Today's news, tomorrow's lesson - 17 billion more planets like Earth in our galaxy

There could be as many as 17 billion planets like Earth in our galaxy.

Today's news, tomorrow's lesson - 8 January

17 billion more planets

By Darren Evans

There could be as many as 17 billion planets like Earth in our galaxy, scientists have discovered, a number that dramatically increases how likely it is that aliens exist.

Scientists used a telescope in space to look at the 100m stars nearest to our own sun and found that 17 per cent have an Earth-sized planet in orbit.

Although it does not mean that all those planets, called exoplanets, are home to life, it does increase the chances of finding ones similar to our own.

Four of these newly discovered exoplanets, which are less than twice the size of Earth, orbit their sun's "habitable zone" where surface temperatures are neither too hot nor too cold and allow liquid water to flow, making alien life a possibility.

However, these planets are so far away, they would take hundreds or thousands of years to get to.

The space telescope, called the Keplar observatory, spots possible exoplanets by detecting the tiny dip in the light coming from a star when a planet passes in front of it, like a mini-eclipse. This is called a transit.

But it is a very difficult task because of the minute amounts of light involved, and not every dip is a planet.

Members of the public helped the team of scientists identify the exoplanets by logging onto a website,, on their computers. The Planet Hunters project invites "citizen scientists" to spot graph patterns signifying the tell-tale dip in brightness as planets pass in front of their parent stars.

Planet Hunters lead scientist Professor Debra Fisher, from Yale University in the US, said: "Now, the hunt is not just targeting any old exoplanet; volunteers are homing in on habitable worlds."

One volunteer, electronics engineer Mark Hadley from Faversham, said: "Now when people ask me what I achieved last year I can say I have helped discover a possible new planet around a distant star. How cool is that?"


  • Do you believe that there is life on other planets? If so, what do you think is out there?
  • Why do you think people are interested in the possibility of alien life?
  • If you were given one day to introduce an alien to our planet, what places, people and things would you show to them?
  • "Citizen scientists" are helping to identify planets where life might be found. Can you think of any other ways that members of the public might be able to help scientists?

Related resources

Tour of the Solar System

  • Take your class on a tour of the Solar System with this PowerPoint presentation.

Create an alien planet

  • A great cross-curricular resource booklet to help children create their own alien environment.

Space and aliens

  • Explore space and aliens with this helpful termly plan.

Space tourism

  • Ask pupils to design a postcard from Space with this lovely activity.

Further news resources

First News front page

  • Help your pupils understand the features of the front page of a newspaper.

Write all about it

  • Get students creating their own news report with this step-by-step guide.

What is the News?

  • A sociological and media perspective on what makes an event 'newsworthy'.

On the box

  • Help pupils to write their own TV news broadcast with this handy PowerPoint.

Structuring stories

  • A scheme of work to help students structure news stories.

In the news this week

Sandy Hook shootings put US gun control debate centre-stage.

The UK experienced its second wettest year on record in 2012, with warnings that the country faces a future of increasing downpours and floods.

Data from a national census conducted in 2011 has revealed that the UK is in the midst of "an astonishing era of demographic change", with the number of foreign-born residents rising by nearly three million since 2001.

Sir Patrick Moore, the popular astronomer and broadcaster, has died aged 89.

In the news archive index