  66. [...] THE EARTH with Peninsula Bike Party! According to this random blog post, there are perhaps 10,000,000,000,000 planets in our galaxy and 1,000,000,000,000,000,000,000,000 [...]

  67. #67 T
    irl
    April 19, 2013

    So there are mega billions of planets that “could” support life (ie in a habitable zone). Do we have any way of telling which ones actually do have life. No. Or even what likely % of planets within habitable zones have life. No. So considering how far planets are from each other what are the odds that we will ever make contact with another living world ?? If we have to actually visit a planet to confirm there is life on it (and that may be necessary coz not all aliens will answer the phone if ye know what i mean) then this would be a project like no other, hopping from planet to planet, breeding & training generations of explorers on the way. Makes ye kind of wonder did some planet do this millions of years ago and they wound up here. heeheehee

  68. #68 Wow
    April 19, 2013

    There are possibilities.

    For example, our atmosphere is VASTLY over specced on Oxygen. This amount of O2 in an atmosphere shows that there are processes like life on here keeping the atmosphere this out of balance.

  69. #69 Linh
    USA
    April 26, 2013

    Make as many comments about Universe and Planets as you could but, please, never inset the idea of “Lord” or “God” in this theme, it’s very absurd and idiot. I hate very much someone – the Christians the most parts – use to impose their belief on the existence of their Lord or God in this discussion .

  70. #70 janak sarwata
    haryana(india)
    May 19, 2013

    life is possible on other planet?and how many planets are currently discoverd? Tell me soon..

  71. #71 Wow
    May 20, 2013

    The religious get cheesed off (as a group, not necessarily as individuals) when atheists bring up “There is no god” in a discussion of the existence of god or where they are talking about it for any reason, so quite why they think it’s fine to talk about there BEING a god when nobody is talking about it really eludes me, unless it’s that A Crowley idea of “Do as thou wilt is the whole of the law”.

    But then they’re sharing several other traits with Satanists then.

  72. #72 Kaitlynn
    June 1, 2013

    Very studious

  73. #73 Lazy Alligator
    June 11, 2013

    I love these articles that summarize just how inconceivably huge the universe is.

    You guys going off about which chemicals mixed to create life, how, and how long it took are all trolls. This article is estimating how many planets there are. Bugger off to your evolution forums. :)

  74. #74 Faith
    Lagos
    June 21, 2013

    I never knew that pluto has gone to rest because is to small. Well u are doing a great job.

  75. #75 Brad
    Oregon
    July 1, 2013

    That’s totally mind boggling. I wonder why God would want to make so many planets.

    One million trillion planets is not a lot to Him, since He is infinite in power, presence, wisdom, wealth, and knowledge.

  76. #76 airon charles hermosa
    cabuyao laguna
    July 24, 2013

    hey friends i want to be a astronomer i will build a building to discover all the ten trillion planets in the universe see that is impossible but with god all is impossible

  77. #77 Wow
    July 25, 2013

    A wonderful demonstration of the effect of psychedelics on the human brain there…

  78. [...] scienceblogs.com [...]

  79. #79 bright nnakwe
    Nigeria
    August 12, 2013

    how many days does it take to get to planet & can u find emty land there?

  80. #80 Tonny
    Nigeria
    August 16, 2013

    Planets or no planets God owns our lifes.keep searching

  81. #81 faiz anjum
    lahore
    August 19, 2013

    i like the way you present

  82. #82 Nelson
    Bethlehem South Africa
    August 27, 2013

    Please u Christian guys respect the man’s proffesion n work his doing,it’s not the place to argue with people who do not believe in the Lord Jesus Christ.Please don’t impose your God or Biblical knowledge Ethan i believe altough not really understanding what he say, gives scienctific and mathemetical explation of how vast the universe is.Please stay with the subject and give the man his due.as for people who does not believe or see as we Christians i humbly apologise 4 my fellow Christian brothers or sisters if there is any.But in as far as life out there is concern i firmly believe they are there, they are however not as us, under free moral agency.YES U HEARD ME RIGHT THERE IS LIFE OUT THERE BUT NOT UNDER FREE MORAL AGENCY.IT MAY SOUND UNBELIVABLE BUT THE SOURCE IS NOT SCIENCTIST,IT SOUND CONTROVESIAL BUT I WISH TO AVOID ANY DEBATES PLEASE

  83. #83 than tun yin
    Myanmar
    August 27, 2013

    I never see like that . very wonderful for me .

  84. #84 jr
    philippines
    September 5, 2013

    if we can discover more than the speed of ligth there is a posibility that we can reach/go to the neareast star. this is a challenge to us to change einstien said that nothing can exceed the speed of light. discover more fastest rockets.

  85. #85 Ray white
    Alberta
    September 5, 2013

    The numbers in the article are pure speculation. Physics indicates that massive stars could have several thousand planets.
    Anyways, if life is rare as in only being found on quintillions of planets….intelligent life ever rarer and only on quadrillions…way too dispersed for much hope of us ever having any evidence of intelligent life ‘out there’.

  86. #86 Ray white
    September 5, 2013

    Re a comment on the Universe being ‘old’. Actually it is still in its infancy. Regardless of what the fate of the Universe is, the scenarios play out over trillions of years. We’re still in the first 1% of the Universe’s existence.

  87. #87 graeme limerick p fabie
    philippines
    September 17, 2013

    i comment that it is possible to live in the new planet like mars or the new one discover above our planets 400000 light years away

  88. #88 DJ the rockstar
    MAURITIUS
    September 25, 2013

    Wow! I impress with this

  89. #89 Bassem Hussein
    Egypt
    October 10, 2013

    The creation of the universe is explained by astrophysicists as a widely accepted phenomenon,
    Popularly known as “The Big Bang”, According to the “The Big Bang” the whole universe was initially one big mass (Primary Nebula) then there was a “Big Bang” (Secondary Separation) which resulted in the formation of Galaxies, then divided to form stars, planets, the sun, the moon etc.
    HOW COULD A BOOK ( THE QURAN ) WHICH FIRST APPEARED IN THE DESERT OF ARABIA 1400 YEARS AGO, CONTAIN THIS PROFOUND SCIENTIFIC TRUTH ?

  90. #90 Lynn
    Wisconsin
    October 12, 2013

    I would like to volunteer for the type of job Jodie Foster had in “Contact”… I don’t mean the high-tech stuff; but the sitting on the top of a hill, with headphones on, listening to outer space. My kind of job!

  91. #91 Cruiser
    Arizona
    October 16, 2013

    Einstein’s theory of relativity insinuates that nothing can move faster than the speed of light. This has recently been proved wrong and has been holding scientists back for years. Neutrinos have been proven to travel faster than light speed, therefore one of the most fundamental hypothesis of early science have been proven wrong.

  92. #92 Michael Kelsey
    SLAC National Accelerator Laboratory
    October 16, 2013

    @Cruiser: I’m so sorry that you’re as far out of the loop as you seem to be. What was proven, more than a year ago, was that the precision timing circuit used by OPERA had a systematic bias due to an improperly plugged in fiber-optic cable, leading to an approximately 70-ns offset in their time-of-flight measurement for neutrinos from CERN to Gran Sasso.

    If you’re going to make wild claims about the overthrow of physics, you really ought to try to know the details of the work that led to that overthrow (or not). Otherwise, you end up appearing to be just another crackpot.

  93. #93 Wow
    October 16, 2013

    Well, the cable was loose and it was fixed under “any other business” but never actually proven to be the cause, it’s just that the change COULD have produced that error in timing and that they’ve not been able to recreate it since then. The uncertainty is that they couldn’t tell if it was done as the cable got fitted better or some other reason.

    It’s feasible and FTL is a bit of an amazing claim.

    IMO they were right to push the note out there because a lot of people tried several ways of thinking

    a) How could it be wrong (nobody figured a loose cable)
    b) What would it men if it were valid

    and it probably got a few more people interested in thinking about it that weren’t really “into” physics any more. That some are kooks is merely a reflection of humanity.

  94. #94 Michael Kelsey
    SLAC National Accelerator Laboratory
    October 16, 2013

    @Wow #93: Almost. As I recall, what happened was that CERN did a short-pulse run (where OPERA could get spill-by-spill timing, rather than averages), and they saw the same offset. After discovering and fixing the cable, they had more short-pulse data where the offset went away. This was described in the updated version of their September 2012 preprint. I think that the before-vs-after effect is fairly conclusive.

  95. #95 Wow
    October 17, 2013

    Well, I never got to see a preprint of anything. The misalignment would have to be very small to create a capacitance of that size and the fittings are pretty much designed that it’s pretty damn secure (this one was considered to be a knock that unsettled it). What I had heard was that they found a possibly loose connector and fixed that, then found it no longer gave the discrepancy. But maybe they’d done some testing to find that loose connector to know out of the probably ten million cables which were not acting to spec.

  96. #96 Wow
    October 17, 2013

    PS the “unclarity” was more along the lines of “we can’t PROVE it, but it is both suitable and sufficient” allied with “and we can’t get it to do that any more”.

    Which is good enough proof to get people sent to prison for capital crimes.

  97. #97 Sinisa Lazarek
    October 17, 2013

    @ Wow

    here is the final paper

    http://arxiv.org/pdf/1109.4897,

    (the one everyone agreed to sign :) )

  98. #98 Wow
    October 17, 2013

    Ta very much.

    Now if only my document viewer didn’t decide to open it up with a default 32 point font…

  99. #99 Wow
    October 17, 2013

    OK, looks like the delay is dispersive medium rather than capacitive. That makes it a big easier to get a 70ns delay with a wonky connector.

    Also appears thermal wobble changing the trigger level had a place to increase error bars.

    I read quick. :-)

  100. #100 Michael Kelsey
    SLAC National Accelerator Laboratory
    October 17, 2013

    @Wow: Just saw all these replies :-) Thanks to Sinisa for the link back to arXiv! Yes, that’s the paper, and I’ll tell you that I shared your initial confusion about how a “loose connector” could cause a delay. I had to talk to some optoelectronics experts at my work to really understand it.

  101. #101 Ethan
    October 17, 2013

    On a side note, Wow, congratulations.

    Your comment #99 on this thread makes an even 4,000 comments for you. Although there are more than 30k approved comments, you are by far the most prolific commenter on my blog, and I wanted to congratulate you on your milestone.

  102. #102 CB
    October 17, 2013

    I knew as soon as I heard the results that every crackpot on earth would glom onto the OPERA neutrino result and never let go. They’d assume that the preliminary result was the bonified truth, and never bother checking on it again (whereas I *wanted* it to be true, yet also wanted to know if it *really* was, so I payed attention to the ensuing investigation).

    Hell, I still hear people using the Pioneer Anomaly as “proof” that all of modern physics is wrong.

    Why would you check on the latest news when you already have your proof? The only difference it could make is that you find out you’re wrong.

  103. #103 Wow
    October 17, 2013

    You spelt that right, yes, Ethan?

    It wasn’t “Millstone”? :-)

  104. #104 Sinisa Lazarek
    October 17, 2013

    hehe… Happy Post Day Wow :)

  105. #105 Ej
    October 30, 2013

    It wonders me how the universe works because it’s seintificly proven that we are not alone people don’t realize how many different species there are in the the galaxy + there are over 50000 different planets

  106. #106 Ej
    On the dark side of the moon
    October 30, 2013

    Never underestimate the universe with its powers

  107. #107 muhammed yaro
    bamako,mali
    October 31, 2013

    this shows that we humans are in a small part of the universe and also the superior of all creations by GOD. We have made researches on the planets outside ours why cant they(other planets) make some research about us?

  108. #108 Diane
    October 31, 2013

    That’s a lot to take in

  109. #109 BRIAN LOVE
    UK
    November 17, 2013

    IF SPACE IS INFINITE, WILL WE EVER DISCOVER HOW MANY PLANETS THERE ARE? AND WHERE DOES GOD AND RELIGION FIT INTO THE SCHEME OF THINGS?

  110. #110 Wow
    November 18, 2013

    No, by definition, if it’s infinite, we will never find out how many planets there are.

    God doesn’t fit anywhere in it.

    And religion is not part of it any more than political affiliation is. It’s something some humans decide to engage in, others self-identify with but otherwise do not engage in, and others ignore.

  111. #111 David L
    November 18, 2013

    “WHERE DOES GOD AND RELIGION FIT INTO THE SCHEME OF THINGS”

    Brian, you use of capitals makes it uncertain as to whether you meant God or god, but your choice of the singular suggests the former. You may not be aware but there are thousands of postulated gods. Depending on how different sects may be before the become a different religion, there are even more religions. Whatever all or any of them may have done in the past, they are now largely constrained to a bit of minor tinkering in areas where Science can’t yet look.

  112. #112 Sean T
    November 18, 2013

    Brian,

    God fits nowhere into the scheme of things because the Christian concept of god is inherently non-scientific. To fit god into the scheme of scientific observation, you must find a way to put god’s existence to the test. That is, you must find some observable part of the universe that would be expected to look different depending on whether god exists or not. If you actually make the observation, and the results indicate that god actually does not exist, you must be then willing to admit that god doesn’t really exist. I suspect that you, and most Christians are either unwilling or incapable of doing this.

    PS. I am assuming that you are coming from a Christian perspective here. I apologize if that’s not the case, but my points pretty much hold up for any concept of god, not just the Christian one.

  113. #113 dr john e w kingsley
    usa
    November 22, 2013

    I strongly believe that earth is the only planet in the universe where such a wide range of life forms exists.

  114. #114 jayden
    newzeland
    December 2, 2013

    good info

  115. #115 harold B. Peterson
    Pontiac, Michigan [USA]
    December 7, 2013

    Beyond, beyond and beyond is what amazes me. There is no walls to the universe or outer space. If there were walls, what would be on the other side of those walls? Therefore, there is eternal time, unlimited space and numbers. This is a mystery.

  116. #116 sholstar
    nigeria
    December 25, 2013

    hmn, wat a wonderful world

  117. #117 Cheezaleezers
    United States
    January 14, 2014

    OMG. I Honestly Thought it would be written out like this, considering our universe never ends…
    100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
    And Also You Think That Earth Is The ONLY Planet in the universe that has life!? Give me a break.

  118. #118 Cheezaleezers
    UT West Jordan US
    January 14, 2014

    Also It is inpossible to know how many. If you took everybody’s brain in the world (smartwise) and put it together it would not be able to get even the exact amount of inches of land in the world.

  119. #119 Cheezaleezers
    Somewhere, Pluto :)
    January 14, 2014

    the universe is never ending
    it cant explode
    it cant just disappear
    it will stay here forever

  120. #120 Collins Boateng
    Ghana/Accra
    January 16, 2014

    i want more information about this topic

  121. #121 Wow
    January 16, 2014

    There’s an entire internet out there with indexing of its contents available for you to use.

    If you wish someone else to do the work of collating and explaining it, then there is a vibrant adult education system you can apply to use.

  122. #122 Douglas
    Earth
    January 19, 2014

    What are the two things that are faster than the speed of light?

  123. #123 Mohammed
    Yemen
    January 25, 2014

    The creation of the heavens and earth is greater than the creation of mankind, but most of the people do not know.

  124. #124 Sawyer
    Somewhere
    January 31, 2014

    Of course we have no idea how many planets we have in our solar system. I was just wondering if anyone would be dumb enough to put 13 (Our main eight plants and our 5 dwarfs)

  125. […] there are around 1,000,000,000,000,000,000,000,000 planets in the universe! The odds that life doesn’t exist somewhere other than earth are pretty […]

  126. #126 thomas
    orange county ca
    March 27, 2014

    i’m an amateur astronomer and i know the 10 to the 24th power is in fact 1 septillion and since i do understand large #’s our known universe is approximately 15 billion light years which translates to around 90 septillion miles.

    i also know that it won’t be in my lifetime which i hope is another 25-30 more years that man will be able to fly the speed of light. it’s called einsteins theory of relativity in which the close you go towards the speed of light the slower time gets,

    this theory has actually been proven experimentally, it’s called time dilation. i believe star trek calls it warp drive.

  127. #127 Stefano
    Como, Italy
    March 28, 2014

    ” La scienza non deve aprire una porta al sapere ma chiuderne una all’ ignoranza.”

    ” Science doesn’t have to open knowledge’s door, but close ignorance’s one. ”
    -Galileo Galilei

  128. #128 Mick Dundee
    Sydney
    March 31, 2014

    The answer is 42.

  129. #129 Sean T
    April 1, 2014

    Yes, Mick, but what’s the question? :)

  130. #130 CHICHI AKEN JOHN
    portharcurt nigerian
    April 9, 2014

    i need to know more about planet and how have bee discovered, with there picture

  131. #131 Michael Kelsey
    SLAC National Accelerator Laboratory
    April 9, 2014

    @CHICHI #130: In English, https://en.wikipedia.org/wiki/Exoplanet. I don’t know whether Wikipedia is available in any of the local languages of Nigeria.

  132. #132 Rdog
    East london
    April 18, 2014

    Fantastic topic and amazing to see a truley global debate taking place. I only hope that future exploration of what is potentially “out there” and how to get to it will only further unify what we have “on here ” and how we make the most of it.

  133. […] TRILLION planets in our galaxy, for an estimated 1,000,000,000,000,000,000,000,000 planets in the universe… You and your easily blown mind are but a speck by […]

  134. #134 Hawk
    June 10, 2014

    It is funny that the estimated number of planets in the observable universe is close to one mole (Avogadros constant)

  135. #135 Shivanu
    Jamui
    June 18, 2014

    Less than imagine

  136. #136 okuoba nana akomeah
    ghana
    July 13, 2014

    good evening, so can one live on the other planets and how does it benefit man and in what way does people find their way to the planet , if i may ask what sort of things can be find there and is it true that the planet is only nine and why do they say that .

  137. […] Some other really good stuff about space and stars and especially planets is found at Starts with a Bang! […]

  138. #138 AAMER RAZA KHAN
    india
    August 22, 2014

    Wow great photo’s……. the univers of all human and substance particle depend in gravitational force.

  139. #139 Jayesh Shivhare
    India
    August 29, 2014

    You know the largest crater on the moon is the South Pole – Aitken Basin . it is 2,240 km in diameter and 13 km in depth . my Aim is Scientists of Paleontologists .

  140. […] in the universe. 4 000 000 000 000 000 000 000 000 planets! (This article suggests there are 100 * 10 ^ 21 planets in the universe, and given that Fermi estimation suggests order of magnitude is more important than actual values, […]

  141. #141 genesis
    philippines
    September 14, 2014

    in the other planet in other solar system . . there’s a posibility that there are other people or living things or anyone who are breathing Living in other planet on the other solar system ?

  142. […] planets) orders of magnitude higher: closer to ten trillion planets in our galaxy, alone!" – Source The problem is, we have a case study of one. Statistically speaking, There is absolutely no […]