Why is the Earth moving away from the sun?
New Scientist
This is indeed my thought on the subject and seems to be scientific common sense. The other possible reasons may also come into play, but then again they could all be contributing factors at the same time. It need not be an either or scenario (and most likely not) but a matter of combining factors.
But I suspect the real problem in knowing the answer is that we have a very short scientific historical record, even if 2000 years ago the measurement was accurate, which it was not.
Why does it matter?
For a number of reasons, starting with climate change here on earth as well as just our understanding the nature of our solar system and then extended to other solar systems of which there are billions... scratch that, trillions.
Things that make you say/think Hmmm?...
New Scientist
Quote:
Skywatchers have been trying to gauge the sun-Earth distance for thousands of years. In the third century BC, Aristarchus of Samos, notable as the first to argue for a heliocentric solar system, estimated the sun to be 20 times farther away than the moon. It wasn't his best work, as the real factor is more like 400. By the late 20th century, astronomers had a much better grip on this fundamental cosmic metric – what came to be called the astronomical unit. In fact, thanks to radar beams pinging off various solar-system bodies and to tracking of interplanetary spacecraft, the sun-Earth distance has been pegged with remarkable accuracy. The current value stands at 149,597,870.696 kilometres. Having such a precise yardstick allowed Russian dynamicists Gregoriy A. Krasinsky and Victor A. Brumberg to calculate, in 2004, that the sun and Earth are gradually moving apart. It's not much – just 15 cm per year – but since that's 100 times greater than the measurement error, something must really be pushing Earth outward. But what? One idea is that the Sun is losing enough mass, via fusion and the solar wind, to gradually be losing its gravitational grip (see Astronomical unit may need to be redefined). Other possible explanations include a change in the gravitational constant G, the effects of cosmic expansion, and even the influence of dark matter. None have proved satisfactory. |
This is indeed my thought on the subject and seems to be scientific common sense. The other possible reasons may also come into play, but then again they could all be contributing factors at the same time. It need not be an either or scenario (and most likely not) but a matter of combining factors.
But I suspect the real problem in knowing the answer is that we have a very short scientific historical record, even if 2000 years ago the measurement was accurate, which it was not.
Why does it matter?
For a number of reasons, starting with climate change here on earth as well as just our understanding the nature of our solar system and then extended to other solar systems of which there are billions... scratch that, trillions.
Things that make you say/think Hmmm?...
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