5. Go on any weather wobsite. It'll tell you the day's visibility. It's usually about 3 miles on a clear day. And oh, look! according to
Nice.
6. You can't, unless you're in a U2 spy plane. The accepted height at which you can see curvature is 60000-90000 feet, which is higher than planes go.
5. First of all visibility doesn't increase with height. If the general visibility is 3 miles, it will still be three miles from the height of a tree, or a 10 metre cliff. So weather visibility is not relevant to point 5. Also, weahter visibility doesn't explain how objects at a distance appear to arise out of the ground as you climb higher.
Secondly, the weather reports aren't saying there is zero visibility of anything after 3 miles. This is obvious. You just have to look at my photos of ships
http://www.flickr.com/photos/pitdroidtech/sets/72157627536447220/, which were taken on a clear day, and the the closest ships was 9km, the furthest about 20-25km, and the distant mountains of Moreton Island were about 30km. These were all visible to the naked eye, and identifiable.
Visibility is a measure of the horizontal opacity of the atmosphere at the point of observation and is expressed in terms of the horizontal distance at which a person should be able to see and identify: in the daytime, a prominent dark object against the sky at the horizon; at night, a known, preferably unfocused, moderately intense light source.
http://www.weather.gov/forecasts/wfo...isibility.htmlObviously a prominent dark object being something small enough but still identifiable at 7 miles (distance to the horizon) in the best of conditions. Any conditions that make the object unidenfiable bring the visibility down to something within the 7 mile radius. So a sailboat on the horizon, identifiable as a sailboat, would indicate a visibility of 7miles. If the same sailboat appears as an unidentifiable blob at the same distance, then visibility is less than 7miles. Various means are used to measure visibility, including laser and smoke detectors and other methods,a s well as estimation.
The maximum visibility on a clear day is 11 kilometres (7 miles), after which a flat ground horizon will fall away to a point that surface conditions cannot be observed.
http://www.theweathernetwork.com/index.php?product=glossary&placecode=&pagecontent=visibilityEven on a clear day there can be reduced visibility. ON a cool calm day, with low humidity, visibility should be at it's greatest. Anything less than those conditions would reduce visibility.
6. Wrong but also right, sort of There is nothing particularly magic about the U2's ceiling. It does however have considerable range advantage compared to interceptor aircraft such as the Mig25RB.
SR-71, 85,000
Mig25RB: 80,000 plus
U2: 70,000 plus
F15: 65,000
Concorde: 60,000
747-400, 45,000
So the Concorde is in that esteemed club. And U2 pilots have reported seeing curvature at 65,000 feet so 60,000 feet isn't out of the question. However what I think you are getting mixed up with is the general cruising altitude of airliners such as the 747, which is about 35,000 feet. Curvature is not visible at this height. So point six as reported on
http://www.smarterthanthat.com/astronomy/top-10-ways-to-know-the-earth-is-not-flat/ is wrong for normal airliners, but true for Concorde and military spy and interceptor aircraft.
However, sciencemuseum.org.uk need a good slap around the head. The picture they show on this link is most certainly not taken from a Concorde.
http://www.sciencemuseum.org.uk/antenna/concorde/122.aspThese pictures below however are from the Concorde. The blackness of space is visible, and curvature is evident in the photos if measure carefully with a ruler, however this could be due to lens curvature.
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_19990811_pg02.html
