Oral route. Many drugs can be administered orally as liquids, capsules, tablets, or chewable tablets. Because the oral route is the most convenient and usually the safest and least expensive, it is the one most often used. However, it has limitations because of the way a drug typically moves through the digestive tract.
Measuring Distances to Stars. Astronomers use several techniques for discovering how far away an object is. The first is called trigonometric parallax and is based on geometry, but it is only good for up to about 500 light-years.
The Orion Nebula is farther away than any of the naked eye stars at a distance of about 1,600 light-years. One light-year is the distance light travels in a single year, about 6 trillion miles (10 trillion kilometers). The exception is the star Betelgeuse, which is a red giant and one of the largest stars known.