Hardly anyone writes about the Parker Solar Probe anymore.
Sure, the spacecraft drew some attention when it launched. After all, it is the fastest moving object ever built by humans. At its maximum speed, powered by the Sun’s gravitational pull, the probe reaches a speed of 430,000 miles per hour, or more than one-sixth of 1 percent of the speed of light. That kind of speed would take you from New York City to Tokyo in less than a minute.
And the Parker Solar Probe also has the distinction of being the first NASA spacecraft named after a living person. At the time of its release, in August 2018, physicist Eugene Parker was 91 years old.
But in the six years since the probe has been traversing outer space and flying past the sun? Not so much. Let’s face it, the astrophysical properties of the sun and its complicated structure are not something most people think about on a daily basis.
However, the tiny probe—its mass is less than a metric ton and its scientific payload is just 110 pounds (50 kg)—is about to spin its star. Literally. On Christmas Eve, the Parker Solar Probe will get its closest approach to the sun yet. It will come within just 3.8 million miles (6.1 million kilometers) of the solar surface, flying into the solar atmosphere for the first time.
Yes, it will be quite hot. Scientists estimate that the probe’s heat shield will withstand temperatures exceeding 2,500 degrees Fahrenheit (1,371 C) on Christmas Eve, which is practically the polar opposite of the North Pole.
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I spoke to NASA’s chief scientist, Nicky Fox, to understand why they are torturing the probe so much. Before moving to NASA headquarters, Fox was the Parker Solar Probe project scientist and explained that scientists really want to understand the origins of the solar wind.
This is the stream of charged particles emanating from the sun’s outermost layer, the corona. Scientists have been wondering about this particular mystery for more than half a century, Fox explained.
“Simply put, we want to find the birthplace of the solar wind,” he said.
Back in the 1950s, before we had satellites or spacecraft to measure the properties of the sun, Parker predicted the existence of this solar wind. The scientific community was quite skeptical about this idea (in fact, many ridiculed Parker) until the Mariner 2 mission began measuring the solar wind in 1962.
When the scientific community began to adopt Parker’s theory, they wanted to know more about the solar wind, which is a fundamental component of the entire solar system. Although the solar wind is invisible to the naked eye, when you see an aurora on Earth, it is the solar wind interacting with the Earth’s magnetosphere in a particularly violent way.