December 3, 2012 - Anniversary of First Close-ups of Jupiter

Aren't we lucky to know so much about our universe, and to see so many fabulous, breathtaking photos of galaxies, nebulae, stars, and planets? Can you imagine living long, long ago, when the nighttime skies were filled with nothing but the moon, specks and smudges of light, and wonder?

Even Jupiter, back then, would have seemed to be just a particularly bright speck of light that “wandered” more than most well-behaved specks of light. How many people who lived thousands of years ago dared to dream that it was an entirely different world—much less that more than a thousand Earths could fit inside that world?

Of course, by the early 1600s, when the telescope was first invented, we began to learn the true nature of our little patch of the universe, including our solar system and our largest planet, Jupiter. Telescopes got better and better, other tools such as spectroscopes were invented, and eventually we began to send unmanned vehicles equipped with cameras out into space.

Image from Pioneer 10
On this date in 1973, our first close encounter with Jupiter occurred as Pioneer 10 passed within 81,000 miles of the huge planet's cloud tops. During the entire fly-by (from November 26 to around December 11), more than 500 images were captured and transmitted back to Earth. These images were much more detailed than anything we had been able to see previously—although these days, of course, we have many better photos from seven more close encounters with NASA spacecraft.

Image from Cassini

Not only were Pioneer 10's images important, but the measurements made of Jupiter's magnetosphere, radiation belts, magnetic field, atmosphere, and interior were very important to our understanding of Jupiter and to the planning and building of future spacecraft.

Did you know...?

  • Pioneer 10 was launched in 1972 and was planned to operate for less than two years (21 months, to be exact). However, it operated and communicated its findings and location with Earth for MORE THAN 30 YEARS!

  • When we last heard from the Pioneer 10 spacecraft, it was about 7 billion miles away from us. Now it is estimated to be about 10 billion miles away. It is hurtling toward the star Aldebaran, and ETA is 2 million years from now. Give or take a decade.

  • Pioneer 10 has a pictorial plaque that provides information about humans and Earth, in case the spacecraft is ever intercepted by a more kindly and curious alien than Captain Klaa. The plaque was designed by Carl Sagan and Frank Drake.

  • The “Pioneer Anomaly” puzzled scientists for years: both Pioneer 10 and 11 are traveling just a little bit slower than expected. Finally, just this year, scientists figured out that heat flowing through the spacecrafts' power systems and instruments is pushing back on the Pioneer spacecraft, slowing them down a bit.

Also on this date:

Anniversary of the demonstration of neon lights 

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