More Habitable Planets May Exist than Previously Believed

October 9, 2012

Unlocking Word Meanings
Read the following words/expressions found in today’s article.

1. habitable (adj.)
[hab-i-tuh-buh l] – (in science) able to support or maintain life; can be lived in
Example: Scientists are looking for habitable planets just like Earth.

2. liquid (n.) [lik-wid] – something that flows
Example: Water, milk, and juice are common liquids.

3. surface (n.) [sur-fis] – outer part or uppermost part of something
Example: The surface of the moon is not smooth because it has many craters.

4. evaporation (n.) [ih-vap-uh-rey-shuh n] – a process wherein liquid turns to gas
Example: Sea water undergoes evaporation because of heat from the sun.

5. internal (adj.) [in-tur-nl] – found on the inside, coming from the inside
Example: The internal structure of a planet contains rocks.

Read the text below.

According to British researchers, the number of habitable planets may be greater than what scientists have estimated in the past.

 Water is the source of life, and scientists believe a planet is considered habitable if it contains liquid water.

For many years, scientists have theorized that for life to exist on a planet, the planet’s surface water had to be liquid. In order for water to be liquid, it had to be in what scientists call the “Goldilocks” zone, an area that is “not too hot and not too cold.”

Planets too near their sun are too hot and lose their surface water due to evaporation. Planets that are far away from their sun are too cold and have frozen surface water. In the old theory, these kinds of planets were not considered habitable.

However, Mr. McMahon, a researcher from Aberdeen University, says the Goldilocks theory is too simple. A planet’s heat does not only come from the sun, he explains. A planet also has its own internal heat.

If a planet is big enough, it may be producing enough internal heat to keep water in liquid form. The planet’s surface water may be frozen, but underneath it, the water may be liquid and full of living things. Even on Earth, many living things are found deep under the surface.

Researchers have also built new computer models to identify whether a planet may have liquid water underneath its frozen surfaces. Aberdeen’s team of researchers is hoping these models can help scientists discover which far away planets can possibly support life.

Viewpoint Discussion
Enjoy a discussion with your tutor. 

Discussion A

·         Do you think it is important for scientists to look for habitable planets? Please explain your answer.
·         If scientists discover life on other planets, what would that mean for us? How would that discovery affect us?

Discussion B

·         Knowledge often changes whenever scientists discover or learn something new. How do you feel when you learn about something new or very different from what you already know?
·         Can you give one scientific fact or theory that interests you? Why do you find this information interesting?


October 9, 2012