Slashdot Mirror
Five Possible Life-Bearing Planets Found
devphil writes "Reuters reports that six new planets have been discovered using the gravity-wobble method. Five of them are in the "habitable zone." More details are online.
" Well, they all appear to be Jupiter size class, so are most likely composed of the same elements. The primary elements of Jupiter are hydrogen and helium gas, which combined with an enormous gravity well don't make it very friendly to carbon based life. But five of the six are in the zone that would support liquid water, deemed a life-necessary element.
Very short lifeforms.
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I think the concentration ought to be on looking for life elsewhere in our solar system, be it past or present. If we do find life on, say, Europa, it'd be a pretty good indication that the Universe belongs to life. Then we could say that these new planets are likely habitation zones. If all our system's candidates turn out as dead as Salt Lake City on a Friday night, then we shrug and keep looking.
I find it ironic that we live in a "modern" age, complete with space flight, and we can't even work up the energy to send serious missions to the most likely close-by homes of extraterrestrial life. I mean, imagine people looking back at the 20th century and snickering over our "life vs. empty universe" debate when the proof lay so close at hand...
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Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
If we disregard any potential life forms not based on carbon and water -- a reasonable thing to do, scientifically, since we have no data points with regards to them -- life on these planets, like life on Jupiter or in Jupiter's atmosphere -- is quite unlikely.
But if these planets are in their stars' habitable zones, then so are the moons of these planets. And one of these moons might, perhaps, be a world with plentiful water that supports macroscopic life.
(Europa, a moon of Jupiter, is widely regarded as the best candidate for extraterrestrial life in our solar system. Although it is outside the traditional 'habitable zone' of the sun, it does have an immense ice covering. Its ocean of ice is believe to extend to around 50km in depth. Beneath this ice, there may be liquid water -- and perhaps organisms living off the geothermal energy generated by Europa's gravitational interaction with Jupiter.)
Bob Kopp
Gas based life forms don't exist because of how hard it is to bind to most gases. Especially the "Noble" gases. Carbon based life forms are abundant because of how easy it is to bind with carbon. it can bond to 4 other atoms, or double bond to two, or double bond to one, and bond to two other atoms.
Some theorize that because silicon has similar properties to carbon (carbon is above silicon on the periodic table), that there may be silicon based life out there. I'd believe it.
They recently managed to collect some of the light reflected off another large planet in orbit around another star. This planet was very close, but very large, and was composed of, IIRC, magnesium, silicon, and potassium (oxygen was also found in trace amounts, which was the big story with this report), which are all very heavy elements. The fact is, we're not quite sure what makes planets have the makeup they do, but the theory that I'm most familiar with says that the solar wind blows most of the lighter elements (helium and hydrogen, for example) out past a certain region, which is why the inner planets contain heavier elements. These planets may very well be something similar to Earth, or, more likely, a planet composed of terrestrial elements compressed into a form we haven't seen before.
Keep holding out hope, Mulders.
The planets have aliens on them, and they obviously must have computer systems... And -their- systems don't run Windows! They probably don't even have a 0.2% market share in the universe!
Fire, Water, Earth, Wind.
And, of course, don't forget Turbonium.
SANTA CRUZ, CA--The world's most prolific team of planet hunters has found six new planets orbiting nearby stars, bringing the total number of planets astronomers have detected outside the solar system to 28. The researchers also found evidence suggesting that two previously discovered planets have additional companions, said Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz.
Vogt and his colleagues, Geoffrey Marcy of UC Berkeley, Paul Butler of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington in Washington, D.C., and Kevin Apps of the University of Sussex, England, made the discoveries using the High Resolution Echelle Spectrograph (HIRES, designed and built by Vogt) on the Keck I Telescope in Hawaii. Their findings will be published in the Astrophysical Journal.
The researchers have been using the facilities at the W. M. Keck Observatory for the past three years to conduct a survey of 500 nearby sunlike stars in search of planets. The project is supported by the NASA Origins Program, which has provided both funding and telescope time, and by the National Science Foundation.
The six new planets increase by about 25 percent the number of known "extrasolar" planets, giving astronomers a substantial amount of additional information about planetary systems, Vogt said. One of the planets, HD 192263, was also recently detected by Nuno Santos and collaborators in Geneva, Switzerland, who reported it while Vogt and his colleagues were preparing their paper.
The new planets orbit stars that are similar in size, age, and brightness to the Sun and are at distances ranging from 65 to 192 light-years from Earth. The planets themselves range in mass from slightly smaller to several times larger than the planet Jupiter (0.8 to 6.5 times the mass of Jupiter). They are probably also similar to Jupiter in their compositions--basically giant balls of hydrogen and helium gas, Vogt said.
The presence of a planet around a star is indicated by a telltale wobble inthe motion of the star as a result of the gravitational force exerted by the orbiting planet. Vogt and his coworkers recently achieved independent confirmation of this method for detecting planets when they were able to predict and measure the dimming of a star as a planet passed in front of it.
The orbits of the new planets, like those of most of the extrasolar planets discovered so far, tend to be quite eccentric, tracing paths that are oval rather than circular. One of the planets, around a star called HD 222582, has the most wildly eccentric orbit yet known, carrying it from as close as 0.39 astronomical units (AU: the distance from Earth to the Sun) to as far as 2.31 AU from its parent star in the course of its 576-day orbit.
"It is beginning to look like neatly stacked, circular orbits such as we see in our own solar system are relatively rare," Vogt said.
Interestingly, five of the six planets are located within the so-called the motion of the star as a result of the gravitational force exerted by the orbiting planet. Vogt and his coworkers recently achieved independent confirmation of this method for detecting planets when they were able to predict and measure the dimming of a star as a planet passed in front of it.
The orbits of the new planets, like those of most of the extrasolar planets discovered so far, tend to be quite eccentric, tracing paths that are oval rather than circular. One of the planets, around a star called HD 222582, has the most wildly eccentric orbit yet known, carrying it from as close as 0.39 astronomical units (AU: the distance from Earth to the Sun) to as far as 2.31 AU from its parent star in the course of its 576-day orbit.
"It is beginning to look like neatly stacked, circular orbits such as we see in our own solar system are relatively rare," Vogt said.
Interestingly, five of the six planets are located within the so-called "habitable zones" of their stars. This is the region where temperatures would allow water to exist in liquid form. Most of the extrasolar planets the researchers have studied have turned out to be outside the habitable zone, either too close to their star or too far away, and therefore too hot or too cold, Vogt said.
"These planets are at just the right distance, with temperatures in one case around 108 degrees Fahrenheit--like a hot day in Sacramento," he said.
Planetary systems with Jupiter-sized planets in oval-shaped orbits are not expected to harbor Earthlike planets, Vogt added. In fact, if an Earthlike planet were put into such a system, it would be quickly ejected by the gravitational influence of the Jupiter-mass planet. Vogt noted, however, that if these Jupiter-sized planets are similar to those in our own solar system, they probably have numerous moons associated with them.
"For a planet in the habitable zone of its star, such moons offer the possibility of liquid water and the eventual emergence of life," he said.
In addition to the discovery of six new planets, the researchers gathered new data on four previously known planets. Two of them, around the stars HD 217107 and HD 187123, showed long-term trends in their orbits indicating the presence of an additional companion. These companions, which may be planets or larger objects (e.g., brown dwarfs), appear to be orbiting their host stars in a long period, taking at least two to three years to complete an orbit, Vogt said. These findings are significant because previously only one other system of multiple planets, around the star Upsilon Andromedae, had been identified.
"It will take years of additional observations to work out the masses and orbits of these companions, but the evidence suggests there are a fair number of multiple planet systems out there," Vogt said.
Specific details about the new planets and their host stars are given below: HD 10697 is a G5IV star, slightly cooler and a bit larger than the Sun. It lies 106 light-years away in the constellation Pisces. Its planet has a minimum mass of 6.35 Jupiter masses and a 1,072-day orbit. The radius of this orbit is about 2.13 AU, but the orbit is somewhat eccentric, so the planet's distance from its star ranges from 1.87 AU to 2.39 AU. At its average orbital distance, it lies just at the outside edge of the habitable zone of its star, and is expected to have an equilibrium temperature (due to energy received from its parent star) of about 15 degrees F.
HD 37124 is a G4V star, slightly cooler than the Sun. It lies 108 light-years away in the constellation Taurus. Its planet has a minimum mass of 1.04 Jupiter masses and a 155.7-day orbit. This orbit is also quite eccentric. At its average orbital distance of 0.55 AU, it sits just within the inner edge of the habitable zone of its star, and is expected to have an equilibrium temperature of about 130 degrees F. This is the lowest metallicity star known to have a planet.
HD 134987 is a G5V star, 83 light-years away in the constellation Libra.Its planet orbits in a 260-day eccentric orbit. This planet has a minimum mass of 1.58 Jupiter masses. At its average orbital distance of 0.81 AU, its expected equilibrium temperature is a balmy 108 degrees F. It lies well within the habitable zone of its star.
HD 177830 is a K2IV star, about 1,000 degrees Kelvin cooler than the Sun, lying about 192 light-years away in the constellation Vulpecula. It harbors a 1.22 Jupiter mass planet in a 392-day, highly eccentric orbit. This orbit carries the planet from as close as 0.63 AU from its star to as far as 1.57 AU. At its mean orbital distance of 1.10 AU its expected temperature is about 192 degrees F. The planet is probably within the habitable zone of its star.
HD 192263 is a K2V star lying 65 light-years away in the constellation Aquila. A planet around this star was first reported by Nuno Santos, a Portuguese graduate student at the University of Geneva. Vogt's team has obtained essentially the same results as Santos: a 0.78 Jupiter mass planet orbiting in a 24.36-day orbit. This orbit has a radius of only 0.15 AU, with little or no eccentricity. It orbits well outside the habitable zone of its star.
HD 222582, a G3V star, is a near solar twin, 137 light-years away in the constellation Aquarius. Its planet orbits in a widly eccentric 576-day orbit, which carries the planet from 0.39 AU to 2.31 AU from the parent star in the course of its oval orbit. This is the most eccentric extrasolar planet orbit yet known. The planet's expected temperature is about -38 degrees F. Its mean orbital distance places it squarely in the habitable zone of its star.
Further information about the planet search is available on the Web at http://www.physics.sfsu.edu/~gmarcy/planetsearch/p lanetsearch.html. Information about the NASA Origins Program can be found at http://origins.jpl.nasa.gov/ and about NSF's astronomy program at http://www.nsf.gov/mps/ast/start.htm.
According to the article, the habitable zone is where the temperature is right for liquid water to form. But how can they tell the temperature there? If Earth had no atmosphere, it would almost always be either too hot or too cold for liquid water. If Venus had a much thinner atmosphere, it could possibly be the right temperature to support liquid water. If they're unsure of the composition of the atmosphere, how can they know liquid water could form on these recently discovered planets?
It is more or less correct to state that such a trip is within our technological grasp, human risk factors aside -- but the reasons we haven't done such a trip are more profound than simply budgetary or nuclear weapons treaty issues.
One interesting issue is that of radiation shielding -- as most of you are probably aware, the Earth's magnetic field shields people on, say, the Shuttle from lots of nasty critters. This wasn't the case for, say, the Apollo missions, but those were relatively short -- a few days; the odds that we would get a solar flare sometime during, say, a 3-year trip to Mars and back are pretty high. Shielding from highly-massive ionized particles (stuff in that lower right-hand of the periodic table) is also tricky -- the interesting thing is that up to a fairly large amount of shielding, you end up just "slowing them down" and making them more dangerous to humans than they were before. (If you don't shield, they by and large pass through and knock apart a few things in your body on the way -- giving you, for instance, a higher chance of getting a tumor.)
There are other severe physiological effects to consider, too. Probably the most serious is a degradation of bone material that occurs in a low-G environment -- this is acceptable, sort of, for even up to a year (cf the Mir missions), but a good chunk of the life sciences community would say the risk (of increased chance of fracture, permanent degradation, etc) is unacceptable when you're talking about a several-year mission. Soooo, people have looked (seriously) at artificial gravity schemes -- spinning people around to simulate gravity. These have problems too, though -- the Coriolis force makes your intuition wrong in many cases, plus putting a rotating ring in space (for instance) requires a pretty hefty penalty in terms of the amount of mass you're propelling. (I should mention that I think these problems will eventually be worked out -- tether schemes and small-scale intermittent-use centrifuges look promising. But it'll be a while.)
All of these are surmountable, probably. (And a substantial minority of people have said that the risk factors I mention above are acceptable for a Mars trip -- astronauts are risk-takers, the thinking goes.) My point is just that it's not as simple as it might seem. I haven't even touched on more basic physical principles that make accelerating anything (much less a manned spacecraft) up to some large fraction of the speed of light a very very difficult problem. But this post is more than long enough already. :-)
Unfortunatly, it will be a while befor we find out for certain: even 1 light year is a little far to walk (~9e12km) :(
Bill - aka taniwha
--
Leave others their otherness. -- Aratak
HD = Henry Draper
Means the object is listed in the Henry Draper Catalog of celestial objects. Another common
catalog is the Durchmusterung id number which start with letters like BD, CD, CP, etc.
The catalog naming is slightly arbitrary, but at least it makes it easy to look up. More common
names that you might have heard of before are things like NGC-xxxx...
P.S. actually this isn't much different than the whole DNS naming system if you think about it...
There are "top level" names like slashdot.org and stuff underneath like www.slashdot.org...
Carbon is one of several elements that adheres to the octet rule, allowing it to form four bonds. I'm not sure if that necessarily makes it a good candidate to create life; after all, phosphorus can form five bonds, sulfur sometimes six, and iodine makes IF7 (seven) but no one makes any theories about them. By that logic, fluorine (a gas, BTW), the most electronegative element, would be a crucial building block in life, as it bonds to just about anything, but in reality you can thank your lucky stars there isn't anymore fluorine on Earth than what we have now. It kills basically whatever biological organism it comes in contact with. ;)
What's more probable is it became the building block of all Earth-based life because of its abundance. This is also why people lean towards silicon as another possiblity - add up all the silicon and all the carbon in the world and you've got a substantial chunk of all the molecules on Earth. It all has to do with abundance - iron makes of a third of the Earth, and it's crucial to many living organisms - ever wonder why your blood tastes like metal? That's the iron in hemoglobin. Likewise, magnesium composes about 15% of the earth, and is key to many biological processes such as photosynthesis. And then of course there's oxygen, the second most abundant element on Earth, which I've heard is used by a few organisms here and there
--
"Some people say that I proved if you get a C average, you can end up being successful in life."
I think there is a world market for maybe five personal web logs.
Why use up perfectly good places for life to evolve when you have much better control of your
:-)
.. the first time I previewed this post before submission, I had mispelled "important" in the above sentence as "impotant". How ironic.)
environment on artificial structures that you can make from raw sunlight and loose asteroidal materials?
Sort of like a Dyson Sphere? Sounds neat, but I'd say it's a bit beyond our technological capacity at the moment. Until we get to that level, maybe would should stick to planets until we grow out of our technological adolescence.
We should explore other worlds, but we should live in space where all aspects of our environment would be at our control: gravity, temperature, pressure, topography, atmospheric composition, design, ecology, zoning and most obviously whether we allow those Windows riff-raff on board.
And you forgot the most important one: Sex in near-zero-gee would be lots more fun!
(Heh
We're going down, in a spiral to the ground
why don't we save life here on earth before we go looking for it in the reaches of space?
:-) It really is News for Nerds. It's in the nature of humankind to study the universe and make observations about it. We've got an inborn curiosity that we're powerless to do anything about. What we're finding is that planets are really not all that special; that they exist in abundance outside of our own planetary system. Now this was pretty much well-established before these findings were published, but the news of six new planets of this nature just further confirms it.
Why can't we do both?
Why do we have to pick and choose?
Why is the space program, and astronomical research of any kind, the favorite whipping boy of folks who claim to want to eliminate government waste? (This latest discovery comes out of academia, by the way.) While I can't comment on waste within the governments of other countries, some of the more lavish expenditures of the United States government are almost legendary. This is the same government that spends millions of dollars buying boats and airplanes that the military doesn't even want. Hundreds of thousands of dollars worth of US taxpayer money went out to study cow farts. And don't even get me started on the six hundred dollar toilet seats.
And it's the space program people complain about?
Look, I'm all for trimming government waste, but the space program is a veritable island in a sea of pork. It's almost a cliche to present a list of new technologies that sprung up as a result of the space program, so I won't do it, but I will offer one opinion about news of this nature:
It's just fucking cool.
So yes, by all means, let's work to solve the problems that we face here at home. But I don't think it's a "this-or-that" situation. We can have our cake and eat it too.
We're going down, in a spiral to the ground
NASA's "Mars Polar Lander" touches down this Friday (December 3) at 3:37 pm EST. Shortly before that it'll be releasing the two "Deep Space 2" probes to bury deeper into Mars' surface - both will be looking for water and organics, signs of life, and in the most promising part of Mars yet - the south polar area. Newsweek has an excellent cover story on this this week (by Sharon Begley, whose science reporting I greatly respect). Aside from Europa, Mars really is the mostly likely place for life in our solar system. Perhaps more likely than Europa given that Mars clearly had a liquid water ocean early in its history. The next few years should be VERY interesting in the search for extraterrestrial life!
Energy: time to change the picture.