Scientists Discover Exoplanet Less Than Twice the Mass of Earth 201
Snowblindeye writes with this excerpt from the European Southern Observatory:
"Well-known exoplanet researcher Michel Mayor today announced the discovery of the lightest exoplanet found so far. The planet, 'e,' in the famous system Gliese 581, is only about twice the mass of Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist. Planet Gliese 581 e orbits its host star — located only 20.5 light-years away in the constellation Libra ('the Scales') — in just 3.15 days. 'With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet,' says co-author Xavier Bonfils from Grenoble Observatory. Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. ... The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. '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,' says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. '"d" could even be covered by a large and deep ocean — it is the first serious "water world" candidate,' continued Udry."
Astronomy (Score:5, Interesting)
How much do we really know about these planets, and how much is guessing? How close are these planets, really, to earth?
Re:Astronomy (Score:5, Funny)
Re:Astronomy (Score:4, Funny)
It's 20 (or so) light years from Earth. According to this [theregister.co.uk] article, we've probably already pissed off any inhabitants...
We still have what, ten years left to invent an FTL drive and get there to preemptively apologize for reality television, right?
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We still have what, ten years left to invent an FTL drive and get there to preemptively apologize for reality television, right?
Faster than light merely means... Faster than light. c + 1 cm/second would count, but would get us there mere microseconds before the announcement that we had started the trip. Leaving now, we would need to go at >2c.
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It's 20 (or so) light years from Earth.
To put that in a context that ordinary nerds without astronomy backgrounds can understand, it's 37,842,113,600,000,000,000,000,000 beard seconds [wikipedia.org] from Earth.
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But only bearded "terrorists" and Stallman-lookalikes use that unit!
Which one are you?? Hmmm...?
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Substitute 150,000mph for 36,000.
http://www.aerospaceweb.org/question/performance/q0023.shtml
Wanna see more: Celestia (Score:5, Informative)
Just select "go to object" and type in "gliese 581", you'll get the orbits of the different planets already found too.
The neat thing is, you can just "cruise" around, speed up time to see how stellar objects move, and so on... Quite cool
Re:Astronomy (Score:5, Informative)
The significance is that our methodology is improving. Only in the past decade or so have we been able to identify stars with possible planets. Only in the past year or two have we been able to directly image a planet (or separate it's image from the parent star). What we know of the planets is based on how close it's orbit is to the star, it's estimated mass, and in a few recent cases, based on limited spectroscopic information.
Now that Kepler's working, over the next 2-3 years we should have a flood of these reports. (keep in mind Kepler's only imaging a 10 x 10 degree patch of sky) In the next decade we will develop the means to directly image a nearby terrestrial sized planet.
All of the planets imaged so far are relatively close, on a galactic scale. A few 10's of light years. There's more than enough information out there to explain how far that is from a human perspective. Let's just say, that based on current technology, none of our great-grand children will get an up close look. (although I suppose we could do a fly by of something like the Gliese 581 system, with a probe, in the next 3-4 generations, if we tried hard enough.
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If we can see planets a vast distance away so well, why are we having to send New Horizons all the way to Pluto to get a good piccie of it? Can't we point Kepler at it or something?
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From his third paragraph:
All of the planets imaged so far are relatively close, on a galactic scale. A few 10's of light years.
So, yes.
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I always hear about these sorts of discoveries, of new planets more and more similar to earth, but having almost no astronomy background, I have no idea how significant they are.
Consider it a bit like breaking a world record, "closest to Earth" is a big title but ultimately you only need to beat the old record by an inch. The answer I'd say is "much, much closer than anything we've observed in the history of mankind and still very, very far away". There's so many variables you could tweak about size, distance from star, temperature, rotation time, composition, magnetic field, atmosphere, jupiter-type asteroid shields and whatnot. We're very far from saying whether anything we find
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...How close are these planets, really, to earth?...
In order to have intelligent life, not only must the planet itself be similar to Earth in all respects, but the star it orbits must be very similar to our Sun. In this case, the star is too cold to emit the proper spectrum of light to use for knitting together atoms of carbon, hydrogen and oxygen, such as occurs here on Earth by the process of photosynthesis in green plants. This means that this star and others like it can be safely scratched from a list o
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In order to have intelligent life, not only must the planet itself be similar to Earth in all respects, but the star it orbits must be very similar to our Sun.
No. We don't know that. We can't even begin to assign odds on what we might find when we turn over a rock on the surface of another world. With our sample size of 1, Earth, we have next to no data to support much to do with extraterrestrial life let alone any basis to declare where intelligent life can and cannot exist.
Oceans under Europa and other such worlds may harbor life, and the possibility of complex life is valid, therefore the possibility of intelligent (at some level) life can't be discounted.
but what about Earth 2... (Score:5, Insightful)
This is very interesting but no where near as exciting as finding another Earth like planet. I suppose we will have to wait for the next generation of telescopes before we find it though.
What is a little surprising though is how many planetary systems we have found that are very different to our own. I can't believe ours is unique but perhaps it's quite rare.
Re:but what about Earth 2... (Score:5, Insightful)
This is very interesting but no where near as exciting as finding another Earth like planet. I suppose we will have to wait for the next generation of telescopes before we find it though.
Well the 'e' planet is somewhat earth-like in mass and possibly earth-like in composition. It's not in the habitable zone for the star, but the closer a planet is to the star the easier it is to detect, and this exoplanet is at the very edge of our ability to detect (thus why this is news -- smallest exoplanet ever found). So you're right, we'll have to wait for technology to advance to find earth-sized rocky planets in the habitable zone (especially of non-dwarf stars).
What is a little surprising though is how many planetary systems we have found that are very different to our own. I can't believe ours is unique but perhaps it's quite rare.
I'm not sure anything we've found suggests that our type of solar system is rare. The limitations of our detection method by and large assures we'd find systems different from our own first. Astrophysicists might not have expected to find gas giants very close in to stars, but if they exist, we were going to find those first. The two main things that seem to have changed to me are that 1) we've gone from having nothing but our own solar system as an example and thus assuming ours was the model for all of them, to have many more examples showing different types and 2) we've learned that solar systems seem to be pretty common.
If we get to the point where detecting a solar system like ours would be simple, and despite finding thousands of others we don't find any like ours, then maybe that points to rarity. Right now though I doubt we're anywhere near being able to say that.
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To elaborate on that (you covered the distance part, yourself), the main factors is detecting exoplanets right now are (1) its easier to detect bigger exoplanets, and (2) its easier to
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If we were using our current detection technology to examine a solar system that has a planet exactly like earth, orbiting a star exactly like our sun, with the same orbital period, etc... how close would the solar system need to be for us to recognize those features? Could we recognize an earth-sized planet orbiting a star in the habitable zone if it were 20 light-years away? What about 30 light-years? How clos
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Second that great question... anyone, have an answer?
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> This is very interesting but no where near as exciting as finding another Earth like planet.
Planet Gliese 581 e is an earth-like planet. It's just not in an earth-like orbit.
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I can't believe ours is unique but perhaps it's quite rare.
Every star and planet is unique. They weren't made from an assembly line y'know!
And don't forget our form of life is equally unique, so it's a real needle-in-the-haystack situation. Kepler can search 10 x 10 degrees at a time, but with limited depth per scan, i.e. it has to change focus for objects 80 light-years away compared to objects 20 light-years away.
Then there's the inconvenient fact that communications take so long between such distant
Re:but what about Earth 2... (Score:5, Funny)
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Whoa, that was wrong.
Yes, but...
In many of the more relaxed civilizations on the Outer Eastern Rim of the Galaxy, the Hitch Hiker's Guide has already supplanted the great Encyclopedia Galactica as the standard repository of all knowledge and wisdom, for though it has many omissions and contains much that is apocryphal, or at least wildly inaccurate, it scores over the older, more pedestrian work in two important respects. First, it is slightly cheaper; and secondly it has the words Don't Panic inscribed in large friendly lette
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Hand in your geek card. Read The Hitchhiker's Guide to the Galaxy. See the doorman for reissuance.
Planets and moons (Score:4, Interesting)
Gliese 581 d is probably too massive to be made only of rocky material...
Even if it isn't habitable, it might still be large enough to have a habitable moon perhaps?
Re:Planets and moons (Score:5, Funny)
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I hope many Bothans died to bring us this information. [penny-arcade.com]
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Only if you eradicate the ewoks first. God those things are annoying. But hopefully tasty.
I'm pretty sure they became extinct after the debris from the Death Star fell on the Sanctuary Moon.
Re:Planets and moons (Score:5, Informative)
One interesting thing about Gliese 581 d not being made of rock is that it might have almost the same surface gravity as Earth:
Volume of a sphere=(4/3)*pi*radius^3
radius of sphere=((.75/pi)*volume)^(1/3)
volume=mass/density
radius=((.75/pi)*mass/density)^(1/3)
mass=7.5*mass of earth
density=2kg/liter (twice that of water)
acceleration due to gravity=Gravitational constant*Mass of planet/(radius)^2
thus, plug this into google=
(Gravitational constant)*(7.5*mass of the earth)/((7.5*mass of the earth)/(2kg/liter)*.75/pi)^(2/3)
google gives us: 9.7764354 m / s^2
Yay!
Now, we just need a breathable atmosphere! And light-speed spaceships (or faster)!
Good news (Score:5, Funny)
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Apologies to xkcd [xkcd.com]
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Yeah, the AC who posted about 14 minutes before you noticed this as well.
Call me when we find an auric world. (Score:5, Funny)
Water worlds always have the crappiest minerals. Oh look more alkalines. Yay. It won't be worth spending the fuel to land on Gliese 581 d, much less the cargo hold space. Gliese 581 e might have iron and other metals, but being so close to the star it probably has major hot spots. So that's probably not worth landing on either until we meet the Melnorme and buy some tech off them.
Oh well. Eliminating planets to explore is good too. There's a lot of stars in the sky, you know, and only so much time to explore them before the UrQuan return.
Re:Call me when we find an auric world. (Score:5, Funny)
Re:Call me when we find an auric world. (Score:5, Funny)
We should check out Vega.
No. What happens on Vega, stays on Vega.
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No, there's probably just a bunch of Vegans there.
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Gliese 581 e might have iron and other metals, but being so close to the star it probably has major hot spots.
Major hot spots? The place will be swarming with college students on spring break before you know it.
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Major hot spots? The place will be swarming with college students on spring break before you know it.
Huh, maybe we can then collect them for the organic information we need to trade with the Melnorme! This could work!
Let's blow this popsicle stand (Score:2, Interesting)
Meh.
As in Moonraker, we send the sexy geniuses first, right? Or do we send the Telephone Sanitizers and hairdressers, like in HHGG?
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Yeah, if we were able to travel at the speed of light.
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Don't the actual passengers get there in a few hours, their own time, or something crazy like that?
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By someone standing on either Earth or the destination planet? Though it just occurred to me, I find it cool that to the photons from my lcd monitors I am traveling towards them at the speed of light.
Re:Let's blow this popsicle stand (Score:5, Funny)
As in Moonraker, we send the sexy geniuses first, right? Or do we send the Telephone Sanitizers and hairdressers, like in HHGG?
Well according to the travel register, you're booked on the first flight! Take that however you want.
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It's actually a cookbook.
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The post it was responding to clearly interpreted "20 light-years" as 20 years travel time, so GP's explanation that it was 20 years if and only if travelling at the speed of light, something we are notably incapable of doing at the current time, was, taken in conte
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Thank you.
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It would be really awkward if we sent a mission to that planet, only to find out that our speed of travel was less than the speed of expansion...
"Crap."
Did any one else read that as... (Score:2, Offtopic)
Did anyone else glance at Gliese and read that as uncomfortably close to Goatse.cx?
By the way, off topic, as it is, how does one prevent from being fooled by tinyurl links to goatse.cx?
Re:Did any one else read that as... (Score:4, Informative)
Re:Did any one else read that as... (Score:4, Informative)
Everything except orbit and mass is speculation (Score:5, Interesting)
The science of extra-solar planet detection is very interesting, but speculation about surface conditions that might exist doesn't reflect the science at all, it's just fodder for the media and bloggers.
The only things we know are extremely rough estimates of orbital parameters and mass, although the host star is well characterised. The speculation is conjuring up quite specific images in people's minds, and while fun, they're not justified. It's leading people without an astronomy background astray.
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"'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', says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough."
Indeed. Who do these scientists think they are, making their work sound interesting?
What class? (Score:2, Interesting)
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Oblig. That's no Exoplanet... (Score:2, Funny)
... it's a Beowulf Cluster.
What, you were maybe expecting something else?
Innuendo (Score:2)
Soulskill writes:
"...it is the first serious "water world" candidate,' continued Udry."
Excellent.
Whiplash. (Score:2)
The orbital period of these exoplanets make Mercury's 88 day loop seem positively sluggish by comparison. The rest of the planets in our system have much longer orbital periods - Earth's is a bit over four times mercury's - to say nothing of the geologic sloth of the outer planets.
That said, from what I know about gravitational microlensing (very little, admittedly), it makes sense that our existing telescopes are picking up a lot of "high speed" planets, and that it's going to take a long time (both in ra
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it's going to take a long time (both in ramping up the tech and in tasking the scope to just sit there and stare at a star, waiting for something to blip by) for the "earth-sized rock in the habitable zone with an earth-length orbital period!" announcements to start rolling in.
I wouldn't think that an "earth-length" orbital period is all that important to determining if a planet can support life or not. Remember, the type of the star it orbits determines where and how large the habitable zone will be, so if
Superluminal planets? (Score:2)
Planet Gliese 581 e orbits its host star -- located only 20.5 light-years away [...] in just 3.15 days.
The planet orbits a star 20.5ly away from it in just over 3 days? I figured if superluminal travel existed it would involve quarks or virtual particles, not entire planets! Not to mention I'm surprised that 20.5ly is apparently a small distance to orbit from ("only 20.5 light years away").
Paging Dr Einstein (Score:2)
Given that they're 20 years away, IN THE MILLENIUM FALCON, is it even interesting if they are habitable or not? I can picture it now, we use a radio telescope to send "Hello" and wait 40 years to get back "A/S/L ?".
In related news... (Score:2)
Soon. (Score:2)
Searching for investors (Score:2)
I'm building an Ark and plan to retire to this paradise planet. The current crime rate is 0% and there are no taxes at all.
Invest now in this limited opportunity and don't be too late to take advantage of this exclusive offer.
Just reply to this thread with your bank routing number and account number along with the amount you wish to invest.
Re:Extraterrestial life (Score:5, Insightful)
To state banally, once again it appears that Earth isn't the center of the Universe, or even an extraordinary spot. Sadly, mankind won't be ever capable of communicating with such a distant places. However, speculation about extraterrestrial life isn't pointless. In range of our capabilities and, moreover, not forbidden by limiting condition on light speed, is a spectroscopic measurement of atmospheres belonging to planets beyond the solar system. Thus, in principle probable, it would be a great achievement to find traces of organic matter.
Those are some bold statements: 1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.
2) Not ever be able to communicate with distant places? You don't know what we will invent in the future. It may come out tomorrow, or it may come out in 300 years - but to say "never".
3) Speculation about other life is not pointless - it feeds our soul and imagination to wonder if there is something else. If humans thought exploring was pointless we would still be living in Africa, definitely never have crossed the ocean, let alone landed on the moon (something that people, 100 years ago, thought was impossible)
Finding organic material will be hard short of landing on the surface. We couldn't even do searches of Mars without sending a robotic device there, and even then it may miss something. It's hard, and may not get done in our lifetime (thought it might) but it is certainly not pointless or impossible, and considering how rare life is we should consider ourselves (and our planet) to be very rare and special, though hopefully not unique.
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1) Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.
The only reason we are able to detect life on Earth is due to proximity - so you're just as guilty of jumping to conclusions as the GP. We've found planets that differ wildly from Earth because the easiest planets to detect are the fuck-all-huge ones. Just because we haven't observed Earth-like planets yet does not mean they aren't all over the bloody place. They're just rather hard to spot with current technologies.
Re:Extraterrestial life (Score:4, Interesting)
If we do an absorption spectrum reading of the atmosphere, which can be done at astronomical distances, and find free oxygen that would be a strong evidence for life on that planet. Oxygen is so reactive that it wouldn't exist very long in a planet's atmosphere before combining with something, unless here is a process like life to replenish it.
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Agreed - lots of stuff could be detected spectroscopically on an Earth-like world.
Those kinds of technologies can't be applied to other planets in our own solar system. I mean, sure, technically we can do a spectrocopic study to rule out Mars being a jungle paradise, but I don't think that is really at issue.
We need probes for nearby planets since we already know they aren't teaming with life, but there is a question as to whether they are absolutely sterile.
Now, if a spectroscopic study of an exoplanet sh
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Considering how many planets we have looked at and that we can't find life on any of them this makes Earth very extraordinary.
You are wrong about this. From the hundreds of planets we have found, we can easily extrapolate that there are many, many more planets (and many more rocky planets, as well) in the solar system than we have thought (maybe even 1 per star!). That makes the fact that we haven't found life yet on the planets we've searched for irrelevant. If there are a billion planets out there, we have to search a lot more before we can say definitively that life is rare in the galaxy.
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You're assuming that light speed is an absolute limit. Remember, 100 years ago, humans thought heavier-than-air travel was physically impossible. The idea that atoms could be divided or joined was also thought to be impossible.
Considering we've barely even taken a few steps off this rock, the idea that our current understanding of physics is complete is laughable.
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Finding organic living matter on other planets would be fantastic, but unfortunately that wont be the first kind of extra-terrestrial life we find (prospective there is any).
Our most advanced instruments are just now able to detect exoplanets, and soon enough they may be able to actually scan the surface for signs of life.
If we COULD send instruments there that could detect microscopic living organisms, we might actually have a lot better luck at finding life.
This just isnt feasible currently, and were goin
Re:Extraterrestial life (Score:5, Funny)
I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.
Yeah, because if a big thing from another planet lands and I look inside and see a big red button attached to some unknown device, I'm gonna just press that puppy right away :-)
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You wouldn't but I would, then I'd lick the casing. My dog might even widdle on the side of the probe or hump one of its legs.
I'm pretty sure one constant throughout the universe will be that life invariably leads to unbelievable stupidity.
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I think it would be a good idea to send a rocket with a screen and dvd player or something, with a big red button on it that plays it.
Yeah, because if a big thing from another planet lands and I look inside and see a big red button attached to some unknown device, I'm gonna just press that puppy right away :-)
Good point. Clearly the button should be green. Duh!
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Don't touch that, you fool! That's the History Eraser button!
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'Pick me up'
Hmm... (grabs)
*POOF*
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One of the fascinating free books I've been able to find for my Sony ereader was a short story "Test Rocket", I think it was called. We sent up a rocket with a mouse as a test. It disappeared. Several years later, an copy of the rocket came back, made out of materials "not of this planet" and three times the size of the original, containing
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Did you even bother to read the summary? The star is about 20 light years away. That's a 20-year round trip for radio communications, sure... but we are currently capable of communicating with "such a distant places" (sic). We have been for the better part of a half a century.
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The star is about 20 light years away. That's a 20-year round trip for radio communications,
40 years round trip. That's a long time to wait for a response. Imagine we sent out a message announcing our presence and saying hello:
"Hello? This is humanity, we are [blah, blah - lots of info about us and Earth]..." ..... .....
40 years later and you get the response:
"Hi!"
How pissed would you be?
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Actually, it would be much wiser to simply continue to talk for the whole twenty years than dialog like that. You would give the recipient a lot of information over that time, and hopefully they would reciprocate.
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Actually, the idea of talking continuously came from an Arthur Clark short story... have Googled but cannot come up with a title :(
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Are you sure it was from Arthur Clark? I once read a short story by Asimov on that, and after some Googling I found this [wikipedia.org].
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Thank you! My memory is bad.
And for the record it is Arthur C. Clarke which both of us spelled incorrectly.
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The kicker is that radio does not travel at the speed of light
Where, pray tell, did you come up with this?
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Where do you get that radio waves don't travel at the speed of light? They're photons. In a vacuum. They're going just as fast as your friggin lasers.
And don't get your hopes up about radio transmissions being picked up either. Take the biggest receiver on Earth (Arecibo - 1000 feet across), put it in space and how far can you go before you can't make out TV/radio transmissions? Pluto.
The carrier can go out farther - maybe a light year before Arecibo loses it. And radar beams even farther (assuming the beam
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Imagine we sent out a message announcing our presence and saying hello:
"Hello? This is humanity, we are [blah, blah - lots of info about us and Earth]..." ..... .....
40 years later and you get the response:
"Hi!"
How pissed would you be?
Not as pissed as I would be if the response was a message telling us how our civilization could grow larger, last longer, and bring more pleasure to our partners.
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I'd expect that any response would sound like static or gibberish, and we might not be able to decode it for a long time. As cheesy as some parts of "Contact" were, that part was probably about right: We receive their "message" and then spend months going, "WTF did they send us?"
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That's a 20-year round trip for radio communications, sure... but we are currently capable of communicating with "such a distant places" (sic). We have been for the better part of a half a century.
Radio communication was invented in 1960?
compromises? (Score:2)
Maybe Life had to make compromises for low gravity planets, like earth, and finds it much easier to organize in high gravity planets with a lesser amount of elements (whatever the hell that means). Humility is a virtue.
Re:Strange biology (Score:4, Informative)
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The Dave Lister count is also much Higher for Red Dwarves.
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No. The correct term is lightest. The writers are not making any indication about density in the summary. They are indicating they they have indeed found the lightest planet discovered using these techniques. This planet wouldn't even be close to being the least dense planet ever discovered. Gas giants are typically far less dense.
(having to wait my obligatory five minutes between posts)
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Actually, wouldn't the correct term be 'least massive'? Heavy and light are measurements of weight generally and are pretty meaningless for objects that are in orbit. Unless it's considered kosher to use lightest/heaviest in this situation, sometimes I think English drifts faster than the average person can keep up with it.
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How often does she call you DJCouchyCouch?
Here you go (Score:2, Funny)
.