快猫短视频

COLLISIONS with planet-sized space debris could help explain long-standing
mysteries about the Sun, according to calculations by British astronomers. Some
of the collisions may have been large enough to knock the Sun off its axis.

快猫短视频s have assumed that the Sun鈥檚 core contains a mixture of elements
similar to that seen on the surface. But resulting models suggest that the young
Sun was too cool for life to emerge on Earth 3.5 billion years ago.

Now Simon Jeffery and colleagues at Armagh Observatory near Belfast say they
can solve this problem by drawing on recent observations of young stars. These
have revealed closely orbiting planets, about the size of Jupiter, and rings of
thick dust and gas. Jeffery says that collisions within such discs would cause
some of their contents鈥攂etween 2 and 100 Earth masses of debris rich in
heavy elements鈥攖o spiral in towards the star.

If the same thing happened during the evolution of the Sun, the Sun鈥檚 core
may contain much less of the heavier elements than the dusted surface. In the
current issue of Observatory(vol 117, p 224), Jeffery says that
revising the models to include a lighter core would predict a Sun warm enough
for life to emerge.

Jeffery also found that the impact of a Jupiter-sized planet could tilt the
Sun if it collided just a few degrees above or below the equator. He says such
an impact could explain why the Sun鈥檚 axis is seven degrees out of plumb with
the rest of the Solar System.

But some experts doubt that Jeffery鈥檚 calculations solve all the problems.
Douglas Gough of Cambridge University, an expert on the Sun鈥檚 structure, says
that 鈥渄irty sun鈥� models put forward in the past do not have the power to resolve
the Sun problem. 鈥淭herefore, I am sceptical.鈥�