News, Science

NASA Discovery: 7 Earth-Sized Planets

Scientists from NASA announced on February 22 that they have discovered seven planets orbiting a nearby star. The planets are all about the same size as Earth, and three of them are in what scientists call the “habitable zone.”

(The habitable zone is the area of space around a star where a planet is most likely to have liquid water on its surface. Scientists believe water is necessary for anything to live on a planet.)

The planets orbit a star called TRAPPIST-1. TRAPPIST-1 is an ultra-cool dwarf star. That means it is much smaller than our Sun, and only about half as hot.

The seven planets are very close to each other. If you were standing on the surface of one, you could see the others in the sky, the way we see the moon.

The planets (which are currently known as b, c, d, e, f, g and h) have much shorter orbits than Earth. It takes Earth about 365 days to orbit the Sun. The longest orbit for a TRAPPIST-1 planet is only 20 Earth days. The shortest is a day and a half.

Our Earth rotates constantly, giving us day and night, but scientists think the TRAPPIST-1 planets may be locked into position, with one side always facing the star and one side always facing away. That means one side would always be in daylight, and the other would always be in night.

The star system is about 39 light years (369 trillion kilometres) from Earth. Using a space shuttle, it would take 1.5 million years to reach Trappist-1.

Scientists will use telescopes on Earth and in space to learn as much as possible about the planets.

For instance:

  • Is there water on the planets?
  • What is their atmosphere made of?
  • Are they rocky, like Earth, or made of gases, like Neptune. (So far, most appear to be rocky.)

Finding the planets is a giant leap forward in our search for life beyond Earth and other planets where humans might be able to live, said scientist Sara Seager during the announcement.

Finding this many possibly habitable planets in one star system means there are probably many more planets like these out there, Seager said.

Related Links

Desktop app with information about exoplanets (planets outside our own solar system).

Travel poster for TRAPPIST-1 star system

NASA Kids’ Club.

By Jonathan Tilly

Writing/Discussion Prompt
Humans might be able to live on planets like those found in the Trappist-1 system.
In your opinion, do discoveries such as this provide evidence that we are not alone in the universe?

Reading Prompt: Text Features
Today’s article includes a section where bullet points are used to explain what scientists at NASA will be studying about this new planetary discovery. Why do you think the author chose to include the information in this way? How does it change your ability to understand the information?

Primary & Junior
Identify a variety of text features and explain how they help readers understand texts 
 (OME, Reading: 2.3).

Identify a variety of text features and explain how they help communicate meaning 
(OME, Reading: 2.3).

Language Feature: Silent L
Have you ever wondered why words such as, like “could” and “would” contain a silent L?
The reason may surprise you… Roughly 300-500 years ago (depending on who you ask), scholars argued about the spelling of words. Ultimately, it was agreed to that words like “should,” could,” and “would,” should have an “l” added to them in order to show their traditional latin spellings. Isn’t that neat?!

What other words can you think of that contain a silent L?