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Longest Lines of Sight on Earth

beyondhorizons.eu

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Re: Longest Lines of Sight on Earth

#101

Post by tromp »

davidmanescu wrote: post #93
liuhenry wrote: post #85

Earlier quoted context omitted.

The answer to the first interpretation is considerably less than twice the height of the cat, and I think it's an interesting result as well: Assuming a 0.3 meter high cat, you only need ~0.12mm of extra rope (about the width of two sheets of paper) to be able to pull it up at a point and let the cat through.

Follow-up question - after extending the rope by 0.12mm and pulling it up to allow the cat to pass under it, how far away are each of the two points where the rope lifts off the ground?

As the article explains, these points are about sqrt(2Rh) = sqrt(2 x 6400km x 0.3m) = sqrt(3840000m^2) ~ 1.96km away from the cat.

Re: Longest Lines of Sight on Earth

#103

Post by davidmanescu »

tromp wrote: post #101
davidmanescu wrote: post #93

Earlier quoted context omitted.

Follow-up question - after extending the rope by 0.12mm and pulling it up to allow the cat to pass under it, how far away are each of the two points where the rope lifts off the ground?

As the article explains, these points are about sqrt(2Rh) = sqrt(2 x 6400km x 0.3m) = sqrt(3840000m^2) ~ 1.96km away from the cat.

Did a back of the envelope trigonometry calculation as an approximation, seems to check out :)

Re: Longest Lines of Sight on Earth

#105

Post by lmm »

tzs wrote: post #24
kazagistar wrote: post #19

Earlier quoted context omitted.

A mountain might be past the "natural" horizon but emerge from beyond it. Thus, two mountains at the right distance and line of sight could easily have a longer horizion distance.

And this is indeed the case for the ones at the top of the list. The longest possible distance to horizon is a little over 330 km, but almost 40 of the items on the list have longer line of site. In fact, it looks like every item on the list is between two points that are each farther away than the other's horizon. That raises the question of among all places on Earth where the longest line of sight is to the horizon…

My guess would be Aconcagua - it's the second-most-prominent mountain in the world (after Everest), and it's close to the ocean so should have line of sight to the horizon, and the Andes are pretty much a straight line in that area (and there are no other major mountain ranges nearby), so it seems likely there wouldn't be any distant peaks that weren't hidden by closer peaks.

Re: Longest Lines of Sight on Earth

#106

Post by 4ad »

rmc wrote: post #88
js8 wrote: post #87

OT: Is there an application that can generate panoramic view from some point of Earth based on map and altitude data (e.g. OpenStreetMaps)?

FYI OSM doesn't (really) store elevation data. Individual mountain peaks are often mapped, and tagged with the elevation. But OSM doesn't store land contours like that. There are some free, open, datasources for that, like SRTM[1], ASTER[2] (and maybe OpenDEM[3], but I don't know what that's like) [1] https://wiki.openstreetmap.org/wiki/SRTM [2] https://wiki.openstreetmap.org/wiki/ASTER [3] http://www.opendem.info/

So how are these contour lines being generated?

My hike of a few months ago:

https://www.gaiagps.com/datasummary/route/67dcc2001bea9e9e39...

Also, if OSM doesn't store elevation data, then why do you need a GPS tracker with a barometric sensor in order to map for OSM?

Re: Longest Lines of Sight on Earth

#109

Post by mauvehaus »

tomxor wrote: post #108

And it's only from 5.971 m high... why people use decimals to indicate 3 orders of magnitude I will never understand... either that or they got the wrong SI unit.

Possibly because they're not (natively?) English-speaking Europeans: https://en.wikipedia.org/wiki/Decimal_mark#Digit_grouping

Re: Longest Lines of Sight on Earth

#110

Post by dwightgunning »

burkaman wrote: post #34
kbenson wrote: post #32

Mt. McKinley (6.194 m.) What country uses '.' as the thousands separator but speaks English? Or is this someone mixing their native language thousands separator with English? Or is there some weird interaction between country and language that makes this the preferred, or at minimum an acceptable standard form? I'm actually hoping it's one of the latter options, that would be something new to me.

.eu suggests this website was not created by native English speakers.

Since when does the TLD imply the native language of the website creator?

Also the .eu TLD, which is a country-TLD for the European Union, consider that the UK (still in the EU), along with Ireland and Malta have English as an official language [1].

1. http://www.nationsonline.org/oneworld/european_languages.htm

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