July 19th 2009 - From Moon to Earth
Posted: Sun Jul 19, 2009 10:54 am
I couldn't understand the article clearly...
confusing...
confusing...
APOD and General Astronomy Discussion Forum
https://asterisk.apod.com/
Maybe too many parts ...Vivian wrote:I couldn't understand the article clearly...
confusing...
Very impressive, but would you fly in this crate with its foil-thin walls?orin stepanek wrote:I think of it as the Model T of space travel.
apodman wrote:Very impressive, but would you fly in this crate with its foil-thin walls?orin stepanek wrote:I think of it as the Model T of space travel.
http://en.wikipedia.org/wiki/Tin_foil_hat wrote:
<<A tin foil hat is a piece of headgear made from one or more sheets of aluminium foil or similar material. Alternatively it may be a conventional hat lined with foil. Some people wear the hats in the belief that they act to shield the brain from such influences as electromagnetic fields, or against mind control and/or mind reading.
The concept of wearing a tin foil hat for protection from such threats has become a popular stereotype and term of derision; the phrase serves as a byword for paranoia and is associated with conspiracy theorists. The reasons for their use include the supposed prevention of perceived harassment from governments, spies or paranormal beings. These draw on the stereotypical images of mind control operating by ESP or technological means, like microwave radiation. The effectiveness of tin foil hats is disputable, however the belief in their necessity is popularly associated with paranoia or mental illness.
_________ Scientific basis
The notion that a tin foil hat can significantly reduce the intensity of incident radio frequency radiation on the wearer's brain has some scientific validity, as the effect of strong radio waves has been documented for quite some time. A well constructed tin foil enclosure would approximate a Faraday cage, reducing the amount of (typically harmless) radiofrequency electromagnetic radiation inside. A common high school physics demonstration involves placing an AM radio on tin foil, and then covering the radio with a metal bucket. This leads to a noticeable reduction in signal strength. The efficiency of such an enclosure in blocking such radiation depends on the thickness of the tin foil, as dictated by the skin depth, the distance the radiation can propagate in a particular non-ideal conductor. For half-millimeter-thick tin foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although it should be noted that tin foil is not sold in this thickness, and numerous layers of tin foil would be required to sustain this effect.
The effectiveness of the tin foil hat as electromagnetic shielding for stopping radio waves is greatly reduced by the fact that it is not a complete enclosure. Placing an AM radio under a metal bucket without a conductive layer underneath demonstrates the relative ineffectiveness of such a setup. Indeed, because the effect of an ungrounded Faraday cage is to partially reflect the incident radiation, a radio wave that is incident on the inner surface of the hat (i.e., coming from underneath the hat-wearer) would be reflected and partially 'focused' towards the user's brain. While tin foil hats may have originated in some understanding of the Faraday cage effect, the use of such a hat to attenuate radio waves belongs properly to the realm of pseudoscience.
A study by graduate students at MIT...
determined that a tin foil hat could either amplify or attenuate incoming radiation depending on frequency; the effect was observed to be roughly independent of the relative placement of the wearer and radiation source. At GHz wavelengths, the skin depth is less than the thickness of even the thinnest foil.
Tin foil hats are seen by some as a protective measure against the effects of electromagnetic radiation (EMR). Despite some allegations that EMR exposure has negative health consequences, at this time, no link has been verifiably proven between the radio-frequency EMR that tin foil hats are meant to protect against and subsequent ill health.>>
Talk about your mystery science.neufer wrote:http://en.wikipedia.org/wiki/Tin_foil_hat wrote:tin ... is ... made from ... aluminium
I still say "steam shovel" ... don't you ?apodman wrote:Talk about your mystery science.neufer wrote:http://en.wikipedia.org/wiki/Tin_foil_hat wrote:tin ... is ... made from ... aluminium
And I still dial the phone and watch the tube. But I'm not the poster boy for modern living.neufer wrote:I still say "steam shovel" ... don't you?
You are delusional. Put your foil hat back on and leave us alone.RonDavis wrote:The Sun is shining onto Earth from above, but onto the Moon from the left. Obviously, this picture is a clumsy fake. I have seen other pictures from the Apollo missions with a similar problem. Maybe that's why some people say the Moon landings never happened.
RonDavis wrote:The Sun is shining onto Earth from above, but onto the Moon from the left. Obviously, this picture is a clumsy fake. I have seen other pictures from the Apollo missions with a similar problem. Maybe that's why some people say the Moon landings never happened.
Of course it is. Anyone who would mistake the window edge for the terminator and conclude the sunlight on the moon is coming from the left is missing several obvious clues:mark swain wrote:The shadow on the right is the command mod window ledge.
Apollo Maniacs wrote:* The cabin has five windows, made of 0.25-inch (6.35mm) double-paned tempered glass on the inside, and 0.7-inch (1.778cm) amorphous-fused silicon on the outside. UV-ray blocking coating is applied in these outer surfaces, and non-reflective coating to the inside.
Like this : Apollo 11 landing site.apodman wrote:- The terminator would not be smooth; it would cross peaks and valleys,
leaving irregular shadows as it crossed surface features.
I have a science experiment for you. Wait till after dark, turn off all the lights in your room except for your computer screen, close your left eye, and use your right hand to occlude the right half of your right eye and observe the blurry transition between your hand and your computer monitor. Your hand should be touching your cheek and your eyebrow. And there you have it, you've managed to recreate one of the primary methods NASA used to make it look like they faked the moon landings! Amazing!RonDavis wrote:The Sun is shining onto Earth from above, but onto the Moon from the left. Obviously, this picture is a clumsy fake. I have seen other pictures from the Apollo missions with a similar problem. Maybe that's why some people say the Moon landings never happened.
Run that past me again?geckzilla wrote:And there you have it, you've managed to recreate one of the primary methods NASA used to make it look like they faked the moon landings! Amazing!
Sarcasm, satire, sardonic wit. If you don't have it when you move to NYC, you acquire it soon afterward. Some use or to indicate their intent, but it's not really dry humor if you do. Truly, if you want to be clumsy about it as Ron suggests, you should poke yourself in the eye when you attempt to create the fake shadow. If you want to make a clumsy shadow rabbit on the wall, you can poke yourself in both eyes. If Ron's eyes are green it is more likely with envy than from poking, as going to the moon and back (so far accomplished only by you-know-who) was so far the coolest thing done in the history of the human race.mark swain wrote:Run that past me again?