The Star Diver

摘要

If you are taking a trip to the sun, you'd better plan on bringing some shade.rnThat is the guiding principle behind NASA's $740 million Solar Probe Plus, scheduled to blast off in 2015. At its closest it will be within 4 million miles of the roiling solar surface, known as the photosphere. (For comparison, scorched Mercury circles the sun at an average distance of 36 million miles.) No spacecraft has attempted anything like this. Swooping so close to the sun means braving temperatures of 2,600 degrees Fahrenheit, above the melting point of stainless steel.