1. About 67,000 mph
2. The milky way
3. A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity.
4. (The picture below)
5. Astronomers can use what are called surface brightness fluctuations (SBF, for short), along with the color of a galaxy, to calculate how far away it is from earth. Light travels about 299,792 kilometers per second.
6. Astronomers define star brightness in terms of apparent magnitude — how bright the star appears from Earth — and absolute magnitude — how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
7. The magnitude of a celestial object as it is actually measured from the earth.
8. As the light from the stars comes through the earth's atmosphere, they appear to be twinkling. This makes the cooler stars appear red and the stars with the higher temperatures appear blue or white. From cool to hot, the colors can appear red, orange, yellow, green and blue.
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10. About 8 minutes and 20 seconds.
11. The energy from the Sun - both heat and light energy - originates from a nuclear fusion process that is occurring inside the core of the Sun. Inside the Sun, this process begins with protons (which is simply a lone hydrogen nucleus) and through a series of steps, these protons fuse together and are turned into helium.
12. A brief eruption of intense high-energy radiation from the sun's surface, associated with sunspots and causing electromagnetic disturbances on the earth, as with radio frequency communications and power line transmissions.
13. Sunspots are darker, cooler areas on the surface of the sun in a region called the photosphere. The photosphere has a temperature of 5,800 degrees Kelvin. Sunspots have temperatures of about 3,800 degrees K. They look dark only in comparison with the brighter and hotter regions of the photosphere around them.
14. Most meteoroids come from the asteroid belt, having been perturbed by the gravitational influences of planets, but others are particles from comets, giving rise to meteor showers. Some meteoroids are fragments from bodies such as Mars or our moon, that have been thrown into space by an impact.
15. Comet: A body of ice, rock and dust that can be several miles in diameter and orbits the sun. Debris from comets is the source of many meteoroids. It originates from a comet or asteroid. Meteor: A meteoroid that enters the earth's atmosphere and vaporizes.
