SUPPLEMENTARY READING
Professor Smith: Today we are going to talk about searching for planets
outside the solar system. In the universe. there are a vast number or
stars and there must be a vast number of planets. Life is likely to exIst
elsewhere. As a matter of fact, astronomers have found hundreds Or
planets beyond our own solar system.
Bart: I have a question. Those planets don't produce any light, so hoW
do scientists find them?
Professor Smith: It's not as difficult as you' may think. Researchers
search for stars that have irregular movements caused by the gravityof
the orbiting planet. Can anyone guess what those researchers do next?
Victoria: Yes, I've read that researchers measure the distance between a
planet and its sun, using high-tech telescopes. As a result, they can tell
the temperature of'the planet. If the temperature is moderate, liquid
water could exist.
Professor Smith: Correct. Those conditions are suitable for life to begin,
as it did on Earth. (162 words)
