Read Online 13 Things That Don't Make Sense by Michael Brooks - Free Book Online
Authors: Michael Brooks
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back to Earth. It is now nearly 8 billion miles away, past the orbits of Neptune
and Pluto, and we will not hear from it again because it no longer has any power left with which to send out a signal. The
probe’s next significant moment will come in 2 million years, when, according to calculations based on the gravitational law
that Newton developed just over three centuries ago, it will hit the star Aldebaran in the constellation Taurus.
However, the Pioneer probes hint that the law might be wrong, or at least wrong for those particular calculations. For the
probes are drifting off course. In every year of travel, the probes veer eight thousand miles farther away from their intended
trajectory. That is not much when you consider that they cover 219 million miles a year; whatever is causing the drift is
around 10 billion times weaker than the Earth’s pull on your feet. Nonetheless, it is there, and casting doubt over the universality
of one of Newton’s greatest achievements.
The idea that the Pioneer probes threaten the known laws of physics is almost universally derided—even by the people trying
to make sense of the anomaly. The fact that is seldom appreciated, though, is that NASA explicitly planned to use them as
a test of Newton’s law. The law failed the test; shouldn’t we be taking that failure seriously?
IN 1969, when most eyes were on the Apollo moon landings, John Anderson was focused on the Pioneer probes. As principal investigator,
he had the job of making sure they would do everything they should—that is, observe the outer planets. It dawned on Anderson,
however, that they could do more.
As spacecraft, the Pioneer probes are unique. Every other craft has the means of checking its orientation and trajectory—by
triangulating its position with certain stars, for example. If the mission scientists find the craft has strayed, they can
fire rocket thrusters to correct any drift. Pioneer 10 and 11, on the other hand, were going to keep themselves stable using
the same trick that keeps a child’s spinning top upright: they were going to spin their way through space. The spin provides
a force that fixes the top’s orientation; on Pioneer, the spin meant the mission scientists wouldn’t have to worry about firing
any thrusters to keep the craft on track.
Anderson realized that, since they were traveling under the influence of gravity alone, the Pioneer trajectories would provide
a perfect test of gravity’s nature. He submitted a proposal to NASA to use the probes for this purpose as well as their main
mission, the investigation of Jupiter and the outer solar system. The NASA authorities agreed it would be a good test, and
funded the extra experiments.
The first Pioneer probe was launched from Cape Canaveral on March 2, 1972. Pioneer 11 went up on April 5, 1973. Another seven
years passed, years in which Richard Nixon resigned, Saigon fell, and Margaret Thatcher became prime minister of Britain.
And then John Anderson noticed something odd.
Through all the years of their journey, the instruments on board the Pioneer probes had been sending back their readings to
Earth. In 1980, the trajectory readings stopped making sense: both spacecraft, it seemed, were being pulled toward the Sun.
Anderson talked to a few astronomers within his team about the anomaly, but he didn’t go public because he couldn’t explain
it. Then, in 1994, he took a phone call from a physicist based at the Los Alamos National Laboratory in New Mexico.
Michael Martin Nieto was on a mission to find out just how reliable our gravity theories were. Whenever he came across other
physicists, he would ask them what seemed like a dumb question: Can we still predict the motion of things using Newton’s inverse
square law if they lie outside our solar system? Eventually, he spoke to someone on Anderson’s team, who said it might not
be such a dumb question—and that he should ask
and Pluto, and we will not hear from it again because it no longer has any power left with which to send out a signal. The
probe’s next significant moment will come in 2 million years, when, according to calculations based on the gravitational law
that Newton developed just over three centuries ago, it will hit the star Aldebaran in the constellation Taurus.
However, the Pioneer probes hint that the law might be wrong, or at least wrong for those particular calculations. For the
probes are drifting off course. In every year of travel, the probes veer eight thousand miles farther away from their intended
trajectory. That is not much when you consider that they cover 219 million miles a year; whatever is causing the drift is
around 10 billion times weaker than the Earth’s pull on your feet. Nonetheless, it is there, and casting doubt over the universality
of one of Newton’s greatest achievements.
The idea that the Pioneer probes threaten the known laws of physics is almost universally derided—even by the people trying
to make sense of the anomaly. The fact that is seldom appreciated, though, is that NASA explicitly planned to use them as
a test of Newton’s law. The law failed the test; shouldn’t we be taking that failure seriously?
IN 1969, when most eyes were on the Apollo moon landings, John Anderson was focused on the Pioneer probes. As principal investigator,
he had the job of making sure they would do everything they should—that is, observe the outer planets. It dawned on Anderson,
however, that they could do more.
As spacecraft, the Pioneer probes are unique. Every other craft has the means of checking its orientation and trajectory—by
triangulating its position with certain stars, for example. If the mission scientists find the craft has strayed, they can
fire rocket thrusters to correct any drift. Pioneer 10 and 11, on the other hand, were going to keep themselves stable using
the same trick that keeps a child’s spinning top upright: they were going to spin their way through space. The spin provides
a force that fixes the top’s orientation; on Pioneer, the spin meant the mission scientists wouldn’t have to worry about firing
any thrusters to keep the craft on track.
Anderson realized that, since they were traveling under the influence of gravity alone, the Pioneer trajectories would provide
a perfect test of gravity’s nature. He submitted a proposal to NASA to use the probes for this purpose as well as their main
mission, the investigation of Jupiter and the outer solar system. The NASA authorities agreed it would be a good test, and
funded the extra experiments.
The first Pioneer probe was launched from Cape Canaveral on March 2, 1972. Pioneer 11 went up on April 5, 1973. Another seven
years passed, years in which Richard Nixon resigned, Saigon fell, and Margaret Thatcher became prime minister of Britain.
And then John Anderson noticed something odd.
Through all the years of their journey, the instruments on board the Pioneer probes had been sending back their readings to
Earth. In 1980, the trajectory readings stopped making sense: both spacecraft, it seemed, were being pulled toward the Sun.
Anderson talked to a few astronomers within his team about the anomaly, but he didn’t go public because he couldn’t explain
it. Then, in 1994, he took a phone call from a physicist based at the Los Alamos National Laboratory in New Mexico.
Michael Martin Nieto was on a mission to find out just how reliable our gravity theories were. Whenever he came across other
physicists, he would ask them what seemed like a dumb question: Can we still predict the motion of things using Newton’s inverse
square law if they lie outside our solar system? Eventually, he spoke to someone on Anderson’s team, who said it might not
be such a dumb question—and that he should ask
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