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In the first century AD, Ptolemy estimated the distance as 1,210 times the radius of Earth, approximately 7.71 million kilometers (0.0515 AU). [177] The theory that the Sun is the center around which the planets orbit was first proposed by the ancient Greek Aristarchus of Samos in the third century BC, [178] and later adopted by Seleucus of ...
Evolution of the solar luminosity, radius and effective temperature compared to the present-day Sun. After Ribas (2009) [3] The uncrewed SOHO spacecraft was used to measure the radius of the Sun by timing transits of Mercury across the surface during 2003 and 2006. The result was a measured radius of 696,342 ± 65 kilometres (432,687 ± 40 ...
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
[7] [15] [16] Equivalently, by this definition, one au is "the radius of an unperturbed circular Newtonian orbit about the sun of a particle having infinitesimal mass, moving with an angular frequency of 0.017 202 098 95 radians per day "; [17] or alternatively that length for which the heliocentric gravitational constant (the product GM ...
For example, according to Kopparapu's habitable zone estimate, although the Solar System has a circumstellar habitable zone centered at 1.34 AU from the Sun, [5] a star with 0.25 times the luminosity of the Sun would have a habitable zone centered at , or 0.5, the distance from the star, corresponding to a distance of 0.67 AU. Various ...
143 K at 3.2 AU to 150 K at 3 AU (Podolak and Zucker, 2010) [5] 3.1 AU (Martin and Livio, 2012) [6] ≈150 K for μm-size grains and ≈200 K for km-size bodies (D'Angelo and Podolak, 2015) [7] The location of the frost line changes over time, potentially reaching a maximum radius of 17.4 AU for a solar-mass star before decreasing after that. [8]
[121] [122] Within 7.5 billion years, the Sun will have expanded to a radius of 1.2 AU (180 × 10 ^ 6 km; 110 × 10 ^ 6 mi)—256 times its current size. At the tip of the red-giant branch , as a result of the vastly increased surface area, the Sun's surface will be much cooler (about 2,600 K (2,330 °C; 4,220 °F)) than now, and its luminosity ...
Jupiter is the only planet whose barycentre with the Sun lies outside the volume of the Sun, though by 7% of the Sun's radius. [ 130 ] [ 131 ] The average distance between Jupiter and the Sun is 778 million km (5.20 AU) and it completes an orbit every 11.86 years.