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  2. Crater counting - Wikipedia

    en.wikipedia.org/wiki/Crater_counting

    Crater counting. Shield volcano in Tharsis region on Mars with marked borders, circles represent impact craters counted by crater counting method. Crater counting is a method for estimating the age of a planet's surface based upon the assumptions that when a piece of planetary surface is new, then it has no impact craters; impact craters ...

  3. Age of Earth - Wikipedia

    en.wikipedia.org/wiki/Age_of_Earth

    The age of Earth is estimated to be 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%).[1][2][3][4] This age may represent the age of Earth 's accretion, or core formation, or of the material from which Earth formed. [2] This dating is based on evidence from radiometric age-dating of meteorite [5] material and is consistent with the ...

  4. Age of the universe - Wikipedia

    en.wikipedia.org/wiki/Age_of_the_universe

    In physical cosmology, the age of the universe is the time elapsed since the Big Bang.Astronomers have derived two different measurements of the age of the universe: [1] a measurement based on direct observations of an early state of the universe, which indicate an age of 13.787 ± 0.020 billion years as interpreted with the Lambda-CDM concordance model as of 2021; [2] and a measurement based ...

  5. Drake equation - Wikipedia

    en.wikipedia.org/wiki/Drake_equation

    The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy. [1][2][3] The equation was formulated in 1961 by Frank Drake, not for purposes of quantifying the number of civilizations, but as a way to stimulate scientific dialogue at the first ...

  6. Solar System - Wikipedia

    en.wikipedia.org/wiki/Solar_System

    Age: 4.568 billion years [b] ... by the known giant planets than other minor planet populations. ... of Venus allowed astronomers to calculate the average Earth–Sun ...

  7. Numerical model of the Solar System - Wikipedia

    en.wikipedia.org/wiki/Numerical_model_of_the...

    A numerical model of the Solar System is a set of mathematical equations, which, when solved, give the approximate positions of the planets as a function of time. Attempts to create such a model established the more general field of celestial mechanics. The results of this simulation can be compared with past measurements to check for accuracy ...

  8. Stellar age estimation - Wikipedia

    en.wikipedia.org/wiki/Stellar_age_estimation

    In addition, knowing the age of one member of a star system can help determine the age of that system. In a star system, stars almost always form at the same time as each other, and given the age of one star, the age of all of the others can be known. [14] However, this method does not work for galaxies. These units are much larger, and are not ...

  9. Cosmic age problem - Wikipedia

    en.wikipedia.org/wiki/Cosmic_age_problem

    The cosmic age problem was a historical problem in astronomy concerning the age of the universe. The problem was that at various times in the 20th century, the universe was estimated to be younger than the oldest observed stars. Estimates of the universe's age came from measurements of the current expansion rate of the universe, the Hubble ...