November 28, 2012

What is the Sun?

Hi I’m Emerald with RedOrbit. In this “What Is” video we’ll find out about the real star of our solar system, the Sun.

Our sun, born roughly 4.6 billion years ago is the object around which our solar system orbits; but in the grand scheme of things, it’s just another medium-size star in a remote corner of the Milky Way galaxy.

However for us earthlings, the sun is hugely important. Without it, our world would be a frozen rock with no light, heat or energy source.

The mass of the Sun accounts for 99.86% of the total mass in the solar system. It could hold 109 planet Earths across its surface and more than a million Earths could fit inside it. The sun is a giant hot ball of scorching gases. How hot? The temperature is about 10,000 degrees Fahrenheit on the surface and more than 27 million degrees Fahrenheit at its core. You would need to explode 100 billion tons of dynamite every second to match the energy produced by the Sun.

Deep in the sun’s core, nuclear fusion reactions convert hydrogen to helium, which generates energy. Particles of light called photons carry this energy through the sun’s radiative zone, to the top layer of the solar interior, the convection zone. There, boiling motions of gases (like in a lava lamp) transfer the energy to the surface. This journey takes more than a million years.

In addition to heat and light, the sun radiates a steady stream of charged particles known as the solar wind. The wind blows about 250 miles a second throughout the solar system. Particles often burst from the sun in a solar flare, which happen when stored energy in magnetic fields is suddenly released. Flares can disrupt satellite communications and knock out power on Earth.

Scientists believe the sun has enough nuclear fuel for another five billion years. After that, the sun will begin to burn helium and expand a hundred times its current size. It will burn as a red giant for another billion years and then collapse into a white dwarf about the size of planet Earth.

Until then, the forecast looks bright for our life-giving star, the sun.

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