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[Music]

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planet earth is an oasis of life

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but without the sun our home planet

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would be little more than a frozen rock

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the sun is a powerful blazing star it

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radiates huge amounts of electromagnetic

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energy in all directions

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earth is only one small recipient of the

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sun's energy

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the sun's rays extend far out into the

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solar system illuminating all the other

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planets

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[Music]

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the sun warms the earth and makes life

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possible here

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its energy also generates clouds cleans

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our water and drives ocean currents

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for three decades nasa's scientists have

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investigated the unique relationship

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between the sun and the earth

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they study the solar power arriving at

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earth and they examine how it breaks

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down into different wavelengths

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thirty percent of incoming solar power

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is reflected back into space by things

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like clouds aerosols ice and snow

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the remaining seventy percent is

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absorbed by the land ocean and

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atmosphere and this solar power is what

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drives the climate system

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the earth's energy budget is a delicate

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balance between incoming solar and

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outgoing thermal energy

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it's the balance between those two forms

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of energy that determines the

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temperature of the planet

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our energy budget is a little bit out of

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balance now and that's due to the carbon

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dioxide and other greenhouse gases in

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the atmosphere

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as humans burn fossil fuels greenhouse

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gases accumulate in the atmosphere and

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block the earth's outgoing heat

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the resulting imbalance will cause the

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earth to heat up over the next century

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accelerating the melting of polar ice

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caps causing sea levels to rise and

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creating more violent global weather

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patterns

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[Music]

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humans affect earth's climate internally

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and the sun is the primary external

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influence

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sunspots in solar weather cause incoming

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solar power to vary

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and long-term fluctuations in the solar

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cycle can impact earth's climate

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[Music]

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as the earth warms scientists strive to

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better understand the sun's direct and

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indirect effect on the earth

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the total irradiance monitor or tim

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instrument was launched in 2003 as part

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of nasa's source mission

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tim measures total solar irradiance with

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state-of-the-art accuracy and has been

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rebuilt as part of nasa's upcoming glory

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mission

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scheduled to launch in 2009 glory will

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also collect data on aerosols one of the

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least understood components of the

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climate puzzle

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as our home planet changes in

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unprecedented ways researchers will

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continue to rely on nasa missions to

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illuminate their understanding of the

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earth and the sun