Read and translate in writing the following excerpt from Scientific American.

Date: 2015-10-07; view: 337.

Magnetic Tornadoes May Heat Solar Corona

The sun's outer atmosphere, or corona, is much hotter than the surface. Giant magnetic tornadoes may be behind the heat transfer.

The sun is hot. That's obvious. But it's where it's hot that has physicists puzzled.

The sun's outer atmosphere, or _____________, is much hotter than the surface, even though the surface is closer to the _________ _________ reactor of the solar interior. Why that should be is one of the big questions in solar physics. There have been several _____________ for how all that heat arrives in the corona, from oscillating __________ waves to jets of hot plasma.

Now a team of European researchers has discovered a new possibility: giant magnetic tornadoes. These supersize ___________ can be some 1,500 kilometers across. And they've been seen on the sun's surface and in its lower atmosphere. With the help of NASA's Solar Dynamics Observatory the researchers spotted the tornadoes reaching up into the corona as well. They reported their finding in the journal Nature.

The solar swirls are plentiful—more than 10,000 of them dot the sun at any given time. And they could funnel quite a bit of energy up into the solar atmosphere. It's too early to say how big a role the tornadoes play in heating the corona. But their discovery is sure to make a hot topic even hotter.

—John Matson

Interstellar gas permeates the Milky Way, but not evenly. The solar system happens now to inhabit an unusually empty patch of space, the local bubble, with only one hydrogen atom per five cubic centimeters of space. In the past we must have drifted through much denser gas clouds, including some more than 100 light years across in whose cold and dark interiors hydrogen forms itself into molecules.

In such nebula, Earth may have caught a cold. Usually, the solar system's interior is protected from harsh interstellar radiation by the solar wind, a stream of charged particles that flows deep into space, forming a huge electromagnetic shield called the heliosphere. When the interstellar gas gets denser, the solar wind can't push as far, and the heliosphere shrinks. Above a density of around 1000 molecules per cubic centimeter, it will contract to within Earth's orbit. That might happen every few hundred million years.

The accumulation of hydrogen in Earth's high atmosphere would alter its chemistry, creating a reflective aloud layer, while dust could mimic the shading effect of sulphate aerosols from volcanic eruptions. Alex Pavlov of the University of Colorado, Boulder, says the dust alone could trigger a global ice age