The Parker Solar Probe which was launched in 2018 has gotten to about 4 million miles from the sun .
The most challenging problem is obviously the extreme heat because the sun's surface temperature is about 10,000 degrees Fahrenheit (roughly 5,500 degrees Celsius). Surprisingly,the area around the sun is even hotter.Some parts of this area are 300 times hotter than the surface.The sun also emits a huge amout of radiation.These radiations become more dangerous as you get closer to the sun.Our sun is 4,5 billion years
