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.
That the moon, on average, is 238,855 miles away â¦ this isnât too hard to fathom. But when we start inching our way out into the solar system, it starts to get a bit profound. Take Pluto. NASAâs New Horizons spacecraft is set to swoop by Pluto this month, which is (on average) 39 Astronomical Units (AU) away. An AU is the distance by which astronomers measure distances; itâs based on the distance between the Earth and our big star, about 93 million miles. Which puts Pluto at a distance of 3.7 billion miles away. Honestly, even a billion is hard to get oneâs mind around.