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poor boy said:
Hows about this one...

A mirror reflects all color and light, correct? Then why is the color of the mirror silver?

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Silver isn't really a color, since you can't make it with any of the primary colors. Silver or "metallic" describes the way that the light is reflected.

Reflection happens when materials absorb incoming photons, and immediately re-emit photons back out into the surroundings. The structure and general optical properties of the material determine how this is done. For instance, in a material that is a certain color, only certain wavelengths are efficiently re-emitted, while the rest of the incoming photons are converted to heat in the material.

In silvery/metallic or white materials, almost all incoming photon energy is re-emitted. The difference between white and metallic is the depth of interaction.

Most uniformly white substances are partially transluscent, i.e. they allow light to penetrate many hundreds of atoms (or more) down below the surface. This allows the photons to be absorbed and re-emitted many different times on its way into and then back out of the material, much like a pinball bounding around a pinball machine. This ultimately randomizes the paths of the exiting photons, and causes a loss (or random dispersion) of any information that the photons were carrying when they first arrived. This results in a uniform white light, without an semblance of reflected images. Optical properties of certain materials (ie not maintaining the original velocity (direction) of the photon during absorption/emission) amd surface properties (very rough surfaces) will enhance this dispersion effect.

Metallic surfaces, on the other hand, only allow penetration into the first few atomic layers of the surface, greatly reducing the randomization of information in the photons. This results in a clear image of the source of the photons in the surface, which if given a color based purely on the wavelengths of light reflected, would classify as white...but because it doesn't look like what we all normally consider to be the color white, we call it silver or metallic.

As a final note, mirrors dont reflect all light, just a large majority of visible light. This is why if you place two mirrors so that they are facing each other, the infinite series of images created seems to fade off into a green haze. The glass and metallic backing are absorbing a small portion of the photons each time they bounce off the mirror, and the glass absorbs less green light than other wavelengths, so the last few reflections are the last bit of green light that hasn't been absorbed yet.

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Chemical Addiction said:
Hey agmotes, what do you think it will take for us to reach other planets in the "goldilocks zone" and possibly find other life, or just to explore beyond our front door.

I believe it will take the death of this planet before we allocate the time/resources to figure out how traverse space. This idea first came to me when I saw a bumper sticker about strip mining. I thought "maybe strip mining can be a good thing" For the human race anyways not the millions of other lifeforms here.

We spend time/resources and brain power researching thimgs that don't really progress the race of man just distract them or makes them feel pretty. Once this planet is irredeemable we won't be studying new cosmetics, or how to use advertisement to sell product, we would focus on the survival of the species.

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I hear ya, and you're right, it may take something crazy like a mass die-off of a significant portion of the world population, the discovery of life elsewhere (especially intelligent life), or a partial collapse of a major portion of the world biome in order to shake people's heads out of their asses.

We also have to remember that, with the exception of solar energy (which is still not a viable solution), we only have access to finite energy sources (fossil, nuclear, and geothermal being the larest and easiest to harness in large quantities. If we piddle around wasting the large energy stores, and run out of them prior to development of solid space travel technology, then we will be stuck wasting time trying to develop a technology that is power hungry, has unique chemical and physical requirements, all on the scraps that are left over after we use up all of the rare metals and semiconductors on entertainment purposes.

And that doesn't even take into account the increasing problem of space garbage building up in orbit. If a major collision were to take place in orbit, it could spawn a runaway series of collisions that spread into other orbits, and forms a shell of small, high speed debris that would make launches into space impossible for at least a few hundred years. This is called Kessler Syndrome, and the more garbage that we leave in orbit, the greater the chances are of this occuring, setting us back centuries or even imprisoning us on a dying planet.

As far as getting to an exoplanet in a nearby solar system, there are two options; multi-generational/longterm (stasis) space travel at subluminal (slower than light) speed, or superluminal  (faster than light) speed travel. Both are currently out of our reach.

In my opinion, you have a much better chance of preserving humans, building robots that can raise humans once the ship arrives, or building a ship (or ships) that can house many generations of humans for centuries than we have of breaking the current laws of physics or producing exotic matter that would be required for superluminal travel.

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Chemical Addiction said:
Thanks for the link, they say the debris travel at up to 17.5k mph but does not give an average speed, I wonder how many are actually going that fast. I had no idea how fast they were moving, I thought they were just kind of floating in orbit slowly going around the planet as it spins. That make the problem much worse than I had envisioned it.

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Well you have to remember the international space station travels at 17,150 miles per hour (that's about 5 miles per second!) itself. So in some cases a net may work but in other cases when they are coming straight at ya it's their speed plus yours combined for 36650 mph.

https://www.google.com/search?q=how+fast+is+the+iss+traveling&ie=utf-8&oe=utf-8


Remember the earth itself moves around the sun at 67000 mph and spins at 460 meters per second--or roughly 1,000 miles per hour.


https://www.google.com/search?q=how+fast+is+the+iss+traveling&ie=utf-8&oe=utf-8#q=how+fast+is+the+earth+moving+around+the+sun


The fastest thing man made is NASA'S Juno Mission spacecraft will slingshot around Earth towards Jupiter, accelerating to 25 miles per second along the way and becoming the fastest man-made object in history. A .50-caliber bullet travels at about half a mile a second, by contrast -- nowhere near the blistering speed of Juno


To nearest star to us is 4.24 light years away and the fastest thing we have would take 54000 years to get there.


http://www.skyandtelescope.com/astronomy-resources/far-closest-star/


The closest planet other then earth that has water on it and is assumed to be the nearest planet that can support life is Kepler-186f and it's 500 light years away. That is traveling at 186000 miles a second for 500 years.

https://www.google.com/search?q=closest+planet+that+can+support+life&ie=utf-8&oe=utf-8

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agmotes165 said:
Space is a bitch

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drawde said:
What if we put big-ass rare earth magnets up there to collect shit into large easier to manage masses?
I guess the distances between things are just far too great. Unless there were someway to oscillate said magnets across trajectories.

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Teach death row inmates to fly giant shuttles equipped with huge electromagnets. Once they have collected a few tons of garbage you hit the auto pilot down here from earth and the death row inmate along with the garbage fly into the sun.


Sorry man I been dabbing hard today