“The sky was all purple, there were people runnin’ everywhere…” so Prince was right yet again…
Our planet is sometimes called the big blue marble, but if you go way back in time, Earth may have also been bright purple.
That’s the hypothesis of Professor Shiladitya DasSarma of the University of Maryland-Baltimore.
His idea is that the earliest microbes on Earth were phototrophs, producing energy for themselves out of sunlight.
Plants are phototrophs too; they use chlorophyll to absorb the energy, which they convert into food.
The difference is that these very early microbes didn’t have chlorophyll.
DasSarma says they probably had a different pigment called retinal, which absorbed green light frequencies from the Sun and reflected red and blue light.
Retinal would have been a good fit for a time when Earth was much hotter than it is now and had a very different atmosphere.
If so, then anyone who might have been lurking around the solar system would have seen a purple third planet instead of the colors we have today.
As to why the colors changed? Well, eventually chlorophyll came along; it’s a more complex but more efficient process.
The microbes that used chlorophyll out-competed the purple ones over time and changed the color of the planet.
The “Purple Earth” hypothesis, as it’s called, is a hypothesis, not a conclusion, but it’s kind of cool to think that the Earth might once have been as purple as the song “1999” suggested.
A company called Immerge Interactive just added a lot of color to a guitar, and I don’t mean the paint job.
They built a six-string filled with LEDs that can be connected to the same system that controls a concert’s stage lights, meaning the guitar’s light show can sync up with the guitar playing.
A good guitar solo really can light up a room now!
Why Early Earth May Have Been Mostly Purple (Real Clear Science)
The LED Guitar (Immerge Interactive via YouTube)
Photo by jpellgen via Flickr/Creative Commons