Scientists have discovered 24 potentially* “superhabitable” planets with conditions that may be better for life than Earth.
The mysterious worlds are older, larger, warmer and possibly wetter than our planet, making them prime* targets for future alien-hunting missions.
Researchers at Washington State University outlined their stunning find in a scientific paper published on October 5.
The planets are 100 light-years from Earth, making them too distant to visit, but possible to study with future advanced space telescopes.
Probes like the European Space Agency’s ARIEL mission, due for launch in 2028, are specially designed to seek signs of life on faraway worlds.
“With the next space telescopes coming up, we will get more information, so it is important to select some targets,” the university’s Professor Dirk Schulze-Makuch said.
“We have to focus on certain planets that have the most promising conditions for complex life.
“However, we have to be careful to not get stuck looking for a second Earth because there could be planets that might be more suitable for life than ours.”
The team created a “superhabitability criteria”, which they lined up against 4500 known exoplanets – planets outside our Solar System.
Habitability wasn’t defined as definite signs of life, but as hosting conditions that make them ripe for its growth.
The criteria included being up to 10 per cent larger than Earth, with a surface temperature 5C above that of our own planet and an age of between 5 billion and 8 billions years. Earth is 4.5 billion years old.
Worlds also had to exist in their star’s habitable zone — defined as the area in which a planet could support water at its surface — and orbit a star that is cooler than our Sun, meaning it has a longer lifespan.
In total, 24 potentially “superhabitable” planets were found that may have conditions better for supporting life than Earth.
None of the planets conclusively* met all five of the criteria laid out by scientists, but one met four of them.
Researchers stressed that the results did not mean the 24 worlds definitely hosted life.
“Habitability does not mean these planets definitely have life, merely the conditions that would be conducive* to life,” the scientists said in a media release.
The distant planets could become key targets for planet-scanning space telescopes of the future.
More than 4500 exoplanets have been detected by scientists but we don’t know much about them.
The next generation of space probes, including the ARIEL mission and NASA’s James Webb Space Telescope, will be able to observe atmospheres in more detail.
ARIEL aims to observe 1000 planets in detail to give us a more accurate picture of potential alien worlds.
By observing a huge number of planets, scientists hope to reveal secrets about their chemistry, formation and evolution.
The research was published in the journal Astrobiology.
WHAT IS AN EXOPLANET?
- An exoplanet is a planet that is located outside of our Solar System and one that is orbiting* its own star, as Earth orbits the Sun
- They are very hard to see with telescopes because they are often hidden by the brightness of their star
- NASA sent the Kepler space telescope into orbit with the purpose of finding Earth-sized exoplanets that might support life
- More than 4500 exoplanets have been discovered so far and more missions to find even more exoplanets are planned
- A good way to spot an exoplanet is to look for “wobbly” stars because a disruption to starlight can indicate that a planet is orbiting it and blocking its light intermittently*
- Exoplanets are very common in the universe and the more we find that look like Earth, the closer we get to knowing whether Earth is the only life-bearing planet
This story was first published on The Sun and is republished here with permission.
GLOSSARY
- potentially: being possible
- prime: important, main
- conclusively: definitely
- conducive: favourable
- orbiting: moving in a circle around an object
- intermittently: every now and then
EXTRA READING
Discovery of Earth-like habitable planet
Astronomers watch birth of a new planet
Water found on super-Earth called K2-18b
New planet in “Goldilocks” zone could support life
QUICK QUIZ
- How many planets are thought to be superhabitable?
- How much bigger than Earth are the superhabitable planets?
- What age are the superhabitable planets?
- What is the name of the European Space Agency mission due to be launched in 2028?
- How many exoplanets have been discovered so far?
LISTEN TO THIS STORY
CLASSROOM ACTIVITIES
1. Draw or make a planet
Draw or create a model of an exoplanet that could be capable of supporting life. Add five labels or captions that provide factual information to explain why the planet you have drawn/made might be habitable.
Time: allow 30 minutes to complete this activity
Curriculum Links: English; Science
2. Extension
If there is life on other planets, the landscape and life might be very different to what we know here on Earth. Imagine that you have been transported to an exoplanet where there is life. Write a vivid description of what you discover there.
Time: allow 20 minutes to complete this activity
Curriculum Links: English
VCOP ACTIVITY
Opener Up-Level It
Make a list of all the openers in the article. Pick three that repeat and see if you can replace them with another word, or shuffle the order of the sentence to bring a new opener to the front.
Don’t forget to re-read the sentence to make sure it still makes sense, and that it actually sounds better.
HAVE YOUR SAY: Do you think there could be life on an exoplanet and what form could it be?
No one-word answers. Use full sentences to explain your thinking. No comments will be published until approved by editors.
