Detecting Distant Exoplanets: PTE Listening: Fill in the Blanks practice questions

When an exoplanet orbits a distant star, it exerts a subtle gravitational pull on that parent body. This interaction causes the star to wobble slightly rather than remaining completely . Astronomers detect this movement by analysing shifts in the star's spectrum of light. As the star moves towards our telescopes, its light waves undergo a slight shift towards shorter wavelengths. When it recedes, the light shifts towards longer wavelengths. By measuring these periodic precisely over many months, researchers can calculate the minimum of the invisible companion and determine the exact duration of its orbital .

Transit photometry is currently the most productive technique for discovering worlds beyond our solar system. The method relies on observing the minute in stellar brightness that occurs when a planet crosses directly between its host star and our line of sight. By monitoring thousands of stars simultaneously, sensitive space telescopes record subtle in brightness over extended intervals. These periodic dips produce a distinct light curve, allowing scientists to determine the physical of the planet relative to its star. Furthermore, any slight timing between consecutive transits can reveal the gravitational of additional hidden planets in the same system.

Gravitational microlensing provides a unique way to detect distant worlds that are otherwise far too faint to observe directly. The phenomenon occurs when a massive foreground star passes almost in front of a more distant background source. The gravitational field of the closer star acts like a natural lens, temporarily magnifying the background light. If the lens star possesses an orbiting companion, that secondary body introduces an extra into the observed brightness pattern. This brief spike reveals the presence of a planet, even one situated thousands of light years away. Consequently, this method is especially for finding low mass worlds orbiting at substantial from their parent stars.