Electromagnetic radiation - Revision history

RichardWSmith: Fixed typo

2024-10-11T05:18:15Z

Fixed typo

RichardWSmith: /* Danger of ultraviolet light */ Made things clearer, added links.

2024-09-26T00:26:55Z

Danger of ultraviolet light: Made things clearer, added links.

RichardWSmith: Fixed error. Thermal IR is 10 nanometers not 10 cm.

2024-08-28T10:33:01Z

Fixed error. Thermal IR is 10 nanometers not 10 cm.

RichardWSmith: Fixed 2 typos.

2024-08-14T19:49:39Z

Fixed 2 typos.

RichardWSmith at 04:52, 4 July 2024

2024-07-04T04:52:30Z

RichardWSmith: Spelling error

2024-07-04T04:45:51Z

Spelling error

RichardWSmith at 04:44, 4 July 2024

2024-07-04T04:44:35Z

RichardWSmith: Talking about dangers of UV light.

2024-07-04T04:44:14Z

Talking about dangers of UV light.

RichardWSmith: Formatting

2024-07-04T04:32:40Z

Formatting

RichardWSmith: formatting

2024-07-04T04:30:52Z

formatting

@@ Line 7: / Line 7: @@
 * Infrared light. ...... 700 nanometers to 1mm.  Around 750 to 1,000 nanometers these waves are thermal IR.
 * Visible light. ....... 400 nanometers for blue light, to 700 nm for red light.
-* Ultraviolet light..... 700 nm to 10 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
+* Ultraviolet light..... 400 nm to 10 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
 * X-rays. ................ 1 Angstrom to 0.1 Angstrom.  These rays can damage deep tissue.  (Note 1 Angstrom = 10 nm.)
 * Gamma-rays. ...... 0.1 Angstrom and shorter.  These can damage deep tissue and can penetrate deep thru many materials.

@@ Line 21: / Line 21: @@
 ==Danger of ultraviolet light==
-Ultraviolet light (UV light) is light with enough energy to damage cells.  Life has adapted to somewhat resist this, but on Earth, the largest protection is by the free oxygen in our atmosphere.  UV light will break apart O2, which then combines into O3 or ozone.  Ozone STRONGLY absorbed UV light, so little reaches the surface of Earth.  Thus, life is largely protected.
+Ultraviolet light (UV light) is light with enough energy to damage cells.  Life has adapted to somewhat resist this, but on Earth, the largest protection is by the free [[Oxygen]] in our atmosphere.  UV light will break apart O2, which then combines into O3 or [[Ozone]].  Ozone STRONGLY absorbed UV light, so little reaches the surface of Earth.  Thus, life is largely protected by the ozone layer in the upper atmosphere.
 Mars has only trace amounts of O2 and O3 in its atmosphere, and about 99% of the UV light reaches the Martian surface.  This has sterilized the Martian surface (tho life may exist underground).  UV light can cause sunburn in humans, cause cataracts in eyes, and make plastics brittle.  Thus Martian space suits must be constructed with this danger in mind.

@@ Line 5: / Line 5: @@
 * Radio waves. ....... 10 cm to 1 km or longer.
 * Micro waves. ....... 1 mm to 10 cm.
-* Infrared light. ...... 700 nano-meters to 1mm.  Around 1 cm these waves are thermal IR.
+* Infrared light. ...... 700 nanometers to 1mm.  Around 750 to 1,000 nanometers these waves are thermal IR.
-* Visible light. ....... 400 nano-meters for blue light, to 700 nm for red light.
+* Visible light. ....... 400 nanometers for blue light, to 700 nm for red light.
 * Ultraviolet light..... 700 nm to 10 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
 * X-rays. ................ 1 Angstrom to 0.1 Angstrom.  These rays can damage deep tissue.  (Note 1 Angstrom = 10 nm.)

@@ Line 7: / Line 7: @@
 * Infrared light. ...... 700 nano-meters to 1mm.  Around 1 cm these waves are thermal IR.
 * Visible light. ....... 400 nano-meters for blue light, to 700 nm for red light.
-* Ultraviolet light..... 5 nm to 700 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
+* Ultraviolet light..... 700 nm to 10 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
-* X-rays. ................ 1 Angstrom to 5 nm.  These rays can damage deep tissue.
+* X-rays. ................ 1 Angstrom to 0.1 Angstrom.  These rays can damage deep tissue.  (Note 1 Angstrom = 10 nm.)
-* Gamma-rays. ...... 1 Angstrom and shorter.  These can damage deep tissue and can penetrate deep thru many materials.
+* Gamma-rays. ...... 0.1 Angstrom and shorter.  These can damage deep tissue and can penetrate deep thru many materials.
-The lowest energy waves are radio waves.  They act like waves.  As the energy increases, the wave length shortens, and the photons act more and more like powerful particles that can damage tissue.
+The lowest energy waves are radio waves.  They act like waves.  As the energy increases, the wave length shortens, and the photons act more and more like powerful particles that can damage tissue and penetrate deep thru materials.
 ==Light levels on Mars==

@@ Line 1: / Line 1: @@
 Electromagnetic radiation are composed of photons, linked waves of electric and magnetic fields.  These include, radio waves, heat waves (infrared), visible light, x-rays, etc.
-A list of the electromagnetic spectrum (note these boundaries are approximate, they blend into each other:
+A list of the electromagnetic spectrum (note that these boundaries are approximate, they blend into each other):
 * Radio waves. ....... 10 cm to 1 km or longer.

@@ Line 23: / Line 23: @@
 Ultraviolet light (UV light) is light with enough energy to damage cells.  Life has adapted to somewhat resist this, but on Earth, the largest protection is by the free oxygen in our atmosphere.  UV light will break apart O2, which then combines into O3 or ozone.  Ozone STRONGLY absorbed UV light, so little reaches the surface of Earth.  Thus, life is largely protected.
-Mars has only trace amounts of O2 and O3 in its atmosphere, and about 99% of the UV light reaches the Martian surface.  This has sterilized the Martian surface (tho life may exist underground).  UV light can cause sunburn in humans, cause cataracts in eyes, and make plastics brittle.  Thus Martian space suits much be constructed with this danger in mind.
+Mars has only trace amounts of O2 and O3 in its atmosphere, and about 99% of the UV light reaches the Martian surface.  This has sterilized the Martian surface (tho life may exist underground).  UV light can cause sunburn in humans, cause cataracts in eyes, and make plastics brittle.  Thus Martian space suits must be constructed with this danger in mind.
 UV light is absorbed by glass, so thick window panes on Mars will block most of the light going thru windows.  Windows could be constructed with materials which more strongly absorb UV light, and this should be considered when constructing Martian glass.
 However, Mars is so far away from the sun, that it only gets 43% of the UV light that Earth gets, so the problems of UV are mitigated by about half.

@@ Line 5: / Line 5: @@
 * Radio waves. ....... 10 cm to 1 km or longer.
 * Micro waves. ....... 1 mm to 10 cm.
-* Infrared light. .... 700 nano-meters to 1mm.  Around 1 cm these waves are thermal IR.
+* Infrared light. ...... 700 nano-meters to 1mm.  Around 1 cm these waves are thermal IR.
-* Visible light. ..... 400 nano-meters for blue light, to 700 nm for red light.
+* Visible light. ....... 400 nano-meters for blue light, to 700 nm for red light.
-* Ultraviolet light... 5 nm to 700 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
+* Ultraviolet light..... 5 nm to 700 nm.  UV light can damage surface tissue, and has sterilized the surface of Mars.
-* X-rays. ............ 1 Angstrom to 5 nm.  These rays can damage deep tissue.
+* X-rays. ............. 1 Angstrom to 5 nm.  These rays can damage deep tissue.
-* Gamma-rays. ........ 1 Angstrom and shorter.  These can damage deep tissue and can penetrate deep thru many materials.
+* Gamma-rays. ...... 1 Angstrom and shorter.  These can damage deep tissue and can penetrate deep thru many materials.
@@ Line 15: / Line 15: @@
 ==Light levels on Mars==
-Mars gets a little less than half the light from the Sun, as Earth.  (Mars is 1.524 AU from the sun. Solar Flux = 1 / (1.524 * 1.524) = 0.4306 or 43% of the light from the sun as Earth.)
+Mars gets a little less than half the light from the Sun, as Earth.  (Mars is 1.524 AU from the sun. Solar Flux at Mars = 1 / (1.524 * 1.524) = 0.4306 or 43% of the light from the sun as Earth.)
 This is enough to grow crops, and our eyes (which adapt wonderfully to varying light levels) won't perceive Mars as dim.

← Older revision		Revision as of 04:30, 4 July 2024
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	Electromagnetic radiation are composed of photons, linked waves of electric and magnetic fields. These include, radio waves, heat waves (infrared), visible light, x-rays, etc.		Electromagnetic radiation are composed of photons, linked waves of electric and magnetic fields. These include, radio waves, heat waves (infrared), visible light, x-rays, etc.
		+
	A list of the electromagnetic spectrum (note these boundaries are approximate, they blend into each other:		A list of the electromagnetic spectrum (note these boundaries are approximate, they blend into each other: