dipper@utastro.UUCP (Debbie Byrd) (10/04/84)
This is the anniversary of the first satellite ever to orbit the Earth. More on what keeps satellites in orbit -- right after this. October 4 A New Dawn Today is the anniversary of the Soviet Sputnik, the first satellite ever to orbit the Earth -- launched on this date in the year 1957. The satellite was tiny and served no purpose but to broadcast radio evidence of its own movement in orbit. Even so, it's unassuming beep was heard on the radio by people all over the Earth -- and Sputnik went down in history as the first step toward humanity's greatest adventure. Sputnik was able to achieve orbit because of the power of the rocket that thrust it off the surface of the Earth. After it goes into orbit, nothing has to HOLD UP a satellite -- because satellites are in a constant state of FREE FALL around the Earth. Think of it this way. If you fire a gun, the distance the bullet travels depends on its initial speed. A faster bullet travels farther than a slower one before gravity causes it to curve downward and fall to Earth's surface. If the bullet could leave the gun with a high-enough speed, it would travel so far so fast that, as it curved downward, Earth's surface would have already CURVED OUT FROM UNDER IT. The bullet would have no choice but to go into orbit around Earth, falling around it indefinitely. Earth-orbiting satellites work in the same way. Powerful rockets give them a tremendous initial thrust -- enough to send them off the Earth at least 5 miles per second. After that, the round shape of the Earth and the relentless force of gravity keep them in orbit. Script by Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin
karn@mouton.UUCP (10/08/84)
Funny, I thought the first satellite to orbit the earth was the moon. Phil