Ray Moscow
06-04-2009, 12:12 PM
OK, I knew that the moon was gradually getting a bit further away from earth, but I didn't know that the earth was moving further away from the sun. But it is, as you might expect if you think about it a bit.
Why is the Earth moving away from the sun? (http://www.newscientist.com/article/dn17228-why-is-the-earth-moving-away-from-the-sun.html)
But the new idea about why this is happening surprised me:
But Takaho Miura of Hirosaki University in Japan and three colleagues think they have the answer. In an article submitted to the European journal Astronomy & Astrophysics, they argue that the sun and Earth are literally pushing each other away due to their tidal interaction.
It's the same process that's gradually driving the moon's orbit outward: Tides raised by the moon in our oceans are gradually transferring Earth's rotational energy to lunar motion. As a consequence, each year the moon's orbit expands by about 4 cm and Earth's rotation slows by 0.000017 second.
Likewise, Miura's team assumes that our planet's mass is raising a tiny but sustained tidal bulge in the sun. They calculate that, thanks to Earth, the sun's rotation rate is slowing by 3 milliseconds per century (0.00003 second per year). According to their explanation, the distance between the Earth and sun is growing because the sun is losing its angular momentum.
Why is the Earth moving away from the sun? (http://www.newscientist.com/article/dn17228-why-is-the-earth-moving-away-from-the-sun.html)
But the new idea about why this is happening surprised me:
But Takaho Miura of Hirosaki University in Japan and three colleagues think they have the answer. In an article submitted to the European journal Astronomy & Astrophysics, they argue that the sun and Earth are literally pushing each other away due to their tidal interaction.
It's the same process that's gradually driving the moon's orbit outward: Tides raised by the moon in our oceans are gradually transferring Earth's rotational energy to lunar motion. As a consequence, each year the moon's orbit expands by about 4 cm and Earth's rotation slows by 0.000017 second.
Likewise, Miura's team assumes that our planet's mass is raising a tiny but sustained tidal bulge in the sun. They calculate that, thanks to Earth, the sun's rotation rate is slowing by 3 milliseconds per century (0.00003 second per year). According to their explanation, the distance between the Earth and sun is growing because the sun is losing its angular momentum.