Cold Neptunes: An Exoplanet Sweet Spot?

Astronomers have discovered numerous exoplanets, primarily those close to their stars. Microlensing, a technique that uses a star's gravity to magnify a distant star's brightness, can detect planets further away. This method is sensitive to smaller planets and can reveal new planetary populations. The MOA-II survey found that planets beyond the snow line, where water freezes, are often similar in mass to Neptune. These planets may influence the formation of habitable planets by sending water-rich asteroids inward. Future missions like NASA's W First will expand on Kepler's work, providing a comprehensive view of exoplanetary systems.

Explain the role of gravity in the microlensing technique.

What advancements does the W First mission aim to achieve in exoplanet discovery?