Local Hubble Expansion
Life on Earth has existed continually for at least 3.5 Gyr and this requires relatively stable conditions during this very long time period. However, since the luminosity of the Sun increases, the Earth should recede from the Sun. We present several examples indicating that the Solar System expands by a speed comparable to the Hubble constant. This guarantees that the Earth received almost constant solar flux during the last 3.5 Gyr. We give three independent arguments showing that the average Earth-Sun distance increases about 5 m/yr due to the finite speed of gravitational interaction. Such a large recession speed cannot be explained by solar wind, tidal forces, plasma outbursts from the Sun, or by the decrease of the Solar mass due to nuclear reactions. Models based on Newtonian mechanics can explain only a few cm per year. The measured average increase in the Earth-Moon distance is 3.84 cm/yr, while Newtonian mechanics is able to explain only 2.1 cm/yr. We claim that this difference is also caused by the finite speed of gravitational interaction. Mars was much closer to the Sun as well, otherwise it could not have had rivers 3.5 Gyr ago, when the Sunâ€™s luminosity was only 75 % of its present value, see  for details. References  M. KÅ™ÃÅ¾ek, L. Somer, Manifestations of dark energy in the Solar system, Grav. Cosmol. 21 (2015), 58â€“71.