Aliens Haven't Visited Earth Because They're Probably Trapped On Their Planets, Scientist Says

Is there life out there in the cosmos? If there are, new research says they're probably unable to get out of their own planets.

There's little chance of meeting alien life forms any time soon, particularly with the technology currently known on Earth.

Alien Life Unlikely To Travel Space

According to a report from Space.com, research has shown that super-Earths — also known as bigger versions of Earth — are more likely to host life than similar-sized planets due to their greater gravitational pulls. With thicker atmospheres, these planets are better protected from harmful rays. Super-Earths have also been spotted in habitable zones where temperatures could theoretically support water and similar life as Earth's.

However, a new study titled "Spaceflight From Super-Earths Is Difficult" points out that the grater gravitational pull could work against these planets as well. Specifically, space travel from these super-Earths is much more challenging due to their higher surface gravity, since fuel mass would have to be that much greater as well.

The study says a classical Apollo moon mission from a super-Earth would require a rocket that's about 400,000 metric tons or 440,000 tons. While chemical rocket launches are possible in super-Earths with mass 10 times greater than Earth, launches from bigger planets are reportedly unrealistic.

From such planets, space travel would only be possible using nuclear-powered rockets.

"Civilizations from super-Earths are much less likely to explore the stars," Michael Hippke, study author and independent researcher affiliated with the Sonneberg Observatory in Germany, explains to Space.com.

"Instead, they would be to some extent arrested on their home planet and, for example, make more use of lasers or radio telescopes for interstellar communication instead of sending probes or spaceships."

Hippke's study has been submitted to the International Journal of Astrobiology.

The Argument Against Hippke's Study

A report on NBC News by Seth Shostak, a SETI Institute senior astronomer, acknowledges the greater challenge it would take to leave a super-Earth, but says it's not as insurmountable as Hippke's study makes it seem.

After all, a super-Earth rocket with a similar design to SpaceX's Falcon Heavy rocket would have to be 15,000 tons and twice as high as the Falcon, which is impressive but not impossible.

Shostak also points out that the bigger mass of a super-Earth offers some advantages, including a thicker atmosphere that could make aviation development faster as well as a greater potential in natural resources and animal diversity.