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Sun's Twin Discovered — the Perfect SETI Target?
astroengine writes "There are 10 billion stars in the Milky Way galaxy that are the same size as our sun. Therefore, it should come as no surprise that astronomers have identified a clone to our sun lying only 200 light-years away. Still, it is fascinating to imagine a yellow dwarf that is exactly the same mass, temperature and chemical composition as our nearest star. In a recent paper reporting on observations of the star — called HP 56948 — astronomer Jorge Melendez of the University of San Paulo, Brazil, calls it 'the best solar twin known to date.' Using HP 56948 as a SETI target seems like a logical step, says Melendez."
First post?
It would be a good target to look for an Exo plant first. Then from spectral measurements see if it has the elements necessary for life (water, oxygen, etc...). Then it makes a good target for SETI to scan.
Unless we think a civilization is intentionally sending out beacons to the universe, isn't SETI pointless?
As our communications technology improves, it becomes lowered powered (unlike my old 3W car phone, my curren cell phone only puts out 300mW of signal max) and the leakage from hundreds, or thousands, or millions of point sources of RF signals becomes more and more like "white noise" to someone that doesn't know how to decode it thanks to spread spectrum signals and high bandwidth data encoded in the streams.
The days of 100,000+ watt AM radio transmitters will likely end soon, so there won't be nearly as much leakage to the cosmos.
So there's probably a 100 year window in a civilization's development where its unintentional broadcasts are detectable.
Will we ever intentionally send out a beacon advertising our existence, knowing that it would likely take 100 years or more before any potentially inhabited planet would receive it? And if we do think there's other life out there, do we really trust it enough to tell it where we are?
...if what we were seeing was actually ourselves, just 400 years ago. A wormhole, acting as a mirror...floating at the point they're looking at?
C'mon...you can dream, can't you?
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Close. It's our sun, but in the evil twin universe. Or are we the evil twin? Hard to say, really.
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Hopefully they will be advanced enough to know that SETI listens to signals, it does not send anything!
Sometimes the light at the end of the tunnel is the headlight of an oncoming train.
Tell us what you find. Until then... who the fuck cares?
Astronomers, people who like astronomy, and people interested in science, just to name a few.
Maybe they could organize an expedition to colonize this fertile planet 70 percent covered with liquid water, only 200 LY away?
If they're advanced enough to do that then they're advanced enough to have detected our planet and its composition long ago. If they wanted to colonize Earth then the plan would have already been put in place and SETI would have nothing to do with it.
So don't worry. It's only a problem if these aliens are for some reason willing to travel 200 light years just to acquire a bunch of slaves. Maybe we should make it clear in our SETI broadcasts that we are very inquisitive creatures, but also lazy and difficult to train?
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First generation of stars create some heavier elements but still nothing for building life. They go nova and what have you. So after the first generation of stars, we're not at what? 5 Billion years?
Massive stars create elements all the way up to iron in their normal life span and all the heavier elements when they go supernova. They have lifespans measured in tens of millions of years.
It doesn't necessarily take a long time to go through several generations of stars. I thought I'd read recently that we'd found extremely old metal-rich stars indicating that they had in fact gone through several generations rapidly.
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1) Send a message, "Hello, are you out there?"
2) 200 years later..., "Yes we are, is there something we can help you with?"
3) 200 years later..., "Can you give us the secret to faster than light travel?"
4) 200 years later..., "Obviously not."
Total time: 800 years.
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For starters, I do. Some of us like to keep track of endeavors as they happen and not merely be at the receiving end of a "finished product" announcement.
There has been close to 4 billion years of life on Earth. All it would take is another world that started that chain of evolution just a few hundred years earlier, or to have, by chance, evolution form sentient life a few hundred years faster, or one of countless other variable changes, and we are not the first sentient life in the universe. When time lines are that long, you can't just hand-wave and say, "yeah, there was enough time for humans to evolve, but no way could it have happened already"
6) ok, you hang up first.
7) no, you hang up first.
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Seriously, there are 10 billions stars essentially equivalent to our Sun, but you have to go 200 light years to find the closest one?
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
The star's ID isn't HP 56948, but HIP 56948 (from the Hipparcos satellite catalog), aka HD 101364, SAO 15590...
Close. It's our sun, but in the evil twin universe. Or are we the evil twin? Hard to say, really.
Hoping that we are the Evil Twin. The women are always better in the Evil Twin Universes.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
Oh, crap. I have a beard. Guess that means....
Check out my sci-fi/humor trilogy at PatriotsBooks.
Exactly! What was the score from last nights game and what has Britney Britney been up to this week?
I drank what? -- Socrates
If there is a lifeform advanced enough to pick up the SETI signals, chances are they've had the technology for thousands of (earth) years. By contrast, just a couple hundred years ago we were reading books by gas lamps and traveling and sending messages by horse and carriage.
Maybe they could organize an expedition to colonize this fertile planet 70 percent covered with liquid water, only 200 LY away? Of course, by that time the original SETI people would be long dead, having gone to their graves happy in the knowledge that they've advanced understanding between alien species...
I doubt there are any resources a spacefaring civilization could find on Earth that they couldn't find much closer to home. Asteroids and comets good sources of water and many metals and other elements. Unless they want fresh meat.
Probably the only reasons to travel 200 light years to visit a developing culture are to study it, befriend it, or annihilate it so it doesn't become a threat later when it becomes more advanced.
Does this mean our sun is a yellow dwarf??
A man spends the first half of his life accumulating stuff, the second trying to get rid of it all.
But is tens of millions of years enough to create those heavy elements?
Yes. It is the same fact of being extremely massive that causes them to burn through their hydrogen fuel quickly that allows them to subsequently fuse additional elements up through iron until they undergo a core-collapse supernova.
And were there enough of them early on in the Universe to have created enough heavier elements so that life - especially intelligent life - is relatively common?
Actually the theory is that there were much more massive stars, and more of them, in the early universe, than form today.
Whether that results in sufficient density of heavy elements in some parts of the galaxy to support early development of terrestrial planets, I just don't know.
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Comparing something incredibly huge to something several orders of magnitude bigger might make the first seem small in comparison, yet it's the mathematical equivalent of a straw man argument: the fact remains that 200ly is an impossible distance, not "practically next door". In fact the first man-made radio signals haven't even reached it yet, assuming they were powerful enough to be detected. And those are travelling at the speed of light, not some miniscule fraction of it.
Seven puppies were harmed during the making of this post.
I worry that China is broadcasting the source code for Windows Vista, and 200 years from now some alien civilization will receive it and think they're schematics for something great. They'll build it, nearly destroy themselves and then come looking for us.
1. "Hello are you out there?"
2. 200 years later, they receive message, send "Yes we are, how can we help?"
3. We receive first response (400 years total now)
4. We send "Can you teach us FTL travel?"
5. They receive the additional response (600 years total now)
6. They reply "thank you for holding, can you verify your phone number please"
7. We receive their message (totaling 800 years now)
8. We hang up in a panic, realizing our entire planet has been outsourced.
Technically, yes. That massive gravitational anchor we circle which provides all of our heat and light is a smallish star.
...But, unless it has terrestrial planets in the Goldilocks zone, it is unlikely to to be a real prospect for SETI.
If you actually read the paper, it appears from the spectral analysis, the authors conclude that HIP56948 should have about 1/2 the "rocky" material formed around it than our sun, and radial velocity measurements seem to exclude giant plants in the inner planetary region. So, although they cannot be sure there are or are-not rocky planets that are terran like in the Goldilocks zone (we don't have a reliable way to figure that out yet from ground based observations), the available evidence seems to indicate that at least the prerequisites are there this would have been a reasonably good bet for the Kepler planetary survey (but it's not part of the mission). However, they are looking forward to seeing more Kepler results to verify if their spectrographic measurements technique on stars that predict the amount of rocky material is consistent with actual Kepler planetary observations** which would increase the chance that there might be Goldilocks planets circling this star and make it possible to select really good candidate star that might have rocky planets from ground based telescope spectrographic data.
**FYI. The technique that the Kepler survey telescope uses is to actually look for photometric image of a planet transiting the star as viewed from the telescope to confirm actual planetary existance and infer it's size and distance from the star from the duration of the transit by Kepler's law (hence the name of the mission).
Unfortunatly, although this star is similar to our Sun, this star is quite a bit younger than our sun (by about 1 billion years and our Sun is about 4.5 billion years old). As a result, we may not have a really good chance with SETI on this system (even if planets exists). It's also really hard to tell which stars come from the same stellar nursery as stars drift quite a bit after formation, but there is apparently some evidence that our sun was part of a very large nursery by dating the remanents of supernova that hit our solar system when it was probably just formed, but a billion years is a long time...
It's great to go back and watch this particular episode of Carl Sagan's Cosmos: Encyclopedia Galactica. He goes through the basic idea of the Drake Equation, opines on listening/detecting life elsewhere in the galaxy. It's really great stuff, and worth watching whether you've seen it before or not.
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Think we'll go over there and find a planet just like Earth, but Rome never fell? Or maybe they had an experiment in causing immortality go horribly wrong?
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Why does everyone assume that alien species must be so much more advanced than us, technologically? Your logic is immediately flawed in that WE can pick up the SETI signals and we haven't had the technology for thousands of Earth years, so why must every other species?
That's easy -- because the universe is really old it's vastly more likely that aliens evolved and developed civilization millions of years before we did -- or we are millions of years before them -- than it is that they are in the exact same 100-year window of technological development. The odds are literally astronomical.
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I like how they mention that the 23 row by 73 column interpretation is "jumbled garbage". The correct image also looks like jumbled garbage. I especially like the image of a human. How the hell is an alien supposed to figure out what that is without having seen a human before?
The most basic possible message: counting.
Before the human-shaped pixel art, the sequence begins with a simple count, with increasing binary numbers from 1 to 10.
It's a pattern, which is recognizable without any cultural reference, only with some knowledge of math, which is needed to handle the radio signal any way, and this pattern is clearly not a random occurrence. Turn the data the other way around and you don't see any easily recognisable pattern at the begin, so they know it's the wrong way.
If you want to make it clear that a message is a message and not garbage, you try to cram in something that is clearly not random, but that is as simple basic maths as possible :
counting from 0 to some number, list of prime numbers, fibonacci sequence...
Then you could append whatever you want. Life forms at the receiving end might not be able to understand what you mean with your picture, but at least they now they've organised the data correctly because that's the only way where the begining makes some sense in a mathematical way.
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And recalling that the planet has faced quite a few mass extinctions, wiping out all the "progress" (I use the word guardedly, of course) that evolution had made upto that point, even if another planet started off at exactly the same time as us, its equivalent of the dinosaurs could have become sapient 65 billion years ago...
Although passive SETI does not send messages, Active SETI (ASETI) or METI does precisely that. As a planet, we have already sent messages to Gliese 581 and a number of other systems. If I'm successful I will even start sending such targeted messages full time from a 20 meter dish in Argentina. Unfortunately my power levels and antenna size probably limit my messages to a radius of about 50-100 light years, but with very large receiving antennas such messages could travel, much farther, possibly out to 200 ly. My goal is to start a full time. 24/7 targeted beacon. Now that has not been done before, but it's only a matter of time. If I'm not successful in my lifetime surely someone else will be eventually. Even some less cowardly government programs like that of the open minded Ukranians do not shy away from sending messages. They just don't do so as part of a permanent program. I believe that will be left to amateur projects like my own.
Does anyone know the declination and right ascension of this solar twin? I can't find any information on it from googling HP 56948. I'm guessing it probably has another more commonly used name.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
What would be the incentive to organize such an expedition? Even if they are way ahead of us, it will be an enormous enterprise. I'm sure if they are so advanced, they would have to compare it with much better alternatives.
A spot of tea? We'd make great pets? I could think of a million reasons why or why not to visit. Nearly all of the good reasons are non-malicious -- Greed would be a huge limiting factor for the malicious motives... Unless their planet is dying or something.
Think of it this way: Let's say we discovered a TV Signal from an alien race that was less advanced than us? What would we do? Bet your bottom dollar the first (US gov) instinct would be: "Don't tell the public! They'll want to send a message, and that could mean war or our eventual demise." Regardless of the distance, as soon as word gets out to the public, every nerd's mom's sat dish is re-purposed and aimed at the distant planet and beaming them everything from GNU/Linux source code to Otherworldly Erotica. (Heh, here's one now!)
Public support for NASA to launch a small satellite carrying a message of peace would be huge, regardless of the time it would take it to get there, and the near hopeless chance of it reaching anyone... Were we very much more advanced than we are now, it would be a huge scientific find and you can be sure that some of us would be making plans to stop by and say "hi".
(You've obviously never met an Explorer or Mountain Climber.)
But if we're talking about communicating with, observing with a telescope, or sending objects to another solar system, 200ly is about as good as it gets.
So you consider having to wait 20 generations (it's a round trip, remember) to hear the answer to your question, if there is an answer, "communicating with" someone? You believe it's possible to "send an object" 200 light years, when it has taken almost 40 years to send an object around 3 light-HOURS away from earth (Voyager 1 is about 120 AU from us now).
I think there is a problem with the wiring of the human brain; when people see the number "200" somehow this is a familiar number used regularly by people. $200 for groceries. $200 for a hotel. $200 here, and there. The brain obviously skips over the difficult-to-understand light year part and just sticks with good old familiar "200".
I argue that 200 light years is as good to us as 2 million light years. We will never get there. Ever. The rest of your argument consists in believing in magic like project Orion which completely ignores passengers being fried by cosmic radiation at 0.08c even if all the other "minor technical details" could be worked out. And then there is the slight problem of a 2500 year trip when compared to an organism that lives at best 70 or 80-odd years with few exceptions. There are only a few structures humans have ever built that have lasted 2500 years or more, and even then they did not endure unscathed. Entire civilizations have come and gone in that time span. What makes you think a complicated space-craft could be kept running for that amount of time?
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"Let's say we discovered a TV Signal from an alien race that was less advanced than us?"
You mean 1000 channels and nothing on?
Well, unless they were *extremely* close to us any civilization that we receive radio waves from is likely at least as advanced as us. Our first radio experiments were in 1887, first audio broadcast in 1906, and analog television broadcasts didn't start until the 1930s in Europe, the 1940s in the US. Add in a 200 year transmission time and the civilisation we just detected a crude television signal from is already in their mid 2100s. Admittedly their science probably wouldn't be advancing in the same manner as ours, but unless their understanding of radio transmission far outstripped their other sciences we'd have to assume that they're at least our technological equals.
Still, lets send that signal, in another 130 years they'll start receiving our own crude TV broadcasts anyway, why not let them know we've spotted them. By that point none of the current politicians will be running for re-election (I hope), so what do they care.
But why send a probe? (satellites by definition are in orbit) The energy required to get it there in less than a few thousand years could instead be spent building and powering the the worlds most incredible directional broadcast antenna with which to say hello.
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SETI doesn't actually expect to receive radio leakage. So the analog window isn't really an issue. If a twin earth were orbiting Alpha Centauri A even the giant Arecibo dish would not be sensitive enough to receive even fairly loud leakage. The signals are far too weak, generally too low in frequency, and are quite often aimed tangentially to the planet surface and not at the zenith. Omnidirectional signals which might have a greater tendency to travel in the right direction are just too weak. None of it can really be distinguished beyond the noise floor even at 1 light year, let alone the 4.2 light years to the nearest star.
It's always possible that alien technology could pick out our own pathetically weak signals from the noise at great distances, but I don't think we can even (realistically) imagine such technology. Perhaps a planetary scale antenna, like carving a paraboloid shape into one side of a moon or planet might allow the detection of leakage to a distance of Alpha Centauri, but obviously we don't have anything like that yet.
Passive SETI hopes to detect either an omnidirectional galactic beacon of pulsar-like magnitude or a directed beam from a source that is deliberately attempting to communicate with us. If this seems tremendously unlikely to you then you understand the problem with traditional SETI. Even if we are surrounded by technical civilizations there is no reason to expect that they know we are here and even if they know they may choose not to attempt communication for various reasons.
I don't think anyone has ever attempted to send a signal to Alpha Centauri for instance. Our closest neighbor. A sun-like G class star. We've had the technology to send a signal since radar was invented before WWII and we have chosen not to do so. Admittedly, for a while it was believed that such a binary system would not allow life to evolve, but still. It would have been quite easy for us to do. Passive SETI relies on a whole bunch of unlikely scenarios or a whole lot of intelligent civs in our part of the Milky Way. It relies a bit too much on getting lucky.
That's why I prefer Active SETI. If you believe a particular star system might have intelligent life then first say hello and then only after enough time has passed for a response do you actually listen. Or just await the arrival of the invasion fleet. Either way you've made contact.
Quite an experience to live in fear, isn't it? That's what it is to be a slave.
Actually the theory is that there were much more massive stars, and more of them, in the early universe, than form today.
Makes sense. All the matter in the current universe was packed into a much smaller space, the initial hydrogen clouds were likely quite dense with minimal angular momentum and would have collapsed into truly stupendous stars.
As I understand it Sol is believed to be a second-generation star that formed about halfway through the time window in which such stars would form, the chemical signature of the initial stellar cloud is the identifying characteristic of such stars (especially the C,O,N and trace heavier elements). That is the essence of the Fermi Paradox - since our star was born halfway through the window there should be no shortage of sunlike stars born billions of years before ours, and with them at least a few civilizations billions of years older than our own.(To put it in proper perspective, their life had plenty of time to reach our current level of development before Sol had even *formed*) If even one of those civilisations spread out among the stars then they, or at least descendants of their bacteria, should be EVERYWHERE, so why don't we see evidence of them?
Personally I favor the efficiency theory - even if they never found anything better than EM radio to communicate with their receivers would rapidly become extremely efficient so transmitters wouldn't need to be as powerful, and to maximize bandwidth their signals would be compressed to the point that they're indistinguishable from random noise, we're well on our way to that point already. Add to that that any long-range transmissions almost certainly would use incredibly tight-beam transmission to maximize range per unit power, and we've got no reason to believe we could detect them unless they came knocking on our door.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
65 billion years is quite unlikely, as the age of the universe is estimated at a little under 14 billion years. 65 million should be about right.