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.
Since Pluto orbits the Sun, like the rest of the planets and dwarf planets, astronomers typically measure the distance of Pluto in terms of Astronomical Units (AU). 1 AU measures the distance of the Earth to the Sun. At its closest point, Pluto is only 29 astronomical units from the Sun (4.4 billion km or 2.75 billion miles). And at its most distant, it can be 49 AU (7.29 billion km, or 4.53 billion miles) from the Sun. In addition to being highly elliptical however, Plutoâs orbit is also inclined at an angle of over 17-degrees.