Walter Bislins has created a very useful tool for visualizing what things should look like from certain positions, and with certain camera settings, on the Globe Earth, or on a hypothetical Flat Earth.
The Simulator includes recreations of classic and modern experiments and observations including the Bedford Level, the Pontchartrain Power Lines and Causeway, and the Chicago Skyline. You can stop the simulation at any point, and examine the scene and the settings used. Here's a (non-interactive) animation of the Bedford Level experiment.
I'd encourage anyone interested in the topic to play around with the various settings and watch all five demos.
On the night of April 25, 2013 at about 09:22 PM (local time), a Bombardier DHC 8 airplane operated by the U.S. Customs & Border Protection equipped with an Infrared camera, captured and followed a very peculiar flying object which yielded a fluctuating infrared signature over Rafael Hernández airport, Aguadilla (Puerto Rico). The object at times seemed to disappear (which was interpreted by some ufologists as “splashing into the ocean”) and also split into two pieces (1).
When I first saw the light it did not seem to moving I had no idea what it was. Venus maybe? Then I saw it actually was moving, so I thought it might be the International Space Stations, which had made a couple of good passes over here in the last two days. I tried to take some photos, and got some blurs like the above. I switched to video and what I saw on the view screen was a strange set of three flowering lights. When I put it on the computer though, it looked like this:
It's a plane of course, and I realised that as it approached me and flew overhead. Lufthansa 459, from San Francisco to Munich. An A340, climbing through 20,000 feet. My first photo was just a pretty piece of motion blur from the camera moving. The...
A classic experiment to demonstrate the curvature of a body of water is to place markers (like flags) a fixed distance above the water in a straight line, and then view them along that line in a telescope. If the water surface is flat then the markers will appear also in a straight line. If the surface of the water is curved (as it is here on Earth) then the markers in the middle will appear higher than the markers at the ends. Here's a highly exaggerated diagram of the effect by Alfred Russel Wallace in 1870:
This is a difficult experiment to do as you need a few miles for the curvature to be apparent. You also need the markers to be quite high above the...
A misleading headline is making people think that a physical object has been teleported from the ground into space, leading to all kinds of excitement and speculation about Star Trek style teleporters.
In fact nothing like that has happened at all, if you actually listen to the BBC piece, you'll find that what has been transmitted is just information. Nothing physical has moved from the ground into space.
The above image appears to show three different metal rods. The left rod is short and straight. The middle rod seems longer and angles sharply to the right. The right rod appears slightly curved, and has a longer segment going off the edge of the photo.
Actually the rods look like this:
Despite the left rod looking like it's just a few inches, it's actually five feet long. And even though the right rod looks like it's bent very close to the end it's actually bent in the middle, as is the center rod.
I set this up to illustrate some of the problems in visualizing both contrails and the paths of planes that don't leave contrails, especially those that are far away, and so at a shallow angle to the viewer.