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Kerbin blueshift at 75km/s?


Agent86

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Its quite cool but I cant reproduce it. Though I do see some weird atmospheric stuff when approaching at these speeds.

As folks are saying, its a renderer artifact I think. Whilst you are travelling very quickly, it's not enough to visibly blue-shift a planet.

edit: your second attempt is twice as fast, but I still reckon its a graphical thing. lightspeed is 30,000 kms right? (3,000,000 ms approx)

Anyone know what fraction of this you would need relative to something to actually visibly shift it? Im betting it's a good chunk

Edited by celem
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Are you sure it's blueshift? Don't you have to be going quite a bit faster for blueshift to occur? ;)

If you want to get technical, blueshift occurs at walking speeds. Just not very much. There would be a blueshift effect but it is so small it could not be noticed until you get closer to lightspeed.

So, to agree, no it is not blueshift as that needs faster speeds to be noticable but to disagree blueshift occurs whenever you move.

Not sure what I am saying, I`m bored at work.

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(Note: This is written by a 15 year old with a partial and ongoing education in GCSE physics. This is all assumption work, take it with a pinch of salt please :) )

(Note 2: I'm excluding the effect of the atmosphere on light leaving Kerbin.)

(Note on note 2: The effect of the atmosphere doesn't matter as long as you're outside of it. I think.)

Assuming we're trying to blue-shift green to be visibly blue...

Green has a frequency of ~550Thz, Blue has a frequency of 630Thz.

We need to shift 80Thz up.

We can use the equation for frequency - Frequency = Velocity/Wavelength.

The wavelengths for green and blue visible light are 510nm and 475nm. If we plug this into the equation, we get the following :-

(Note - I don't think it matters what my outcome velocities are. They won't be the speed out light exactly, because I'm mixing and matching my frequencies and wavelengths. The difference between the two numbers should be all that matters, however.)

GREEN

V = (5.5×10^14)tHz x 510nm

V = 280,500,000,000,000,000 nm/s

BLUE

V = (6.3×10^14)tHz x 475nm

V = 299,250,000,000,000,000 nm/s

If we then subtract 'green-speed' from 'blue-speed', we get a difference of 18,750,000,000,000,000 nm/s.

Thus, one must travel at 18,750,000,000,000,000 nm/s, or 18750000m/s towards the source of the 'green' radiation in order for it to appear blue to the observer.

Or, 15.9889311% the speed of light.

Edited by BeefTenderloin
Had the speed in m/s, not nm/s
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