Thursday, 12 June 2008

Fascinating facts about the Sun

I was reading today how NASA is planning to send a probe to the Sun, which got me reading Wikipedia's article on the subject. I thought I already had a fair appreciation for the topic, but some of the facts in there are simply amazing. Most of the figures are just impossible to wrap your head around. How's these for starters:

  1. The energy output of the Sun is equivalent to about 200,000 times the output of all the atomic weapons ever detonated on Earth, every second.
  2. The Sun is so perfectly spherical that even with a diameter of 1.4 million kilometers, the variation in diameter is only 10 km.
  3. Even including Jupiter, which is hundreds of times more massive than Earth, the Sun still accounts for more than 99.8% of the mass in the solar system.
  4. The Sun (along with the whole solar system) is moving through space, around the core of the Milky Way, at about 800,000 km/h.
  5. In about a billion year's time, the Sun will get so hot that all of the water and atmosphere on Earth will be evaporated and any life will be long gone. After about five billion years, as the Sun goes through it's death throes, it will expand to engulf the Earth itself.
  6. Almost 7 billion tons of mass are lost from the Sun every hour as the solar wind. This wind pushes out a bubble in intergalactic space that extends beyond Pluto.
  7. The visible surface of the Sun is a relatively cool 5000 degrees (Celsius or kelvin; it's all about the same at this point), yet the outer coronal mass is over 1 million degrees. Compare this to fusion reactors on Earth that operate at around 100 million degrees.
  8. By mass, the hot core of the Sun puts out a million times less energy than the human body.
  9. As the photons are created in the core, absorbed and re-emitted, it takes them tens of thousands of years to reach the outer surface of the Sun, then only 8 more minutes to reach Earth.