We've explored a lot in our Solar System over the past few decades: Jupiter's moons, Mars, Neptune, even a comet!
But one place we haven't gone is into the Sun, for kind of obvious reasons. But that is about to change.
In July this year, NASA plans to send a car-sized probe known as the Parker Solar Probe into the corona, or outer atmosphere, of the Sun - that's the crown of light you see surrounding the body of the sun during a solar eclipse.
A few previous missions like Helios-2 in the 1970s orbited the sun at a faraway distance to give us a closer look, but the Parker Solar Probe will get much, much closer - about a tenth of the distance.
Scientists hope that this mission will solve the mystery that has plagued solar science for decades: Why is the corona hotter than the surface of the Sun?
Astronomers actually think the corona is 200 times hotter than the Sun's surface, due to varying lengths in wavelengths that we have measured in and around the Sun. This is unusual, because everywhere else in the Universe, heat will fade out as proximity grows.
Think of a candle. If you hold your hand up to the flame, it’s hot. As you move away, you feel less of that heat. Now, imagine if you began to feel MORE heat as you pulled away - that is what’s happening with the Sun.
The corona, which is made out of highly ionized elements like iron, helium and calcium, is so hot that the Sun's gravity can't hold onto it. As those atoms get all agitated by the extreme heat, ribbons of plasma called solar winds peel off from the corona and begin accelerating away from the Sun at speeds of up to 900 kilometers (~600 miles) per second.
These solar winds contain high levels of radiation that can harm satellites as well as astronauts in deep space.
So, NASA wants Solar Probe Plus to help us understand what's heating the corona and accelerating those solar winds.
The craft will use Venus' gravitation to sling it around the Sun 24 times over seven years, getting closer to the corona with each orbit. On it's closest approach, the craft will skirt the outer edge of the corona, and that's why the solar probe will have a thermal protection system.
It'll be made out of carbon composite and silica foam, which is the same stuff we used on space shuttles. The probe's electrical systems will be powered by two sets of solar arrays, because… there's a lot of sunlight when you're going into the sun. And the first set of arrays will be bigger and will be used on the initial leg of it's journey. Once the probe enters the corona however, those panels will retract and two tinier liquid-cooled arrays will do the rest of the work.
As the probe flies through the corona, it will begin counting, collecting, and analyzing particles including electrons, protons, and ions.
Meanwhile, a telescope will create intricate 3D images of the corona and solar winds and send all that data back to Earth. The craft will spend a total of thirty hours within the corona before NASA turns off it's transmitter and leaves it to it's fate. And it's a fiery one.
Scientists hope that all the data gleaned from this mission will help us understand the corona's dynamics so we can get better at forecasting solar wind events and planning future missions into deep space.
So thanks in advance, Solar Probe Plus, for everything you're going to teach us!
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Sources: This story was originally published on SciShow Space. I am republishing a lightly edited version on SkyFeed in light of interest in the subject. Hofmeister, Caitlin. "Sending a Probe to the Sun." SciShow Space, YouTube. 30 Dec, 2014. Web video.
Citation: Rovira, Lia N. "We Are Sending a Probe into the Sun." SkyFeed. 23 May 2018. Web article.