Thursday Thirteen #10

Thirteen Facts About The Sun

1…. Our Sun is, in fact, merely a star. It looks so big and bright, and we feel its heat, because it is much closer to us than any other star. Without the Sun's heat, light and energy, the Earth would be a barren, lifeless lump of rock.

2.... The Sun is made up of hot gases, which contain many common Earth elements, such as hydrogen, helium, calcium, sodium, magnesium, and iron.

3.... the Sun is about 1.4 million kilometers (900,000 miles) across, more than a hundred times the width of the Earth. If the Sun were a hollowed-out ball, about one million Earth-sized bodies could fit inside it.

4.... The Sun is 93 million miles away from Earth, roughly 150 million km.

5.... The Sun is around 4.5 billion years old, and is expected to remain pretty much as it is at the moment, for another 5 billion years or so. By that time, it will have expended all its hydrogen and will enter a new phase of existence. The Sun will then start to expend helium. As a result, it will expand to about 100 times its current size, becoming a red giant. Once it expends all its helium, it will collapse and become a white dwarf. Bye bye planet Earth!

6.... The Sun is a typical G2 star. G stars have a temperature of between 5000 to 6000 K. Their colour ranges from white to yellow.

7.... The light or photons emitted by the Sun cover a broad spectrum. There are very long wavelengths such as radio, as well as short wavelengths such as x-ray.

8.... Long term exposure to UV and x-rays is very dangerous, and can lead to skin cancer. Luckily, the Earth's atmosphere shields us from the more harmful of the Sun's photons. If it didn't, there would be little, if any, life on Earth.

9.... The Sun frequently experiences rapid magnetic field reconfigurations, during which large volumes of material will be ejected into interplanetary space. Such occurrences are known as Coronal Mass Ejections or CMEs. A large CME can spew a million tons of material towards the planets at up to a million miles an hour. If any of this material reaches Earth's outer atmosphere, it can affect satellites, knocking them out of orbit and damaging their surfaces. This, in turn, disrupts communications. This solar material can also disrupt power grids and cause power outages.

10... The Sun's brightness or total irradiance, fluctuates by a few tenths of a per cent over its 11 year solar cycle.

11... The Sun is, in fact, a giant, natural thermonuclear reactor. It converts hydrogen to helium in its core. The process produces the heat that we know as sunshine.

12... The reason the Sun hasn't exploded as a giant nuclear bomb, is because it is held together in an equilibrium state. Mutual gravitational attractions between all its atoms compress the solar centre. This both produces and contain the nuclear reactions taking place within the Sun. The solar atmosphere outside the energy producing core adjusts itself, so that the enormous amount of energy emerging from the Sun's surface, does so in the form of radiation, rather than a giant explosion.

13... Interaction between solar winds and Earth's geomagnetic field, causes energy particles (mainly electrons and protons) to enter Earth's upper atmosphere. These particles interact with nitrogen and oxygen molecules, which produce the red and green lights seen in phenomena such as the Aurora Borealis or Aurora Australis.

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