Possible “habitable zone” planetary system discovered only 20 light years away

After more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile, astronomers have discovered in this system the lightest exoplanet found so far: Gliese 581 e (foreground) is only about twice the mass of our Earth. The Gliese 581 planetary system now has four known planets, with masses of about 1.9 (planet e, left in the foreground), 16 (planet b, nearest to the star), 5 (planet c, centre), and 7 Earth-masses (planet d, with the bluish color). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days, while Gliese 581 e completes its orbit in 3.15 days.

IMAGE: European Southern Observatory Click for larger image of this artist rendition. After more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile, astronomers have discovered in this system the lightest exoplanet found so far: Gliese 581 e (foreground) is only about twice the mass of our Earth. The Gliese 581 planetary system now has four known planets, with masses of about 1.9 (planet e, left in the foreground), 16 (planet b, nearest to the star), 5 (planet c, centre), and 7 Earth-masses (planet d, with the bluish color). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days, while Gliese 581 e completes its orbit in 3.15 days.

From RedOrbit and Science News Astronomers Discover Lightest Exoplanet Yet

Astronomers claim to have discovered an exoplanet that is the most similar to Earth in terms of mass than any previously discovered.

Found in the constellation Libra, the planet known as Gliese 581 represents about twice the mass of Earth.

Astronomers have previously identified some 300 exoplanets, but most are much larger than Earth.

“This is by far the smallest planet that’s ever been detected,” said Michael Mayor, from the Geneva Observatory, Switzerland.

“This is just one more step in the search for the twin of the Earth.

“At the beginning, we discovered Jupiter-like planets several hundred times the mass of the Earth; and now we have the sensitivity with new instruments to detect very small planets very close to that of the Earth,” he told BBC News.

Mayor worked alongside an international team of scientists who made the observation using the low-mass-exoplanet hunting device known as the HARPS spectrograph, which is attached to the 3.6 meter ESO telescope at La Silla, Chile.

“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ – a region around the host star with the right conditions for water to be liquid on a planet’s surface,” Mayor said in a statement.

“With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, said co-author Xavier Bonfils from Grenoble Observatory.

Although the planet passes too close to its star for life to be possible, scientists claim that another planet in the system may be.

Previous observations using the HARPS showed that the host star was known to harbor a system with a Neptune-sized planet and two “super-Earths”.

Gliese 581 d was discovered two years ago with a mass of about seven times that of Earth. It orbits its parent star in 66.8 days, according to astronomers.

“Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” said team member Stephane Udry.

“‘d’ could even be covered by a large and deep ocean – it is the first serious ‘water world’ candidate,” she added.

Sophisticated modern technology allows astronomers to observe exoplanets by studying the tiny wobble in star motion. The discovery of low-mass red dwarf stars like Gliese 581 adds potential of finding other low-mass exoplanets in the habitable zones, scientists said.

“With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” said Bonfils. “The hunt continues.”

“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 – the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”

The international team’s findings will be published in the journal Astronomy & Astrophysics.

From Science News:

“The object, a mere 20.5 light-years away, could be as tiny as 1.9 Earths and isn’t likely to exceed twice that amount.”

This diagram shows the position of the four planets in the Gliese 581 system. The newly found, innermost body is Gliese 581 e, the smallest exoplanet yet discovered. The habitable zone (blue region), where water could exist as a liquid, clearly includes the outermost planet, Gliese 581 d.

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102 thoughts on “Possible “habitable zone” planetary system discovered only 20 light years away

  1. Does the headline need revision?

    “Although the planet passes too close to its star for life to be possible, scientists claim that another planet in the system may be.”

  2. I’d say it isn’t nearly as important that we found the possibility of life at Gliese 581as it is the possibility that they have found us… 8^)

  3. Now all they need do is to see if they can find intelligent life on the third planet from our nearest star.

  4. Only 20 light years?

    Well, as soon as we defeat the laws of physics and create a faster than light space shuttle, maybe we can make the round trip in a decade or two?

    A mass 7 times that of Earth. A nice bit of gravity on that baby then. I bet it attracts a few more extinction level asteroids than the Earth does.

  5. Stef-

    During which time the earth will have aged significantly more than that, relativistically. Space travel is certainly much harder than used to be generally believed. Remember “Space 1999″?

  6. If they start finding habitable planets harboring civilized space-faring life like crazy then how long before it goes like in Star Wars and we see a Galactic Senate, or what if the galaxy already has a president named Beeblebrox?

    Even though no life is found yet, what about the water world? Would be nice to draw it through a portal to irrigate and green up the deserts on Earth (if it ever becomes possible)?

  7. This is really exciting.
    In related news… The president has asked NASA to immediately dispatch a message to any space aliens who may be living on that planet.

    Hey all you great individuals on the newly discovered planet,
    First, I, as the President of one of the family of nations of Planet Earth, would like to go ahead and apologize to your entire population for anything we may have done to have offended you, like perhaps reruns of Gilligan’s Island. Also I would like to let you know that if you find yourselves here in America, be assured that you are entitled to the best education that unions can supply, AND food stamps and welfare. Do not ever worry that you may be putting us out, we have plenty of money and we are currently printing it as fast as we can.
    Welcome to America!!
    Don’t forget to vote!!!

  8. As long as they get to see every episode of Single Female Lawyer, we should be OK. Wait, no, can’t happen since that hasn’t been 20 years yet. Maybe they’re watching something else.

    Mark

    PS: a Futurama joke.

  9. Clearly the Habitable zone must assume a certain % of Carbon Dioxide, because as we all know, plants must have a very precise CO2 content to be habitable.

  10. Ah, hope springs eternal for a race of aliens we can meet, trade with, go to war against and perhaps go to bed with too. Every scientist’s holy grail? Every science-fiction geek’s holy grail then as well.

  11. Send Al gore. After listening to him bloviating for five minutes there’s no way the inhabitants will ever think it worthwhile to warp over here and conquer what’s left of our little pile of smouldering ash.

  12. Looking at the diagram, earth would be in the blue zone directly above the 1.0 AU mark, high on the chart. To have a habitable zone 0.1 AU away, the star would have to be about as bright (color temperature) as a low wattage incandescent light bulb. A Gliesian in the zone would have a dimmer sun that would still feel as warm on the skin (or scales) as our sun does.

    It would be a very happy place, because Christmas would come every other month.

  13. Someday, an expedition from Gliese 581will come to Earth. They will find no intelligent life but they will find evidence of our existence in the ruins of our cities. After a time they will decode the various languages on the signs that outlawed CO2 and wonder how we could have ever been so stupid. They will see plant life returning and pushing up through the concrete and asphalt, breaking it up into smaller and smaller pieces. The alien scientists will enter us into their equivalent of what we knew as the “Darwin Awards” and then make plans for colonization of the planet.

    Wait a minute. Al Gore, James Hansen et al are probably the first wave of a plan hatched on Gliese 581to get us all to suffocate ourselves. There still may be time… 8^)

  14. “and now we have the sensitivity with new instruments…”

    This was the subject of a graduate seminar I attended in 1976. The speaker was clearly frustrated by the lack of state of the art sensing devices available to the scientist. And the lack of a comprehensive effort to create better sensors.
    His comment was something on the order of ‘ If scientists today could have the sensors that should have been available (ie. state-of-the-art) at the time, the advancement of science would have been a full ten years beyond what it was currently . But since very little efforts were being made to advance sensor technology…they were currently ten years behind. ‘

    I believe his comments were right on the mark. Advancement in sensor technology has worked wonders in some cases…like the extended capabilities of the Hubble telescope. But it has made life miserable for others…like pollutant control. I remember when PCB limits were controlled down to ~1ppm in the early 70’s because that was about the limit of convenient detection. By the early 90’s that limit had dropped to ~10ppb. the science at the time did not confirm that the danger levels were just as significant at a level of 100 times lower, but the new instrumentation/detection methods were that much better. Today those levels are approaching 10ppt and there is some talk about lowering the allowable limits of PPB levels even lower…

    Jim

  15. “can humans survive in an environment with twice the g’s found on earth?”

    Only the skinny ones…

  16. What is this nonsense about wanting to find liquid water ? Don’t they know that to be habitable, planets need solid ice, and no carbon dioxide; liquid water is the last thing you would want on a habitable planet.

    Somebody should tell NASA to update the data on this planet, and bring it more into line with computer simulations of what life is like.

    George

  17. Jeff Alberts (13:11:10) :
    Would a planet of 1.9 Earth masses have doubled gravity? Is gravity that linear? I would think it would depend on the composition too.

    With a larger planet, you have more mass, but someone on the surface is farther away from the additional mass, so probably not doubled.

    It would indeed depend on density, but here again, Earth with its iron core is a dense planet so that argues against double gravity.

  18. Before we all get to excited, these guys have to determine the CO2 content of the atmosphere so’s we can determine the global warming coeficient of 581. Then we can get this over to Hansen and Gore and turn all the developmental authority to them. They may want to roll into the new CO2 cap and trade legislation an additional fee for CO2 sequestration on this planet. God forbid we miss this chance to save this planet. So when this planet goes to hell in a handbasket 581 will be just right for humans and we can move on over there.

    Damn!!! Gore and Hansen are are one awesome couple of guys HUH!!!!

  19. Jeff Alberts (13:11:10) :

    “Would a planet of 1.9 Earth masses have doubled gravity? Is gravity that linear? I would think it would depend on the composition too.”

    Assuming you were not being tongue in cheek.

    No, gravity at the surface is proportional to the mass but inversely proportional to the square of the radius. If it has a mass equal to 1.9 times the earth it is likely also larger. Unless it is much denser than the Earth which seems unlikely it is unlikely to have anywhere near 2 times the surface gravity of the Earth. We would have to know radius to know the acceleration of gravity there.

  20. Pops

    On the other hand, they may decide to come over and stick it to us good so that we don’t send any more like him!

  21. It’s amazing how many things had to fall in place for advanced life on earth to be possible.

    Here’s but a few things:

    _ A strong magnetic field – made possible by our molten metal core.
    _ A large moon that helps shield the planet from comets and asteroids.
    _ The correct mixture of various elements.
    _ An orbit that puts the planet inside the habitable zone.
    _ A relatively stable sun.

    The list goes on and on. I find it fascinating that all metals on earth came from a star that went supernova billions of years ago.

    The 64 dollar question remains — how typical or atypical is our planet?

  22. Correct there Wondering Aloud. Remember, the moon only has about 1/81 the mass of the Earth but it’s gravity is about 1/6 of the earths. A planet with 1.9 x EM would probably have a gravity at the surface of 1.2-1.6 Earth gravity but depends on the density of its composition and the radius. Probably quite ok as far as gravity goes. I would think that the 20 light years poses more of a problem than any extra gravity such a planet might have.

  23. Double the mass means double the gravity at the same distance. But since more mass means a larger planet, the surface will be at a greater distance, reducing the gravity. We can calculate exactly how much gravity is reduced:

    Assuming the average density is unchanged, twice the mass means twice the volume. Volume of a sphere is proportional to the cube of the radius (i.e. the radius raised to the power of 3). Therefore the radius is proportional the cube root of the volume (i.e. the volume raised to the power of a 1/3). Hence 2 times the volume means the radius is multiplied by the cube root of 2 (i.e. 2 raise to the power of a 1/3). My calculator says this is about 1.26 . So the twice the volume means a radius that is 1.26 times larger.

    With the surface being 1.26 times further away, and knowing that gravity is inversely proportional to the square of the distance (Newton), we can say that the gravity will be reduced by the square of 1.26 (i.e. 1.26 to the power of 2). Which my calculator says is about 1.59 .

    So that doubled gravity will be reduced at the surface by 1.59 times. 2 divided by 1.59 is about 1.26 .

    Finally, assuming the same density as the Earth (a big assumption, but hopefully in the right ballpark), we can say that twice the mass of the Earth means it’s surface gravity will be about 1.26 times as large as the Earth’s.

    (I now await corrects for some horrendous mistake, since I have only worked this out verbally, rather than on paper.)

    P.S. I think all of this maths simplifies to raising 2 to the power of 1/3 . So you can easily do it for masses other than 2 times that of the Earth.

  24. I was also confused by the title.

    Gliese 581 e is not in the habitable zone and it was the planet discovered today.

    Gliese 581 d is the only planet in the system (yet discovered) that is clearly in the Habitable Zone. And it was discovered 2 years ago.

    The rest of your article is accurate, so please update your title so that it can be accurate too. Thank you.

  25. If we find a Twin-Earth, I hope there is not a Twin-Gore-Hensen-Mann on it.

    There are lots of people with more than double of my weight and they can still walk and lift things. So, a subtantial increase of gravity should not be a problem once used to it. The only problem would be that we would not be able to dunk a basketball.

    But a planet with a 1.9 G would certainly have a denser atmosphere at it’s surface, thus increasing the atmosphere/surface temperature significantly. Would that be cold enough to permit liquid water? Or even permit the binding/function of proteins and other living molecules? I have serious reservations on that one.

  26. > If they start finding habitable planets harboring civilized
    > space-faring life like crazy then how long before it goes
    > like in Star Wars and we see a Galactic Senate, or what if
    > the galaxy already has a president named Beeblebrox?

    Yeah, then they’ll form the intergalactic panel on space climate change (IGPSCC), blame dark matter, say the debate is over.

    They will claim that polaris is threatened because of the ever increasing amount of dark matter in the universe which is causing the universe to expand at an ever increasing rate. In fact, it is expanding faster than the models predicted.

    They will declare that dark matter is a danger to the public and summarily decide to tax half the systems in the galaxy out of existance.

  27. Bruce Hall (14:47:19) :

    The main test of intelligent life is to be intelligent enough to not make tools to kill each other and/or destroy their planet. We have a long way to go to call ourselves intelligent.

  28. @Ray
    That may also explain why we have not detected any intelligent life (and in fact explain why all habitable planets in the galaxy have not already been colonised by an intelligent alien race). i.e. Before any “intelligent” species becomes too intelligent, it wipes itself with weapons of mass-destruction (or else searching for the Higgs Boson before they colonise other planets & accidentally get their home planet consumed by a ‘micro’ black hole).

  29. The new Kepler orbiting telescope ought to bring a host of new discoveries and ought to be fascinating to watch it all unfold. I’m getting the feeling that suns lacking at least one planet will turn out to be more of an exception than the rule.

  30. Follow-up to my previous post on gravity & mass:

    We know the Moon has 1/6th the surface gravity of the Earth. Using my final equation (raising mass to the power of 1/3), I can reverse that to say 1/6th the gravity means the mass is (1/6) raised to the power of 3, which is about 0.0046 of the mass (or 1/216 if you prefer). Thus if the Moon has the same density as the Earth (probably not too far off given it was once part of the Earth’s mantle) then the Moon should have 216 times less mass than the Earth.

    Google says the Moon is actually 83 times less mass than the Earth, so my calculation is 2.6 times out. Not TOO bad, all assumptions considered!

  31. “”” Jeff Alberts (13:11:10) :

    Would a planet of 1.9 Earth masses have doubled gravity? Is gravity that linear? I would think it would depend on the composition too. “””

    A uniform earthlike planet that was twice the mass, would be cube root of two times the diameter, so m/r^2 would be 2/2^2/3 = 2^1/3 = 1.26 times the surface gravity.

    But if it is not uniform density throughout, then all bets are off and it would be different; my guess assuming a denser core is that it would then be bigger than cube root of 2 times, so gravity would be less.

    So that waould say 1.26 is the maximum gravity a 2x mass planet would have.

    George

  32. Remember the key words “earth like”; so presumably it isn’t a solid Uranium sphere, which would have higher gravity, but be smaller.

  33. “”” Ray (15:06:30) :

    Bruce Hall (14:47:19) :

    The main test of intelligent life is to be intelligent enough to not make tools to kill each other and/or destroy their planet. We have a long way to go to call ourselves intelligent. “”

    Why would you expect to find intelligent life anywhere else.

    The search for ET intelligent life is based on the false assumption that intelligence brings superior survivability.

    In reality, Intelligence is just Mother Nature’s latest gimmic in the search for survival; and so far it looks like a loser.

    So we’ve had maybe 1-200,000 years of “intelligent” life, but the dinosaurs survived for 140 million years just by being big and mean and ugly.

    So humans send out a plaque with Pi to 27 decimal places on it to show how smart we are at geometry; but what if those intelligent aliens use Roman numerals; they wouldn’t know what to do with our hieroglyphics, and decimal number positional value system.

    Remember, WE made up ALL of our mathematics out of whole cloth; so it has NO universal significance, and to assume that some other alien life form would get it, is simply not very intelligent.

    Maybe one of these days we will get our first binary digit of actual observable data about intelligent life outside a thin shell of about +/- 15-20 km about mean sea level on planet earth; but until then; it’s pretty ho hum, and I don’t plan on hanging around for that one.
    So we better get our s*** together, and solve OUR problems here on earth ourselves; because there isn’t anyone out there who is going to solve them for us.

    George

  34. Chris H (14:45:35) :

    Finally, assuming the same density as the Earth (a big assumption, but hopefully in the right ballpark), we can say that twice the mass of the Earth means it’s surface gravity will be about 1.26 times as large as the Earth’s.

    (I now await corrects for some horrendous mistake, since I have only worked this out verbally, rather than on paper.)

    I don’t have time to work this out myself, but I think you and George have the same right results. One thing I can add is that the period of a satellite orbiting close to the planet will have a period of about 90 minutes, just like Earth.

    A long time ago I worked out the period of someone orbiting Deimos, and was using Earth’s density because I didn’t know of a better one. When I came up with 90 minutes, I played a bit more and discovered that density alone determines the low-body orbital period of a satellite. See http://wermenh.com/deimos.html for more details like why someone was orbiting Deimos (hint – he jumped).

  35. George E. Smith (15:38:18) :

    But if it is not uniform density throughout, then all bets are off and it would be different; my guess assuming a denser core is that it would then be bigger than cube root of 2 times, so gravity would be less.

    Some non-uniformity is quite permissible. One of the few things I remember about such stuff is that a thin spherical shell of material of some density has a gravitational field outside of the shell exactly the same as an equivalent point mass at the center. (Inside the shell the field is zero.) So that means if the planet is nicely sorted, e.g. iron in the center, then silicates, then water, your first result is right.

    Still pretty heavy, Mars’ 1/2 g sounds about right. A planet is a great place to evolve, a lousy place to thrive. I’m rather fond of O’Neill colonies, long spinning cylinders in Earth or Solar orbit.

  36. Tom in Texas (15:58:49) :

    Ray (15:06:30) :

    I think tools have gotten us as far as we have.

    And any tool can be used to kill – club, screwdriver, hammer, electric drill…

    ————–

    But we are now building bigger clubs, bigger screwdrivers, bigger hammers, bigger electric drills… that can kill millions of people in one blow. We built bigger and better at it. So why stop there?

    Like Cap. Kirk said, “All you need to do is say no to war.”

  37. Should I say “cool” or “hot stuff”!

    It’s so hard to know these days.

    Anyway, great!

  38. Ray:

    Like Cap. Kirk said, “All you need to do is say no to war.”

    That sure is a wonderful sentiment, isn’t it?

    But what happens when someone attacks you? Do you just “say no to war”?

    There is a name for those folks: “slaves.”

    Better to be the big dog on the block. Then it’s not likely you’ll be attacked.

  39. But what is the size, in solar masses, of the star? What is its power oputput. These planets are all very close to the center.

  40. What is the point of searching for said objects when we have no means to get to them? We should focus on our own backyard first before we go starring off down the road. Heck we cant even get the moon probably anymore.

    Also all they do to find these things is study the wobble of the star, so they dont even know if these planets are rocky, atmosphereic or liquid, let alone what types of air, rock or liquid, so the whole “second earth” deal is greatly blown out of proportion. Just because a planet might have near earth like mass, it doesnt make it an earth.

  41. So what surface temperature would be considered habitable by Hanson and Gore? Per AGW theory, I would guess that it must be about 15 C +/- 2 C. I think that would make for a very small habitable zone!!

  42. Have we discounted the possibility of life (but not as we know it Jim) that does not need water – like silicat based life in a liquid ammonia substrate for example?

  43. “Have we discounted the possibility of life (but not as we know it Jim) that does not need water – like silicat based life in a liquid ammonia substrate for example?”

    Yes Phil’s Dad, that possibility was utterly ripped to shreds by Dr. Spock on Star Trek episode 14.

  44. Robert Wood (16:45:20) :

    > But what is the size, in solar masses, of the star? What is its power oputput. These planets are all very close to the center.

    That’s one thing that makes them easier to locate. Earth-like planets in Earth-like orbits around Earth-like suns are tough to spot so far.

    A couple attributes of the close orbit is the the planet would have massive tides, and is likely tidally locked to the star. Hot side, cold side, nicer ring, with a steady wind blowing toward the hot side. Possibly an ice cap that reaches to the top of the atmosphere. No kayakers.

    Would be nice to have a weather satellite feed from there.

  45. Smokey, that was a great article in the Onion:

    http://www.theonion.com/content/news/al_gore_places_infant_son_in

    The very last sentence contained this truth:

    “A bold and eye-catching unitard will give Kal-Al, last son of Earth, a formidable tool for protecting his new planet, a power more awesome than any his father could have dreamed of: the power of charisma.”

    Which made me wonder… is there even ONE of the screeching banshees of climate doom, who contains a scintilla of charisma, or a hint of the beginning of a real human personality?

    Anyone have any candidates?

  46. http://biocab.org/Astrobiology.html#anchor_25

    Sorry for posting a link to one of my articles, but on that article I explain what the optimal conditions for the origin of living beings on a given planet could be. Planets more massive than Earth could host living beings on them without any problem if other conditions are satisfied. What astronomers must seek is for stars which aren’t too hot neither too cold, which have planets with water, acetylene, methane and carbon dioxide. A planet with a mass equal to 1.9 the mass of Earth still could be a good candidate to lodge life. The water presence doesn’t guarantee the existence of living beings on any celestial body, but it would increase the possibilities of their existence.

    From my conference on Astrobiology:

    Stars which are warmer or colder than the Sun shouldn’t be excluded from the catalogue because they could have planets which would be orbiting at distances where they would be receiving loads of cosmic radiation adequate for life.”

  47. Chris H: Plugging in that the earth is 83 times as massive as the moon, one would make the plausible guess that the earth would have 83^1/3 as strong gravity.
    That would be 4.36 times rather than 6 times. There seems to be an additional mass factor- the more massive the object, the denser it is, at least for terrestrial sized planets. Using just the earth and moon as data points, gravity is proportional to mass to the 0.4055 rather than 0.333…
    Using those figures for the 1.9 mass planet, 1.9^.4055 = 1.297, not much larger than your original figure.

  48. Alan D. McIntire (17:46:37) :

    Chris H: Plugging in that the earth is 83 times as massive as the moon, one would make the plausible guess that the earth would have 83^1/3 as strong gravity.
    That would be 4.36 times rather than 6 times. There seems to be an additional mass factor- the more massive the object, the denser it is, at least for terrestrial sized planets. Using just the earth and moon as data points, gravity is proportional to mass to the 0.4055 rather than 0.333…
    Using those figures for the 1.9 mass planet, 1.9^.4055 = 1.297, not much larger than your original figure.

    Exactly, living beings on a planet with 1.9 Earth’s mass would have no problems. However, it’s not enough to find water and a Sun-like star. We must find all the factors which could make the existence of life a possibility on that planet. Indeed, the discovery of all factors on a planet doesn’t guarantee the emerging and/or existence of living beings on that planet.

  49. Mike Bryant (17:38:36) :

    Which made me wonder… is there even ONE of the screeching banshees of climate doom, who contains a scintilla of charisma, or a hint of the beginning of a real human personality?

    Anyone have any candidates?

    Can someone both be a “screeching banshee” and have “a scintilla of charisma?”

    I’ll suggest Kerry Emanuel – http://wind.mit.edu/~emanuel/home.html – seems to handle himself well on interviews and at a Southern New England Weather Conference his spoke at once. I like his book “Divine Wind.”

    He’s moderating a bit on his early it’s-all-a-heat-engine stance having seen what El Nino can do to a perfectly good Atlantic Hurricane season, though you probably don’t want him in the same room as Bill Gray still.

  50. Ric,
    I believe that Emanuel has changed his views once or twice. He is a thoughtful person who still believes that, perhaps hurricanes will worsen in a warming world. You are correct he is hardly a screeching banshee. He seems more like Lucia, who is thoughtful and uses the scientific method. I think he is more of a lukewarmer, not an alarmist, not a climate doomsayer.
    Mike

  51. Stef (12:12:22) and Sunfighter:

    Good points. Until we get people’s heads in the real world (e.g. there is no “warp speed”, we’ve got that whole light-speed barrier thing) they will be preoccupied with things like this. Just what has happened to the space program??

  52. Adam from Kansas (12:25:30) : “…What if the galaxy already has a president named Beeblebrox?”

    And it surely does! Gentlebeings, I give you the chief of the Galactic Senate, President Beeblebrox:

  53. Smokey (16:43:23) :

    “Better to be the big dog on the block. Then it’s not likely you’ll be attacked.”

    This is called being a bully. And that is exactly what the majority of people in the rest of the world think of the Americans, and even more after having a bully-in-chief as president.

  54. Ray (20:00:31) :

    Smokey (16:43:23) :

    “Better to be the big dog on the block. Then it’s not likely you’ll be attacked.”

    This is called being a bully. And that is exactly what the majority of people in the rest of the world think of the Americans, and even more after having a bully-in-chief as president.

    No, it’s called being the big dog on the block, Ray. It makes being a bully unnecessary, and it makes it a lot less likely you’ll be attacked. Or are you an umbrella-waving, peace-in-our-times wuss? Didn’t work in 1938, and it’s not going to work today anywhere but in your mind.

  55. MC (13:31:48) :

    Damn!!! Gore and Hansen are are one awesome couple of guys HUH!!!!

    For the sake of brevity only may I suggest instead: Damn Gore and Hansen!!!

  56. George E. Smith (15:53:39):

    The search for ET intelligent life is based on the false assumption that intelligence brings superior survivability.

    In reality, Intelligence is just Mother Nature’s latest gimmic in the search for survival; and so far it looks like a loser.

    I disagree with those who think that intelligence brings a superior survivability. Intelligence is not privative of human beings. Besides, the evolution of intelligence is stochastic because it exhibits microstates which order and trajectories are algebraically unpredictable. So we cannot model the evolution of intelligence.

  57. Ray (20:00:31) :

    “This is called being a bully.”

    No. A bully is someone who uses strength or power to intimidate. As true leaders have pointed out from the Roman Republic to Ronald Reagan: if you want peace, prepare for war.

    Question: do you want peace?

  58. With the subject of politics having been raised (USA), I guess we will see this thread degenerate rather quickly…. :-(

  59. ..two of the most complex carbon-rich molecules ever found in interstellar space

    So carbon’s not all bad, then!

    The item was reported on the front page of The Guardian (famous for its spelling mistakes) as containing an important link to ‘animo’ acids. It’s not surprising that their science reporting is so uncritical when they can’t even pick that up…

  60. Leon Brozyna:-)

    “Intelligent Life”? Well, derrrrr! Intelligence is just one part of human existence, but it is pretty useless if not applied to anythin, & enhanced with the power of rational thought, a small mearure of aggression, a good deal of compassion & understanding, & a willingness to expore outside the cave! The third rock from our sun (great show) has an abudance of “intelligent life”, however, it is largely endowed with irrational thought, complacency, & a lack of adventure.

    I suspect that there is oodles of extra-terrestrial life out there quite nearby, but they are using some form of disruption shield to prevent our “sensors” from detecting them, simply because they’ve seen & heard the double-act of Gore & Hansen, the UN, the IPCC, the EU, & said to themselves, “Just as we thought, no intelligent life there then!

    Robert Wood;-)

    Don’t worry, it’s hip to be cool when you’re hot! or is it hot to be cool when you’re hip?

  61. Ray,

    Who that waves the white flag like yourself ends up getting peace? People like you throughout history end up pushed out of your land, or turned into a slave.

    You can only stop a bully by beating up the bully. If you can’t beat up the bully then you will always be his servant. Your boy Darwin taught us this, ‘survival of the fittest.

    You are either Poland or Germany in 1938
    You are either the Native Americans or the Europeans in the 17th Century
    etc.

    Seems like you prefer to be on the side that gets destroyed. Please do not be our leader when we meet another life form face to face. You will lead us to defeat.

  62. I would think that, assuming the same density, the gravity at the surface of a planet would be proportional to the radius. The volume (and therefore mass) varies as the cube of the radius, and the inverse effect varies as the square of the radius. The power of R would then be 3 minus 2, which is 1.
    I calculate that the gravity would be 4*PI*K*R/3/G where K is the density, R radius and G the gravitational constant.
    Chris

  63. I always, always feel a chill down my spine everytime someone mentions “Gliese 581″, and this is why.

    I do not belive UFO are extraterrestial beings, I do look at those books about UFO as amusing (I haven’t read one in well over 20 years), and also as some pathetic stuff… except when I read something about Gliese 581 and habitable zones and planets the size of earth, etc.
    And this is why: taking Roger pielkes take on “what would have to happen to make you change your mind”, my was finding a earthlike planet in Gliese 581!
    I always remember this star because one of those stories on one of those bookes about abuducties (it stood in my imagination as I was growing up) was about an alien abuction and under hypnosis and all that crap in the stories the blablabla investigators draw what the person was descrbibing and it what was the star they told that person they came from?… YEs Gliese 581 !!!!

  64. Here’s another thought about CO2 and the Gliesians.

    CO2 is transparent to visible light and absorbs in four bands in the infrared. A Gliese planet in the Goldilocks zone (not too hot, not too cold, just right) will be getting roughly the same TSI as earth, but downshifted, with more of the energy in the CO2 capture bands than earth gets. CO2 would be much more of a ghg there than on earth.

    Our eyes are adapted to the sun’s main energy band. Gliesians’ eyes would be adapted more toward the infrared, which would make CO2 a visible component of their atmosphere.

  65. “Ray (22:37:40) :

    You will never get peace at the point of a gun.”

    Hmmmm what have we been enjoying for the last 60 years with Germany and Japan?
    When the bully at school hit me in second grade, I doubled him over with a lucky punch to his solar plexus… We were great friends from that moment til I lost track of him five years later… Ray Mould are you out there??

  66. Great topic for this excellent science blog.

    Readers should follow the recently launched Kepler mission. Its telescope stares at the Lyra-Cygnus region of our Milky Way galaxy for the next several years detecting the very faint winks as the 2% or so of planets in the same plane as us transit their star. If our primitive understanding of solar system formation is somewhat correct, Kepler should detect dozens of worlds orbiting in the liquid water ‘habitable zones’ of their primary stars. First results of HZ region planets will come from close in orbiting terrestrial planets of faint red M0 stars, possibly as early as Thanksgiving. Planets orbiting further out around bright stars like the G2 sun will take around 4 years from now to detect, as positive detection requires 3 repeat occultations to ensure against false positives. Kepler is an exciting mission for those curious if there are other well situated possibly habitable planets elsewhere. Fortunately, not everyone at NASA is an ideolog like James Hansen.

    http://kepler.nasa.gov/

  67. John Galt (13:55:51) :

    . . . The 64 dollar question remains — how typical or atypical is our planet?

    Since there are an enormous (if not infinite) number of stars in the Universe, and since many of them clearly have planets, the likelihood is that, even if our planet is atypical, there are still a very large number of such ‘atypical’ planets.

    The real problem is how to get to them. One way is surely a Matter Transporter that transmits the information needed to reconstitute a living being at light speed, but unfortunately the distances are so great that light speed doesn’t get you very far in a short time.

    So we really need a physics that supersedes Einstein, so we can invent the FTL (Faster Than Light) Hyperdrive or Intersplit (Jack Vance’s term) that will enable us to galavant about the Galaxy (and beyond) with abandon. Never say “never.”

    But time’s a-wastin’. When I was a lad I assumed that by the 21st century I’d be on a ship headed for Alpha Centauri. Yet here we are, still phutzing about in Low-Earth Orbit, wondering if we can afford to return to the Moon—not to mention Mars. And fighting a rearguard action against neo-Luddites and eco-Marxists who want to take us backwards to “40 acres and a mule.”

    What a disappointment!

    /Mr Lynn

  68. James P (02:16:06) :

    …two of the most complex carbon-rich molecules ever found in interstellar space

    So carbon’s not all bad, then!

    Indeed, life is made of carbon. All living beings on Earth are made of carbon; no way for other elements. Three organic compounds essential for the emergence of life -everywhere in the known Universe- are methane, acetylene and hydrogen cyanide. These compounds are condenser agents which promotes the biopolymerization of proteins and carbohydrates. Of course, other compounds known like agglomerative substrates are needed; for example, fullerenes and silicon carbyde. Thus, life forms can exist on other extrasolar planets.

    Regarding the class of star, it’s a determinant factor for the emergence and support of living beings. We could say that life stars are class F and class G. Nevertheless, the possibility of living beings which can survive on planets orbiting other classes of stars exists if they grow on twilight zones.

  69. Interesting how artists have taken to conceptualizing other planets and stars as seen from outer space. “Photographic” detail in art is appealing, but one element of these images that always makes me wonder is the “filter interference”, here taking the form of hexagonal ghost images spaced along the sun’s “shaft” of light. Since all humans will ever see of extra-terrestrial planets or stars will be through layers of glass or plastic, I suppose the optics will always include such distortions. Still, it’s a layer of “reality” which always makes me do a double-take.

    Maybe some optics or physics buff could explain why the images are hexagonal.

  70. The Gliesian system will be around a long time — M-type red dwarfs have main-sequence lifetimes in the trillions of yrs.

  71. Searching for life around a red dwarf star is probably an exercise in futility. High variability and flares knock the chances way, way down.

  72. Bill P (09:10:46) :
    . . . “Photographic” detail in art is appealing, but one element of these images that always makes me wonder is the “filter interference”, here taking the form of hexagonal ghost images spaced along the sun’s “shaft” of light. . . .
    Maybe some optics or physics buff could explain why the images are hexagonal.

    That’s a reflection (or rather a shadow) of the iris leaves off the internal surfaces of the camera lens. The iris is the adjustable part inside the lens that controls the amount of light going through the lens. Some lenses have more than six leaves and thus produce a differently shaped reflection.

  73. “”” Ric Werme (16:27:40) :

    George E. Smith (15:38:18) :

    But if it is not uniform density throughout, then all bets are off and it would be different; my guess assuming a denser core is that it would then be bigger than cube root of 2 times, so gravity would be less.

    Some non-uniformity is quite permissible. One of the few things I remember about such stuff is that a thin spherical shell of material of some density has a gravitational field outside of the shell exactly the same as an equivalent point mass at the center. (Inside the shell the field is zero.) So that means if the planet is nicely sorted, e.g. iron in the center, then silicates, then water, your first result is right. “””

    Well Ric, you just tripped yourself up with your own shoe laces.

    It is indeed true that any properly spherical shell (of any radial density function) appears externally to be a point mass at the centre, and inside the shell the gravity (due to the shell) is zero. Also if there were a uniform electric charge on the surface there is no electric field inside (Biot-Savart Law). If you go down inside the earth; the gravity depends only on the material inside your radius (assuming the earth is spherical which it isn’t)

    But meanwhile back at your shell. Yes it has an equivalent mass acting as if it were at the center, but the surface gravity depends on the radius of the surface, so if the shell were so thin as to have no mass, but there was an iron core inside with a lot of mass, the relationship between the mass and the gravity would be different from that of a uniform sphere.

    Assuming that the density is highest at the center (not a truly safe assumption), then any non uniform (bur radially symmetric) mass distribution, would have a bigger total radiaus for a given total mass, than a uniform sphere, so it would have lower surface gravity than a uniform sphere of the same mass.

  74. And fighting a rearguard action against neo-Luddites and eco-Marxists who want to take us backwards to “40 acres and a mule.”

    Sorry, no mule, methane, y’know.

  75. That’s a reflection (or rather a shadow) of the iris leaves off the internal surfaces of the camera lens. The iris is the adjustable part inside the lens that controls the amount of light going through the lens. Some lenses have more than six leaves and thus produce a differently shaped reflection.

    Mike, I’m sure you’re right. I think I’ve seen that effect myself when I used to take pictures with my Nikon. Haven’t shot a photo with that camera for awhile.

    I was reading a Mir Shaviv blog entry recently, about his trip to Lapland, where he sees the concentric rings of his own filter while he’s trying to photograph the Aurora. His commentary on this is interesting.

    Auroras in Lapland
    Posted March 26th, 2009 by shavivcosmic rays Science weather & climate

    http://www.sciencebits.com/auroras

  76. Bill P (14:14:26) :
    . . . I was reading a Mir Shaviv blog entry recently, about his trip to Lapland, where he sees the concentric rings of his own filter while he’s trying to photograph the Aurora. His commentary on this is interesting.
    Auroras in Lapland
    http://www.sciencebits.com/auroras

    Those are great aurora photos, and just the pure green, too. The concentric circles are from internal reflections inside the UV filter, and the circular shape is due to a slight concavity or convexity in the filter. Machinists use precision ground glass disks called optical flats to check surface imperfections. Placing them on a surface with a monochrome light will produce interference bands that you can count to measure unflatness to wavelength precision.

    Those really are neat photos.

  77. I was reading a Mir Shaviv blog entry recently, about his trip to Lapland, where he sees the concentric rings of his own filter while he’s trying to photograph the Aurora. His commentary on this is interesting.

    Lens artifacts are also a big contributor to UFO reports.

    And the so-called “Rods phenomenon” is due to the way modern video cameras process frames. Though the die-hard believers still think they’re inter-dimensional entities.

  78. Uh oh,
    Someone mentioned that it might be a good idea if Al Gore visited the newly discovered planet. Now NASA has announced that it is snowing on Gliese 581 a thru d…

  79. Jeff Alberts (12:59:42) :
    “And fighting a rearguard action against neo-Luddites and eco-Marxists who want to take us backwards to “40 acres and a mule.”

    Sorry, no mule, methane, y’know.

    Guess it’ll have to be “40 acres and a wife.”

    You can figure out which will be pulling the plough.

    /Mr Lynn

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