What size of planet would prevent space travel due to gravity? Part 2
Our readers continue to grapple with this question, coming at it from different angles – and also considering how big a planet has to be to retain its atmosphere
To prevent space travel, a planet's gravity must reach approximately 1.2 times Earth's gravity. This is due to the necessity of a certain escape velocity, which, in this case, is set as the speed of light. The size of the planet required to achieve this gravity depends on its density. Assuming Earth's average density, a planet would need to have a radius of about 170 million kilometers.
However, by definition, such a massive planet would also be a black hole, making it unlikely for inhabitants to tackle this problem. Retaining an atmosphere also plays a role, with a gravity of around 1.2 g being sufficient. This means that a gravity range of 0.6 to 1.2 g could potentially prevent both space travel and atmospheric retention.
Therefore, for life forms requiring an atmosphere and the ability to travel in space, the gravity range should ideally be around 0.8 g, which is strong enough to retain the atmosphere while still allowing for easier rocket launches and space travel.
Written by urgent.news from New Scientist's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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- What Can We Actually Find on an Exoplanet? Part 4: Looking For Us universetoday.com
