Space capabilities from SpaceX Super Heavy Starship and being able to build in space will enable 1000 to 1 million times larger projects on the moon and in cis-lunar orbits.

OWL-Moon
OWL-MOON: Very high resolution spectro-polarimetric interferometry and imaging
from the Moon: exoplanets to cosmology

A 100-meter space telescope on the moon will let us directly observe the height of mountains on exoplanets.

A giant moon telescope will let us answer three major questions in astronomy.
1) the detection of biosignatures on habitable exoplanets,
2) the geophysics of exoplanets and
3) cosmology.

Detecting Alien Life in Other Solar Systems

One of our main science objectives is the characterization of exoplanets and biosignatures. There are about ten potentially habitable planet candidates up to 10 pc. But there is no guarantee that even a single one will present biosignatures. We must enlarge the sample and go up to say 40 pc. An Earth-sized planet at 1 AU from a G star has a planet/star brightness ratio of 3.10^−9 for an albedo of 0.3. Thus, for a 8th magnitude star, it means a 32nd magnitude target. For 1 nm spectral resolution spectroscopy needed to detect atomic and molecular emission lines, consider the goal of 1000 photons detected in 3 hours. This needs a 50-meter telescope. To detect 500 photons in the bottom of absorption lines having a depth 10 times the continuum in 3 hours, one would need a 100-meter telescope.