Read Space Chronicles: Facing the Ultimate Frontier Online
Authors: Neil deGrasse Tyson,Avis Lang
I
f you could somehow rise above the plane of the solar system, you would see each star in our Sun’s neighborhood moving to and fro at ten to twenty kilometers a second. Collectively, however, those stars orbit the galaxy in wide, nearly circular paths, at speeds in excess of two hundred kilometers a second. Most of the hundreds of billions of stars in the Milky Way lie within a broad, flat disk, and—like the orbiting objects in all other spiral galaxies—the clouds, stars, and other constituents of the Milky Way thrive on big, round orbits.
If you continue to rise above the plane of the Milky Way, you would see the beautiful Andromeda galaxy, two and a half million light-years away. It’s the spiral galaxy closest to us, and all the currently available data suggest we’re on a collision course, plunging ever deeper into each other’s gravitational embrace. Someday we will be a twisted wreck of strewn stars and colliding gas clouds. Just wait six or seven billion years. With better measurements of our relative motions, astronomers may discover a strong sideways component in addition to the motion that brings us together. If so, the Milky Way and Andromeda will instead swing past each other in an elongated orbital dance.
W
henever you’re going ballistic, you’re in free fall. Each of the stones whose trajectory Newton illustrated was in free fall toward Earth. The one that achieved orbit was also in free fall toward Earth, but our planet’s surface curved out from under it at exactly the same rate as it fell—a consequence of the stone’s extraordinary sideways motion. The International Space Station is also in free fall toward Earth. So is the Moon. And, like Newton’s stones, they all maintain a prodigious sideways motion that prevents them from crashing to the ground.
A fascinating feature of free fall is the persistent state of weightlessness aboard any craft with such a trajectory. In free fall, you and everything around you fall at exactly the same rate. A scale placed between your feet and the floor would also be in free fall. Because nothing is squeezing the scale, it would read zero. For this reason, and no other, astronauts are weightless in space.
But the moment the spacecraft speeds up or begins to rotate or undergoes resistance from Earth’s atmosphere, the free-fall state ends and the astronauts weigh something again. Every science-fiction fan knows that if you rotate your spacecraft at just the right speed, or accelerate your spaceship at the same rate as an object falls to Earth, you will weigh exactly what you weigh on your doctor’s scale. Thus, during those long, boring journeys, you can always, in principle, simulate Earth gravity.
Another notable application of Newton’s orbital mechanics is the slingshot effect. Space agencies often launch probes from Earth that have too little energy to reach their planetary destinations. Instead, the orbital wizards aim the probes along cunning trajectories that swing near a moving source of gravity, such as Jupiter. By falling toward Jupiter in the same direction as Jupiter moves, a probe can gain as much speed as the orbital speed of Jupiter itself, and then sling forward like a jai alai ball. If the planetary alignments are right, the probe can repeat the feat as it swings by Saturn, Uranus, or Neptune in turn, stealing more energy with each close encounter. Even a one-time shot at Jupiter can double a probe’s speed through the solar system.
Down at the other end of the mass spectrum, there are creative ways to entertain yourself. I’ve always wanted to live where gravity is so weak that you could throw baseballs into orbit and effectively play catch with yourself. It wouldn’t be hard. No matter how slow you pitch, there’s an asteroid somewhere in the solar system with just the right gravity for you to accomplish this feat. Throw with caution, though. If you throw too fast,
e
could reach 1, and you’d lose the ball forever.
• • •
CHAPTER FIFTEEN
RACE TO SPACE
*
O
ne floodlit midnight in early October 1957, beside the river Syr Darya in the Republic of Kazakhstan—while office workers in New York were taking their afternoon break—Soviet rocket scientists were launching a two-foot-wide, polished aluminum sphere into Earth orbit. By the time New Yorkers sat down to dinner, the sphere had completed its second full orbit, and the Soviets had informed Washington of their triumph: Sputnik 1, humanity’s first artificial satellite, was tracing an ellipse around Earth every ninety-six minutes, reaching a peak altitude of nearly six hundred miles.
The next morning, October 5, a report of the satellite’s ascent appeared in
Pravda,
the ruling Communist Party’s official newspaper. (“Sputnik,” by the way, loosely translates to “fellow traveler.”) Following a few paragraphs of straight facts,
Pravda
adopted a celebratory tone, ending on a note of undiluted propaganda:
The successful launching of the first man-made earth satellite makes a most important contribution to the treasure-house of world science and culture. . . . Artificial earth satellites will pave the way to interplanetary travel and apparently our contemporaries will witness how the freed and conscientious labor of the people of the new socialist society makes the most daring dreams of mankind a reality.
The space race between Uncle Sam and the Reds had begun. Round one had ended in a knockout. Ham radio operators could track the satellite’s persistent beeps at 20.005 megacycles and vouch for its existence. Bird-watchers and stargazers alike—if they knew when and where to look—could see the shiny little ball with their binoculars.
And that was only the beginning: the Soviet Union won not only round one but nearly all the other rounds as well. Yes, in 1969 America put the first man on the Moon. But let’s curb our enthusiasm and look at the Soviet Union’s achievements during the first three decades of the Space Age.
Besides launching the first artificial satellite, the Soviets sent the first animal into orbit (Laika, a stray dog), the first human being (Yuri Gagarin, a military pilot), the first woman (Valentina Tereshkova, a parachutist), and the first black person (Arnaldo Tamayo-Méndez, a Cuban military pilot). The Soviets sent the first multiperson crew and the first international crew into orbit. They made the first spacewalk, launched the first space station, and were the first to put a manned space station into long-term orbit.
Space Tweets #17 & #18
April 12, 2011: 50 yrs ago, Yuri Gagarin is launched into orbit by Soviets. He’s the 4th mammal species to achieve this feat
Apr 12, 2011 10:04
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Just an FYI: First mammals to achieve orbit, in order: Dog, Guinea
Pig, Mouse, Russian Human, Chimpanzee, American HumanApr 12, 2011 10:20
AM
They were also the first to orbit the Moon, the first to land an unmanned capsule on the Moon, the first to photograph Earthrise from the Moon, the first to photograph the far side of the Moon, the first to put a rover on the Moon, and the first to put a satellite in orbit around the Moon. They were the first to land on Mars and the first to land on Venus. And whereas Sputnik 1 weighed 184 pounds and Sputnik 2 (launched a month later) weighed 1,120 pounds, the first satellite America had planned to send aloft weighed slightly more than three pounds. Most ignominious of all, when the United States tried its first actual launch after Sputnik—in early December 1957—the rocket burst into flames at the (suborbital) altitude of three feet.
I
n July 1955, from a podium at the White House, President Eisenhower’s press secretary had announced America’s intention to send “small” satellites into orbit during the International Geophysical Year (July 1957 through December 1958). A few days later a similar announcement came from the chairman of the Soviet space commission, who maintained that the first satellites shouldn’t have to be all that small and that the USSR would send up a few of its own in the “near future.”
And so it did.
In January 1957, the Soviet missile maven and ultrapersuasive space advocate Sergei Korolev (never referred to in the Soviet press by name) warned his government that America had declared its rockets to be capable of flying “higher and farther than all the rockets in the world,” and that “the USA is preparing in the nearest months a new attempt to launch an artificial Earth satellite and is willing to pay any price to achieve this priority.” His warning worked. In the spring of 1957, the Soviets began testing precursors to orbiting satellites: intercontinental ballistic missiles that could loft a two-hundred-pound payload.
On August 21, their fourth try, they succeeded. Missile and payload made it all the way from Kazakhstan to Kamchatka—some four thousand miles. TASS, the official Soviet news agency, uncharacteristically announced the event to the world:
A few days ago a super-long-range, intercontinental multistage ballistic missile was launched. . . . The flight of the missile took place at a very great, hitherto unattained, altitude. Covering an enormous distance in a short time, the missile hit the assigned region. The results obtained show that there is the possibility of launching missiles into any region of the terrestrial globe.
Strong words. Strong motives. Enough to spook any adversary into action.
Meanwhile, in mid-July the British weekly
New Scientist
had informed its readers about the Soviet Union’s growing primacy in the space race. It had even published the orbit of an impending Soviet satellite. But America took little notice.
In mid-September Korolev told an assembly of scientists about the imminent launches of both Soviet and American “artificial satellites of the Earth with scientific goals.” Still America took little notice.
Then came October 4.
S
putnik 1 kicked many heads out of the sand. Some people in power went, well, ballistic. Lyndon B. Johnson, at the time the Senate majority leader, warned, “Soon [the Soviets] will be dropping bombs on us from space like kids dropping rocks onto cars from freeway overpasses.” Others were anxious to downplay both the geopolitical implications of the satellite and the capabilities of the USSR. Secretary of State John Foster Dulles wrote that the importance of Sputnik 1 “should not be exaggerated” and rationalized America’s nonperformance thus: “Despotic societies which can command the activities and resources of all their people can often produce spectacular accomplishments. These, however, do not prove that freedom is not the best way.”
On October 5, under a page-one banner headline (and alongside coverage of a flu epidemic in New York City and the showdown in Little Rock with the segregationist Arkansas governor, Orval Faubus), the
New York Times
ran an article that included the following reassurances:
Military experts have said that the satellites would have no practicable military application in the foreseeable future. . . .Their real significance would be in providing scientists with important new information concerning the nature of the sun, cosmic radiation, solar radio interference and static-producing phenomena.
What? No military applications? Satellites were simply about monitoring the Sun? Behind-the-scenes strategists thought otherwise. According to the summary of an October 10 meeting between President Eisenhower and his National Security Council, the United States had “always been aware of the cold war implications of the launching of the first earth satellite.” Even America’s best allies “require assurance that we have not been surpassed scientifically and militarily by the USSR.”
Eisenhower didn’t have to worry about ordinary Americans, though. Most remained unperturbed. Or maybe the spin campaign worked its magic. In any case, plenty of ham radio operators ignored the beeps, plenty of newspapers ran their satellite articles on page three or five, and a Gallup poll found that 60 percent of people questioned in Washington and Chicago expected that the United States would make the next big splash in space.
A
merica’s cold warriors, now fully awake to the military potential of space, understood that US postwar prestige and power had been challenged. Within a year, money to help restore them would be pumped into science education, the education of college teachers, and research useful to the military.
Back in 1947, the President’s Commission on Higher Education had proposed as a goal that a third of America’s youth should graduate from a four-year college. The National Defense Education Act of 1958 was a key, if modest, push in that direction. It provided low-interest student loans for undergraduates as well as three-year National Defense Fellowships for several thousand graduate students. Funding for the National Science Foundation tripled right after Sputnik; by 1968 it was a dozen times the pre-Sputnik appropriation. The National Aeronautics and Space Act of 1958 hatched a new, full-service civilian agency called the National Aeronautics and Space Administration—NASA. The Defense Advanced Research Projects Agency, or DARPA, was born the same year.
All those initiatives and agencies funneled the best American students into science, math, and engineering. The government got a lot of bang for its buck; graduate students in those fields, come wartime, got draft deferments; and the concept of federal funding for education got validated.
But some kind of satellite, built by any means necessary, had to be launched ASAP. Luckily, during the closing weeks and immediate aftermath of World War II in Europe, the United States had acquired a worthy challenger to Sergei Korolev: the German engineer and physicist Wernher von Braun, former leader of the team that had developed the terrifying V-2 ballistic missile. We also acquired more than a hundred members of his team.
Instead of being put on trial at Nuremburg for war crimes, von Braun became America’s savior, the progenitor and public face of the US space program. His first high-profile task was to provide the first rocket for the first successful launch of America’s first satellite. On January 31, 1958—less than four months after Sputnik 1’s round-the-world tour—he and his rocketeers got the thirty-pound Explorer 1, plus its eighteen pounds of scientific instrumentation, into orbit.
Space Tweet #19
An object in orbit has high sideways speed so it falls to Earth at exactly the same rate that the round Earth curves below it
May 14, 2010 11:56
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