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Notes: The Sun

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The Sun

The Sun is a yellow star (a hot ball of glowing gases) at the heart of our solar system.

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The Sun

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Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest particles of debris – in its orbit.

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The Sun

The connection and interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate, radiation belts and auroras.

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The Sun

The sun has a diameter of 1.35 million km across

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1,300,000 km

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The Sun

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The sun has a volume of approximately 1 million times that of Earth

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The Sun

Density (mass divided by volume): ~¼ that of Earth

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Earth: 5.51 g/cm³

Sun: 1.41 g/cm³

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The Sun

There are no clear boundaries between the layers of the sun

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The Sun

1 rotation every 27 days

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not all parts rotate at the same speed

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Four Main Layers

3 Atmosphere

  • Corona
  • Chromosphere
  • Photosphere

1 Inner

  • Core

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Corona

  • Outer atmosphere layer made of gas particles
  • Molecules are far apart
  • Atmosphere is thin
  • ~1,700,000 ℃�

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Chromosphere

  • Middle atmosphere layer
  • 8000 km thick
  • Solar flares occur here and travel out as far as 16,000 km
  • ~4,000 - 50,000 ℃

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Photosphere

  • Innermost atmosphere layer
  • 550 km thick
  • ~6,000 ℃�
  • Referred to as the “surface” of the sun
  • Source of visible light (the light we see!!)

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Core

  • 347,000 km across
  • ~15,000,000 ℃

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  • Where energy of the Sun is made
    • Fission and fusion reactions occur here
    • Hydrogen is fused into helium

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Core

  • Radiative zone
    • Energy is transferred by electromagnetic radiation
    • ~2,500,000 ℃

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Core

  • Convective zone
    • Heated gas rises and cools
    • Varies between 200,000 and 5,700 ℃

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Activity on the Sun - Prominences

  • solar storms - huge arches of glowing gas from one sunspot to another
  • up to 1,000,000 km
  • Send gas and energy into space
  • May last several weeks or up to a year

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Activity on the Sun - Solar Flare

  • Sudden eruption of electrically charged particles usually near sunspots
  • Storms seen as bright burst of light�
  • May last up to 1 hour
  • Release massive amounts of energy

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Activity on the Sun - Solar Wind

  • Continuous streams of high energy particles released by the Corona
  • May increase during solar flares
  • Can effect radio and TV waves

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Activity on the Sun - Sunspots

  • Storms in lower atmosphere
  • 16 - 160,000 km across
  • Activity increases every 10-11 years
  • Cool, dark areas of gas within the photosphere caused by powerful magnetic fields