Scientists study the effects of light on plant life cycles in Beltsville, Maryland, August 1953.Photograph by Jack Fletcher, National Geographic
Let’s play a little thought exercise: Which color(s) of light do you think would be better/worse for plant growth? What makes you think that?
Please show your work, and everyone gets an A+ just for trying.
Wouldn’t it be ironic if astronauts got to go up to space only to see no stellar beauty?
While it’s true that astronauts often can’t see stars from orbit, it doesn’t have to do with whether or not there’s an atmosphere. It’s actually pretty simple, and it’s the same reason you can’t see stars in the middle of the day: That dang sun.
If the sun is out, it reflects a massive amount of light off Earth’s surface, far more light than any stars (other than our sun) are giving off. On Earth, the molecules in the atmosphere scatter the sun’s light and make our sky blue and starless in the day time. To an astronaut on the day side of Earth, there’s no atmosphere to scatter a blue sky, but the effect on the stars is equally obfuscating.
Staring into the void, an astronaut’s eyes don’t have the dynamic range to see tiny, dim dots of light when there’s other sources of illumination around. It’s similar to how it’s hard to look out a window into the dark of night when you’re in a lit room.
The same thing happens on the moon. That’s why Apollo pictures are so brilliantly lit, but the sky above them is devoid of stars.
If an astronaut is on the night side of Earth, and there’s no light from the moon, then they can definitely see stars. Here’s some gorgeous video proof:
Here’s A Light Fixture That Runs On Bacteria
As we phase out incandescent lights for compact fluorescents, we save energy but take the risk of mercury pollution (there’s heavy metals galore in CFLs). What if we could light our homes with biology?
Similar to the Glowing Plant project from earlier this week, here’s Philips concept for a microbial lamp powered by the chemistry of biological luminescence. It’s part of Philips’ "Microbial Home" future concept, which also includes urban beehives and bacterial waste recycling.
You can get off the grid, and onto the petri dish.
What Is “Sky Blue” Anyway? Color Science!
In my latest episode on YouTube, you may have seen the “official sky blue” color that popped up. Curious where that came from? Want to use it in your artwork?
I converted 475 nm light, the predominant blue wavelength that’s scattered by our atmosphere (and the reason the sky is blue) into hex code (top), and then added in various amounts of white. Depending on how much water vapor and microscopic dust is in the atmosphere, white light gets mixed in with that pure blue.
I’ll probably get in trouble for declaring this “official sky blue”, and RGB colorspace isn’t a perfect model of the eye, but I have science on my side, so there!
If you’d like to try yourself, check out this wavelength-to-RGB tool based on the color algorithm developed by Dan Bruton.
Curious how this sorcery happens? You bet you are.
An insect like a wasp or a water strider can rest atop the water, held up by surface tension. This means that the cohesive force of the water molecules sticking to each other is stronger than the force of the bug being pushed down by gravity. This works because it spreads its weight out over a large surface area (like snowshoes).
That creates a slight indentation in the top of the water, changing the direction that the light coming down is refracted and re-directing it slightly sideways (that’s where the bright halos around the dark areas come from). And what’s the absence of light?
All those words in picture form:
A Tribute To Light
Cristóbal Vila gives us the short film Lux Aeterna, a journey in light, watched best in full screen. Light, that particle and wave, that bendable and splittable duality that sets a speed limit for anything with mass … it travels billions of miles to illuminate our days, nights, and dreams, and it even gives weight to a shadow.
Is light a particle or a wave? An animated explanation.
Both? Neither? A little bit of this, a little bit of that? Light has a less-than-illuminated history that seems to get more complicated and interesting with time. Very cool look at what we do and don’t know about light’s behavior.
Also useful as a way to make fun of the ancient Greeks, because little light horsemen? Really? You Greeks are hilarious.