Seven ‘beautiful’ Earth-sized planets found
NASA has discovered a solar system 39 light years away with a record seven exoplanets. It is more evidence that the universe is teeming with Earth-like worlds. How should it make us feel?
Have you ever looked up at the night sky and wondered whether, somewhere out there in the blackness of space, a planet not unlike Earth revolves around a foreign sun?
Scientists now know that the answer is a resounding yes — and on Wednesday NASA made an astonishing announcement: it had found not one, but seven potentially Earth-like planets at once.
They are all orbiting a small, faint star called Trappist-1, around 39 light years away. Each planet is a similar size to Earth, and they are close enough to the cool sun to be the perfect temperature for liquid water — and maybe even life.
“This is really something new,” said the astrophysicist Ignas Snellen.
The findings confirm the idea that Earth-like planets are extremely common. In fact, back in 2013, NASA predicted that there could be at least 17 billion Earth-like planets in the Milky Way alone — possibly as many as 50 billion.
The vast majority of those are not inhabited, of course — or even habitable. Only some will be in the “Goldilocks zone” of a star’s orbit, while many will have unfriendly atmospheres thick with hydrogen and helium. And it is unclear how many of the planets might harbour the water molecules which are so vital to life as we understand it. So none of this is proof of alien life — though those who dream of other worlds will be hugely excited by the news.
Nevertheless, this latest discovery is momentous in itself. Scientists are now focusing on discovering whether any of the new planets have atmospheres. The James Webb Telescope, which will replace the Hubble telescope next year, will give a much clearer picture of the distant solar system.
The idea that these planets are just seven of a potential 50 billion — in our galaxy alone — is staggering. When Earth was first photographed from outer space in images like Earthrise and The Blue Marble, its fragile, isolated beauty changed the way people thought about our planet. It was, said one photographer, “the beginning of the environmental movement”.
Could thinking about billions of other worlds have an equally mind-altering effect?
Just a speck
To some, the vast array of other planets makes life here on Earth seem totally insignificant. When we are just a speck on the edge of infinity, they ask, why worry about bills or deadlines or social expectations? Discoveries like these teach us that we might as well do as we please — the universe does not care.
For others, the vastness and dignity of space sparks exactly the opposite revelation: being part of something so unfathomably enormous is humbling. The fact that our lives are played out on the corner of such an awesome stage gives our actions greater significance, they say, not less.
- How does it make you feel to know that our galaxy contains billions of other Earths?
- Would it still be worth exploring the universe if we knew that we could never find life outside Earth?
- Create a piece of art, music or writing with the title ‘17 billion worlds’.
- Research the particular features of planet Earth that make it suitable for the development of life, and present this information in a poster.
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What do you think?
Q & A
- Still no aliens, then?
- Not yet, sorry. But it is a major step in the hunt for extraterrestrial life: scientists say that these seven planets could help them start the search for alien life sooner than they thought — within the next decade, rather than on a much longer timescale. The next stage is to study which of these planets has conditions most likely to support life.
- So what are my odds of meeting ET someday?
- That’s a question on which scientists disagree wildly. One expert recently estimated that our galaxy contains tens of thousands of ‘civilisations’. But academics at Princeton University recently stated confidently that Earth was probably the only cradle of life in the entire universe.
- Earth-like planets
- To qualify as “Earth-like”, a planet does not have to have water, let alone rainforests, pizzas and Justin Bieber. The phrase simply describes any dense, small-to medium sized planet with a rocky surface.
- 50 billion
- After scanning a distant constellation, in 2013 a team of astronomers discovered that 17% of its stars had Earth-like planets in close orbit. The Milky Way contains around 100 billion stars, suggesting that there are at least 17 billion such planets in our galaxy. If you include harder-to-detect planets further out in orbit, the number rises to 50 billion.
- Goldilocks zone
- In the orbit of each star lies a “habitable zone”, in which planets could theoretically be found that support life. The main requirement is that it is neither too hot nor too cold. Just like the fairytale, in other words, the temperature must be “just right”.
- This photo of the Earth hovering just over the moon’s surface was taken on the Apollo 8 flight, the first manned mission to orbit the moon. It has been called the most influential photo of all time.