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.
One of the most common rulers is the light year. The light year is is the distance that light travel in one year (365 1/4 days). It is most commonly used for the distances to stars and other galaxies. The nearest star is 4.2 light years away from our sun. We are 8.3 light minutes away form the Sun. the distance to the outer most planet Pluto is about 13 light hours.