Another reason is that good colorful paints became very expensive when they banned many of the chemicals that made them bond well and endure weather. Today's colorful paints wouldn't be expensive anymore but people just don't want colors that stand out anymore.

Many answerers don't know a lot about the subject at the time of reading the question, but get intrigued and just start reading about it. It's pretty fun actually, you get to learn it yourself first and then hone your writing skills by distilling the information into an easy to read comment.

I read of a study which concluded that teaching others immediately after learning something new is the most reliable way to retain the information. Personally I believe it is too!

Thermal conductivity and specific heat capacity don't go hand in hand. But heat capacitance depends on the material and its mass. Aerogel is extremely light and that why it doesn't burn you even when it's red hot.

The lactose can't be a requirement for another propellant to work, right?

Can we really not accurately detect "obvious features" like skin tone of a person based on the DNA? It's baffling to me. Those 30 predicted faces seem to have features randomly from all over the world.