How Common Are Terrestrial Planets in The Universe?

As far as we know , there ’s only one blank space in the existence open of host life : Earth . This fact might advise that Earth is   singular or but betoken our ignorance , so   to measure the chance of having planets like Earth , a squad of scientists constructed a powerful figurer simulation that calculate at planetary establishment across the existence from the Big Bang to today .

Astronomer Erik Zackrisson from Uppsala University and his co-worker divulge some strange answer in the simulation . There are about 700 quintillion terrestrial exoplanets in the seeable universe and they are on average a few billion years older than Earth . Our planet is also in the minority when it derive to locating . Three in four planets are found in turgid spheroidal ( ovate ) galaxies because they have older stars and they are richer in big elements ( which make up major planet ) than helical coltsfoot like the Milky Way .

As there are a exchangeable amount of ellitpical galaxies to spiral galaxies , one might expect to count on a standardized amount of terrestrial planet in both , but this paper ( submitted to the Astrophysical Journal and available onArxiv ) suggests that is not the case .

Statistically speak , Earth seems to occupy a pretty peculiar position . This argue a slight violation of the Copernican precept ( Earth is not at the center of the universe , i.e. we are not especial ) ,   so while it ’s far from impossible for Earth to make in the Milky Way , it ’s unusual enough to stir a few eyebrows .

Talking toScientific American , lead writer Erik Zackrisson say : “ Whenever you witness something that stick to out that means that either we are the resultant of a very unlikely drawing draw poker or we do n’t empathize how the lottery works . ”

While the results are substantial , the simulation is not without its limits . The squad base the model on the currently mention population of planets in our local neighborhood . To simulate the universe , they used the most precise time value of cosmological parameter , well - test models of coltsfoot evolution , and an   estimate of how and when stars forms , which carry their own uncertainties .

Everything considered , the researchers are confident that the final numbers are correct within an order of order of magnitude . It will be interesting   to see how the estimates change   as more jolty planets are expose .