Sciency Words: In Situ

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us all expand our scientific vocabularies together. Today’s term is:


Today I’m continuing to blog from the surface of Titan, Saturn’s largest and most mysterious moon. No more reading about Titan in books and journals or on the Internet. Right now, I can do my Titan research “in situ,” as the real scientists would say.

Ag19 Life on Titan

“In situ” basically means “on location.” It comes from the Latin words for “on” and “location.” Alternative translations include “in the place” or “situated in,” but I think “on location” works best for our purposes.

Just about any time you find the phrase “in situ” in a scientific text, you can mentally substitute the words “on location” without changing the meaning of the sentence one bit.

  • The Mars rovers conduct in situ experiments to identify Martian geological features.
  • In the future, colonists cannot depend on supply missions from Earth for all their needs. They’ll have to make use of in situ resources.
  • Triton (Neptune’s largest moon) probably didn’t form in situ, but was captured by Neptune’s gravity after forming elsewhere.

Regarding in situ planetary science, contrast it with the observational science done using telescopes or laboratory experiments that attempt to recreate conditions on other worlds. Or you could contrast in situ research against something like a sample return mission, where material is brought back to Earth rather than analyzed on location (I mean, in situ).

Meanwhile on Titan

While in situ research has its advantages, it’s still only as good as the human doing the research. If life exists on Titan, it’s bound to be very different from life on Earth, with biochemistry totally unlike our own.

I can’t just look into a methane lake and see if any alien microbes are swimming around. I have to know what to look for before I look. I have to know which experiments to do before I do them. Which is why I still have to read books and journals and Internet articles about Titan. Otherwise, I might miss something important.

P.S.: Ah! It’s got my leg! Send help!

6 thoughts on “Sciency Words: In Situ

  1. When one does in situ experiments, it generally means you are performing them at the same conditions you usually find it in. For example, since automotive catalysts sit at a couple hundred degrees when they’re working in your car’s tailpipe, in situ experiments would mean measuring it properties at that same temperature . Now they have the term “in operando,” which means doing the measurements when the catalyst is actually functioning. Painful to do sometimes, but it’s the only way to know what’s really going on..

    Liked by 1 person

    1. Interesting. That’s a different usage than I’m familiar with. At least regarding space sciences, I still think the “on location” translation works best, but terms do sometimes have different meanings in different fields.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.