How many Earth-like planets could there be? 214 (1/2) – Science Mysteries Explained

What exactly is an “organic compound”?
Scientists are always talking about organic compounds as being evidence of life. But
what makes a compound organic?
Life on Earth is based on a single chemistry that uses carbon, oxygen, hydrogen, nitrogen, phosphorus, and
sulfur. We call that chemistry “organic” simply because it’s the chemistry of life!
Chemists talk about dierent chemistries—distinct
sets of molecules, compounds, and reactions that
always seem to occur in groups. The way metals
bond to each other and rust is one type of chemis-
Another type is called “organic chemistry.” This
involves a huge number of dierent carbon-based
compounds, water, and oxygen.
Today, organic compounds are those chemicals
that contain a large amount of carbon. They’re
called this because for many centuries scientists
thought these compounds could only be produced
in living things, and that they would not otherwise
occur in nature.
Modern chemistry and atomic theory have
shown us that many of the organic compounds
can be made by just mixing chemicals together
in a lab. One of the first organic substances to be
synthesized was urea—a component of animal
urine. Because chemists were able to make it
by mixing potassium cyanate and ammonium
sulfate—neither of which is an organic com-
pound—it changed the way we thought about
chemistry forever. We realized that organic
compounds are just one set in a broader system
of chemistry and couldn’t be rigidly defined
after all.
“Organic” is a fairly sloppy term, scientifical-
ly speaking. Saying an organic compound is one
that contains lots of carbon doesn’t really help,
because stainless steel has lots of carbon in it—
and it’s obviously not organic!