The answer is D. Exosphere
Exosphere is the outermost Layer of the Atmosphere that goes out about 500 - 10,000 Km in altitude.
It's the place where satellites and the space shuttle orbit the earth. Because it's difficult to define the boundary between exosphere and the outer space, exosphere may be considered as a part of outer space
Explanation:
Earthquakes shake and volcanoes erupt. Sections of the crust are on the move. Mountains push up and wear down. These and many other processes contribute to the rock cycle, which makes and changes rocks on or below the Earth's surface.
The most abundant fossil fuel is coal... Coal isn't only our most abundant fossil fuel,it's also the one with perhaps the longest history. The U.S. has more coal reserves than any other country in the world. In fact, one-fourth of the all the known coal in the world is in the U.S.
Answer:
Answered
Explanation:
(i) 1 Astronomical Unit (A.U.) = 1.496 x 10^8 Km.
Therefore, distance of Voyager I from Earth = 71 AU = 71 x 1.496 x 10^8 = 1.062 x 10^10 Km.
(ii) The nearest star to Earth than sun is the Proxima Centauri in the Alpha Centauri system. The Proxima Centauri is 4.22 light years away from Earth.
As, 1 Light year = 63241.1 AU
The distance of the Proxima Centauri from Earth = 4.22 x 63241.1 AU = 266877.3 AU
The distance of the Voyager I from Earth = 71 AU
The number of times the distance of the Proxima Centauri from Earth is greater than that of Voyager I is = 266877.3 / 71
= 3758.835 times.
(iii) Speed of light is 1.079 x 10^9 Km/hr
Light travels 1.079 x 10^9 km in 1 hr
Therefore, 1. 062 x 10^10 Km is traveled by light in = (1.062 x 10^10) / (1.079 x 10^9) hr = 9.84 hours
That means when Voyager I was 71 AU from Earth, a observational data from Voyager I at the speed of light took 9.84 hours to reach Earth.