# How would aliens locate us? **URL:** \ **Category:** Factual Questions\ **Created:** [October 30, 2014, 9:09pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055 "2014-10-30T21:09:50Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Henryunderborn](https://avatars.discourse-cdn.com/v4/letter/h/58f4c7/32.png) [@Henryunderborn](https://boards.straightdope.com/u/Henryunderborn)\ **Post date:** [October 30, 2014, 9:09pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/1 "2014-10-30T21:09:50Z")
Realistically. 1.How would aliens go about tracking us down, or happen to come across us? 2.Would they follow transmission trails? 3.Would they interpret information by relative composition of specific environmental or cosmic patterns? 4. How much into the depth of space have we uncovered “empty” territory. 5. What sort of wrong turns or curves in the road, could actually be holding occupied territory? Where as we, previously overlooked it. What would be required of other beings to successfully zone in on our existence, with all our reaches out into space? Can someone give me the pop up book version on the vast interaction of broadcasting out into space, and looking in on empty galaxies? (existent aspects here on earth, wouldn’t be too unappreciated either.) ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [October 30, 2014, 11:07pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/2 "2014-10-30T23:07:51Z")
Here’s an analysis of a few powerful transmissions we have already sent, showing that there is a non-trivial chance that we have already been detected. Detection Probability of Terrestrial Radio Signals by a Hostile Super-civilization > **[Detection Probability of Terrestrial Radio Signals by a Hostile...](https://arxiv.org/abs/0804.2754)** > > Comparison of the total number of the radar astronomy transmissions with > respect to that used for sending messages to extra-terrestrial civilizations > reveals that the probability of detection of the radio signals to > extraterrestrials (ETs) is one... This analysis is by Alexander Zaitsev, who is a proponent of actively sending transmissions to selected targets, not an option recommended by everybody. ---
**Author:** ![Henryunderborn](https://avatars.discourse-cdn.com/v4/letter/h/58f4c7/32.png) [@Henryunderborn](https://boards.straightdope.com/u/Henryunderborn)\ **Post date:** [October 31, 2014, 12:22am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/3 "2014-10-31T00:22:34Z")
by “non trivial” the way you said it, do you mean, we would have already made contact? Bringing the question, is there a willingness, to be responded to; or are you saying we could not have missed reception? ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 31, 2014, 12:27am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/4 "2014-10-31T00:27:28Z")
> [@eburacum45](#): > > Here’s an analysis of a few powerful transmissions we have already sent, showing that there is a non-trivial chance that we have already been detected. That is not what this paper says. It says simply that there has been 1 million times more illumination from radar astronomy transmissions than METI transmissions, therefore the probability of detection of radar signals is 1 million times higher than for METI transmissions. However, there is nothing in this paper that suggests what either probability actually is, or that the probability is “non-trivial.” I am not aware of the author’s other work but this unscientific sentence, combined with the smiley-face favicon, makes me wonder if this whole paper is tongue-in-cheek, despite its scientific underpinning: > [@Dr. Alexander L. Zaitsev](#): > > If the Aliens reached the level of a super-civilization, it might send a space fleet to the Earth to either destroy it or to convert us to slaves. ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [October 31, 2014, 1:39am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/5 "2014-10-31T01:39:29Z")
Just a wag… they would have to be using the same CB radio that we use. I.e. their electronics must in some way be compatible with ours, or they won’t hear us and we won’t hear them… ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [October 31, 2014, 2:11am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/6 "2014-10-31T02:11:15Z")
The moment there’s any biological contact, it won’t be us or the intelligent aliens who will be in charge. It’s be Earth’s microbes versus their microbes. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [October 31, 2014, 5:09am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/7 "2014-10-31T05:09:10Z")
Since we can detect planets already, and are on the verge of being able to detect habitable ones (and would do much better with bigger telescopes in space) I’d suspect that the aliens would already have it narrowed down. They’d have to be within 100 light years, of course. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [October 31, 2014, 8:26am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/8 "2014-10-31T08:26:42Z")
> [@CookingWithGas](#): > > That is not what this paper says. It says simply that there has been 1 million times more illumination from radar astronomy transmissions than METI transmissions, therefore the probability of detection of radar signals is 1 million times higher than for METI transmissions. However, there is nothing in this paper that suggests what either probability actually is, or that the probability is “non-trivial.” I am not aware of the author’s other work but this unscientific sentence, combined with the smiley-face favicon, makes me wonder if this whole paper is tongue-in-cheek, despite its scientific underpinning: Zaitzev’s idea is that we may as well send directed messages, since the power of these radar transmissions (and others, such as defence radar, which could possibly be detected tens of light years away) already exceed the power of METI transmissions by many orders of magnitude. This paper is one answer (among many) to his critics who say we should not actively send messages; in a very minor way I am one of those critics, having spoken to him on space forums. This does not take into account the fact that METI transmissions would be aimed specifically at certain target stars, while only a few of these radar transmissions have come anywhere near a reasonable candidate star. But an alien civilisation might have established detector stations on large numbers of stars, in which case we could easily have been detected (or may be detected in the future when these transmissions arrive). More on METI here > **[Active SETI](https://en.wikipedia.org/wiki/Active_SETI)** > > Active SETI (Active Search for Extra-Terrestrial Intelligence) is the attempt to send messages to intelligent extraterrestrial life. Active SETI messages are predominantly sent in the form of radio signals. Physical messages like that of the Pioneer plaque may also be considered an active SETI message. Active SETI is also known as METI (Messaging to Extra-Terrestrial Intelligence). > 'Active SETI' was a term as early as 2005, though some decades after the term SETI. The term METI was coined in 200... ---
**Author:** ![armstrongm](https://avatars.discourse-cdn.com/v4/letter/a/50afbb/32.png) [@armstrongm](https://boards.straightdope.com/u/armstrongm)\ **Post date:** [October 31, 2014, 8:34am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/9 "2014-10-31T08:34:07Z")
I do not mean to cause an argument here but this is assuming that there are aliens. I have one major problem with this assumption I thought you may find interesting. Research was done by people far more clever than me the findings were this. That gamma ray bursts would destroy life before it could get going in the early parts of the Universe. So his question was when did they become rare enough for life to get going? He did research that said if we say life has a better chance further from the centre of any galaxy as a gamma ray burst is less likely to do harm there as they are more spread out. Then the region for life is smaller than thought. Then doing simulations and analysis found that life can only be 5 billion years old. Complexity does proceed intelligence for life. This takes time and organisms must evolve. Life on earth is 4.6 billion years old that is very nearly as old as it could ever be. Therefore we may be the most intelligent species. ---
**Author:** ![armstrongm](https://avatars.discourse-cdn.com/v4/letter/a/50afbb/32.png) [@armstrongm](https://boards.straightdope.com/u/armstrongm)\ **Post date:** [October 31, 2014, 8:38am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/10 "2014-10-31T08:38:44Z")
However, if we assume there are aliens then it is most likely through the tracking of radio signals from earth. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [October 31, 2014, 11:55am UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/11 "2014-10-31T11:55:23Z")
Here’s an analysis of the gamma-ray burst data by Anders Sandberg. [http://aleph.se/andart2/tag/gamma-ray-burst/](http://aleph.se/andart2/tag/gamma-ray-burst/) His conclusion is that (even in the galactic centre) there are locations which are safe from gamma-ray bursts for hundred of millions of years. ---
**Author:** ![Henryunderborn](https://avatars.discourse-cdn.com/v4/letter/h/58f4c7/32.png) [@Henryunderborn](https://boards.straightdope.com/u/Henryunderborn)\ **Post date:** [October 31, 2014, 1:10pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/12 "2014-10-31T13:10:43Z")
> [@armstrongm](#): > > I do not mean to cause an argument here but this is assuming that there are aliens. I have one major problem with this assumption I thought you may find interesting. Research was done by people far more clever than me the findings were this. > > That gamma ray bursts would destroy life before it could get going in the early parts of the Universe. So his question was when did they become rare enough for life to get going? He did research that said if we say life has a better chance further from the centre of any galaxy as a gamma ray burst is less likely to do harm there as they are more spread out. Then the region for life is smaller than thought. Then doing simulations and analysis found that life can only be 5 billion years old. > > Complexity does proceed intelligence for life. This takes time and organisms must evolve. Life on earth is 4.6 billion years old that is very nearly as old as it could ever be. Therefore we may be the most intelligent species. wow. really makes you think. I ever just saw the pretty of the stars on a dark night. blanket above all we live to the day, or share in a night. To consider, for all the science fiction, that has enthused our minds, contrast to all our life obligations; we by creation itself, are the only beings to be considered. I have always been a stern atheist. I am organic to the thoughts and shared time. To some point, it will end for me. The notion of other life being out there was just, on the whim, sure why not. But now for all these years of civilized human inhabitance. Transcending the stone age and religion into the vast comprehension of life as we know it. -blink- it hasn’t even begun yet anywhere else. AND to that-- all the wild life we destroyed here on earth. -wow- are we worth it? did we do right by our selves, if the birth of one baby is the precious effort of life. What is it of the thousands of years collective of a retarded mass of people. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [October 31, 2014, 7:37pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/13 "2014-10-31T19:37:26Z")
> [@armstrongm](#): > > Complexity does proceed intelligence for life. This takes time and organisms must evolve. Life on earth is 4.6 billion years old that is very nearly as old as it could ever be. Therefore we may be the most intelligent species. This assumes a lot. First, it assumes that we evolved in the minimal amount of time possible. Given the number of mass extinctions, this seems unlikely. Second, it assumes that at most one intelligent species evolves within a safe zone mentioned in the linked blog. If not, even a one million year head start from another species - which is clearly in the noise of cosmic time frames - would make a massive difference in the status of the species. That’s one gripe I have with lots of sf. To have two species be able to fight in any kind of reasonable way, they have to be at nearly the same stage of development, advanced enough that they are magic, or old and static. None of these seem likely. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 31, 2014, 8:40pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/14 "2014-10-31T20:40:00Z")
> [@](#): > > Quoth **Lukeinva** : > > Just a wag… they would have to be using the same CB radio that we use. I.e. their electronics must in some way be compatible with ours, or they won’t hear us and we won’t hear them… They’re using the same laws of physics we are, so their radio waves will be the same as ours. They might choose to use different frequencies, but it’s not particularly hard to scan for all frequencies. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 31, 2014, 9:00pm UTC](https://boards.straightdope.com/t/how-would-aliens-locate-us/703055/15 "2014-10-31T21:00:44Z")
Wouldn’t they be looking for remote planets in the same way we are doing with a space telescope?