Sun color related to atmospheric pressure?

[Moontanman]

If the Sun is redder at sunrise and sunset due to passing through more atmosphere would a planet with 10x the atmosphere of the earth but with the same composition make the sun appear redder?

[Ophiolite]

I stand ready to be corrected, but I think the majority of the reddening comes from the particulates in the atmosphere. This is why, for example, there were great sunsets worldwide after Krakatoa erupted and the Tunguska bolide struck. If that is the case then I would expect a redder sun, up to a point, but thereafter a redder and dimmer sun. Logical?

[Jdizz]

If the Sun is redder at sunrise and sunset due to passing through more atmosphere would a planet with 10x the atmosphere of the earth but with the same composition make the sun appear redder?

 

I've been reading papers that talk about the shifting of monochromatic laser light in a pressurized pipe to verify light losing energy to a medium.

 

Check section seven for more info on these experiments.

 

santilli-foundation.org/docs/Santilli-isoredshift.pdf

[Moontanman]

I've been reading papers that talk about the shifting of monochromatic laser light in a pressurized pipe to verify light losing energy to a medium.

 

Check section seven for more info on these experiments.

 

santilli-foundation.org/docs/Santilli-isoredshift.pdf

 

 

If I am reading this correctly I would expect in a 10 bar atmosphere the sky would still be blue but the disc of the sun would appear redder than the one we see on earth at zenith and the sun would appear more and more red as it left zenith and approached the horizon. Am i reading that correctly?

 

I stand ready to be corrected, but I think the majority of the reddening comes from the particulates in the atmosphere. This is why, for example, there were great sunsets worldwide after Krakatoa erupted and the Tunguska bolide struck. If that is the case then I would expect a redder sun, up to a point, but thereafter a redder and dimmer sun. Logical?

 

 

I would expect a denser atmosphere to contain a heavier load of particulates therefore it would make sense the sun would appear redder but the sky should still be blue or possibly blue/white. Someplace i read that the composition of the atmosphere is also important, an atmosphere containing high levels of methane would appear green instead of blue. I can't remember where I read that...

[swansont]

Rayleigh scattering is responsible for the blue sky and red sunrise/sunset, and is for particles much smaller than the wavelength; the scattering strongly depends on the wavelength. For larger particles it's Mie scattering, which is forward-biased. So it depends on the size of the particulates. Though I expect it's the smaller ones that stay airborne for a while and cause the coloring well after the event.

 

http://en.wikipedia.org/wiki/Rayleigh_scattering

http://en.wikipedia.org/wiki/Mie_scattering

[Moontanman]

Thanks swansonT, I looks like my hypothetical atmosphere would cause the sun, even at it's zenith to be redder or orangish but the sky would still be blue.

[John Cuthber]

If the air was rather less than 10 times denser, you would be able to see the back of your head due to refraction.

 

(light nearer the surface travels through slightly denser air and is held back so light tends to curve slightly downwards. With a denser atmosphere light would curve down far enough to hit the ground. Somewhere in between it would follow the curvature of the earth.)

 

Not sure what that does for a sunset.

[Moontanman]

If the air was rather less than 10 times denser, you would be able to see the back of your head due to refraction.

 

(light nearer the surface travels through slightly denser air and is held back so light tends to curve slightly downwards. With a denser atmosphere light would curve down far enough to hit the ground. Somewhere in between it would follow the curvature of the earth.)

 

Not sure what that does for a sunset.

 

 

Actually sunset is not what I was thinking of, The sun at noon is the question, I know that sunset would be redder, that would be true with any air pressure.

 

It's interesting that you could see the back of your head. i know that on venus you would see your self at the bottom of a bowl due to refraction but venus has 90 bar atmosphere, i wasn't aware that 10 bar would do the same thing. I want to get the apparent conditions correct from the point of view of some one on the surface of this hypothetical planet.

 

Originally i was thinking of a large moon around a massive gas giant. Avatar screwed the pooch on that idea but i am starting over with new parameters. My idea was a moon in the same situation as Jupiter's Io with a huge energy input from interactions with the gas giants immense magnetic fields and radiation belts.

 

The Moon is 25,000 kilometers in diameter 4 earth masses and density of 2924 kg squared surface gravity of 10.21 ms This should result in an extensive atmosphere in the way Titan has an extensive atmosphere.

 

I am stymied by the heat retention of that atmosphere I see no way to calculate what the greenhouse effect would be.

 

Here are some of the parameters.

 

 

Feature Sol Sol Ratio Comment

Type G2 G2

Mass (M0) 1.00 1.00 1.00 Solar mass M0 = 1.99E+30 kg

Distance from Earth (ly) 0.00 0.00 1.00E+00 Light year = 9.47E+15 m

Age on Main Sequence (Gyr) 10.00 10.00 1.00

Age (Gyr) 4.60 4.60 1.00

Radius (R0) 1.00 1.00 1.00 Solar radius R0 = 6.96E+08 m

Surface gravity (m/s²) 274.2 274.2 1.00

Escape Velocity (km/s) 618 618 1.00

Luminosity (L0) 1.00 1.00 1.00

Absolute magnitude Mv 4.7 4.7

Apparent magnitude mv -26.9 -26.9

Surface temperature (K) 5796 5796 1.00

Peak wavelength (micron) 0.50 0.50 1.00

Ecosphere inner radius (AU) 0.99 0.99 1.00

Ecosphere outer radius (AU) 1.38 1.38 1.00

Star formation

Luminosity (L0) 0.71 0.71 1.00 Solar luminosity L0=3.90E+26 W

Radius (R0) 0.92 0.92 1.00 Solar radius R0=6.96E+08 m

Absolute magnitude 5.1 5.1

Apparent magnitude -26.6 -26.6

Temperature (K) 5539 5539 1.00

Peak wavelength (micron) 0.52 0.52 1.00

Ecosphere inner radius (AU) 0.84 0.84 1.00

Ecosphere outer radius (AU) 1.16 1.16 1.00

Terran [unnamed]

Feature Earth The_Moon Earth The_Moon Earth/

Earth The_Moon/

The_Moon Comment

Formation

Rotation period (hr) 21.96 0.00 36.00 646.82 1.64 inf -ve is retrograde

Temperature range of orbit (°C) -38.6 to -43.2 -13.9 to -19.0 -137.7 to -140.4 -123.4 to -126.4

General

Type Terrestrial Terrestrial Terrestrial Terrestrial

Mean orbital distance (106 km) 149.60 0.38 448.80 0.38 3.00 1.00 Astronomical Unit=1.50E+08 km

Eccentricity 0.020 0.060 0.020 0.060 1.00 1.00

Axial tilt (°) 23.4 0.0 23.4 0.0 1.00 -nan

Year (Earth days) 365.2 27.3 1897.8 13.6 5.20 0.50

Star system escape velocity (km/s) 42.12 42.12 24.32 24.32 0.58 0.58 From planetary orbit

Angular diameter of star (°) 0.53 0.53 0.18 0.18 0.33 0.33

Angular diameter of moon (°) 0.52 1.91 0.52 1.91 1.00 1.96

Solar day (hr) 24.00 11110.29 36.03 618.51 1.50 0.06

Radius (km) 6370 1743 12500 1743 1.96 1.00

1/Ellipticity 294.1 300.0 294.1 300.0 1.00 1.00

Lithosphere

Mass (Earth Masses) 1.00 0.01 0.01 0.01 4.00 1.00 Earth Mass=5.98E+24 kg

Maximum Mass (Earth Masses) 3211.7 -nan 3600.5 -nan 1.12 -nan

Density (kg/m³) 5523 2696 2924 2696 0.53 1.00 Albedo 0.33 0.00 0.33 0.00 1.00 -nan

Inertia Factor 0.34 -nan 0.38 -nan 1.14 -nan

Typical surface gravity (m/s²) 9.83 1.31 10.21 1.31 1.04 1.00

Equatorial surface gravity (m/s²) 9.81 1.32 10.20 1.32 1.04 1.00

Polar surface gravity (m/s²) 9.86 1.31 10.24 1.31 1.04 1.00

Escape velocity (km/s) 11.19 2.14 15.98 2.14 1.43 1.00

Rotation period (hr) 23.9 696.0 36.0 696.0 1.50 1.00 -ve is retrograde

Shortest possible period (hr) 2.63 3.77 3.62 3.77 1.37 0.70 Any faster and planet breaks up

Geosynchronous orbit (km) 35724 84021 75224 84021 2.11 1.00 above the surface

Plate tectonics end (Gyr) 5.10 0.19 13.65 0.19 2.68 1.00 After this carbon is buried in the oceans (terrestrial planets only).

Maximum mountain height (m) 16570 124062 15952 124062 0.96 1.00 Mountains in practice smaller, terrestrial planets only

Horizon distance (m) 3091 1617 4330 1617 1.40 1.00 at eye level, 1.5 m

Atmosphere and Ocean

Atmospheric pressure (mbar) 1013 0 10130 0 10.00 -nan

Minimum RMM for atmosphere (g) 2.54 69.37 1.24 69.37 0.49 1.00 Gasses lighter than this escape over geological time (Hydrogen = 1)

Atmospheric RMM (g) 33.84 0.00 33.79 0.00 1.00 -nan

Specific heat capacity (cp) (J mol-1 K-1) 27.6 0.0 27.4 0.0 1.0 -nan

Speed of sound at surface (m/s) 318.8 0.0 253.6 0.0 0.80 -nan

Temperature range of orbit (°C) -17.7 to 3.6 -125.7 to -113.4 -125.7 to -22.8 -110.1 to 3.6 Without greenhouse effect

Greenhouse effect (°C) 36.00 0.00 36.00 0.00 1.00 -nan

Typical surface temperature (°C) 15.8 6.4 -91.1 -111.8 With greenhouse effect

Scale height (m) 7222 0 4386 0 0.61 -nan

Dry adiabatic lapse rate (°C/km) 12.07 0.00 12.60 0.00 1.04 -nan

f (Coriolis effect) at 45°N * 1E4 1.03 0.04 0.69 0.04 0.66 1.00

Mid-ocean tide height (m) 0.46 16.52 1.11 65.73 2.43 3.98

 

Commentary

 

Terran system:

For Earth:

Hydrogen will escape from proposed atmosphere

For The_Moon:

 

Plate tectonics may have ceased.

Proposed rotation period too short, as it would have been spinning too fast when formed

The_Moon will give total eclipse of Sol on Earth

Earth will give total eclipse of Sol on The_Moon

[unnamed] system:

For Earth:

Hydrogen will escape from proposed atmosphere

Gas fractions in body's atmosphere don't add up, must be nearer 100 %

For The_Moon:

 

Plate tectonics may have ceased.

 

That was difficult to make sense of but I don't know how to link to the finished calculation.

 

That was difficult to make sense of but I don't know how to link to the finished calculation.