1. Transit Method:
* Space Telescopes:
* Kepler: Launched in 2009, it monitored a specific patch of sky for star brightness changes caused by planets passing in front of them (transiting). Discovered thousands of exoplanets.
* TESS (Transiting Exoplanet Survey Satellite): Currently in operation, surveying the entire sky for transiting exoplanets.
* CHEOPS (Characterising Exoplanet Satellite): Focused on studying the size and density of already known exoplanets.
* JWST (James Webb Space Telescope): The most powerful space telescope ever built, capable of observing exoplanet atmospheres for signs of life.
* Ground-based Telescopes:
* Automated telescopes: Continuously monitor the sky for transiting planets.
2. Radial Velocity Method (Doppler Spectroscopy):
* Spectrographs: Analyze the light from stars to detect minute shifts in their wavelengths caused by the gravitational tug of orbiting planets.
3. Direct Imaging:
* Adaptive Optics: Used to compensate for atmospheric distortion, allowing telescopes to take sharper images.
* Specialized Telescopes: Like the Very Large Telescope (VLT) in Chile, use powerful instruments to block out the light of stars, revealing faint planets orbiting them.
4. Microlensing:
* Ground-based telescopes: Observe the temporary brightening of a star when a planet passes between it and Earth, acting as a gravitational lens.
5. Astrometric Method:
* Space telescopes like Gaia: Measures the tiny wobble in a star's position caused by the gravitational pull of an orbiting planet.
6. Pulsar Timing:
* Radio telescopes: Detect slight variations in the timing of pulsars (rapidly rotating neutron stars), which can be caused by orbiting planets.
7. Other Tools:
* Computer simulations: Help scientists understand the formation and evolution of planets.
* Data analysis techniques: Analyze massive amounts of data to find patterns and identify potential exoplanet candidates.
These tools, combined with sophisticated data analysis techniques, have revolutionized our understanding of exoplanets and helped us discover thousands of worlds beyond our own solar system.
