Mergers have left four airline companies controlling more than 80 percent of the U.S. market. And they have been very slow to add new flights. That makes planes more crowded. U.S. airlines are filling more than 85 percent of their seats in some months â close to record levels, according to the government.
Pluto is thought to be made of mostly ice. It probably also has a small rocky core which might contain some metals. The ice on the surface of Pluto is made of frozen nitrogen, methane and carbon monoxide.The ice covering Pluto reflects a lot of sunlight making it appear brighter than it would if it had been covered with a darker rocky material. 1  Javascript must be enabled to use Cool Cosmos.t probably also has a small rocky core which might contain some metals. The ice on the surface of Pluto is made of frozen nitrogen, methane and carbon monoxide. The ice covering Pluto reflects a lot of sunlight making it appear brighter than it would if it had been covered with a darker rocky material.
Pluto is 2,304 kilometers (1,432 miles) at the equator, and is only about the size of Russia. Pluto only has a mass of about one 400th that of Earth. Pluto is composed of several different materials, Pluto's thin crust is simply composed of ice, Pluto's mantel is quite rich in water and ice, Pluto's large core is probably about 70% rock, and 30% water ice.