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  • ChaoticNeutralCzech@feddit.orgtoScience Memes@mander.xyz•Space Cats
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    2 months ago

    Depends on their response to wavelengths at rest, including IR (for blueshift) and UV (for redshift).

    Redshift doesn’t literally mean things appear red: the colors just remap, for example:

    320 nm 🕶️ → 400 nm 🟪
    400 nm 🟪 → 500 nm 🟩
    500 nm 🟩 → 625 nm 🟧
    625 nm 🟧 → 781 nm 💿 (IR, CD laser wavenength)

    For easy calculation, I chose an exactly 25% increase in wavelength, achievable if the cat is receding at 25 % of the speed of light.

    Or vice versa for blueshift. For example, a low-pressure sodium lamp in old street lights is near-monochromatic at 589 nm (pale yellow), which will reach 678nm red at 15% redshift, while a CD infrared laser incoming at the same 0.15𝑐 speed will have the same apparent red light at 678nm but because of blueshift.

    TL;DR

    🏳️‍🌈 ↓ Blueshift

    🏳️‍🌈 ↑ Redshift
    Redshift in absorption lines in starlight











  • ChaoticNeutralCzech@feddit.orgtoScience Memes@mander.xyz•2 Faced
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    3 months ago

    The “adult for comparison” (light blue) seems quite different in each, even for 1960s hand-drawn diagrams (see source attribution; they would use transparencies, grid paper or pencil guides). Maybe vector “compression” (keeping only every 𝑛ᵗʰ vertex, perhaps fitting path in between to best resemble original) took place? I do that with potraced paths often but always check how the result looks.