P3.3.1 Detecting Planets Flashcards
Which type of telescope did Galileo use?
Refracting telescope
How many lenses does a refracting telescope have?
Two
What is the function of the eyepiece lens?
Magnifies the image
What is the function of the objective lens?
Produces a real image of a distant object
What is the problem with Galileo’s telescope?
Different colours of light are refracted different amounts. So an image of an object that emits different colours might not be clear.
What does a reflecting telescope use instead of lenses?
Curved (concave) mirror, a flat mirror and an eyepiece lens
Which type of telescope is the Hubble Space Telescope (HST)
Reflecting telescope, it has curved mirrors.
What is an exoplanet?
A planet that orbits distant stars
What is the name of the telescope used to detect exoplanets?
Kepler space observatory
What does Kepler detect?
It detects changes in light intensity. It focuses on the same part of the sky all the time.
What happens to the light intensity when a planet moves in front of a star?
The intensity drops.
What does it mean if there is a larger drop in light intensity?
It is a larger exoplanet.
Compare reflecting and refracting telescopes.
1) Refracting telescopes use lenses to refract light. 2) Reflecting telescopes use mirrors to reflect light. 3) Refracting telescopes do not produce clear images as different colours of light are refracted by different amounts. 4) Reflecting telescopes produce better images as light is focused by the curved mirror. 5) The HST is a reflecting telescope. It focusses faint light from distant exoplanets using a large mirror. A large lens would be too heavy to send into space. 6) Space based telescopes use mirrors. Ground based telescopes use lenses or mirrors.
How could you tell which of two exoplanets has the shortest year?
The one which is in front of the star for a shorter period of time.
Label this diagram.
Label this diagram.
