In February, Nasa announced the discovery of a star known as TRAPPIST-1 which was found to have seven planets orbiting it.
The newly found solar system, which is the closest to have been found to Earth, piqued the interest of alien hunters as three of its planets fall into the star’s habitable zone – the region around a host star where conditions are neither too hot nor too cold to support life.
However, new research has found that the star system’s planets may not have any large moons due to how compact it is.
Some scientists believe that the origin of life on Earth was aided by the fact that our planet has a large moon.
The TRAPPIST-1 star system
It is theorised, but not proven, that the gravitational pull of a large moon on a planet can stabilise the planets axis rotation, leading to a stronger ecosystem and a greater chance of life beginning.
Researcher Stephen Kane, an associate professor of astronomy at San Francisco State University, said that the possible absence of moons in the TRAPPIST-1 system could indicate that it is not as habitable as previously thought.
TRAPPIST-1 is much more compact than our star system
He told Space.com: "The presence of the moon has helped to stabilise changes in the tilt of the Earth's rotational axis, which in turn creates longer periods of climate stability.
"So although it's difficult to say what the Earth would be like without a moon, we can certainly describe ways in which it has positively influenced our present environment.”
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Astronomers hoped that TRAPPIST-1 may contain life
He added: "A moon can only exist around a planet if it lies between these two boundaries: too close and it will be destroyed, too far away and it will escape the gravitational influence of the planet.
"The results of the study described in my paper show that, for most planets in compact planetary systems, the Hill radius and Roche limit are close enough to each other that there is no space in which a moon can exist and so such planets cannot have moons in orbit around them."