04-12-2017, 04:11 PM
SBH - I assume you're thinking more of liquid water rather than water in its other phases, i.e., steam or ice. In that case, it's very difficult for ground-based telescopes to detect liquid water, even on Mauna Kea, because there is so much of it in the atmosphere. The wavelengths you would use to detect water are essentially blocked by the atmosphere which is why that particular line of investigation is much better done from space.
On the other hand, the MK observatories have been involved in several detections of water in its other forms, especially ice. They have been used to detect water ice on comets and asteroids in our solar system, including to some extent Mars and other solar system minor objects. They have also been extensively used to study water ice elsewhere in the Milky Way, especially in molecular clouds and star forming regions. I spent a lot of my time as a young astronomer doing exactly those types of observations, often using spectroscopic observations of water and CO ices to attempt to identify other molecules that were hard or impossible to detect from Earth (e.g., carbon dioxide and molecular oxygen and nitrogen).
So, yes, they are used to detect water, but no so much liquid water.
On the other hand, the MK observatories have been involved in several detections of water in its other forms, especially ice. They have been used to detect water ice on comets and asteroids in our solar system, including to some extent Mars and other solar system minor objects. They have also been extensively used to study water ice elsewhere in the Milky Way, especially in molecular clouds and star forming regions. I spent a lot of my time as a young astronomer doing exactly those types of observations, often using spectroscopic observations of water and CO ices to attempt to identify other molecules that were hard or impossible to detect from Earth (e.g., carbon dioxide and molecular oxygen and nitrogen).
So, yes, they are used to detect water, but no so much liquid water.