A NASA spacecraft has officially ‘touched’ the sun, after it plunged through the unexplored solar atmosphere known as the corona, passing just eight million miles from the core of the star.
NASA’s Parker Solar Probe battled temperatures of 2370F and radiation 500 times stronger than on Earth as it made its eighth approach to the celestial body, finally passing through its upper atmosphere.
The flight occurred in April but scientists have only just been able to confirm the probe traveled through the corona, after waiting months for the data to arrive back from the spacecraft.
‘Parker Solar Probe ‘touching the Sun’ is a monumental moment for solar science and a truly remarkable feat,’ said Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate, in a statement at a meeting of the American Geophysical Union.
‘Not only does this milestone provide us with deeper insights into our Sun’s evolution and (its) impacts on our solar system, but everything we learn about our own star also teaches us more about stars in the rest of the universe.’
New research gathered from the solar milestone, which cost NASA $1.5billion, has now been included in the Physical Review Letters.
‘Fascinatingly exciting,’ said project scientist Nour Raouafi of Johns Hopkins University.
A picture provided by NASA shows an artist’s rendering of the Parker Solar Probe approaching the Sun. On Tuesday, Dec. 14, 2021, NASA announced that the spacecraft has plunged through the unexplored solar atmosphere known as the corona in April, and will keep drawing ever closer to the sun and diving deeper into the corona
As Parker Solar Probe travelled through the corona on its eight attempt, the spacecraft flew by structures called coronal streamers (pictured). These streamers can be seen as bright features moving upward in the set of pictures in the front row and angled downward in the bottom row. Such a view is only possible due to the spacecraft’s ability to go above and below the streamers inside the corona. Until now, streamers have only been seen from afar. They are visible from Earth during total solar eclipses.
This handout photograph courtesy of NASA shows the United Launch Alliance Delta IV Heavy rocket launching NASA’s Parker Solar Probe to touch the Sun, Sunday, August 12, 2018 from Launch Complex 37 at Cape Canaveral Air Force Station, Florida. – NASA launched a $1.5 billion spacecraft toward the Sun on a historic mission to protect the Earth by unveiling the mysteries of dangerous solar storms
Sun: The basics
The sun is the star at the heart of the Solar System, a nearly perfect sphere of hot plasma, radiating energy.
It has a diameter of 1.39 million km, and is 330 times the mass of the Earth.
Three quarters of the star is made of hydrogen, followed by helium, oxygen, carbon, neon and iron.
It is a G-type main sequence star and is sometimes called a yellow dwarf.
The Sun formed from the gravitational collapse of matter in a large molecular cloud that gathered in the centre.
The rest flattened into an orbiting disc that formed everything else.
Facts and Figures
Name: Sun
Known planets: Eight
Spectral type: G2
Distance from galactic centre: 2.7×10^17 km
Mass: 1.9885×10^30 kg
Radius: 696,342 km
Luminosity: 3.828×10^26 W
Temperature: 9,929 F
Age: 4.6 billion years
Launched in 2018, the probe was named after American solar astrophysicist Eugene Parker, who created a theory of a supersonic solar wind, increased our understanding of the sun’s corona and of magnetic fields.
The probe that carries his name was built to answer fundamental questions about the solar wind that is released from the corona, flinging energetic particles across the solar system.
The space craft was eight million miles from the centre of the sun when it first crossed the jagged, uneven boundary between the solar atmosphere and outgoing solar wind.
The spacecraft dipped in and out of the corona at least three times, and each of those ‘dips’ was a smooth transition, according to scientists working on data from the probe.
‘The first and most dramatic time we were below for about five hours… Now you might think five hours, that doesn’t sound big,’ the University of Michigan’s Justin Kasper told reporters.
But he noted that Parker was moving so fast it covered a vast distance during that time, tearing along at more than 62 miles (100 kilometers) per second.
Due to the sun’s lack of a solid surface, the corona is where the action is; exploring this magnetically intense region up close can help scientists better understand solar outbursts that can interfere with life here on Earth.
The corona has a superheated atmosphere, made of solar material bound to the sun by gravity and magnetic forces, according to NASA.
And as rising heat and pressure push the material away fromt he sun, it reaches a point where gravity and magnetic fields are too weak to contain it – marking the end of the solar atmosphere and start of solar wind.
These winds drag the magnetic field of the Sun with it as it races across the solar system, to Earth and beyond.
Until now, researchers were unsure exactly where the critical surface lay, putting it up to 20 times the size of the sun beyond the surface – or up to 8.6 million miles.
However, as Parker gets closer to the sun during its spiral trajectory, solar physicists are able to learn more, and found that these estimates were correct.
‘We were fully expecting that, sooner or later, we would encounter the corona for at least a short duration of time,’ said Justin Kasper, lead author on a new paper about the milestone published in Physical Review Letters.
‘But it is very exciting that we’ve already reached it.’
The corona appeared dustier than expected, according to Raouafi. Future coronal excursions will help scientist better understand the origin of the solar wind, he said, and how it is heated and accelerated out into space.
It has spikes and valleys that wrinkle the surface. Discovering where these protrusions line up with solar activity coming from the surface can help scientists learn how events on the sun affect the atmosphere and solar wind.
The closest point to the surface came when Parker was just 6.5 million miles away, where it moved into a feature of the corona known as a pseudostreamer.
Pseudostreamers are massive structures that rise above the sun’s surface and can be seen from Earth during solar eclipses – and passing through them is like flying into the eye of a storm, NASA explained.
‘Inside the pseudostreamer, the conditions quieted, particles slowed, and number of switchbacks dropped – a dramatic change from the busy barrage of particles the spacecraft usually encounters in the solar wind.’
As Parker Solar Probe approaches closer to the Sun, it’s crossing into unexplored territory and making new discoveries. This image represents Parker Solar Probe’s distances from the Sun for some of these milestones and discoveries
It took seven orbits around Venus for Parker to finally get close to the sun’s surface in April. New discoveries on the sun’s upper atmosphere, also known as the corona, will better explain the origins of the solar wind and its flares
This is the first time a human-made spacecraft has found itself embroiled up in a region of the sun where the magnetic fields were strong enough to dominate the movement of particles.
This first passage into the corona, lasting a few hours, is one of a number planned for the Parker probe. It will eventually spiral closer to the sun, reaching a point just 3.83 million miles from the surface.
Its next visit to the corona will be in January 2022, according to the NASA astronomers.
‘I’m excited to see what Parker finds as it repeatedly passes through the corona in the years to come,’ said Nicola Fox, division director for the Heliophysics Division at NASA Headquarters. ‘The opportunity for new discoveries is boundless.’
‘It is a really important region to get into because we think all sorts of physics potentially turn on,’ Kasper said. ‘And now we’re getting into that region and hopefully going to start seeing some of these physics and behaviors.’
Preliminary data suggest Parker also dipped into the corona during its ninth close approach in August, but scientists said more analyses are needed. It made its 10th close approach last month.
Parker will keep drawing ever closer to the sun and diving deeper into the corona until its grand finale orbit in 2025.
The latest findings were also published by the American Physical Society.
HOW WILL THE PARKER SOLAR PROBE GET SO CLOSE TO THE SUN?
The Parker Solar Probe mission will require 55 times more energy than would be needed to reach Mars, according to NASA.
It launched atop a United Launch Alliance Delta IV Heavy, one of the most powerful rockets in the world, with a third stage attached.
But, its trajectory and speed are critical in getting to the correct orbit.
As Earth, and everything on it, are traveling at about 67,000 miles per hour in a direction that’s sideways to the sun, craft must be launched backward to cancel out the sideways motion, NASA explains.
The Parker probe is heading past the sun, so it will need to remove about 53,000 miles per hour, according to the space agency.
The Parker Solar Probe will swing around Venus a total of seven times, with each pass slowing it down some and pushing it closer and closer to the sun. These orbits are shown in the animation above
This will require a boost from the powerful Delta IV rocket, and several gravity assists from Venus to slow it down.
The probe will rely on a series of gravity assists from Venus to slow down its sideways motion, allowing it to get just 3.8 million miles away from the sun’s surface.
‘In this case, rather than speeding up the spacecraft, as in a typical gravity assist, Venus slows down its sideways motion so the spacecraft can get close to the sun,’ NASA explains.
‘When it finally does get close, Parker Solar Probe will have lost much of its sideways speed, but gained a great deal of overall speed thanks to the sun’s gravity.
‘Parker Solar Probe will hurtle past the sun at 430,000 miles per hour.’
At its closest approach, it will get just 3.8 million miles from the surface of the sun, making it the only spacecraft to ever venture so close.