Detecting planets around stars typically requires the use of telescopes or spacecraft equipped with specialized instruments and techniques. While planets cannot be observed directly from Earth without the aid of telescopic observation, there are indirect methods that allow astronomers to infer the presence of planets.
One common indirect method is the radial velocity method, also known as the Doppler method. This technique relies on observing the slight wobble of a star caused by the gravitational tug of an orbiting planet. By carefully measuring the star's spectrum and tracking changes in its velocity, scientists can infer the presence of an unseen planet.
Another widely used method is the transit method. This technique involves monitoring a star's brightness over time and looking for periodic dips in its light caused by a planet passing in front of it. By measuring the timing and depth of these dips, astronomers can gather information about the planet's size, orbit, and other properties.
Both of these methods require sensitive instruments and careful observations. They are typically conducted using ground-based or space telescopes equipped with specialized instruments and detectors capable of detecting the subtle changes in starlight associated with planets.
In summary, while it is not possible to directly detect planets around stars without telescopes or spacecraft, astronomers have developed indirect methods that allow them to infer the presence of exoplanets by carefully studying the properties and behavior of the host stars.