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Alien Contact Unlikely For Another 1,500 Years, Says Study (msn.com)
An anonymous reader writes: Astronomers at Cornell University predict based off estimates that alien contact is unlikely for another 1,500 years. MSN reports: "According to the astronomers, signals from Earth would need to reach half of all the solar systems in the Milky Way in order to be picked up by an intelligent life form. Given that signals from TV and radio were first sent into space as a byproduct of broadcasting 80 years ago, it will take around 1,500 more years for aliens to receive, decode and respond to the signals." A co-author of the paper who will present it at the American Astronomical Society's meeting on June 16, Evan Solomonides, said, "We haven't heard from aliens yet, as space is a big place -- but that doesn't mean no one is out there. It's possible to hear any time at all, but it becomes likely we will have heard around 1,500 years from now. Until then, it is possible that we appear to be alone -- even if we are not. But if we stop listening or looking, we may miss the signals. So we should keep looking." Stephen Hawking and Russian entrepreneur Yuri Milner announced a $100 million research program in April to send robotic probes the size of postage stamps to nearby stars within a generation.
I've already made contact
we want to get paid
The Solar System is 25,000 light years from the center of the galaxy. So, it takes 25,000 years for signals from Earth to reach half of the solar systems in the galaxy... and another 25,000 years for them to respond.
http://www.geoffreylandis.com
I'm pretty sure the aliens are coming back next week... on June 24th at a theater near you. "Independence Day: Resurgence"
How long until those signals are indistinguishable from background? It's not just that the signal is there, but that the SNR is low enough to stand out.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
1500 years to get there, 1500 years for the reply?
The assumption is that we have to initiate contact for them to respond. Why wouldn't they be trying to initiate contact also? In theory, we could hear from them tomorrow if they are more advanced and initiated contact long ago.
The worst assumption is that anyone would actually be intersted in speaking with us. One look at the TV signals and they'd immediatly place a quarantine around our solar system.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
"predict from estimates" Really?
Seriously, does anyone even 'journalist' anymore?
This is a simple wild-ass guess based on NOTHING. Aside from that simple fact...
They "guess" that signals would have to reach "half the systems in the Milky Way" to have a reasonable chance of being intercepted...but then say that this will happen in only another 1500 years.
Quick hint: just looking at it as a 2d issue, the Milky Way is 100,000 ly across, more or less. It doesn't take a mathematician to realize that a 1500-ly radius circle doesn't come CLOSE to hitting 'half the systems in the Milky Way'.
For those mathematically bent, a 50k ly radius circle has an area of about 8x10^9 sq ly.
A 1500 ly radius circle is 7x10^6...so about 1/1000 of the galaxy, not half.
"Experts", eh?
-Styopa
More or less since the first signal we blasted out for tv and radio where omni-directional , count about 1/r^2 decay in intensity. A few hundred AU at most a few light year (e.g. we are almost not detectable if we had a SETI outpost placed on our nearest neighbors). Basically what our SETI is trying to detect , is intentional unidirectional powerful "we are here" signal sent by an ET civ, like we did in direction of Gliese or M13. There is a nice table with all signals including TV and maximum range : http://www.faqs.org/faqs/astro... scroll to "Table 1 Detection ranges" for assumption and detection range. Basically the only signals ET could detect beyond 10 LY, is our own intentional signals sent from various folk in the last 4 decades, and those maximum are around a few hours duration top.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
So humanity has 1500 more years to live before the aliens come and destroy us.
Only if the aliens can travel at the speed of light
The "scientists" at Cornell who are getting headlines with this breaking news haven't the foggiest clue how far away the nearest alien intelligent species is from Earth. Possibilities range from living here already among us or lurking in the solar system to "there are no alien intelligent species in the Cosmos", we could be unique. If you assume -- not unreasonably -- that evolution of advanced life requires an extremely unlikely accident -- like a collision with a proto-planet that is just the right size to strip away some atmosphere components and deposit others and rearrange the distribution of massive elements in the developing crust and then produce a moon that initially is very close and produces huge tides, plus a magnetic core, plus the right distance from the right sun, plus the good fortune not to be hit AGAIN just as intelligence is teed up, plus the enormous good fortune of the developing species making it over the self-extinction hump -- we might be alone in the entire galaxy or in very rare company extragalactically, even with a trillion trillion star systems to choose from. Or, the odds could be a D&D 20 sided dice roll per star. We just don't know. There is no evidence, and our theories of planetary evolution and abiogenesis are just that -- theories with very little substantive evidence to support them.
Then there are the other silly aspects of their claim. It is rapidly looking like a developing civilization is likely to have only a narrow window where they radiate a substantial amount of organized radio wave energy, so one has an even narrower window for retarded detection. Also that emitted (wasted!) energy at its peak is on the order of maybe a megawatt or two in any given channel on its brightest day, and the 1/r^2 law is pitiless. Just one light year away your 10^6 watts are spread out across 4\pi (10^15)^2 ~ 10^31 square meters. Let's see: 10^6/10^31 = 10^{-25} watts per square meter. If you turned an entire planetary surface into a directed antenna, it would have a cross sectional area on the order of 10^14 square meters, leaving you with 10 whole trillionths of a watt receiver power. Sure, why not, a piece of cake we can amplify that and resolve signal from noise -- using a planet-sized antenna and black magic.
So a better answer is that we will never be visited by space aliens who "pick up our TV signals" any more than we will pick up their signals. If some NEARBY civilization is crazy enough to point a directional, tight beam radio station right at the solar system and pump it with a terawatt or so, sure, maybe we could receive it here. But resolving the waste signal of a civilization order of tens of light years or more away? The amazing thing is that anybody manages to get this sort of thing funded. Simple arithmetic makes a fairly powerful argument that any SETI effort is a complete waste of time and money. No matter how cool -- and dangerous -- it might be.
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Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.