日光微暖middle of the next solar maximum which could affect the functions of communications satellites," said Professor Richard Harrison, head of space physics at the Rutherford Appleton Laboratory in Oxfordshire．
At the peak of the cycle, violent outbursts called coronal mass ejections (日冕物质抛射) occur in the Sun's atmosphere, throwing out great quantities of electrically-charged matter．" A coronal mass ejection can carry a billion tons of solar material into space at over a million kilometres per hour．Such events can expose astronauts to a deadly amount, can disable satellites, cause power failures on Earth and disturb communications," Professor Harrison added．The risk is greatest during a solar maximum when there is the greatest number of sunspots.
Next week in America, NASA is scheduled to launch a satellite for monitoring solar activity called the Solar Dynamics Observatory (SDO), which will take images of the Sun that are 10 times clearer than the most advanced televisions available.
The Rutherford Appleton Laboratory helped to make the high-tech cameras that will capture images of the solar flares (太阳耀斑) and explosions as they occur.
Professor Richard Hold away, the lab's director, said that the SDO should be able to provide early warning of a solar flare or explosion big enough to affect satellite communications on Earth "If we have advance warning, we'll be able to reduce the damage．What you don't want is things switching off for a week with no idea of what's caused the problem," he said.
72．The phrase "communications blackout" in paragraph 1 most probably refers to during the 2012 Olympics.
A．the extinguishing of the Olympic torch
B．the collapse of broadcasting systems
C．the transportation breakdown in London
D．the destruction of weather satellites
73．What can be inferred about the solar activity described in the passage?
A．The most fatal matter from the corona falls onto Earth.
B．The solar storm peak occurs in the middle of each cycle.
C．It takes several seconds for the charged matter to reach Earth.
D．The number of sunspots declines after coronal mass ejections.
74．According to the passage, NASA will launch a satellite to _ _
A．take images of the solar system
B．provide early warning of thunderstorms
C．keep track of solar activities
D．improve the communications on Earth
75．Which of the following might be the best title of the passage?
A．Solar Storms: An Invisible Killer
