What is a star? Star- a gigantic ball of very hot gases that give off heat and light (electromagnetic radiation)  Stars are different sizes, colors, ages, and distances from Earth  Stars that are closer to Earth may appear larger, even though they are smaller than others

Brightness, Color, and Temperature of Stars Betelgeuse red 3,000°C Aldebaren red-orange 5,000°C Sun yellow 6,000°C Altair white 10,000°C Spica blue 35,000°C A star’s color tells you how hot it is. Red stars are the coolest. White, or blue-white stars are the hottest.

Let’s watch the Brain Pop Video! The Life Cycle of Stars: nebula protostar star red giant white dwarf Stages of a Medium-Sized Star

 The Sun is actually a MEDIUM-SIZED star, but appear so large to us because it is the CLOSEST STAR to Earth.  There are Giant Stars that are times the size of the Sun, and Supergiants that can be up to 300 times larger than the sun! How does the Sun measure up as a star?

Relative size of the Sun

The Sun’s Layers

 Sunspots occur in the Sun’s Photosphere. They are areas that are cooler, or not as hot, as the rest of the photosphere.  Galileo noticed these dark spots, and how they moved across the face of the sun. He realized that the sun must rotate.  Now we know that the Sun rotates at an angle, rotating more slowly at the poles than at the equator. Sunspots

 Loops and fountains of blazing gases may keep out of the chromosphere and reach into the corona.  These ribbons of glowing gas are called prominences.  They may last a few days or months.  Eruptions can also occur in the chromosphere, and we call these “solar flares”.  A solar flare causes a temporary bright spot in the chromosphere that can last minutes or hours.  Solar flares give off more X-rays and other electromagnetic radiation, and this can sometimes interrupt radio communication on Earth. VIDEO: video.htmlhttp:// video.html Solar Eruptions

 A star is born in a cloud of dust and gas called a nebula.  Stars can die in different ways, depending on their mass: 1.It can use up all of its fuel (hydrogen) 2.It can become a white dwarf, explode (supernova) and leave behind a neutron star 3.It can become a black hole (the star collapses in on itself) The Life of Stars

The beginning of a SUPERNOVA