[HN Gopher] Which stars can see Earth as a transiting exoplanet? ___________________________________________________________________ Which stars can see Earth as a transiting exoplanet? Author : colinprince Score : 23 points Date : 2021-10-27 21:27 UTC (1 hours ago) (HTM) web link (academic.oup.com) (TXT) w3m dump (academic.oup.com) | pavlov wrote: | Would Sol look obviously inhabited on the radio spectrum? | | This is a common sci-fi trope ("Contact"), but I have no idea | whether it's actually true that our radio emissions would be | trivially detectable tens of light years away. | wyldfire wrote: | What if they had an array similar to the one used in "Contact" | to receive the response? | fermuch wrote: | Our radio waves have traveled for about 200 light years. | Proxima centauri, our closest star, is located at 4246 Light | years from us. | | Very, very unlikely that someone can hear us, even if they | tried. Space is huge. | gpderetta wrote: | I think your Alpha Centauri distance is off by 3 orders of | magnitude :) | | Edit: I think there are thousands of stars within 200ly of | Earth. | ajakate wrote: | Proxima centauri is actually ~4 light years away. Space is | really big, but there are a handful of stars in relative | vicinity of us (under 250 ly) | | https://en.wikipedia.org/wiki/Proxima_Centauri | | http://www.icc.dur.ac.uk/~tt/Lectures/Galaxies/LocalGroup/Ba. | .. | ortusdux wrote: | The inverse square law really dilutes out most signals - | https://www.quora.com/How-far-do-radio-signals-travel-into-s... | ThomasWinwood wrote: | As I understand it the amount of time we were tossing radio | into space was quite brief, and more modern radio traffic is | directed at the ground (since after all if you're leaking | signals into space you're wasting power). | | One of the papers cited in the OP argues that a good indicator | that there's _something_ interesting about a planet is the | combination of molecular oxygen and methane in its atmosphere - | the former is a strong oxidiser, while the latter is a reducing | gas, so there 's some dynamic system producing free methane in | the atmosphere. | f00zz wrote: | Crazy to think that we have catalogued thousands of exoplanets, | even though we basically can only detect them if they pass in | front of their stars along our line of sight. Space is big, but | also pretty crowded. | lmilcin wrote: | The best way to search for extraterrestial life I heard is a | swarm of drones placed in such a distance from the Sun that it | acts as a gravitational lens to greatly magnify any planet around | any star in even quite large distance from our system. | | I think realistic resolutions in kilometers per pixel are | theoretically possible even with existing technology (assuming we | can build the swarm and position it in the right place quite far | from the Sun and then maintain communication). | | The disadvantage is you need many separate fleets of drones to | map more than one target. | shoto_io wrote: | Yes. This video explains it rather nicely: | https://www.youtube.com/watch?v=NQFqDKRAROI | northwest_nfts wrote: | Yeah, that sounds similar to the idea of the Terrascope. I | think the positioning of drones for the sun might be so wide to | be infeasible for the next century. (Like, the drones would | have to be in the Kuiper belt) | | I haven't watched this YT video recently, but I think he also | touches on a Sol-scope and a Jupiter-scope | https://www.youtube.com/watch?v=jgOTZe07eHA | [deleted] ___________________________________________________________________ (page generated 2021-10-27 23:00 UTC)