your mission Your mission is to explore how energy from the sun can be put to work on Earth How can sunshine light homes heat water and be turned into electricity What technologies can help us use more solar power Can sunshine replace other energy sources that are polluting the planet How will solar power help shape our energy future Check the facts in What You Know then begin your mission to learn just how powerful solar energy can be what you know (cid:204) Right now more than 80 percent of the energy that powers our modern lifestyle comes from oil coal and natural gas These are all fossil fuels (cid:204)(cid:3)Scientists want to produce energy in ways that are more efficient less expensive and better for the environment than our present energy sources (cid:204)(cid:3)Sunshine or solar energy is currently used to light homes heat water and produce electricity 4
The sun might play an important role in meeting our future energy needs (cid:204) Energy from the sun comes to Earth in the form of solar radiation Jared O’Neil wants to know more about solar power He plans to spend the next few weeks interviewing scientists and others who can help him learn more about solar energy and the work it can do Your mission starts when you open Jared’s journal 5
April 18 A Huge Ball of Gas I know the sun is a powerful star Solar energy helps plants grow and powers the wind and the rain Without the sun’s energy our planet would be just another lifeless rock in space Today I’m visiting a university in Nebraska Professor Tara Anderson is a solar astronomer who works there She has agreed to show me the sun through the university’s special telescope First she tells me I should never ever look at the sun on my own Doing that can cause serious damage to my eyes (cid:53)(cid:73)(cid:70)(cid:1)(cid:84)(cid:86)(cid:79)(cid:1)(cid:74)(cid:84)(cid:1)(cid:85)(cid:73)(cid:70)(cid:1)(cid:68)(cid:77)(cid:80)(cid:84)(cid:70)(cid:84)(cid:85)(cid:1)(cid:84)(cid:85)(cid:66)(cid:83)(cid:1)(cid:85)(cid:80)(cid:1)(cid:38)(cid:66)(cid:83)(cid:85)(cid:73)(cid:15)(cid:1)(cid:42)(cid:85)(cid:1)(cid:73)(cid:66)(cid:84)(cid:1)(cid:67)(cid:70)(cid:70)(cid:79)(cid:1)(cid:66)(cid:68)(cid:85)(cid:74)(cid:87)(cid:70)(cid:1)(cid:71)(cid:80)(cid:83)(cid:1) (cid:68)(cid:85)(cid:74) (cid:70) (cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:71)(cid:80)(cid:83) (cid:83) (cid:78)(cid:80)(cid:83)(cid:70)(cid:1)(cid:85)(cid:73)(cid:66)(cid:79)(cid:1)(cid:21)(cid:15)(cid:22)(cid:1)(cid:67)(cid:74)(cid:77)(cid:77)(cid:74)(cid:80)(cid:79)(cid:1)(cid:90)(cid:70)(cid:66)(cid:83)(cid:84)(cid:15) 6
Through the telescope the sun looks just like the huge ball of hot gas that it is Professor Anderson explains that the sun is huge It’s so big that more than 1 million Earths could fit inside of it The sun’s energy comes from nuclear explosions deep inside it The sun’s core is about 27 million degrees Fahrenheit or 15 million degrees Celsius says Professor Anderson All that energy eventually heads out into space in electromagnetic waves Most of the solar radiation reaching the earth is in the form of visible light It comes in all the colors of the rainbow She tells me that green plants have a light-absorbing substance called chlorophyll The energy that chlorophyll absorbs powers a chemical reaction between water and carbon dioxide That reaction is called photosynthesis and it’s how green plants make energy Photosynthesis makes carbon-based sugars Plants and the animals that eat the plants depend on these sugars to live You probably know that most of the energy we use today comes from fossil fuels Professor Anderson says Fossil fuels come from animals and plants that died long ago Over a very long time they became buried deep underground Heat and pressure from the rocks above them turned their remains into rich energy sources 7
