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Extrasolar planets, or exoplanets, are planets that orbit a star other than our Sun. They exist outside of our solar system. Since their first confirmed discovery in 1992, exoplanets have intrigued scientists because they offer insight into the breadth of planetary systems found in the galaxy.

Scientists are keen to study them as they may host conditions that allow for life. Detecting and analyzing these distant worlds helps us understand the diversity of planetary systems and the possible habitability.

Exoplanets vary widely in size, composition, and distance from their host stars. Some resemble Earth, while others are gas giants like Jupiter, or even icy worlds that orbit far from their stars. Understanding exoplanets helps us know more about the potential for life beyond Earth, expanding our knowledge of the universe and possibly our place within it.

General Relativity is a theory of gravitation proposed by Albert Einstein in 1915. It revolutionized the understanding of gravity by describing it not as a force, but as a consequence of the curvature of space-time caused by mass. Think of space-time as a flexible sheet that bends when a heavy object (like a star or planet) is placed on it. This curvature is what we perceive as gravity.

This theory has significant implications for astronomical observations, such as the prediction of the deflection of light. This deflection is crucial in a phenomenon known as gravitational lensing, where the light from a distant star or galaxy is bent around a closer massive object between the star and the observer.

The bending of light helps scientists observe objects that would otherwise be too far away or obscured by other celestial bodies. General Relativity laid the groundwork for understanding how massive bodies influence the path of light, enabling methods like microlensing to discover far-off exoplanets.

There are several methods used to detect exoplanets, each with its unique advantages and challenges. For instance, the Transit Method measures the dimming of a star as a planet passes in front of it. This method is very effective for finding planets that orbit close to their stars.

The Radial Velocity Method involves detecting changes in the star's light spectrum, caused by gravitational tugging from an orbiting planet. It provides information about a planet's mass and the shape of its orbit.

Microlensing is another powerful method. It utilizes the effect of gravity bending light, as proposed by Einstein's General Relativity. When a massive object like a star moves in front of another distant star, it magnifies the distant star's light. Anomalies in this magnification can occur if the foreground star has a planet, revealing its existence.

Microlensing is unique because it can detect planets at great distances from Earth and around stars that do not emit much light. It is especially helpful in finding planets that orbit far from their host stars, which are often too faint to detect with other methods. Understanding these detection methods expands our capability to discover diverse types of exoplanets.