The World's most unanswered science questions:

Everything to do with light and colour is covered on this page. Before diving straight into the questions, here's a quick table showing the special symbols and what they mean.

This symbol means that the question is difficult to find out in practise. However, through lateral thinking and common sense, an answer is possible. This symbol means that the question is nigh-on impossible to verify by experiment alone. However, through lateral thinking and common sense, an answer is possible.
This symbol means that the question is delving into the theoretical realm and is once again difficult to test. The answer/s are possibly right - but not guaranteed! The ultimate! Questions with this symbol push the boundaries of theoretical knowledge - and are nigh on impossible to verify by experiment. Any answers are based on our current understanding of the universe - and thus are subject to error.


  • Mirrors inside mirrors
  • Switching off the sun
  • The deletion of the atmosphere and ozone layer
  • The non-contoured moon
  • The Eclipse
  • Noise from the eye
  • Unusual light filters
  • The Magnified Sun
  • Luminous Liquid Light
  • The Humble Light Bulb
  • Dazzling light and silhouettes
  • Can the blind see in dreams?
  • The Perfect Microscope
  • Effects of Speed of light at 1 MPS
  • Microscopes, light waves and perceived color
  • Multiple Focus Lens
  • Street Lamps, Sky and Auras
  • Soft Shadows and Light Sources
  • Colorless Gases and Liquids
  • Communication and Monitor Display Technology
  • Blue and Yellow really green??
  • Where is Magenta in the Colour Spectrum?
  • Reverse Colour and the After image
  • The Mirror Timebomb
  • Tasting the Impossible
  • Extreme Wavelengths of Light
  • Deadly Rays, Microwaves and Lasers
  • Light Waves and Heat
  • Tons of light and no heat?? Tons of heat and no light??
  • How many unique pictures could you ever see?
  • The poor green light on monitors

  • Mirrors inside mirrors
    Q: When two mirrors are directly facing each other, they reflect off each other infinitely producing a mirror inside mirror effect. If this was graphically slowed down, would you see a kind of build-up effect where each mirror is "drawn in"? After all, light only travels at a finite speed. In other words, is it true that while you're still looking at the multiple reflections, millions more are constantly being made due to light travelling at only a finite speed?
    For a further breakdown of this phenomena and its cool side effects, visit the Light and Colour Trivia page.
    Switching off the sun
    Q: If the sun suddenly went from the sky (switched off), would...
    A: The place outside looks as though the sun is still there (the sky itself looks like daytime), but no visible sun was actually in the sky.
    B: Everything blacks out except the sun itself - which eventually also disappears.
    C: Everything immediately blacks out.
    D: Everything blacks out after a period of time.

    The deletion of the atmosphere and ozone layer
    Q: If the atmosphere was taken away, you would see just the sun and the black sky. How much darker (brighter?) would Earth be and what would everything look like?

    Shouldn't the moon crescent look something like A or at least B...? Nope - it's actually mostly like C...
    The non-contoured moon
    Q: When there is a half moon, you are seeing a circle cut in half. Shouldn't there be a smooth black to white (silver) gradient rather than this instant "white-one-half black-the-other" effect?

    The Eclipse
    Q: Why is an eclipse more harmful to look at than just the sun?

    Noise from the eye

    You've probably seen this before whether you realise it or not. It's actually the strange geometric noise you see if you shut your eyes very tight for a minute.
    Q: If you close your eyes, there is a very faint but noticeable flickering 'random light mess'. Is this simply 'damage' that has accumulated over the years, or is it some kind of brain activity? Can people who are blind also see this?

    Unusual light filters
    Q: Is there a kind of light filtering device which filters out the entire range of 'invisible' light (infra-red and ultraviolet) whilst retaining the full visible spectrum? Also, same question, but filtering out only the full visible light instead.

    Would one see A or B ?
    The Magnified Sun
    Q: Why is looking through a telescope at the sun more harmful than usual? Isn't it just enlarging the size of the sun - not the brightness? See Diagram for clearer explanation of question.

    Caution: Never ever look at the sun through binoculars or a telescope, as it can easily blind someone permanently for even an instant of viewing.

    Luminous Liquid Light
    Q: There are certain types of liquids which produce their own light independently, or when mixed:
    Can all the primary colors be obtained from these liquids or just white light?

    Q B: If this liquid light was compressed, then would the light become stronger e.g. 5x compression = 5x light intensity.
    QC: If the liquid was heated to become liquid-light vapour, would the air around become luminous?
    Q D: If the liquid was frozen, what effects would this have on the light?
    Q E: What does the liquid taste like? Is it toxic?
    Q F: How long does the light last for?
    Q G: How (if?) can you 'recharge' the light?

    The Humble Light Bulb
    Q: Light bulbs have not changed much since Edison first introduced them many years ago. They all still have one thing in common though - they run out sooner or later. If they exist, how much more expensive are the infinitely lasting light bulbs? If car lights and LEDs can last so long, then surely they can do the same for the household bulbs?
    Q: The light coming from a coloured light bulb is (mostly) white and therefore requires a coloured glass bulb filter to show any colour. Can coloured light come from a transparent glass bulb? Also, what wavelengths of light do light bulbs emit? Is it 'coincidentally' just the RGB waves that are needed to make white light perhaps?
    Q: Whilst we're on the subject of light bulbs, how many would it take to get the brightness that the sun gives out? 10,000 watt perhaps? Rooms would look great this bright :)

    Dazzling light and silhouettes
    Q: When you are dazzled by a bright light source and what you see becomes a dark 'silhouette', is that what you are 'meant' to see - or is it some kind of fault with the eye or brain?

    Can the blind see in dreams?
    Q: Can people who are blind at birth see sights in their dreams?

    The Perfect Microscope
    Q: How close is technology to this kind of microscope:
    First stage:
    Monitor display. Real-time zoom in or out operation with 4-way real-time scrolling. The speed of scroll would be proportional to zoom level.
    Second stage: Same as above but with picture displayed in 3 dimensions with auto-focus and near to infinite zoom potential. On top of ordinary zooming, there would also be an option to /enlarge/ the screen's picture. Other options such as moving and rotating the object and/or lens could be added. Perhaps a variable focus setting enabling everything or a defined distance (or anything in between) to be displayed.

    Effects of Speed of light at 1 MPS
    Q: What would everything look like if the speed of light was slowed down to - ooooh... right down to 1 metre per second ?

    Microscopes, light waves and perceived color
    Q: Apparently, a microscope can only zoom in so far before visible wavelengths of light become inadequate to reflect the object. Is this a fault ('fault'?) with the microscope or is it the very nature of light? If it's the second explanation that stops us from seeing closer, then isn't it possible to shine higher frequencies of light on the subject and then cycle (transpose) down the colors to what they should be?
    Advances have been made in seeing ever smaller details with light alone. Visit here for one such technique.
    Multiple Focus Lens
    Q: Is there a lens which shows all parts in focus simultaneously?

    Street Lamps, Sky and Auras
    Q: At night when you look out, the sky is a sort of dull dark brown. If all street lights and lamps were switched off, would the sky instantly turn pitch black?
    Q: A street lamp at night has an aura of light around it. Is this a fault of the eye or is it just the surrounding air and dust particles reflecting light (just like fog and mist)? Or is it both maybe?

    Obviously in this case, there's also the brightness of the sky to take into consideration, but just pretend this was on the moon or something :)
    Soft Shadows and Light Sources
    Q: If you study the shadow of a particular object, you may find that its edges aren't sharp. This is generally referred to as a "soft shadow". Is it true that if all the light were concentrated into one point, the shadow would become 'sharp'?

    Colorless Gases and Liquids
    Q: Is pure air absolutely transparent (colorless) so that if you were to look off into the distance miles away, the horizon would be just as clear as the foreground?
    Same question with oxygen, nitrogen, helium and water.

    Communication and Monitor Display Technology
    Q: How close are we to the kind of technology which allows sound and visual connection between two people miles apart via a 50 Hz screen refresh not more than a centimetre thick?

    Blue and Yellow really green??
    Q: Why is 'everyone' taught that blue and yellow make green? Simple knowledge on the basics of colour should show that the actual colour (for additive AND subtractive mixing) is black/grey/white. (In the same way, red+cyan and green+magenta also equals black/white...)

    Where is Magenta in the Colour Spectrum?
    Q: Where is magenta 'meant' to be in the color spectrum - after blue or before red? The 'blue' (shorter wavelength) end of the visible color spectrum contains magenta/purple/violet/indigo (red/blue mixes). It seems that red also exists after blue!
    Effectively, this implies that there are 1 reds in the color spectrum (!)
    So what's going on? Did it get second helpings?

    Reverse Colour and the After image
    Q: If you look through a yellow filter for a few minutes, everything afterwards appears blue and vice versa. Is this a 'fault' with the eye or mind? Or is it because the sudden switch confuses the mind? Basically, are we really seeing what we should be seeing?

    The Mirror Timebomb
    Q: What kind of effect would you see if an object (with a light source) was surrounded by a mirrored sphere?

    Also, if a pulse of light was released (this time with no object) inside a closed mirrored sphere - and no energy was lost through heat, would the light remain indefinitely - evenly spread throughout the sphere ?
    (If so, then this effectively means that if the light were to stay constantly on, the brightness inside the enclosed mirrored sphere would increase infinitely!!).

    For a cool demonstration of this phenomena and its effects, visit the Light and Colour Trivia page.

    Tasting the Impossible
    Q: Colour and sound have easily been quantified. Visible light is split into red, green and blue.... and music is made up of countless waves of air pressure (which can be represented mathematically).
    However, are there fundamental attributes to the sense of taste? (and I'm not just talking about the senses of the tongue here, but the sense of smell.)
    Q: Is it possible to change the colour of water to pitch black - without affecting the taste or texture? Q: What would water 'taste' like if it had the texture of something like plasticine or Ice-cream?!
    Extreme Wavelengths of Light
    Q: What's at the far ends of the electromagnetic spectrum? Any chance of these extreme wavelengths producing unusual and unforeseen effects?
    Q: Is it true that the shorter the wavelength of light is, the more chance the ray has of going through a solid object? And is it exactly proportional i.e. half wavelength means exactly double penetration?

    Deadly Rays, Microwaves and Lasers
    Q: At the same amplitude, what exact frequency of light is least and most harmful to expose oneself to? Ultra violet or Infra red? Radio waves or X-rays?... Same question, except this time which is most damaging to the eyes?...
    Q: I've heard that if you take the lid off a CD drive while it's on, the laser can blind you. How true is this? Is it permanent blindness? (warning - don't try it) Q: Exactly how dangerous is it to remove the microwave generator from a microwave - would you notice it just heat you up, or would there would be invisible danger which isn't immediately apparent? (warning - don't try it).
    Light Waves and Heat
    Q: Which frequency of light from the sun produces the least heat? What frequency produces the most heat?

    Tons of light and no heat?? Tons of heat and no light??
    Q: Could something be very hot (say... 1,000,000) and still have no light being emitted?
    Q: Reverse of above question: Could something be very bright and still have no heat being generated?
    How many unique pictures could you ever see?

    One of the pictures in the 900,000,000 digit number - and not at all a blatant excuse to display one of my Gallery pictures... ;-)
    Q: How many uniquely different pictures could you ever, ever see?
    For a further breakdown of how I reached this number, visit the Light and Colour Trivia page.

    The poor green light on monitors
    Q: Why is the green light on my monitor so pale? Are all monitors this bad?

    The Eclipse of Mars - See a new colour you've never seen before!!

    ...Well... at least never before on your monitor.
    The colour you are about to witness is actually true Cyan ... a colour that is heavily diluted on the vast optical illusions 10 majority of monitors (thanks to colour pollution). It's a pity one needs an optical illusion to demonstrate this, but at least you can see what you've been missing ;-) Anyway on with the illusion....
    Stare at the white dot in the centre of the red circle. The longer - the better (two minutes and you'll get a much stronger effect). Always try to keep focused on the white dot. It'll be worth it.
    Soon after staring, you'll start to see a thin rim of light around the edge. Don't stop staring though yet! Wait another minute - keeping your head perfectly still.
    Once you've done this, slowly - move your head backwards - making sure to keep your eyes focused on the dot at all times. The circle's rim will glow brilliantly with true Cyan! Keep on moving your head slowly backwards, and it'll glow very hot!...
    The blue/cyan colour chart to the right isn't part of the illusion, but there to demonstrate that the ultra cyan you have just seen is not in the monitor's color palette! It should be, but isn't.
    It's an amazing effect and I'm happy to say I 'discovered' it =D These 2 colours (red and this exact shade of cyan) work better than any other colour combination for many reasons, but click here for the ultra-brilliant green version.
    Also visit the Optical Illusions page for some unique never-seen-before Optical Illusions.

    Message your comments and possible answers to the Skytopia Forum

    Back to top

    Return to Science Index

    All graphics on this site are copyright D. White 2002 onwards.
    Please ask for permission should you wish to use the text material on these pages.