clipped from: www.newscientist.com   
Skywatchers have been trying to gauge the sun-Earth distance for thousands of years
Takaho Miura of Hirosaki University in Japan and three colleagues
argue that the sun and Earth are literally pushing each other away due to their tidal interaction.
The sun and Earth are moving apart by about 15 cm per year - the culprit may be tides raised on the sun by our home planet (Image: NASA)
The current value stands at 149,597,870.696 kilometres.
Russian dynamicists Gregoriy A. Krasinsky and Victor A. Brumberg to calculate
that the sun and Earth are gradually moving apart.
just 15 cm per year
something must really be pushing Earth outward. But what?
Other possible explanations
a change in the gravitational constant G, the effects of cosmic expansion, and even the influence of dark matter.
It's the same process that's gradually driving the moon's orbit outward:
the moon's orbit expands by about 4 cm and Earth's rotation slows by 0.000017 second.
the distance between the Earth and sun is growing because the sun is losing its angular momentum.
the Sun is losing enough mass,
to gradually be losing its gravitational grip