Реферат: Solar System Essay Research Paper The Sun

large, as much as 50,000 km in diameter. Sunspots are caused by

complicated and not very well understood interactions with the Sun’s

magnetic field.

A small region known as the chromosphere lies above the photosphere.

The highly rarified region above the chromosphere, called the corona,

extends millions of kilometers into space but is visible only during eclipses

(left). Temperatures in the corona are over 1,000,000 K.

The Sun’s magnetic field is very strong (by terrestrial standards) and

very complicated. Its magnetosphere (also known as the heliosphere

extends well beyond Pluto.

In addition to heat and light, the Sun also emits a low density stream of charged

particles (mostly electrons and protons) known as the solar wind which

propagates throughout the solar system at about 450 km/sec. The solar wind and

the much higher energy particles ejected by solar flares can have dramatic effects

on the Earth ranging from power line surges to radio interference to the beautiful

aurora borealis.

Recent data from the spacecraft Ulysses show that the solar wind emanating from the polar

regions flows at nearly double the rate, 750 kilometers per second, that it does at lower latitudes.

The composition of the solar wind also appears to differ in the polar regions. And the Sun’s magnetic

field seems to be surprisingly uniform.

Further study of the solar wind will be done by the recently launched Wind, ACE and SOHO

spacecraft from the dynamically stable vantage point directly between the Earth and the Sun about

1.6 million km from Earth.

The solar wind has large effects on the tails of comets and even has measurable effects on the

trajectories of spacecraft.

Spectacular loops and prominences are often visible on the Sun’s limb (left).

The Sun’s output is not entirely constant. Nor is the amount of sunspot activity.

There was a period of very low sunspot activity in the latter half of the 17th century called the

Maunder Minimum. It coincides with an abnormally cold period in northern Europe sometimes