It is not enough for scientists to find rocky planets in a star's habitable zone, the region where a planet can host liquid water, as we know it.
That is just the beginning. Nitrogen and the ratio of land to sea may play a role in a planet's habitability. One of the key characteristics of a life-supporting, rocky exoplanet is that it must be young, according to a team of scientists. To support life, a planet needs enough heat to power a carbon cycle, which is created due to the radioactive decay of elements such as uranium and thorium.
Exoplanets without active degassing are more likely to be cold.
What makes a planet hospitable? Our assumptions may be wrong.
The release of gasses held within a planet into the atmosphere through volcanoes is caused by radioactive decay. Carbon dioxide is added to the atmosphere by degassing. The scientists explained in a new paper that older planets may not be able to retain their heat because they have consumed their radioactive resources.
We don't know how long radioactive elements can last because they decay over time.
How long can an exoplanet sustain radioactive decay? The amount of radioactive elements on each exoplanet can vary.
Under the most pessimistic conditions, we estimate that this critical age is only around 2 billion years old for an Earth-mass planet and around 5 billion to 6 billion years for higher-mass planets.
There are habitable zones around planets.
Current technology cannot determine what elements exist on an exoplanet. The light from a planet's star can indicate what elements are present in the system as a whole.
Scientists will be able to determine the composition of exoplanets atmospheres with the James Webb Space Telescope, which will reveal more clues as to the ages and potential ability of these worlds to be heated by radioactive decay.
The research was published in a journal.
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